National Library of Energy BETA

Sample records for wave velocity variations

  1. P wave velocity variations in the Coso region, California, derived...

    Open Energy Info (EERE)

    defined with layers of blocks. Slowness variations in the surface layer reflect local geology, including slow velocities for the sedimentary basins of Indian Wells and Rose...

  2. Elastic wave velocity measurement combined with synchrotron X...

    Office of Scientific and Technical Information (OSTI)

    Elastic wave velocity measurement combined with synchrotron X-ray measurements at high ... Title: Elastic wave velocity measurement combined with synchrotron X-ray measurements at ...

  3. Elastic wave velocities in polycrystalline Mg[subscript 3]Al...

    Office of Scientific and Technical Information (OSTI)

    Title: Elastic wave velocities in polycrystalline Mgsubscript 3Alsubscript 2Sisubscript 3Osubscript 12-pyrope garnet to 24 GPa and 1300 K Authors: Chantel, Julien ; ...

  4. Estimating propagation velocity through a surface acoustic wave sensor

    DOE Patents [OSTI]

    Xu, Wenyuan; Huizinga, John S.

    2010-03-16

    Techniques are described for estimating the propagation velocity through a surface acoustic wave sensor. In particular, techniques which measure and exploit a proper segment of phase frequency response of the surface acoustic wave sensor are described for use as a basis of bacterial detection by the sensor. As described, use of velocity estimation based on a proper segment of phase frequency response has advantages over conventional techniques that use phase shift as the basis for detection.

  5. Anisotropic parameter estimation using velocity variation with offset analysis

    SciTech Connect (OSTI)

    Herawati, I.; Saladin, M.; Pranowo, W.; Winardhie, S.; Priyono, A.

    2013-09-09

    Seismic anisotropy is defined as velocity dependent upon angle or offset. Knowledge about anisotropy effect on seismic data is important in amplitude analysis, stacking process and time to depth conversion. Due to this anisotropic effect, reflector can not be flattened using single velocity based on hyperbolic moveout equation. Therefore, after normal moveout correction, there will still be residual moveout that relates to velocity information. This research aims to obtain anisotropic parameters, ? and ?, using two proposed methods. The first method is called velocity variation with offset (VVO) which is based on simplification of weak anisotropy equation. In VVO method, velocity at each offset is calculated and plotted to obtain vertical velocity and parameter ?. The second method is inversion method using linear approach where vertical velocity, ?, and ? is estimated simultaneously. Both methods are tested on synthetic models using ray-tracing forward modelling. Results show that ? value can be estimated appropriately using both methods. Meanwhile, inversion based method give better estimation for obtaining ? value. This study shows that estimation on anisotropic parameters rely on the accuracy of normal moveout velocity, residual moveout and offset to angle transformation.

  6. Temporal Velocity Variations beneath the Coso Geothermal Field...

    Open Energy Info (EERE)

    Double Difference Tomography of Compressional and Shear Wave Arrival Times Abstract Microseismic imaging can be an important tool for characterizing geothermal reservoirs....

  7. Stochastic simulation for the propagation of high-frequency acoustic waves through a random velocity field

    SciTech Connect (OSTI)

    Lu, B.; Darmon, M.; Leymarie, N.; Chatillon, S.; Potel, C.

    2012-05-17

    In-service inspection of Sodium-Cooled Fast Reactors (SFR) requires the development of non-destructive techniques adapted to the harsh environment conditions and the examination complexity. From past experiences, ultrasonic techniques are considered as suitable candidates. The ultrasonic telemetry is a technique used to constantly insure the safe functioning of reactor inner components by determining their exact position: it consists in measuring the time of flight of the ultrasonic response obtained after propagation of a pulse emitted by a transducer and its interaction with the targets. While in-service the sodium flow creates turbulences that lead to temperature inhomogeneities, which translates into ultrasonic velocity inhomogeneities. These velocity variations could directly impact the accuracy of the target locating by introducing time of flight variations. A stochastic simulation model has been developed to calculate the propagation of ultrasonic waves in such an inhomogeneous medium. Using this approach, the travel time is randomly generated by a stochastic process whose inputs are the statistical moments of travel times known analytically. The stochastic model predicts beam deviations due to velocity inhomogeneities, which are similar to those provided by a determinist method, such as the ray method.

  8. 3-D moveout inversion in azimuthally anisotropic media with lateral velocity variation: Theory and a case study

    SciTech Connect (OSTI)

    Grechka, V.; Tsvankin, I.

    1999-08-01

    Reflection moveout recorded over an azimuthally anisotropic medium (e.g., caused by vertical or dipping fractures) varies with the azimuth of the source-receiver line. Normal-moveout (NMO) velocity, responsible for the reflection traveltimes on conventional-length spreads, forms an elliptical curve in the horizontal plane. While this result remains valid in the presence of arbitrary anisotropy and heterogeneity, the inversion of the NMO ellipse for the medium parameters has been discussed so far only for horizontally homogeneous models above a horizontal or dipping reflector. Here, the authors develop an analytic moveout correction for weak lateral velocity variation in horizontally layered azimuthally anisotropic media. The correction term is proportional to the curvature of the zero-offset travel-time surface at the common midpoint and, therefore, can be estimated from surface seismic data. After the influence of lateral velocity variation on the effective NMO ellipses has been stripped, the generalized Dix equation can be used to compute the interval ellipses and evaluate the magnitude of azimuthal anisotropy (measured by P-wave NMO velocity) within the layer of interest. This methodology was applied to a 3-D wide-azimuth data set acquired over a fractured reservoir in the Powder River Basin, Wyoming. The processing sequence included 3-D semblance analysis (based on the elliptical NMO equation) for a grid of common-midpoint supergathers, spatial smoothing of the effective NMO ellipses and zero-offset traveltimes, correction for lateral velocity variation, and generalized Dix differentiation. The estimates of depth-varying fracture trends in the survey area, based on the interval P-wave NMO ellipses, are in good agreement with the results of outcrop and borehole measurements and the rotational analysis of four component S-wave data.

  9. Minimal position-velocity uncertainty wave packets in relativistic and non-relativistic quantum mechanics

    SciTech Connect (OSTI)

    Al-Hashimi, M.H. Wiese, U.-J.

    2009-12-15

    We consider wave packets of free particles with a general energy-momentum dispersion relation E(p). The spreading of the wave packet is determined by the velocity v={partial_derivative}{sub p}E. The position-velocity uncertainty relation {delta}x{delta}v{>=}1/2 |<{partial_derivative}{sub p}{sup 2}E>| is saturated by minimal uncertainty wave packets {phi}(p)=Aexp(-{alpha}E(p)+{beta}p). In addition to the standard minimal Gaussian wave packets corresponding to the non-relativistic dispersion relation E(p)=p{sup 2}/2m, analytic calculations are presented for the spreading of wave packets with minimal position-velocity uncertainty product for the lattice dispersion relation E(p)=-cos(pa)/ma{sup 2} as well as for the relativistic dispersion relation E(p)={radical}(p{sup 2}+m{sup 2}). The boost properties of moving relativistic wave packets as well as the propagation of wave packets in an expanding Universe are also discussed.

  10. Developing regionalized models of lithospheric thickness and velocity structure across Eurasia and the Middle East from jointly inverting P-wave and S-wave receiver functions with Rayleigh wave group and phase velocities

    SciTech Connect (OSTI)

    Julia, J; Nyblade, A; Hansen, S; Rodgers, A; Matzel, E

    2009-07-06

    In this project, we are developing models of lithospheric structure for a wide variety of tectonic regions throughout Eurasia and the Middle East by regionalizing 1D velocity models obtained by jointly inverting P-wave and S-wave receiver functions with Rayleigh wave group and phase velocities. We expect the regionalized velocity models will improve our ability to predict travel-times for local and regional phases, such as Pg, Pn, Sn and Lg, as well as travel-times for body-waves at upper mantle triplication distances in both seismic and aseismic regions of Eurasia and the Middle East. We anticipate the models will help inform and strengthen ongoing and future efforts within the NNSA labs to develop 3D velocity models for Eurasia and the Middle East, and will assist in obtaining model-based predictions where no empirical data are available and for improving locations from sparse networks using kriging. The codes needed to conduct the joint inversion of P-wave receiver functions (PRFs), S-wave receiver functions (SRFs), and dispersion velocities have already been assembled as part of ongoing research on lithospheric structure in Africa. The methodology has been tested with synthetic 'data' and case studies have been investigated with data collected at an open broadband stations in South Africa. PRFs constrain the size and S-P travel-time of seismic discontinuities in the crust and uppermost mantle, SRFs constrain the size and P-S travel-time of the lithosphere-asthenosphere boundary, and dispersion velocities constrain average S-wave velocity within frequency-dependent depth-ranges. Preliminary results show that the combination yields integrated 1D velocity models local to the recording station, where the discontinuities constrained by the receiver functions are superimposed to a background velocity model constrained by the dispersion velocities. In our first year of this project we will (i) generate 1D velocity models for open broadband seismic stations in the

  11. The nonlinear theory of slow-wave electron cyclotron masers with inclusion of the beam velocity spread

    SciTech Connect (OSTI)

    Kong, Ling-Bao; Wang, Hong-Yu; Hou, Zhi-Ling; Jin, Hai-Bo; Du, Chao-Hai

    2013-12-15

    The nonlinear theory of slow-wave electron cyclotron masers (ECM) with an initially straight electron beam is developed. The evolution equation of the nonlinear beam electron energy is derived. The numerical studies of the slow-wave ECM efficiency with inclusion of Gaussian beam velocity spread are presented. It is shown that the velocity spread reduces the interaction efficiency. -- Highlights: •The theory of slow-wave electron cyclotron masers is considered. •The calculation of efficiency under the resonance condition is presented. •The efficiency under Gaussian velocity spreads has been obtained.

  12. Structure of the Crust beneath Cameroon, West Africa, from the Joint Inversion of Rayleigh Wave Group Velocities and Receiver Functions

    SciTech Connect (OSTI)

    Tokam, A K; Tabod, C T; Nyblade, A A; Julia, J; Wiens, D A; Pasyanos, M E

    2010-02-18

    Cameroon using 1-D shear wave velocity models obtained from the joint inversion of Rayleigh wave group velocities and P-receiver functions for 32 broadband seismic stations. From the 1-D shear wave velocity models, we obtain new insights into the composition and structure of the crust and upper mantle across Cameroon. After briefly reviewing the geological framework of Cameroon, we describe the data and the joint inversion method, and then interpret variations in crustal structure found beneath Cameroon in terms of the tectonic history of the region.

  13. Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

    DOE Patents [OSTI]

    Benjamin, R.F.

    1983-10-18

    An apparatus for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously.

  14. Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

    DOE Patents [OSTI]

    Benjamin, R.F.

    1987-03-10

    An apparatus is disclosed for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously. 3 figs.

  15. Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

    DOE Patents [OSTI]

    Benjamin, Robert F.

    1987-01-01

    An apparatus for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously.

  16. Ion Bernstein waves in a plasma with a kappa velocity distribution

    SciTech Connect (OSTI)

    Nsengiyumva, F.; Mace, R. L.; Hellberg, M. A.

    2013-10-15

    Using a Vlasov-Poisson model, a numerical investigation of the dispersion relation for ion Bernstein waves in a kappa-distributed plasma has been carried out. The dispersion relation is found to depend significantly on the spectral index of the ions, κ{sub i}, the parameter whose smallness is a measure of the departure from thermal equilibrium of the distribution function. Over all cyclotron harmonics, the typical Bernstein wave curves are shifted to higher wavenumbers (k) if κ{sub i} is reduced. For waves whose frequency lies above the lower hybrid frequency, ω{sub LH}, an increasing excess of superthermal particles (decreasing κ{sub i}) reduces the frequency, ω{sub peak}, of the characteristic peak at which the group velocity vanishes, while the associated k{sub peak} is increased. As the ratio of ion plasma to cyclotron frequency (ω{sub pi}/ω{sub ci}) is increased, the fall-off of ω at large k is smaller for lower κ{sub i} and curves are shifted towards larger wavenumbers. In the lower hybrid frequency band and harmonic bands above it, the frequency in a low-κ{sub i} plasma spans only a part of the intraharmonic space, unlike the Maxwellian case, thus exhibiting considerably less coupling between adjacent bands for low κ{sub i}. It is suggested that the presence of the ensuing stopbands may be a useful diagnostic for the velocity distribution characteristics. The model is applied to the Earth's plasma sheet boundary layer in which waves propagating perpendicularly to the ambient magnetic field at frequencies between harmonics of the ion cyclotron frequency are frequently observed.

  17. The thin section rock physics: Modeling and measurement of seismic wave velocity on the slice of carbonates

    SciTech Connect (OSTI)

    Wardaya, P. D. Noh, K. A. B. M. Yusoff, W. I. B. W.; Ridha, S.; Nurhandoko, B. E. B.

    2014-09-25

    This paper discusses a new approach for investigating the seismic wave velocity of rock, specifically carbonates, as affected by their pore structures. While the conventional routine of seismic velocity measurement highly depends on the extensive laboratory experiment, the proposed approach utilizes the digital rock physics view which lies on the numerical experiment. Thus, instead of using core sample, we use the thin section image of carbonate rock to measure the effective seismic wave velocity when travelling on it. In the numerical experiment, thin section images act as the medium on which wave propagation will be simulated. For the modeling, an advanced technique based on artificial neural network was employed for building the velocity and density profile, replacing image's RGB pixel value with the seismic velocity and density of each rock constituent. Then, ultrasonic wave was simulated to propagate in the thin section image by using finite difference time domain method, based on assumption of an acoustic-isotropic medium. Effective velocities were drawn from the recorded signal and being compared to the velocity modeling from Wyllie time average model and Kuster-Toksoz rock physics model. To perform the modeling, image analysis routines were undertaken for quantifying the pore aspect ratio that is assumed to represent the rocks pore structure. In addition, porosity and mineral fraction required for velocity modeling were also quantified by using integrated neural network and image analysis technique. It was found that the Kuster-Toksoz gives the closer prediction to the measured velocity as compared to the Wyllie time average model. We also conclude that Wyllie time average that does not incorporate the pore structure parameter deviates significantly for samples having more than 40% porosity. Utilizing this approach we found a good agreement between numerical experiment and theoretically derived rock physics model for estimating the effective seismic wave

  18. MEASUREMENT OF COMPRESSIONAL-WAVE SEISMIC VELOCITIES IN 29 WELLS AT THE HANFORD SITE

    SciTech Connect (OSTI)

    PETERSON SW

    2010-10-08

    Check shot seismic velocity surveys were collected in 100 B/C, 200 East, 200-PO-1 Operational Unit (OU), and the Gable Gap areas in order to provide time-depth correlation information to aid the interpretation of existing seismic reflection data acquired at the Hanford Site (Figure 1). This report details results from 5 wells surveyed in fiscal year (FY) 2008, 7 wells in FY 2009, and 17 wells in FY 2010 and provides summary compressional-wave seismic velocity information to help guide future seismic survey design as well as improve current interpretations of the seismic data (SSC 1979/1980; SGW-39675; SGW-43746). Augmenting the check shot database are four surveys acquired in 2007 in support of the Bechtel National, Inc. Waste Treatment Plant construction design (PNNL-16559, PNNL-16652), and check shot surveys in three wells to support seismic testing in the 200 West Area (Waddell et al., 1999). Additional sonic logging was conducted during the late 1970s and early 1980s as part of the Basalt Waste Isolation Program (BWIP) (SSC 1979/1980) and check shot/sonic surveys as part of the safety report for the Skagit/Hanford Nuclear project (RDH/10-AMCP-0164). Check shot surveys are used to obtain an in situ measure of compressional-wave seismic velocity for sediment and rock in the vicinity of the well point, and provide the seismic-wave travel time to geologic horizons of interest. The check shot method deploys a downhole seismic receiver (geophone) to record the arrival of seismic waves generated by a source at the ground surface. The travel time of the first arriving seismic-wave is determined and used to create a time-depth function to correlate encountered geologic intervals with the seismic data. This critical tie with the underlying geology improves the interpretation of seismic reflection profile information. Fieldwork for this investigation was conducted by in house staff during the weeks of September 22, 2008 for 5 wells in the 200 East Area (Figure 2); June 1

  19. Seismic Velocity Structure and Depth-Dependence of Anisotropy in the Red Sea and Arabian Shield from Surface Wave Analysis

    SciTech Connect (OSTI)

    Hansen, S; Gaherty, J; Schwartz, S; Rodgers, A; Al-Amri, A

    2007-07-25

    We investigate the lithospheric and upper mantle structure as well as the depth-dependence of anisotropy along the Red Sea and beneath the Arabian Peninsula using receiver function constraints and phase velocities of surface waves traversing two transects of stations from the Saudi Arabian National Digital Seismic Network. Frequency-dependent phase delays of fundamental-mode Love and Rayleigh waves, measured using a cross-correlation procedure, require very slow shear velocities and the presence of anisotropy throughout the upper mantle. Linearized inversion of these data produce path-averaged 1D radially anisotropic models with about 4% anisotropy in the lithosphere, increasing to about 4.8% anisotropy across the lithosphere-asthenosphere boundary (LAB). Models with reasonable crustal velocities in which the mantle lithosphere is isotropic cannot satisfy the data. The lithospheric lid, which ranges in thickness from about 70 km near the Red Sea coast to about 90 km beneath the Arabian Shield, is underlain by a pronounced low-velocity zone with shear velocities as low as 4.1 km/s. Forward models, which are constructed from previously determined shear-wave splitting estimates, can reconcile surface and body wave observations of anisotropy. The low shear velocity values are similar to many other continental rift and oceanic ridge environments. These low velocities combined with the sharp velocity contrast across the LAB may indicate the presence of partial melt beneath Arabia. The anisotropic signature primarily reflects a combination of plate- and density-driven flow associated with active rifting processes in the Red Sea.

  20. Derivation of site-specific relationships between hydraulic parameters and p-wave velocities based on hydraulic and seismic tomography

    SciTech Connect (OSTI)

    Brauchler, R.; Doetsch, J.; Dietrich, P.; Sauter, M.

    2012-01-10

    In this study, hydraulic and seismic tomographic measurements were used to derive a site-specific relationship between the geophysical parameter p-wave velocity and the hydraulic parameters, diffusivity and specific storage. Our field study includes diffusivity tomograms derived from hydraulic travel time tomography, specific storage tomograms, derived from hydraulic attenuation tomography, and p-wave velocity tomograms, derived from seismic tomography. The tomographic inversion was performed in all three cases with the SIRT (Simultaneous Iterative Reconstruction Technique) algorithm, using a ray tracing technique with curved trajectories. The experimental set-up was designed such that the p-wave velocity tomogram overlaps the hydraulic tomograms by half. The experiments were performed at a wellcharacterized sand and gravel aquifer, located in the Leine River valley near Gttingen, Germany. Access to the shallow subsurface was provided by direct-push technology. The high spatial resolution of hydraulic and seismic tomography was exploited to derive representative site-specific relationships between the hydraulic and geophysical parameters, based on the area where geophysical and hydraulic tests were performed. The transformation of the p-wave velocities into hydraulic properties was undertaken using a k-means cluster analysis. Results demonstrate that the combination of hydraulic and geophysical tomographic data is a promising approach to improve hydrogeophysical site characterization.

  1. Dual variational principles for nonlinear traveling waves in multifluid plasmas

    SciTech Connect (OSTI)

    Webb, G. M.; McKenzie, J. F.; Mace, R. L.; Ko, C. M.; Zank, G. P.

    2007-08-15

    A Hamiltonian description of nonlinear, obliquely propagating traveling waves in a charge neutral, electron-proton, multifluid plasma is developed. The governing equations are written as a dual spatial Hamiltonian system. In the first formulation, the Hamiltonian is identified with the longitudinal, x-momentum flux integral P{sub x}=const, in which the energy integral {epsilon}={epsilon}{sub 0} acts as a constraint, and the Hamiltonian evolution operator is d/dx, where x is the position coordinate in the wave frame. In the second Hamiltonian formulation, the Hamiltonian is proportional to the conserved energy integral {epsilon}, in which the momentum integral P{sub x}=const acts as a constraint, and the Hamiltonian evolution operator d/d{tau}=u{sub x}d/dx is the Lagrangian time derivative where u{sub x} is the x component of the electron and proton fluids. The analysis is facilitated by using the de Hoffman-Teller frame of magnetohydrodynamic shock theory to simplify the transverse electron and proton momentum equations. The system is exactly integrable in cases in which the total transverse momentum fluxes of the system are zero in the de Hoffman-Teller frame. The implications of this constraint for the Alfven Mach number of the traveling wave are discussed. The physical conditions for the formation of whistler oscillitons based on the whistler dispersion equation are discussed.

  2. Shear Wave Velocity Structure of Southern African Crust: Evidence for Compositional Heterogeneity within Archaean and Proterozoic Terrains

    SciTech Connect (OSTI)

    Kgaswane, E M; Nyblade, A A; Julia, J; Dirks, P H H M; Durrheim, R J; Pasyanos, M E

    2008-11-11

    Crustal structure in southern Africa has been investigated by jointly inverting receiver functions and Rayleigh wave group velocities for 89 broadband seismic stations spanning much of the Precambrian shield of southern Africa. 1-D shear wave velocity profiles obtained from the inversion yield Moho depths that are similar to those reported in previous studies and show considerable variability in the shear wave velocity structure of the lower part of the crust between some terrains. For many of the Archaean and Proterozoic terrains in the shield, S velocities reach 4.0 km/s or higher over a substantial part of the lower crust. However, for most of the Kimberley terrain and adjacent parts of the Kheis Province and Witwatersrand terrain, as well as for the western part of the Tokwe terrain, mean shear wave velocities of {le} 3.9 km/s characterize the lower part of the crust along with slightly ({approx}5 km) thinner crust. These findings indicate that the lower crust across much of the shield has a predominantly mafic composition, except for the southwest portion of the Kaapvaal Craton and western portion of the Zimbabwe Craton, where the lower crust is intermediate-to-felsic in composition. The parts of the Kaapvaal Craton underlain by intermediate-to-felsic lower crust coincide with regions where Ventersdorp rocks have been preserved, and thus we suggest that the intermediate-to-felsic composition of the lower crust and the shallower Moho may have resulted from crustal melting during the Ventersdorp tectonomagmatic event at c. 2.7 Ga and concomitant crustal thinning caused by rifting.

  3. Investigation of structural heterogeneity at the SPE site using combined P–wave travel times and Rg phase velocities

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rowe, Charlotte A.; Patton, Howard J.

    2015-10-01

    Here, we present analyses of the 2D seismic structure beneath Source Physics Experiments (SPE) geophone lines that extended radially at 100 m spacing from 100 to 2000 m from the source borehole. With seismic sources at only one end of the geophone lines, standard refraction profiling methods cannot resolve seismic velocity structures unambiguously. In previous work, we demonstrated overall agreement between body-wave refraction modeling and Rg dispersion curves for the least complex of the five lines. A more detailed inspection supports a 2D reinterpretation of the structure. We obtained Rg phase velocity measurements in both the time and frequency domains,more » then used iterative adjustment of the initial 1D body-wave model to predict Rg dispersion curves to fit the observed values. Our method applied to the most topographically severe of the geophone lines is supplemented with a 2D ray-tracing approach, whose application to P-wave arrivals supports the Rg analysis. In addition, midline sources will allow us to refine our characterization in future work.« less

  4. Coherent molecular transistor: Control through variation of the gate wave function

    SciTech Connect (OSTI)

    Ernzerhof, Matthias

    2014-03-21

    In quantum interference transistors (QUITs), the current through the device is controlled by variation of the gate component of the wave function that interferes with the wave function component joining the source and the sink. Initially, mesoscopic QUITs have been studied and more recently, QUITs at the molecular scale have been proposed and implemented. Typically, in these devices the gate lead is subjected to externally adjustable physical parameters that permit interference control through modifications of the gate wave function. Here, we present an alternative model of a molecular QUIT in which the gate wave function is directly considered as a variable and the transistor operation is discussed in terms of this variable. This implies that we specify the gate current as well as the phase of the gate wave function component and calculate the resulting current through the source-sink channel. Thus, we extend on prior works that focus on the phase of the gate wave function component as a control parameter while having zero or certain discrete values of the current. We address a large class of systems, including finite graphene flakes, and obtain analytic solutions for how the gate wave function controls the transistor.

  5. Determination of elastic properties of a MnO{sub 2} coating by surface acoustic wave velocity dispersion analysis

    SciTech Connect (OSTI)

    Sermeus, J.; Glorieux, C.; Sinha, R.; Vereecken, P. M.; Vanstreels, K.

    2014-07-14

    MnO{sub 2} is a material of interest in the development of high energy-density batteries, specifically as a coating material for internal 3D structures, thus ensuring rapid energy deployment. Its electrochemical properties have been mapped extensively, but there are, to the best of the authors' knowledge, no records of the elastic properties of thin film MnO{sub 2}. Impulsive stimulated thermal scattering (ISTS), also known as the heterodyne diffraction or transient grating technique, was used to determine the Young's modulus (E) and porosity (?) of a 500?nm thick MnO{sub 2} coating on a Si(001) substrate. ISTS is an all optical method that is able to excite and detect surface acoustic waves (SAWs) on opaque samples. From the measured SAW velocity dispersion, the Young's modulus and porosity were determined to be E?=?25??1?GPa and ?=421%, respectively. These values were confirmed by independent techniques and determined by a most-squares analysis of the carefully fitted SAW velocity dispersion. This study demonstrates the ability of the presented technique to determine the elastic parameters of a thin, porous film on an anisotropic substrate.

  6. Azimuthally Anisotropic 3D Velocity Continuation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Burnett, William; Fomel, Sergey

    2011-01-01

    We extend time-domain velocity continuation to the zero-offset 3D azimuthally anisotropic case. Velocity continuation describes how a seismic image changes given a change in migration velocity. This description turns out to be of a wave propagation process, in which images change along a velocity axis. In the anisotropic case, the velocity model is multiparameter. Therefore, anisotropic image propagation is multidimensional. We use a three-parameter slowness model, which is related to azimuthal variations in velocity, as well as their principal directions. This information is useful for fracture and reservoir characterization from seismic data. We provide synthetic diffraction imaging examples to illustratemore » the concept and potential applications of azimuthal velocity continuation and to analyze the impulse response of the 3D velocity continuation operator.« less

  7. Theoretical study of the thermodynamic properties, phase transition wave, and phase transition velocity for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine

    SciTech Connect (OSTI)

    Long, Yao; Chen, Jun

    2015-09-21

    We develop a phonon-electron free energy model to study the thermodynamic properties and phase transitions of δ-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine. The bulk modulus, thermal expansion coefficient, specific heat, Hugoniot curve, and phase transition curve are calculated in wide temperature and pressure ranges. The results are in agreement with the available experiments at zero pressure, and are reasonable predictions at high pressure for the lack of experiment. Two kinds of phase transition waves are investigated. We find the velocity of shock-induced phase transition wave is between 3400 m/s and 4700 m/s, and the velocity of self-sustaining phase transition wave is between 1300 m/s and 1900 m/s.

  8. Effect of ion temperature on ion-acoustic solitary waves in a plasma with a q-nonextensive electron velocity distribution

    SciTech Connect (OSTI)

    Roy, Kaushik; Saha, Taraknath; Chatterjee, Prasanta

    2012-10-15

    The effect of ion temperature on the existence of arbitrary amplitude ion-acoustic solitary waves is studied in a two component plasma in presence of a q-nonextensive velocity distributed electrons by using Sagdeev's pseudo potential technique. The range of relevent parameters for which solitons may exist is discussed. It is observed that both q, the nonextensive parameter and the ion temperature {sigma}, play significant roles in the formation and existence of solitons.

  9. Dielectric waveguide with transverse index variation that support a zero group velocity mode at a non-zero longitudinal wavevector

    DOE Patents [OSTI]

    Ibanescu, Mihai; Joannopoious, John D.; Fink, Yoel; Johnson, Steven G.; Fan, Shanhui

    2005-06-21

    Optical components including a laser based on a dielectric waveguide extending along a waveguide axis and having a refractive index cross-section perpendicular to the waveguide axis, the refractive index cross-section supporting an electromagnetic mode having a zero group velocity for a non-zero wavevector along the waveguide axis.

  10. Influence of plasma beta on the generation of lower hybrid and whistler waves by an ion velocity ring distribution

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Winske, D.; Daughton, W.

    2015-02-02

    We present results of three-dimensional electromagnetic particle-in-cell simulations of the lower hybrid ion ring instability, similar to our earlier results [D. Winske and W. Daughton, Phys. Plasma, 19, 072109, 2012], but at higher electron beta (βe = ratio of electron thermal pressure to magnetic pressure = 0.06, rather than at 0.006) with Ti = Te. At higher electron beta the level of lower hybrid waves at saturation normalized to the ion thermal energy (βi = 0.06 also) is only slightly smaller, but the corresponding magnetic fluctuations are about an order of magnitude larger, consistent with linear theory. After saturation, themore » waves evolve into whistler waves, through a number of possible mechanisms, with an average growth rate considerably smaller than the linear growth rate of the lower hybrid waves, to a peak fluctuation level that is about 20% above the lower hybrid wave saturation level. The ratio of the peak magnetic fluctuations associated with the whistler waves relative to those of the saturated lower hybrid waves, the ratio of the nonlinear growth rate of whistlers relative to the linear growth rate of lower hybrid waves, the amount of energy extracted from the ring and the amount of heating of the background ions and electrons are comparable to those in the lower electron beta 3-D simulation. This suggests that even at higher electron beta, the linear and nonlinear physics of the lower hybrid ion ring instability is dominated by electrostatic, wave-particle rather than wave-wave interactions.« less

  11. Influence of plasma beta on the generation of lower hybrid and whistler waves by an ion velocity ring distribution

    SciTech Connect (OSTI)

    Winske, D.; Daughton, W.

    2015-02-02

    We present results of three-dimensional electromagnetic particle-in-cell simulations of the lower hybrid ion ring instability, similar to our earlier results [D. Winske and W. Daughton, Phys. Plasma, 19, 072109, 2012], but at higher electron beta (βe = ratio of electron thermal pressure to magnetic pressure = 0.06, rather than at 0.006) with Ti = Te. At higher electron beta the level of lower hybrid waves at saturation normalized to the ion thermal energy (βi = 0.06 also) is only slightly smaller, but the corresponding magnetic fluctuations are about an order of magnitude larger, consistent with linear theory. After saturation, the waves evolve into whistler waves, through a number of possible mechanisms, with an average growth rate considerably smaller than the linear growth rate of the lower hybrid waves, to a peak fluctuation level that is about 20% above the lower hybrid wave saturation level. The ratio of the peak magnetic fluctuations associated with the whistler waves relative to those of the saturated lower hybrid waves, the ratio of the nonlinear growth rate of whistlers relative to the linear growth rate of lower hybrid waves, the amount of energy extracted from the ring and the amount of heating of the background ions and electrons are comparable to those in the lower electron beta 3-D simulation. This suggests that even at higher electron beta, the linear and nonlinear physics of the lower hybrid ion ring instability is dominated by electrostatic, wave-particle rather than wave-wave interactions.

  12. Investigation of structural heterogeneity at the SPE site using combined Pwave travel times and Rg phase velocities

    SciTech Connect (OSTI)

    Rowe, Charlotte A.; Patton, Howard J.

    2015-10-01

    Here, we present analyses of the 2D seismic structure beneath Source Physics Experiments (SPE) geophone lines that extended radially at 100 m spacing from 100 to 2000 m from the source borehole. With seismic sources at only one end of the geophone lines, standard refraction profiling methods cannot resolve seismic velocity structures unambiguously. In previous work, we demonstrated overall agreement between body-wave refraction modeling and Rg dispersion curves for the least complex of the five lines. A more detailed inspection supports a 2D reinterpretation of the structure. We obtained Rg phase velocity measurements in both the time and frequency domains, then used iterative adjustment of the initial 1D body-wave model to predict Rg dispersion curves to fit the observed values. Our method applied to the most topographically severe of the geophone lines is supplemented with a 2D ray-tracing approach, whose application to P-wave arrivals supports the Rg analysis. In addition, midline sources will allow us to refine our characterization in future work.

  13. Stochastic acceleration of electrons by fast magnetosonic waves in solar flares: the effects of anisotropy in velocity and wavenumber space

    SciTech Connect (OSTI)

    Pongkitiwanichakul, Peera; Chandran, Benjamin D. G.

    2014-11-20

    We develop a model for stochastic acceleration of electrons in solar flares. As in several previous models, the electrons are accelerated by turbulent fast magnetosonic waves ({sup f}ast waves{sup )} via transit-time-damping (TTD) interactions. (In TTD interactions, fast waves act like moving magnetic mirrors that push the electrons parallel or anti-parallel to the magnetic field). We also include the effects of Coulomb collisions and the waves' parallel electric fields. Unlike previous models, our model is two-dimensional in both momentum space and wavenumber space and takes into account the anisotropy of the wave power spectrum F{sub k} and electron distribution function f {sub e}. We use weak turbulence theory and quasilinear theory to obtain a set of equations that describes the coupled evolution of F{sub k} and f {sub e}. We solve these equations numerically and find that the electron distribution function develops a power-law-like non-thermal tail within a restricted range of energies E in (E {sub nt}, E {sub max}). We obtain approximate analytic expressions for E {sub nt} and E {sub max}, which describe how these minimum and maximum energies depend upon parameters such as the electron number density and the rate at which fast-wave energy is injected into the acceleration region at large scales. We contrast our results with previous studies that assume that F{sub k} and f {sub e} are isotropic, and we compare one of our numerical calculations with the time-dependent hard-X-ray spectrum observed during the 1980 June 27 flare. In our numerical calculations, the electron energy spectra are softer (steeper) than in models with isotropic F{sub k} and f {sub e} and closer to the values inferred from observations of solar flares.

  14. Modulational instability of ion-acoustic waves in a plasma with a q-nonextensive electron velocity distribution

    SciTech Connect (OSTI)

    Bains, A. S.; Gill, T. S.; Tribeche, Mouloud

    2011-02-15

    The modulational instability (MI) of ion-acoustic waves (IAWs) in a two-component plasma is investigated in the context of the nonextensive statistics proposed by Tsallis [J. Stat. Phys. 52, 479 (1988)]. Using the reductive perturbation method, the nonlinear Schroedinger equation (NLSE) which governs the MI of the IAWs is obtained. The presence of the nonextensive electron distribution is shown to influence the MI of the waves. Three different ranges of the nonextensive q-parameter are considered and in each case the MI sets in under different conditions. Furthermore, the effects of the q-parameter on the growth rate of MI are discussed in detail.

  15. In-plane ultrasonic velocity measurement of longitudinal and shear waves in the machine direction with transducers in rotating wheels

    DOE Patents [OSTI]

    Hall, M.S.; Jackson, T.G.; Knerr, C.

    1998-02-17

    An improved system for measuring the velocity of ultrasonic signals within the plane of moving web-like materials, such as paper, paperboard and the like. In addition to velocity measurements of ultrasonic signals in the plane of the web in the MD and CD, one embodiment of the system in accordance with the present invention is also adapted to provide on-line indication of the polar specific stiffness of the moving web. In another embodiment of the invention, the velocity of ultrasonic signals in the plane of the web are measured by way of a plurality of ultrasonic transducers carried by synchronously driven wheels or cylinders, thus eliminating undue transducer wear due to any speed differences between the transducers and the web. In order to provide relatively constant contact force between the transducers and the webs, the transducers are mounted in a sensor housings which include a spring for biasing the transducer radially outwardly. The sensor housings are adapted to be easily and conveniently mounted to the carrier to provide a relatively constant contact force between the transducers and the moving web. 37 figs.

  16. In-plane ultrasonic velocity measurement of longitudinal and shear waves in the machine direction with transducers in rotating wheels

    DOE Patents [OSTI]

    Hall, Maclin S.; Jackson, Theodore G.; Knerr, Christopher

    1998-02-17

    An improved system for measuring the velocity of ultrasonic signals within the plane of moving web-like materials, such as paper, paperboard and the like. In addition to velocity measurements of ultrasonic signals in the plane of the web in the MD and CD, one embodiment of the system in accordance with the present invention is also adapted to provide on-line indication of the polar specific stiffness of the moving web. In another embodiment of the invention, the velocity of ultrasonic signals in the plane of the web are measured by way of a plurality of ultrasonic transducers carried by synchronously driven wheels or cylinders, thus eliminating undue transducer wear due to any speed differences between the transducers and the web. In order to provide relatively constant contact force between the transducers and the webs, the transducers are mounted in a sensor housings which include a spring for biasing the transducer radially outwardly. The sensor housings are adapted to be easily and conveniently mounted to the carrier to provide a relatively constant contact force between the transducers and the moving web.

  17. Modulational instability of ion-acoustic waves in plasma with a q-nonextensive nonthermal electron velocity distribution

    SciTech Connect (OSTI)

    Bouzit, Omar Tribeche, Mouloud E-mail: mtribeche@usthb.dz; Bains, A. S.

    2015-08-15

    Modulation instability of ion-acoustic waves (IAWs) is investigated in a collisionless unmagnetized one dimensional plasma, containing positive ions and electrons following the mixed nonextensive nonthermal distribution [Tribeche et al., Phys. Rev. E 85, 037401 (2012)]. Using the reductive perturbation technique, a nonlinear Schrödinger equation which governs the modulation instability of the IAWs is obtained. Valid range of plasma parameters has been fixed and their effects on the modulational instability discussed in detail. We find that the plasma supports both bright and dark solutions. The valid domain for the wave number k where instabilities set in varies with both nonextensive parameter q as well as non thermal parameter α. Moreover, the analysis is extended for the rational solutions of IAWs in the instability regime. Present study is useful for the understanding of IAWs in the region where such mixed distribution may exist.

  18. Variation of Langmuir wave polarization with electron beam speed in type III radio bursts

    SciTech Connect (OSTI)

    Malaspina, David M.; Cairns, Iver H.; Ergun, Robert E.

    2013-06-13

    Observations by the twin STEREO spacecraft of in-situ electric field waveforms and radio signatures associated with type III radio bursts have demonstrated that the polarization of electron beam-driven waves near the local plasma frequency depends strongly on the speed of the driving electron beam. We expand upon a previous study by including all radio bursts with in-situ waveforms observed by STEREO in 2011. The expanded data set contains five times more radio bursts (35 up from 7) and three times as many Langmuir waves (663 up from 168). While this expanded study supports the results of the original study, that faster (slower) beam electrons drive waves with strong (weak) electric fields perpendicular to the local magnetic field, the larger data set emphasizes that the observation of strong perpendicular electric fields at high electron beam speeds is probabilistic rather than definite. This property supports the interpretation of wave polarization dependence on beam speed as Langmuir/z-mode waves shifted to small wave number through interaction with turbulent solar wind density fluctuations.

  19. Wave

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    1 Summer 2001 Heat Wave This summer has proved to be downright hot in the Southern Great ... Not only is a summer heat wave uncomfortable, but it can also be ARM Facilities Newsletter ...

  20. Final Data Report: P- and S-Wave Velocity Logging Borings C4993, C4996, and C4997 Part B: Overall Logs

    SciTech Connect (OSTI)

    Diehl, John; Steller, Robert

    2007-03-20

    Insitu borehole P- and S-wave velocity measurements were collected in three borings located within the Waste Treatment Plant (WTP) boundaries at the Hanford Site, southeastern Washington. Geophysical data acquisition was performed between August and October of 2006 by Rob Steller, Charles Carter, Antony Martin and John Diehl of GEOVision. Data analysis was performed by Rob Steller and John Diehl, and reviewed by Antony Martin of GEOVision, and report preparation was performed by John Diehl and reviewed by Rob Steller. The work was performed under subcontract with Battelle, Pacific Northwest Division with Marty Gardner as Battelles Technical Representative and Alan Rohay serving as the Technical Administrator for Pacific Northwest National Laboratory (PNNL). This report describes the field measurements, data analysis, and results of this work.

  1. Mass variation of a thin liquid film driven by an acoustic wave

    SciTech Connect (OSTI)

    Batson, W.; Agnon, Y.; Oron, A.

    2015-06-15

    In this work, we investigate the dynamics of a thin liquid film subjected to an acoustic field in its bounding vapor space. For large acoustic wavelengths, the field imposes a spatially uniform, temporally periodic temperature and pressure at the vapor side of the film interface, which leads to a periodic driving force for mass exchange with the vapor. Neglecting the dynamics of the vapor space, we adopt the “one-sided” model for evaporation/condensation of thin liquid films. In the interest of determining the effect of oscillatory mass exchange on film stability, we consider films in thermodynamic equilibrium with the mean vapor conditions. The effects of oscillatory phase change on both linear stability and nonlinear dynamics are investigated for slightly inclined ceiling films that are destabilized by gravity and subject to thermocapillary effects. At linear order, this mass exchange is not found to alter the band of unstable wave numbers and only marginally affects the growth rates. Additionally, the mass exchanged during evaporation is balanced by condensation so that the total mass of the liquid film is conserved. However, due to nonlinear effects, we find that traveling waves encouraged by the inclination are subject to net mass loss. It is then found that normal thermocapillary effects enhance this loss, and that anomalous thermocapillarity mitigates or even reverses the loss to a mass gain.

  2. Fiber-optic voltage sensor with cladded fiber and evanescent wave variation detection

    DOE Patents [OSTI]

    Wood, Charles B.

    1992-01-01

    A fiber optic voltage sensor is described which includes a source of light, a reference fiber for receiving a known percentage of the light and an electrostrictive element having terminals across which is applied, a voltage to be measured. The electrostrictive element is responsive to the applied voltage to assume an altered physical state. A measuring fiber also receives a known percentage of light from the light source and is secured about the electrostrictive element. The measuring fiber is provided with a cladding and exhibits an evanescent wave in the cladding. The measuring fiber has a known length which is altered when the electrostrictive element assumes its altered physical state. A differential sensor is provided which senses the intensity of light in both the reference fiber and the measuring fiber and provides an output indicative of the difference between the intensities.

  3. Fiber-optic voltage sensor with cladded fiber and evanescent wave variation detection

    DOE Patents [OSTI]

    Wood, C.B.

    1992-12-15

    A fiber optic voltage sensor is described which includes a source of light, a reference fiber for receiving a known percentage of the light and an electrostrictive element having terminals across which is applied, a voltage to be measured. The electrostrictive element is responsive to the applied voltage to assume an altered physical state. A measuring fiber also receives a known percentage of light from the light source and is secured about the electrostrictive element. The measuring fiber is provided with a cladding and exhibits an evanescent wave in the cladding. The measuring fiber has a known length which is altered when the electrostrictive element assumes its altered physical state. A differential sensor is provided which senses the intensity of light in both the reference fiber and the measuring fiber and provides an output indicative of the difference between the intensities. 3 figs.

  4. The various manifestations of collisionless dissipation in wave propagation

    SciTech Connect (OSTI)

    Benisti, Didier; Morice, Olivier; Gremillet, Laurent

    2012-06-15

    The propagation of an electrostatic wave packet inside a collisionless and initially Maxwellian plasma is always dissipative because of the irreversible acceleration of the electrons by the wave. Then, in the linear regime, the wave packet is Landau damped, so that in the reference frame moving at the group velocity, the wave amplitude decays exponentially with time. In the nonlinear regime, once phase mixing has occurred and when the electron motion is nearly adiabatic, the damping rate is strongly reduced compared to the Landau one, so that the wave amplitude remains nearly constant along the characteristics. Yet, we show here that the electrons are still globally accelerated by the wave packet, and in one dimension, this leads to a non local amplitude dependence of the group velocity. As a result, a freely propagating wave packet would shrink, and therefore, so would its total energy. In more than one dimension, not only does the magnitude of the group velocity nonlinearly vary, but also its direction. In the weakly nonlinear regime, when the collisionless damping rate is still significant compared to its linear value, the group velocity is directed towards the outside of the wave packet and tends to increase its transverse extent, while the opposite is true once the wave is essentially undamped. The impact of the nonlinear variation of the group velocity on the transverse size of the wave packet is quantified, and compared to that induced by the self-focussing due to wave front bowing.

  5. Characterization of the alumina-zirconia ceramic system by ultrasonic velocity measurements

    SciTech Connect (OSTI)

    Carreon, Hector; Ruiz, Alberto; Medina, Ariosto; Barrera, Gerardo; Zarate, Juan

    2009-08-15

    In this work an alumina-zirconia ceramic composites have been prepared with {alpha}-Al{sub 2}O{sub 3} contents from 10 to 95 wt.%. The alumina-zirconia ceramic system was characterized by means of precise ultrasonic velocity measurements. In order to find out the factors affecting the variation in wave velocity, the ceramic composite have been examined by X-ray diffraction (XRD) and (SEM) scanning electron microscopy. It was found that the ultrasonic velocity measurements changed considerably with respect to the ceramic composite composition. In particular, we studied the behavior of the physical material property hardness, an important parameter of the ceramic composite mechanical properties, with respect to the variation in the longitudinal and shear wave velocities. Shear wave velocities exhibited a stronger interaction with microstructural and sub-structural features as compared to that of longitudinal waves. In particular, this phenomena was observed for the highest {alpha}-Al{sub 2}O{sub 3} content composite. Interestingly, an excellent correlation between ultrasonic velocity measurements and ceramic composite hardness was observed.

  6. Effect of spatial density variation and O+ concentration on the growth and evolution of electromagnetic ion cyclotron waves

    SciTech Connect (OSTI)

    Denton, R. E.; Jordanova, V. K.; Fraser, B. J.

    2014-10-01

    We simulate electromagnetic ion cyclotron (EMIC) wave growth and evolution within three regions, the plasmasphere (or plasmaspheric plume), the plasmapause, and the low-density plasmatrough outside the plasmapause. First, we use a ring current simulation with a plasmasphere model to model the particle populations that give rise to the instability for conditions observed on 9 June 2001. Then, using two different models for the cold ion composition, we do a full scale hybrid code simulation in dipole coordinates of the EMIC waves on a meridional plane at MLT = 18 and at 1900 UT within a range of L shell from L = 4.9 to 6.7. EMIC waves were observed during June 9, 2001 by Geostationary Operational Environmental Satellite (GOES) spacecraft. While an exact comparison between observed and simulated spectra is not possible here, we do find significant similarities between the two, at least at one location within the region of largest wave growth. We find that the plasmapause is not a preferred region for EMIC wave growth, though waves can grow in that region. The density gradient within the plasmapause does, however, affect the orientation of wave fronts and wave vector both within the plasmapause and in adjacent regions. There is a preference for EMIC waves to be driven in the He+ band (frequencies between the O+ and He+ gyrofrequencies) within the plasmasphere, although they can also grow in the plasmatrough. If present, H+ band waves are more likely to grow in the plasmatrough. This fact, plus L dependence of the frequency and possible time evolution toward lower frequency waves, can be explained by a simple model. Large O+ concentration limits the frequency range of or even totally quenches EMIC waves. This is more likely to occur in the plasmatrough at solar maximum. Such large O+ concentration significantly affects the H+ cutoff frequency and hence the width in frequency of the stop band above the He+ gyrofrequency. EMIC wave surfaces predicted by cold plasma theory

  7. Effect of spatial density variation and O+ concentration on the growth and evolution of electromagnetic ion cyclotron waves

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Denton, R. E.; Jordanova, V. K.; Fraser, B. J.

    2014-10-01

    We simulate electromagnetic ion cyclotron (EMIC) wave growth and evolution within three regions, the plasmasphere (or plasmaspheric plume), the plasmapause, and the low-density plasmatrough outside the plasmapause. First, we use a ring current simulation with a plasmasphere model to model the particle populations that give rise to the instability for conditions observed on 9 June 2001. Then, using two different models for the cold ion composition, we do a full scale hybrid code simulation in dipole coordinates of the EMIC waves on a meridional plane at MLT = 18 and at 1900 UT within a range of L shell frommore » L = 4.9 to 6.7. EMIC waves were observed during June 9, 2001 by Geostationary Operational Environmental Satellite (GOES) spacecraft. While an exact comparison between observed and simulated spectra is not possible here, we do find significant similarities between the two, at least at one location within the region of largest wave growth. We find that the plasmapause is not a preferred region for EMIC wave growth, though waves can grow in that region. The density gradient within the plasmapause does, however, affect the orientation of wave fronts and wave vector both within the plasmapause and in adjacent regions. There is a preference for EMIC waves to be driven in the He+ band (frequencies between the O+ and He+ gyrofrequencies) within the plasmasphere, although they can also grow in the plasmatrough. If present, H+ band waves are more likely to grow in the plasmatrough. This fact, plus L dependence of the frequency and possible time evolution toward lower frequency waves, can be explained by a simple model. Large O+ concentration limits the frequency range of or even totally quenches EMIC waves. This is more likely to occur in the plasmatrough at solar maximum. Such large O+ concentration significantly affects the H+ cutoff frequency and hence the width in frequency of the stop band above the He+ gyrofrequency. EMIC wave surfaces predicted by cold

  8. Effect of spatial density variation and O+ concentration on the growth and evolution of electromagnetic ion cyclotron waves

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Denton, R. E.; Jordanova, V. K.; Fraser, B. J.

    2014-10-01

    We simulate electromagnetic ion cyclotron (EMIC) wave growth and evolution within three regions, the plasmasphere (or plasmaspheric plume), the plasmapause, and the low-density plasmatrough outside the plasmapause. First, we use a ring current simulation with a plasmasphere model to model the particle populations that give rise to the instability for conditions observed on 9 June 2001. Then, using two different models for the cold ion composition, we do a full scale hybrid code simulation in dipole coordinates of the EMIC waves on a meridional plane at MLT = 18 and at 1900 UT within a range of L shell frommore »L = 4.9 to 6.7. EMIC waves were observed during June 9, 2001 by Geostationary Operational Environmental Satellite (GOES) spacecraft. While an exact comparison between observed and simulated spectra is not possible here, we do find significant similarities between the two, at least at one location within the region of largest wave growth. We find that the plasmapause is not a preferred region for EMIC wave growth, though waves can grow in that region. The density gradient within the plasmapause does, however, affect the orientation of wave fronts and wave vector both within the plasmapause and in adjacent regions. There is a preference for EMIC waves to be driven in the He+ band (frequencies between the O+ and He+ gyrofrequencies) within the plasmasphere, although they can also grow in the plasmatrough. If present, H+ band waves are more likely to grow in the plasmatrough. This fact, plus L dependence of the frequency and possible time evolution toward lower frequency waves, can be explained by a simple model. Large O+ concentration limits the frequency range of or even totally quenches EMIC waves. This is more likely to occur in the plasmatrough at solar maximum. Such large O+ concentration significantly affects the H+ cutoff frequency and hence the width in frequency of the stop band above the He+ gyrofrequency. EMIC wave surfaces predicted by cold plasma

  9. Seismic Surface-Wave Tomography of Waste Sites

    SciTech Connect (OSTI)

    Leland Timothy Long

    2002-12-17

    Surface-wave group-velocity tomography is an efficient way to obtain images of the group velocity over a test area. Because Rayleigh-wave group velocity depends on frequency, there are separate images for each frequency. Thus, at each point in these images the group velocities define a dispersion curve, a curve that relates group velocity to frequency. The objective of this study has been to find an accurate and efficient way to find the shear-wave structure from these dispersion curves. The conventional inversion techniques match theoretical and observed dispersion curves to determine the structure. These conventional methods do not always succeed in correctly differentiating the fundamental and higher modes, and for some velocity structures can become unstable. In this research a perturbation technique was developed. The perturbation method allows the pre-computation of a global inversion matrix which improves efficiency in obtaining solutions for the structure. Perturbation methods are stable and mimic the averaging process in wave propagation; hence. leading to more accurate solutions. Finite difference techniques and synthetic trace generation techniques were developed to define the perturbations. A new differential trace technique was developed for slight variations in dispersion. The improvements in analysis speed and the accuracy of the solution could lead to real-time field analysis systems, making it possible to obtain immediate results or to monitor temporal change in structure, such as might develop in using fluids for soil remediation.

  10. Investigation of Wave Energy Converter Effects on Wave Fields: A Modeling Sensitivity Study in Monterey Bay CA.

    SciTech Connect (OSTI)

    Roberts, Jesse D.; Grace Chang; Jason Magalen; Craig Jones

    2014-08-01

    A n indust ry standard wave modeling tool was utilized to investigate model sensitivity to input parameters and wave energy converter ( WEC ) array deploym ent scenarios. Wave propagation was investigated d ownstream of the WECs to evaluate overall near - and far - field effects of WEC arrays. The sensitivity study illustrate d that b oth wave height and near - bottom orbital velocity we re subject to the largest pote ntial variations, each decreas ed in sensitivity as transmission coefficient increase d , as number and spacing of WEC devices decrease d , and as the deployment location move d offshore. Wave direction wa s affected consistently for all parameters and wave perio d was not affected (or negligibly affected) by varying model parameters or WEC configuration .

  11. Simultaneous structure and elastic wave velocity measurement...

    Office of Scientific and Technical Information (OSTI)

    Authors: Kono, Yoshio ; Park, Changyong ; Sakamaki, Tatsuya ; Kenny-Benson, Curtis ; Shen, Guoyin ; Wang, Yanbin 1 ; UC) 2 + Show Author Affiliations (CIW) ( Publication Date: ...

  12. DeFrees Small Wave Basin | Open Energy Information

    Open Energy Info (EERE)

    Current Velocity Range(ms) 0.0 Programmable Wavemaking Yes Wavemaking Description Computer controlled hydraulic paddle, arbitrary wave shape possible Wave Direction...

  13. Penetration of lower hybrid current drive waves in tokamaks

    SciTech Connect (OSTI)

    Horton, W.; Aix-Marseille University, 58, Bd Charles Livon, 13284 Marseille ; Goniche, M.; Peysson, Y.; Decker, J.; Ekedahl, A.; Litaudon, X.

    2013-11-15

    Lower hybrid (LH) ray propagation in toroidal plasma is shown to be controlled by combination of the azimuthal spectrum launched by the antenna, the poloidal variation of the magnetic field, and the scattering of the waves by the drift wave fluctuations. The width of the poloidal and radial radio frequency wave spectrum increases rapidly as the rays penetrate into higher density and scatter from the drift waves. The electron temperature gradient (ETG) spectrum is particularly effective in scattering the LH waves due to its comparable wavelengths and phase velocities. ETG turbulence is also driven by the radial gradient of the electron current profile giving rise to an anomalous viscosity spreading the LH driven plasma currents. The LH wave scattering is derived from a Fokker-Planck equation for the distribution of the ray trajectories with diffusivities derived from the drift wave fluctuations. The condition for chaotic diffusion for the rays is derived. The evolution of the poloidal and radial mode number spectrum of the lower hybrid waves are both on the antenna spectrum and the spectrum of the drift waves. Antennas launching higher poloidal mode number spectra drive off-axis current density profiles producing negative central shear [RS] plasmas with improved thermal confinement from ETG transport. Core plasma current drive requires antennas with low azimuthal mode spectra peaked at m = 0 azimuthal mode numbers.

  14. Data interpretation of joint compressional and shear wave survey in mountainous region

    SciTech Connect (OSTI)

    Fugiu, D. )

    1992-01-01

    The join utilization of compressional and shear wave data leads one to discover nonstructural hydrocarbon traps such as stratigraphic trap, lithologic trap, fracture trap, etc. and to ascertain fluid situation in formation, lithologic variation and fracture zone, so that the accuracy of seismic data interpretation is improved greatly. In this paper, the author describes how to determine shear wave horizon, how to interpret carbonate reservoir and how to discover gas accumulation zone in HBC area in Sichuan Province. It is very important to pay more attention to analyzing the ratio between compressional wave amplitude and shear wave amplitude, and the ratio between compressional wave velocity and shear wave velocity in data interpretation. The amplitude ratio anomaly and the velocity ratio anomaly in HBC area can be usually seen at anticlinal axis areas and small noses. Generally speaking, the amplitude ratio anomaly area reflects gas accumulation and the velocity ratio anomaly area exhibits dense fracture zone. Good results have been obtained from exploratory wells in the areas where there occur the two anomalies simultaneously.

  15. Localized parallel parametric generation of spin waves in a Ni{sub 81}Fe{sub 19} waveguide by spatial variation of the pumping field

    SciTech Connect (OSTI)

    Brächer, T.; Pirro, P.; Heussner, F.; Serga, A. A.; Hillebrands, B.

    2014-03-03

    We present the experimental observation of localized parallel parametric generation of spin waves in a transversally in-plane magnetized Ni{sub 81}Fe{sub 19} magnonic waveguide. The localization is realized by combining the threshold character of parametric generation with a spatially confined enhancement of the amplifying microwave field. The latter is achieved by modulating the width of the microstrip transmission line which is used to provide the pumping field. By employing microfocussed Brillouin light scattering spectroscopy, we analyze the spatial distribution of the generated spin waves and compare it with numerical calculations of the field distribution along the Ni{sub 81}Fe{sub 19} waveguide. This provides a local spin-wave excitation in transversally in-plane magnetized waveguides for a wide wave-vector range which is not restricted by the size of the generation area.

  16. Generalized Dix equation and analytic treatment of normal-movement velocity for anisotropic media

    SciTech Connect (OSTI)

    Grechka, V.; Tsvankin, I.; Cohen, J.K.

    1999-03-01

    Despite the complexity of wave propagation in anisotropic media, reflection moveout on conventional common-midpoint (CMP) spreads is usually well described by the normal-moveout (NMO) velocity defined in the zero-offset limit. In their recent work, Grechka and Tsvankin showed that the azimuthal variation of NMO velocity around a fixed CMP location generally has an elliptical form (i.e., plotting the NMO velocity in each azimuthal direction produces an ellipse) and is determined by the spatial derivatives of the slowness vector evaluated at the CMP location. This formalism is used here to develop exact solutions for the NMO velocity in anisotropic media of arbitrary symmetry. The high accuracy of the NMO expressions is illustrated by comparison with ray-traced reflection traveltimes in piecewise-homogeneous, azimuthally anisotropic models. The authors also apply the generalized Dix equation to field data collected over a fractured reservoir and show that P-wave moveout can be used to find the depth-dependent fracture orientation and to evaluate the magnitude of azimuthal anisotropy.

  17. ADVANCED WAVE-EQUATION MIGRATION

    SciTech Connect (OSTI)

    L. HUANG; M. C. FEHLER

    2000-12-01

    Wave-equation migration methods can more accurately account for complex wave phenomena than ray-tracing-based Kirchhoff methods that are based on the high-frequency asymptotic approximation of waves. With steadily increasing speed of massively parallel computers, wave-equation migration methods are becoming more and more feasible and attractive for imaging complex 3D structures. We present an overview of several efficient and accurate wave-equation-based migration methods that we have recently developed. The methods are implemented in the frequency-space and frequency-wavenumber domains and hence they are called dual-domain methods. In the methods, we make use of different approximate solutions of the scalar-wave equation in heterogeneous media to recursively downward continue wavefields. The approximations used within each extrapolation interval include the Born, quasi-Born, and Rytov approximations. In one of our dual-domain methods, we use an optimized expansion of the square-root operator in the one-way wave equation to minimize the phase error for a given model. This leads to a globally optimized Fourier finite-difference method that is a hybrid split-step Fourier and finite-difference scheme. Migration examples demonstrate that our dual-domain migration methods provide more accurate images than those obtained using the split-step Fourier scheme. The Born-based, quasi-Born-based, and Rytov-based methods are suitable for imaging complex structures whose lateral variations are moderate, such as the Marmousi model. For this model, the computational cost of the Born-based method is almost the same as the split-step Fourier scheme, while other methods takes approximately 15-50% more computational time. The globally optimized Fourier finite-difference method significantly improves the accuracy of the split-step Fourier method for imaging structures having strong lateral velocity variations, such as the SEG/EAGE salt model, at an approximately 30% greater

  18. Pyrotechnic deflagration velocity and permeability

    SciTech Connect (OSTI)

    Begeal, D R; Stanton, P L

    1982-01-01

    Particle size, porosity, and permeability of the reactive material have long been considered to be important factors in propellant burning rates and the deflagration-to-detonation transition in explosives. It is reasonable to assume that these same parameters will also affect the deflagration velocity of pyrotechnics. This report describes an experimental program that addresses the permeability of porous solids (particulate beds), in terms of particle size and porosity, and the relationship between permeability and the behavior of pyrotechnics and explosives. The experimental techniques used to acquire permeability data and to characterize the pyrotechnic burning are discussed. Preliminary data have been obtained on the burning characteristics of titanium hydride/potassium perchlorate (THKP) and boron/calcium chromate (BCCR). With THKP, the velocity of a pressure wave (from hot product gases) in the unburned region shows unsteady behavior which is related to the initial porosity or permeability. Simultaneous measurements with pressure gauges and ion gauges reveal that the pressure wave precedes the burn front. Steady burning of BCCR was observed with pressure gauge diagnostics and with a microwave interferometry technique.

  19. Internal Detonation Velocity Measurements Inside High Explosives

    SciTech Connect (OSTI)

    Benterou, J; Bennett, C V; Cole, G; Hare, D E; May, C; Udd, E

    2009-01-16

    In order to fully calibrate hydrocodes and dynamic chemistry burn models, initiation models and detonation models of high explosives, the ability to continuously measure the detonation velocity within an explosive is required. Progress on an embedded velocity diagnostic using a 125 micron diameter optical fiber containing a chirped fiber Bragg grating is reported. As the chirped fiber Bragg grating is consumed by the moving detonation wave, the physical length of the unconsumed Bragg grating is monitored with a fast InGaAs photodiode. Experimental details of the associated equipment and data in the form of continuous detonation velocity records within PBX-9502 are presented. This small diameter fiber sensor has the potential to measure internal detonation velocities on the order of 10 mm/{micro}sec along path lengths tens of millimeters long.

  20. Solitary kinetic Alfven waves in dusty plasmas

    SciTech Connect (OSTI)

    Li Yangfang; Wu, D. J.; Morfill, G. E.

    2008-08-15

    Solitary kinetic Alfven waves in dusty plasmas are studied by considering the dust charge variation. The effect of the dust charge-to-mass ratio on the soliton solution is discussed. The Sagdeev potential is derived analytically with constant dust charge and then calculated numerically by taking the dust charge variation into account. We show that the dust charge-to-mass ratio plays an important role in the soliton properties. The soliton solutions are comprised of two branches. One branch is sub-Alfvenic and the soliton velocity is obviously smaller than the Alfven speed. The other branch is super-Alfvenic and the soliton velocity is very close to or greater than the Alfven speed. Both compressive and rarefactive solitons can exist. For the sub-Alfvenic branch, the rarefactive soliton is bell-shaped and it is much narrower than the compressive one. However, for the super-Alfvenic branch, the compressive soliton is bell-shaped and narrower, and the rarefactive one is broadened. When the charge-to-mass ratio of the dust grains is sufficiently high, the width of the rarefactive soliton, in the super-Alfvenic branch, will broaden extremely and a electron depletion will be observed. It is also shown that the bell-shaped soliton can transition to a cusped structure when the velocity is sufficiently high.

  1. Traveling-wave photodetector

    DOE Patents [OSTI]

    Hietala, Vincent M.; Vawter, Gregory A.

    1993-01-01

    The traveling-wave photodetector of the present invention combines an absorptive optical waveguide and an electrical transmission line, in which optical absorption in the waveguide results in a photocurrent at the electrodes of the electrical transmission line. The optical waveguide and electrical transmission line of the electrically distributed traveling-wave photodetector are designed to achieve matched velocities between the light in the optical waveguide and electrical signal generated on the transmission line. This velocity synchronization provides the traveling-wave photodetector with a large electrical bandwidth and a high quantum efficiency, because of the effective extended volume for optical absorption. The traveling-wave photodetector also provides large power dissipation, because of its large physical size.

  2. Traveling-wave photodetector

    DOE Patents [OSTI]

    Hietala, V.M.; Vawter, G.A.

    1993-12-14

    The traveling-wave photodetector of the present invention combines an absorptive optical waveguide and an electrical transmission line, in which optical absorption in the waveguide results in a photocurrent at the electrodes of the electrical transmission line. The optical waveguide and electrical transmission line of the electrically distributed traveling-wave photodetector are designed to achieve matched velocities between the light in the optical waveguide and electrical signal generated on the transmission line. This velocity synchronization provides the traveling-wave photodetector with a large electrical bandwidth and a high quantum efficiency, because of the effective extended volume for optical absorption. The traveling-wave photodetector also provides large power dissipation, because of its large physical size. 4 figures.

  3. Evidence for wave heating of the quiet-sun corona

    SciTech Connect (OSTI)

    Hahn, M.; Savin, D. W.

    2014-11-10

    We have measured the energy and dissipation of Alfvénic waves in the quiet Sun. A magnetic field model was used to infer the location and orientation of the magnetic field lines along which the waves are expected to travel. The waves were measured using spectral lines to infer the wave amplitude. The waves cause a non-thermal broadening of the spectral lines, which can be expressed as a non-thermal velocity v {sub nt}. By combining the spectroscopic measurements with this magnetic field model, we were able to trace the variation of v {sub nt} along the magnetic field. At each footpoint of the quiet-Sun loops, we find that waves inject an energy flux in the range of 1.3-5.5 × 10{sup 5} erg cm{sup –2} s{sup –1}. At the minimum of this range, this amounts to more than 80% of the energy needed to heat the quiet Sun. We also find that these waves are dissipated over a region centered on the top of the loops. The position along the loop where the damping begins is strongly correlated with the length of the loop, implying that the damping mechanism depends on the global loop properties rather than on local collisional dissipation.

  4. AnisWave 2D

    Energy Science and Technology Software Center (OSTI)

    2004-08-01

    AnisWave2D is a 2D finite-difference code for a simulating seismic wave propagation in fully anisotropic materials. The code is implemented to run in parallel over multiple processors and is fully portable. A mesh refinement algorithm has been utilized to allow the grid-spacing to be tailored to the velocity model, avoiding the over-sampling of high-velocity materials that usually occurs in fixed-grid schemes.

  5. Explosive plane-wave lens

    DOE Patents [OSTI]

    Marsh, S.P.

    1988-03-08

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive. 4 figs.

  6. Explosive plane-wave lens

    DOE Patents [OSTI]

    Marsh, S.P.

    1987-03-12

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive. 3 figs., 3 tabs.

  7. Explosive plane-wave lens

    DOE Patents [OSTI]

    Marsh, Stanley P. (Los Alamos, NM)

    1988-01-01

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive.

  8. Lithospheric Thickness Modeled from Long Period Surface Wave Dispersion

    SciTech Connect (OSTI)

    Pasyanos, M E

    2008-05-15

    The behavior of surface waves at long periods is indicative of subcrustal velocity structure. Using recently published dispersion models, we invert surface wave group velocities for lithospheric structure, including lithospheric thickness, over much of the Eastern Hemisphere, encompassing Eurasia, Africa, and the Indian Ocean. Thicker lithosphere under Precambrian shields and platforms are clearly observed, not only under the large cratons (West Africa, Congo, Baltic, Russia, Siberia, India), but also under smaller blocks like the Tarim Basin and Yangtze craton. In contrast, it is found that remobilized Precambrian structures like the Saharan Shield and Sino-Korean Paraplatform do not have well-established lithospheric keels. The thinnest lithospheric thickness is found under oceanic and continental rifts, as well as along convergence zones. We compare our results to thermal models of continental lithosphere, lithospheric cooling models of oceanic lithosphere, lithosphere-asthenosphere boundary (LAB) estimates from S-wave receiver functions, and velocity variations of global tomography models. In addition to comparing results for the broad region, we examine in detail the regions of Central Africa, Siberia, and Tibet. While there are clear differences in the various estimates, overall the results are generally consistent. Inconsistencies between the estimates may be due to a variety of reasons including lateral and depth resolution differences and the comparison of what may be different lithospheric features.

  9. Evaluation of Aluminum Participation in the Development of Reactive Waves in Shock Compressed HMX

    SciTech Connect (OSTI)

    Pahl, R. J.; Trott, W. M.; Snedigar, S.; Castaneda, J. N.

    2006-07-28

    A series of gas gun tests has been performed to examine contributions to energy release from micron-sized and nanometric aluminum powder added to sieved (212-300{mu}m) HMX. In the absence of added metal, 4-mm-thick, low-density (64-68% of theoretical maximum density) pressings of the sieved HMX respond to modest shock loading by developing distinctive reactive waves that exhibit both temporal and mesoscale spatial fluctuations. Parallel tests have been performed on samples containing 10% (by mass) aluminum in two particle sizes: 2-{mu}m and 123-nm mean particle diameter, respectively. The finely dispersed aluminum initially suppresses wave growth from HMX reactions; however, after a visible induction period, the added metal drives rapid increases in the transmitted wave particle velocity. Wave profile variations as a function of the aluminum particle diameter are discussed.

  10. Evaluation of aluminum participation in the development of reactive waves in shock compressed HMX.

    SciTech Connect (OSTI)

    Castaneda, Jaime N.; Pahl, Robert J.; Snedigar, Shane; Trott, Wayne Merle

    2005-07-01

    A series of gas gun tests has been performed to examine contributions to energy release from micron-sized and nanometric aluminum powder added to sieved (212-300{micro}m) HMX. In the absence of added metal, 4-mm-thick, low-density (64-68% of theoretical maximum density) pressings of the sieved HMX respond to modest shock loading by developing distinctive reactive waves that exhibit both temporal and mesoscale spatial fluctuations. Parallel tests have been performed on samples containing 10% (by mass) aluminum in two particle sizes: 2-{micro}m and 123-nm mean particle diameter, respectively. The finely dispersed aluminum initially suppresses wave growth from HMX reactions; however, after a visible induction period, the added metal drives rapid increases in the transmitted wave particle velocity. Wave profile variations as a function of the aluminum particle diameter are discussed.

  11. Velocity pump reaction turbine

    DOE Patents [OSTI]

    House, P.A.

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  12. Velocity pump reaction turbine

    DOE Patents [OSTI]

    House, Palmer A.

    1982-01-01

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  13. Velocity pump reaction turbine

    DOE Patents [OSTI]

    House, Palmer A.

    1984-01-01

    An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

  14. Time-resolved particle velocity measurements at impact velocities of 10 km/s

    SciTech Connect (OSTI)

    Furnish, M.D.; Chhabildas, L.C.; Reinhart, W.D.

    1998-08-01

    Hypervelocity launch capabilities (9--16 km/s) with macroscopic plates have become available in recent years. It is now feasible to conduct instrumented plane-wave tests using this capability. Successfully conducting such tests requires a planar launch and impact at hypervelocities, appropriate triggering for recording systems, and time-resolved measurements of motion or stress at a particular point or set of points within the target or projectile during impact. The authors have conducted the first time-resolved wave-profile experiments using velocity interferometric techniques at impact velocities of 10 km/s. These measurements show that aluminum continues to exhibit normal release behavior to 161 GPa shock pressure, with complete loss of strength of the shocked state. These experiments have allowed a determination of shock-wave window transparency in conditions produced by a hypervelocity impact. In particular, lithium fluoride appears to lose transparency at a shock stress of 200 GPa; this appears to be the upper limit for conventional wave profile measurements using velocity interferometric techniques.

  15. ARM - Measurement - Hydrometeor fall velocity

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    velocity Fall velocity of hydrometeors (e.g. rain, snow, graupel, hail). Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the...

  16. MODELING SUPER-FAST MAGNETOSONIC WAVES OBSERVED BY SDO IN ACTIVE REGION FUNNELS

    SciTech Connect (OSTI)

    Ofman, L.; Liu, W.; Title, A.; Aschwanden, M.

    2011-10-20

    Recently, quasi-periodic, rapidly propagating waves have been observed in extreme ultraviolet by the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA) instrument in about 10 flare/coronal mass ejection (CME) events thus far. A typical example is the 2010 August 1 C3.2 flare/CME event that exhibited arc-shaped wave trains propagating in an active region (AR) magnetic funnel with {approx}5% intensity variations at speeds in the range of 1000-2000 km s{sup -1}. The fast temporal cadence and high sensitivity of AIA enabled the detection of these waves. We identify them as fast magnetosonic waves driven quasi-periodically at the base of the flaring region and develop a three-dimensional MHD model of the event. For the initial state we utilize the dipole magnetic field to model the AR and include gravitationally stratified density at coronal temperature. At the coronal base of the AR, we excite the fast magnetosonic wave by periodic velocity pulsations in the photospheric plane confined to a funnel of magnetic field lines. The excited fast magnetosonic waves have similar amplitude, wavelength, and propagation speeds as the observed wave trains. Based on the simulation results, we discuss the possible excitation mechanism of the waves, their dynamical properties, and the use of the observations for coronal MHD seismology.

  17. Propagation and dispersion of transverse wave trains in magnetic flux tubes

    SciTech Connect (OSTI)

    Oliver, R.; Terradas, J.; Ruderman, M. S.

    2014-07-01

    The dispersion of small-amplitude, impulsively excited wave trains propagating along a magnetic flux tube is investigated. The initial disturbance is a localized transverse displacement of the tube that excites a fast kink wave packet. The spatial and temporal evolution of the perturbed variables (density, plasma displacement, velocity, ...) is given by an analytical expression containing an integral that is computed numerically. We find that the dispersion of fast kink wave trains is more important for shorter initial disturbances (i.e., more concentrated in the longitudinal direction) and for larger density ratios (i.e., for larger contrasts of the tube density with respect to the environment density). This type of excitation generates a wave train whose signature at a fixed position along a coronal loop is a short event (duration ≅ 20 s) in which the velocity and density oscillate very rapidly with typical periods of the order of a few seconds. The oscillatory period is not constant but gradually declines during the course of this event. Peak values of the velocity are of the order of 10 km s{sup –1} and are accompanied by maximum density variations of the order of 10%-15% the unperturbed loop density.

  18. 10-ft Wave Flume Facility | Open Energy Information

    Open Energy Info (EERE)

    None Available Sensors Flow, Pressure Range(psi), Turbulence, Velocity, Wave Probe Data Generation Capability Real-Time No Test Services Test Services Yes Past Pertinent...

  19. DeFrees Large Wave Basin | Open Energy Information

    Open Energy Info (EERE)

    Current Velocity Range(ms) 0.0 Programmable Wavemaking Yes Wavemaking Description Computer controlled 4m hydraulic wave paddle stroke allows a series of solitary waves to be...

  20. Laboratory Measurements of Velocity and Attenuation in Sediments

    SciTech Connect (OSTI)

    Zimmer, M A; Berge, P A; Bonner, B P; Prasad, M

    2004-06-08

    Laboratory measurements are required to establish relationships between the physical properties of unconsolidated sediments and P- and S-wave propagation through them. Previous work has either focused on measurements of compressional wave properties at depths greater than 500 m for oil industry applications or on measurements of dynamic shear properties at pressures corresponding to depths of less than 50 m for geotechnical applications. Therefore, the effects of lithology, fluid saturation, and compaction on impedance and P- and S-wave velocities of shallow soils are largely unknown. We describe two state-of-the-art laboratory experiments. One setup allows us to measure ultrasonic P-wave velocities at very low pressures in unconsolidated sediments (up to 0.1 MPa). The other experiment allows P- and S-wave velocity measurements at low to medium pressures (up to 20 MPa). We summarize the main velocity and attenuation results on sands and sand - clay mixtures under partially saturated and fully saturated conditions in two ranges of pressures (0 - 0.1 MPa and 0.1 - 20 MPa) representative of the top few meters and the top 1 km, respectively. Under hydrostatic pressures of 0.1 to 20 MPa, our measurements demonstrate a P- and S-wave velocity-dependence in dry sands around a fourth root (0.23 -0.26) with the pressure dependence for S-waves being slightly lower. The P- velocity-dependence in wet sands lies around 0.4. The Vp-Vs and the Qp-Qs ratios together can be useful tools to distinguish between different lithologies and between pressure and saturation effects. These experimental velocities at the frequency of measurement (200 kHz) are slightly higher that Gassmann's static result. For low pressures under uniaxial stress, Vp and Vs were a few hundred meters per second with velocities showing a strong dependence on packing, clay content, and microstructure. We provide a typical shallow soil scenario in a clean sand environment and reconstruct the velocity profile of

  1. Wave merging mechanism: formation of low-frequency Alfven and magnetosonic waves in cosmic plasmas

    SciTech Connect (OSTI)

    Tishchenko, V N; Shaikhislamov, I F

    2014-02-28

    We investigate the merging mechanism for the waves produced by a pulsating cosmic plasma source. A model with a separate background/source description is used in our calculations. The mechanism was shown to operate both for strong and weak source background interactions. We revealed the effect of merging of individual Alfven waves into a narrow low-frequency wave, whose amplitude is maximal for a plasma expansion velocity equal to 0.5 1 of the Alfven Mach number. This wave is followed along the field by a narrow low-frequency magnetosonic wave, which contains the bulk of source energy. For low expansion velocities the wave contains background and source particles, but for high velocities it contains only the background particles. The wave lengths are much greater than their transverse dimension. (letters)

  2. GENERATION OF MAGNETOHYDRODYNAMIC WAVES IN LOW SOLAR ATMOSPHERIC FLUX TUBES BY PHOTOSPHERIC MOTIONS

    SciTech Connect (OSTI)

    Mumford, S. J.; Fedun, V.; Erdlyi, R.

    2015-01-20

    Recent ground- and space-based observations reveal the presence of small-scale motions between convection cells in the solar photosphere. In these regions, small-scale magnetic flux tubes are generated via the interaction of granulation motion and the background magnetic field. This paper studies the effects of these motions on magnetohydrodynamic (MHD) wave excitation from broadband photospheric drivers. Numerical experiments of linear MHD wave propagation in a magnetic flux tube embedded in a realistic gravitationally stratified solar atmosphere between the photosphere and the low choromosphere (above ? = 1) are performed. Horizontal and vertical velocity field drivers mimic granular buffeting and solar global oscillations. A uniform torsional driver as well as Archimedean and logarithmic spiral drivers mimic observed torsional motions in the solar photosphere. The results are analyzed using a novel method for extracting the parallel, perpendicular, and azimuthal components of the perturbations, which caters to both the linear and non-linear cases. Employing this method yields the identification of the wave modes excited in the numerical simulations and enables a comparison of excited modes via velocity perturbations and wave energy flux. The wave energy flux distribution is calculated to enable the quantification of the relative strengths of excited modes. The torsional drivers primarily excite Alfvn modes (?60% of the total flux) with small contributions from the slow kink mode, and, for the logarithmic spiral driver, small amounts of slow sausage mode. The horizontal and vertical drivers primarily excite slow kink or fast sausage modes, respectively, with small variations dependent upon flux surface radius.

  3. Discrimination of porosity and fluid saturation using seismic velocity analysis

    DOE Patents [OSTI]

    Berryman, James G.

    2001-01-01

    The method of the invention is employed for determining the state of saturation in a subterranean formation using only seismic velocity measurements (e.g., shear and compressional wave velocity data). Seismic velocity data collected from a region of the formation of like solid material properties can provide relatively accurate partial saturation data derived from a well-defined triangle plotted in a (.rho./.mu., .lambda./.mu.)-plane. When the seismic velocity data are collected over a large region of a formation having both like and unlike materials, the method first distinguishes the like materials by initially plotting the seismic velocity data in a (.rho./.lambda., .mu./.lambda.)-plane to determine regions of the formation having like solid material properties and porosity.

  4. White light velocity interferometer

    DOE Patents [OSTI]

    Erskine, D.J.

    1997-06-24

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

  5. White light velocity interferometer

    DOE Patents [OSTI]

    Erskine, David J.

    1997-01-01

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

  6. White light velocity interferometer

    DOE Patents [OSTI]

    Erskine, David J.

    1999-01-01

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

  7. White light velocity interferometer

    DOE Patents [OSTI]

    Erskine, D.J.

    1999-06-08

    The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

  8. Unitaxial constant velocity microactuator

    DOE Patents [OSTI]

    McIntyre, T.J.

    1994-06-07

    A uniaxial drive system or microactuator capable of operating in an ultra-high vacuum environment is disclosed. The mechanism includes a flexible coupling having a bore therethrough, and two clamp/pusher assemblies mounted in axial ends of the coupling. The clamp/pusher assemblies are energized by voltage-operated piezoelectrics therewithin to operatively engage the shaft and coupling causing the shaft to move along its rotational axis through the bore. The microactuator is capable of repeatably positioning to sub-nanometer accuracy while affording a scan range in excess of 5 centimeters. Moreover, the microactuator generates smooth, constant velocity motion profiles while producing a drive thrust of greater than 10 pounds. The system is remotely controlled and piezoelectrically driven, hence minimal thermal loading, vibrational excitation, or outgassing is introduced to the operating environment. 10 figs.

  9. Unitaxial constant velocity microactuator

    DOE Patents [OSTI]

    McIntyre, Timothy J.

    1994-01-01

    A uniaxial drive system or microactuator capable of operating in an ultra-high vacuum environment. The mechanism includes a flexible coupling having a bore therethrough, and two clamp/pusher assemblies mounted in axial ends of the coupling. The clamp/pusher assemblies are energized by voltage-operated piezoelectrics therewithin to operatively engage the shaft and coupling causing the shaft to move along its rotational axis through the bore. The microactuator is capable of repeatably positioning to sub-manometer accuracy while affording a scan range in excess of 5 centimeters. Moreover, the microactuator generates smooth, constant velocity motion profiles while producing a drive thrust of greater than 10 pounds. The system is remotely controlled and piezoelectrically driven, hence minimal thermal loading, vibrational excitation, or outgassing is introduced to the operating environment.

  10. Seismicity and Improved Velocity Structure in Kuwait

    SciTech Connect (OSTI)

    Gok, R M; Rodgers, A J; Al-Enezi, A

    2006-01-26

    The Kuwait National Seismic Network (KNSN) began operation in 1997 and consists of nine three-component stations (eight short-period and one broadband) and is operated by the Kuwait Institute for Scientific Research. Although the region is largely believed to be aseismic, considerable local seismicity is recorded by KNSN. Seismic events in Kuwait are clustered in two main groups, one in the south and another in the north. The KNSN station distribution is able to capture the southern cluster within the footprint of the network but the northern cluster is poorly covered. Events tend to occur at depths ranging from the free surface to about 20 km. Events in the northern cluster tend to be deeper than those in south, however this might be an artifact of the station coverage. We analyzed KNSN recordings of nearly 200 local events to improve understanding of seismic events and crustal structure in Kuwait, performing several analyses with increasing complexity. First, we obtained an optimized one-dimensional (1D) velocity model for the entire region using the reported KNSN arrival times and routine locations. The resulting model is consistent with a recently obtained model from the joint inversion of receiver functions and surface wave group velocities. Crustal structure is capped by the thick ({approx} 7 km) sedimentary rocks of the Arabian Platform underlain by normal velocities for stable continental crust. Our new model has a crustal thickness of 44 km, constrained by an independent study of receiver functions and surface wave group velocities by Pasyanos et al (2006). Locations and depths of events after relocation with the new model are broadly consistent with those reported by KISR, although a few events move more than a few kilometers. We then used a double-difference tomography technique (tomoDD) to jointly locate the events and estimate three-dimensional (3D) velocity structure. TomoDD is based on hypoDD relocation algorithm and it makes use of both absolute and

  11. Hydrokinetic canal measurements: inflow velocity, wake flow velocity, and turbulence

    SciTech Connect (OSTI)

    Gunawan, Budi

    2014-06-11

    The dataset consist of acoustic Doppler current profiler (ADCP) velocity measurements in the wake of a 3-meter diameter vertical-axis hydrokinetic turbine deployed in Roza Canal, Yakima, WA, USA. A normalized hub-centerline wake velocity profile and two cross-section velocity contours, 10 meters and 20 meters downstream of the turbine, are presented. Mean velocities and turbulence data, measured using acoustic Doppler velocimeter (ADV) at 50 meters upstream of the turbine, are also presented. Canal dimensions and hydraulic properties, and turbine-related information are also included.

  12. Crust and Upper Mantle P Wave Velocity Structure Beneath Valles...

    Open Energy Info (EERE)

    by mantle-derived melts has occurred. Authors Lee K. Steck, Clifford H. Thurber, Michael C. Fehler, William J. Lutter, Peter M. Roberts, W. Scott Baldridge, Darrik G....

  13. MAGNETIC METHOD FOR PRODUCING HIGH VELOCITY SHOCK WAVES IN GASES

    DOE Patents [OSTI]

    Josephson, V.

    1960-01-26

    A device is described for producing high-energy plasmas comprising a tapered shock tube of dielectric material and having a closed small end, an exceedingly low-inductance coll supported about and axially aligned with the small end of the tapered tube. an elongated multiturn coil supported upon the remninder of the exterior wall of the shock tube. a potential source and switch connected in series with the low-inductance coil, a potential source and switch connected in series with the elongated coil, means for hermetically sealing the large end of the tube, means for purging the tube of gases, and means for admitting a selected gas into the shock tube.

  14. APPARATUS FOR PRODUCING HIGH VELOCITY SHOCK WAVES IN GASES

    DOE Patents [OSTI]

    Scott, F.R.; Josephson, V.

    1960-02-01

    >A device for producing a high-energy ionized gas region comprises an evacuated tapered insulating vessel and a substantially hemispherical insulating cap hermetically affixed to the large end of the vessel, an annular electrode having a diameter equal to and supported in the interior wall of the vessel at the large end and having a conductive portion inside the vessel, a second electrode supported at the small end of the vessel, means connected to the vessel for introducing a selected gas therein, a source of high potential having two poles. means for connecting one pole of the high potential source to the annular electrode, and means for connecting the other pole of the potential source to the second electrode.

  15. Comparison of Hydrocode Simulations with Measured Shock Wave Velocities

    SciTech Connect (OSTI)

    Hixson, R. S.; Veeser, L. R.

    2014-11-30

    We have conducted detailed 1- and 2-dimensional hydrodynamics calculations to assess the quality of simulations commonly made to understand various shock processes in a sample and to design shock experiments. We began with relatively simple shock experiments, where we examined the effects of the equation of state and the viscoplastic strength models. Eventually we included spallation in copper and iron and a solid-solid phase transformation in iron to assess the quality of the damage and phase transformation simulations.

  16. Viscoacoustic wave form inversion of transmission data for velocity...

    Office of Scientific and Technical Information (OSTI)

    and attenuation. An efficient frequency domain implementation is applied that consists of performing a series of single frequency inversions sweeping from low to high frequency. ...

  17. Conversion of borehole Stoneley waves to channel waves in coal

    SciTech Connect (OSTI)

    Johnson, P.A.; Albright, J.N.

    1987-01-01

    Evidence for the mode conversion of borehole Stoneley waves to stratigraphically guided channel waves was discovered in data from a crosswell acoustic experiment conducted between wells penetrating thin coal strata located near Rifle, Colorado. Traveltime moveout observations show that borehole Stoneley waves, excited by a transmitter positioned at substantial distances in one well above and below a coal stratum at 2025 m depth, underwent partial conversion to a channel wave propagating away from the well through the coal. In an adjacent well the channel wave was detected at receiver locations within the coal, and borehole Stoneley waves, arising from a second partial conversion of channel waves, were detected at locations above and below the coal. The observed channel wave is inferred to be the third-higher Rayleigh mode based on comparison of the measured group velocity with theoretically derived dispersion curves. The identification of the mode conversion between borehole and stratigraphically guided waves is significant because coal penetrated by multiple wells may be detected without placing an acoustic transmitter or receiver within the waveguide. 13 refs., 6 figs., 1 tab.

  18. GMTI radar minimum detectable velocity.

    SciTech Connect (OSTI)

    Richards, John Alfred

    2011-04-01

    Minimum detectable velocity (MDV) is a fundamental consideration for the design, implementation, and exploitation of ground moving-target indication (GMTI) radar imaging modes. All single-phase-center air-to-ground radars are characterized by an MDV, or a minimum radial velocity below which motion of a discrete nonstationary target is indistinguishable from the relative motion between the platform and the ground. Targets with radial velocities less than MDV are typically overwhelmed by endoclutter ground returns, and are thus not generally detectable. Targets with radial velocities greater than MDV typically produce distinct returns falling outside of the endoclutter ground returns, and are thus generally discernible using straightforward detection algorithms. This document provides a straightforward derivation of MDV for an air-to-ground single-phase-center GMTI radar operating in an arbitrary geometry.

  19. MACCS2/Deposition Velocity Workshop

    Office of Energy Efficiency and Renewable Energy (EERE)

    The Department of Energy’s Chief of Nuclear Safety hosted a MACCS2/Deposition Velocity Workshop on June 5-6, 2012, in Germantown, Maryland. Approximately 70 participants attended. The purpose of...

  20. DIFFERENTIAL GROUP-VELOCITY DETECTION OF FLUID PATHS

    SciTech Connect (OSTI)

    Leland Timothy Long

    2005-12-20

    For nearly 50 years, surface waves that propagate through near-surface soils have been utilized in engineering for the determination of the small-strain dynamic properties of soils. These techniques, although useful, have not been sufficiently precise to use in detecting the subtle changes in soil properties that accompany short-term changes in fluid content. The differential techniques developed in this research now make it possible to monitor small changes (less than 3 cm) in the water level of shallow soil aquifers. Using inversion techniques and tomography, differential seismic techniques could track the water level distribution in aquifers with water being pumped in or out. Differential surface wave analysis could lead to new ways to monitor reservoir levels and verify hydrologic models. Field data obtained during this investigation have measured changes in surface-wave phase and group velocity before and after major rain events, and have detected subtle changes associated with pumping water into an aquifer and pumping water out of an aquifer. This research has established analysis techniques for observing these changes. These techniques combine time domain measurements to isolate surface wave arrivals with frequency domain techniques to determine the effects as a function of frequency. Understanding the differences in response as a function of wave frequency facilitates the inversion of this data for soil velocity structure. These techniques have also quantified many aspects of data acquisition and analysis that are important for significant results. These include tight control on the character of the source and proper placement of the geophones. One important application is the possibility that surface waves could be used to monitor and/or track fluid movement during clean-up operations, verifying that the fluid reached all affected areas. Extending this to a larger scale could facilitate monitoring of water resources in basins without having to drill many

  1. Modeling fault-zone guided waves of microearthquakes in a geothermal...

    Open Energy Info (EERE)

    velocity structure have been estimated. It is suggested here that the identification and modeling of such guided waves is an effective tool to locate fracture-induced,...

  2. FIRST SIMULTANEOUS OBSERVATION OF AN H{alpha} MORETON WAVE, EUV WAVE, AND FILAMENT/PROMINENCE OSCILLATIONS

    SciTech Connect (OSTI)

    Asai, Ayumi; Isobe, Hiroaki; Ishii, Takako T.; Kitai, Reizaburo; Ichimoto, Kiyoshi; UeNo, Satoru; Nagata, Shin'ichi; Morita, Satoshi; Nishida, Keisuke; Shibata, Kazunari; Shiota, Daikou; Oi, Akihito; Akioka, Maki

    2012-02-15

    We report on the first simultaneous observation of an H{alpha} Moreton wave, the corresponding EUV fast coronal waves, and a slow and bright EUV wave (typical EIT wave). We observed a Moreton wave, associated with an X6.9 flare that occurred on 2011 August 9 at the active region NOAA 11263, in the H{alpha} images taken by the Solar Magnetic Activity Research Telescope at Hida Observatory of Kyoto University. In the EUV images obtained by the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory we found not only the corresponding EUV fast 'bright' coronal wave, but also the EUV fast 'faint' wave that is not associated with the H{alpha} Moreton wave. We also found a slow EUV wave, which corresponds to a typical EIT wave. Furthermore, we observed, for the first time, the oscillations of a prominence and a filament, simultaneously, both in the H{alpha} and EUV images. To trigger the oscillations by the flare-associated coronal disturbance, we expect a coronal wave as fast as the fast-mode MHD wave with the velocity of about 570-800 km s{sup -1}. These velocities are consistent with those of the observed Moreton wave and the EUV fast coronal wave.

  3. Wave-function functionals

    SciTech Connect (OSTI)

    Pan Xiaoyin; Slamet, Marlina; Sahni, Viraht

    2010-04-15

    We extend our prior work on the construction of variational wave functions {psi} that are functionals of functions {chi}:{psi}={psi}[{chi}] rather than simply being functions. In this manner, the space of variations is expanded over those of traditional variational wave functions. In this article we perform the constrained search over the functions {chi} chosen such that the functional {psi}[{chi}] satisfies simultaneously the constraints of normalization and the exact expectation value of an arbitrary single- or two-particle Hermitian operator, while also leading to a rigorous upper bound to the energy. As such the wave function functional is accurate not only in the region of space in which the principal contributions to the energy arise but also in the other region of the space represented by the Hermitian operator. To demonstrate the efficacy of these ideas, we apply such a constrained search to the ground state of the negative ion of atomic hydrogen H{sup -}, the helium atom He, and its positive ions Li{sup +} and Be{sup 2+}. The operators W whose expectations are obtained exactly are the sum of the single-particle operators W={Sigma}{sub i}r{sub i}{sup n},n=-2,-1,1,2, W={Sigma}{sub i{delta}}(r{sub i}), W=-(1/2){Sigma}{sub i{nabla}i}{sup 2}, and the two-particle operators W={Sigma}{sub n}u{sup n},n=-2,-1,1,2, where u=|r{sub i}-r{sub j}|. Comparisons with the method of Lagrangian multipliers and of other constructions of wave-function functionals are made. Finally, we present further insights into the construction of wave-function functionals by studying a previously proposed construction of functionals {psi}[{chi}] that lead to the exact expectation of arbitrary Hermitian operators. We discover that analogous to the solutions of the Schroedinger equation, there exist {psi}[{chi}] that are unphysical in that they lead to singular values for the expectations. We also explain the origin of the singularity.

  4. Slow Neutron Velocity Spectrometer Transmission Studies Of Pu

    DOE R&D Accomplishments [OSTI]

    Havens, W. W. Jr.; Melkonian, E.; Rainwater, L. J.; Levin, M.

    1951-05-28

    The slow neutron transmission of several samples of Pu has been investigated with the Columbia Neutron Velocity Spectrometer. Data are presented in two groups, those covering the energy region from 0 to 6 ev, and those covering the region above 6 ev. Below 6 ev the resolution was relatively good, and a detailed study of the cross section variation was made. Work above 6 ev consisted of merely locating levels and obtaining a rough idea of their strengths.

  5. Visualization of Shock Wave Driven by Millimeter Wave Plasma in a Parabolic Thruster

    SciTech Connect (OSTI)

    Yamaguchi, Toshikazu; Shimada, Yutaka; Shiraishi, Yuya; Shibata, Teppei; Komurasaki, Kimiya; Oda, Yasuhisa; Kajiwara, Ken; Takahashi, Koji; Kasugai, Atsushi; Sakamoto, Keishi; Arakawa, Yoshihiro

    2010-05-06

    By focusing a high-power millimeter wave beam generated by a 170 GHz gyrotron, a breakdown occurred and a shock wave was driven by plasma heated by following microwave energy. The shock wave and the plasma around a focal point of a parabolic thruster were visualized by a shadowgraph method, and a transition of structures between the shock wave and the plasma was observed. There was a threshold local power density to make the transition, and the propagation velocity at the transition was around 800 m/s.

  6. Wave transmission over submerged breakwaters

    SciTech Connect (OSTI)

    Kobayashi, N.; Wurjanto, A. )

    1989-09-01

    Monochromatic wave reflection and transmission over a submerged impermeable breakwater is predicted numerically by slightly modifying the numerical model developed previously for predicting wave reflection and run-up on rough or smooth impermeable slopes. The slight modification is related to the landward boundary condition required for the transmitted wave propagating landward. In addition to the conservation equations of mass and momentum used to compute the flow field, an equation of energy is derived to estimate the rate of energy dissipation due to wave breaking. The computed reflection and transmission coefficients are shown to be in agreement with available small-scale test data. The numerical model also predicts the spatial variation of the energy dissipation, the mean water level difference, and the time-averaged volume flux per unit width, although available measurements are not sufficient for evaluating the capabilities and limitations of the numerical model for predicting these quantities.

  7. Three axis velocity probe system

    DOE Patents [OSTI]

    Fasching, George E.; Smith, Jr., Nelson S.; Utt, Carroll E.

    1992-01-01

    A three-axis velocity probe system for determining three-axis positional velocities of small particles in fluidized bed systems and similar applications. This system has a sensor head containing four closely-spaced sensing electrodes of small wires that have flat ends to establish a two axis plane, e.g. a X-Y plane. Two of the sensing electrodes are positioned along one of the axes and the other two are along the second axis. These four sensing electrodes are surrounded by a guard electrode, and the outer surface is a ground electrode and support member for the sensing head. The electrodes are excited by, for example, sinusoidal voltage having a peak-to-peak voltage of up to 500 volts at a frequency of 2 MHz. Capacitive currents flowing between the four sensing electrodes and the ground electrode are influenced by the presence and position of a particle passing the sensing head. Any changes in these currents due to the particle are amplified and synchronously detected to produce positional signal values that are converted to digital form. Using these digital forms and two values of time permit generation of values of the three components of the particle vector and thus the total velocity vector.

  8. Investigation of Wave Energy Converter Effects on Near-shore Wave Fields: Model Generation Validation and Evaluation - Kaneohe Bay HI.

    SciTech Connect (OSTI)

    Roberts, Jesse D.; Chang, Grace; Jones, Craig

    2014-09-01

    The numerical model, SWAN (Simulating WAves Nearshore) , was used to simulate wave conditions in Kaneohe Bay, HI in order to determine the effects of wave energy converter ( WEC ) devices on the propagation of waves into shore. A nested SWAN model was validated then used to evaluate a range of initial wave conditions: significant wave heights (H s ) , peak periods (T p ) , and mean wave directions ( MWD) . Differences between wave height s in the presence and absence of WEC device s were assessed at locations in shore of the WEC array. The maximum decrease in wave height due to the WEC s was predicted to be approximately 6% at 5 m and 10 m water depths. Th is occurred for model initiation parameters of H s = 3 m (for 5 m water depth) or 4 m (10 m water depth) , T p = 10 s, and MWD = 330deg . Subsequently, bottom orbital velocities were found to decrease by about 6%.

  9. Seismic Velocities Contain Information About Depth, Lithology, Fluid Content, and Microstructure

    SciTech Connect (OSTI)

    Berge, P A; Bonner, B P

    2002-01-03

    Recent advances in field and laboratory methods for measuring elastic wave velocities provide incentive and opportunity for improving interpretation of geophysical data for engineering and environmental applications. Advancing the state-of-the-art of seismic imaging requires developing petrophysical relationships between measured velocities and the hydrogeology parameters and lithology. Our approach uses laboratory data and rock physics methods. Compressional (Vp) and shear (Vs) wave velocities, Vp/Vs ratios, and relative wave amplitudes show systematic changes related to composition, saturation, applied stress (analogous to depth), and distribution of clay for laboratory ultrasonic measurements on soils. The artificial soils were mixtures of Ottawa sand and a second phase, either Wyoming bentonite or peat moss used to represent clay or organic components found in natural soils. Compressional and shear wave velocities were measured for dry, saturated, and partially-saturated conditions, for applied stresses between about 7 and 100 kPa, representing approximately the top 5 m of the subsurface. Analysis of the results using rock physics methods shows the link between microstructure and wave propagation, and implications for future advances in seismic data interpretation. For example, we found that Vp in dry sand-clay mixtures initially increases as clay cements the sand grains and fills porosity, but then Vp decreases when the clay content is high enough that the clay matrix controls the elastic response of the material. Vs decreases monotonically with increasing clay content. This provides a method for using Vp/Vs ratios to estimate clay content in a dry soil.

  10. Method of accelerating photons by a relativistic plasma wave

    DOE Patents [OSTI]

    Dawson, John M.; Wilks, Scott C.

    1990-01-01

    Photons of a laser pulse have their group velocity accelerated in a plasma as they are placed on a downward density gradient of a plasma wave of which the phase velocity nearly matches the group velocity of the photons. This acceleration results in a frequency upshift. If the unperturbed plasma has a slight density gradient in the direction of propagation, the photon frequencies can be continuously upshifted to significantly greater values.

  11. Detonation waves in pentaerythritol tetranitrate

    SciTech Connect (OSTI)

    Tarver, C.M.; Breithaupt, R.D.; Kury, J.W.

    1997-06-01

    Fabry{endash}Perot laser interferometry was used to obtain nanosecond time resolved particle velocity histories of the free surfaces of tantalum discs accelerated by detonating pentaerythritol tetranitrate (PETN) charges and of the interfaces between PETN detonation products and lithium fluoride crystals. The experimental records were compared to particle velocity histories calculated using very finely zoned meshes of the exact dimensions with the DYNA2D hydrodynamic code. The duration of the PETN detonation reaction zone was demonstrated to be less than the 5 ns initial resolution of the Fabry{endash}Perot technique, because the experimental records were accurately calculated using an instantaneous chemical reaction, the Chapman{endash}Jouguet (C-J) model of detonation, and the reaction product Jones{endash}Wilkins{endash}Lee (JWL) equation of state for PETN detonation products previously determined by supracompression (overdriven detonation) studies. Some of the PETN charges were pressed to densities approaching the crystal density and exhibited the phenomenon of superdetonation. An ignition and growth Zeldovich{endash}von Neumann{endash}Doring (ZND) reactive flow model was developed to explain these experimental records and the results of previous PETN shock initiation experiments on single crystals of PETN. Good agreement was obtained for the induction time delays preceding chemical reaction, the run distances at which the initial shock waves were overtaken by the detonation waves in the compressed PETN, and the measured particle velocity histories produced by the overdriven detonation waves before they could relax to steady state C-J velocity and pressure. {copyright} {ital 1997 American Institute of Physics.}

  12. STARSPOT-INDUCED OPTICAL AND INFRARED RADIAL VELOCITY VARIABILITY IN T TAURI STAR HUBBLE I 4

    SciTech Connect (OSTI)

    Mahmud, Naved I.; Johns-Krull, Christopher M.; Hartigan, Patrick M.; Crockett, Christopher J.; Prato, L.; Jaffe, Daniel T.; Beichman, Charles A. E-mail: cmj@rice.edu E-mail: crockett@lowell.edu E-mail: dtj@astro.as.utexas.edu

    2011-08-01

    We report optical ({approx}6150 A) and K-band (2.3 {mu}m) radial velocities obtained over two years for the pre-main-sequence weak-lined T Tauri star Hubble I 4. We detect periodic and near-sinusoidal radial velocity variations at both wavelengths, with a semi-amplitude of 1395 {+-} 94 m s{sup -1} in the optical and 365 {+-} 80 m s{sup -1} in the infrared. The lower velocity amplitude at the longer wavelength, combined with bisector analysis and spot modeling, indicates that there are large, cool spots on the stellar surface that are causing the radial velocity modulation. The radial velocities maintain phase coherence over hundreds of days suggesting that the starspots are long-lived. This is one of the first active stars where the spot-induced velocity modulation has been resolved in the infrared.

  13. Measuring In-Situ Mdf Velocity Of Detonation

    DOE Patents [OSTI]

    Horine, Frank M.; James, Jr., Forrest B.

    2005-10-25

    A system for determining the velocity of detonation of a mild detonation fuse mounted on the surface of a device includes placing the device in a predetermined position with respect to an apparatus that carries a couple of sensors that sense the passage of a detonation wave at first and second spaced locations along the fuse. The sensors operate a timer and the time and distance between the locations is used to determine the velocity of detonation. The sensors are preferably electrical contacts that are held spaced from but close to the fuse such that expansion of the fuse caused by detonation causes the fuse to touch the contact, causing an electrical signal to actuate the timer.

  14. Predicting stress-induced velocity anisotropy in rocks

    SciTech Connect (OSTI)

    Mavko, G.; Mukerji, T.; Godfrey, N.

    1995-07-01

    A simple transformation, using measured isotropic V{sub P} and V{sub S} versus hydrostatic pressure, is presented for predicting stress-induced seismic velocity anisotropy in rocks. The compliant, crack-like portions of the pore space are characterized by generalized compressional and shear compliances that are estimated form the isotropic V{sub P} and V{sub S}. The physical assumption that the compliant porosity is crack-like means that the pressure dependence of the generalized compliances is governed primarily by normal tractions resolved across cracks and defects. This allows the measured pressure dependence to be mapped form the hydrostatic stress state to any applied nonhydrostatic stress. Predicted P- and S-wave velocities agree reasonably well with uniaxial stress data for Barre Granite and Massillon Sandstone. While it is mechanically similar to methods based on idealized ellipsoidal cracks, the approach is relatively independent of any assumed crack geometry and is not limited to small crack densities.

  15. PRECISION RADIAL VELOCITIES WITH CSHELL

    SciTech Connect (OSTI)

    Crockett, Christopher J.; Prato, L.; Mahmud, Naved I.; Johns-Krull, Christopher M.; Jaffe, Daniel T.; Beichman, Charles A. E-mail: lprato@lowell.edu E-mail: cmj@rice.edu

    2011-07-10

    Radial velocity (RV) identification of extrasolar planets has historically been dominated by optical surveys. Interest in expanding exoplanet searches to M dwarfs and young stars, however, has motivated a push to improve the precision of near-infrared RV techniques. We present our methodology for achieving 58 m s{sup -1} precision in the K band on the M0 dwarf GJ 281 using the CSHELL spectrograph at the 3 m NASA Infrared Telescope Facility. We also demonstrate our ability to recover the known 4 M{sub JUP} exoplanet Gl 86 b and discuss the implications for success in detecting planets around 1-3 Myr old T Tauri stars.

  16. Newberry EGS Seismic Velocity Model

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Templeton, Dennise

    2013-10-01

    We use ambient noise correlation (ANC) to create a detailed image of the subsurface seismic velocity at the Newberry EGS site down to 5 km. We collected continuous data for the 22 stations in the Newberry network, together with 12 additional stations from the nearby CC, UO and UW networks. The data were instrument corrected, whitened and converted to single bit traces before cross correlation according to the methodology in Benson (2007). There are 231 unique paths connecting the 22 stations of the Newberry network. The additional networks extended that to 402 unique paths crossing beneath the Newberry site.

  17. Self-Consistent Full-Wave/Fokker-Planck Calculations for Ion Cyclotron Heating in Non-Maxwellian Plasmas

    SciTech Connect (OSTI)

    Jaeger, E.F.; Berry, L.A.; Batchelor, D.B.; Carter, M.D.; D'Azevedo, E.; Harvey, R.W.; Myra, J.R.; D'Ippolito, D.A.; Dumont, R.J.; Smithe, D.N.; Bonoli, P.T.; Wright, J.C.

    2005-09-26

    Self-consistent solutions for the wave electric field and particle distribution function are calculated for ion cyclotron heating in non-Maxwellian plasmas. The all-orders wave solver AORSA is generalized to treat non-thermal velocity distributions arising from fusion reactions, neutral beam injection, and wave driven diffusion in velocity space. Quasi-linear diffusion coefficients are derived directly from the wave electric fields and used to calculate velocity distribution functions with the CQL3D Fokker-Planck code. Self-consistent results are obtained by iterating the full-wave and Fokker-Planck solutions.

  18. ocean waves

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    waves - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced Nuclear Energy Nuclear

  19. VELOCITY INDICATOR FOR EXTRUSION PRESS

    DOE Patents [OSTI]

    Digney, F.J. Jr.; Bevilacqua, F.

    1959-04-01

    An indicator is presented for measuring the lowspeed velocity of an object in one direction where the object returns in the opposite direction at a high speed. The indicator comprises a drum having its axis of rotation transverse to the linear movement of the object and a tape wound upon the drum with its free end extending therefrom and adapted to be connected to the object. A constant torque is applied to the drum in a direction to wind the tape on the drum. The speed of the tape in the unwinding direction is indicated on a tachometer which is coupled through a shaft and clutch means to the drum only when the tape is unwinding.

  20. Investigation of microscale shock phenomena using a line-imaging optically recording velocity interferometer system

    SciTech Connect (OSTI)

    Trott, Wayne M.; Asay, James R.

    1998-07-10

    An optically recording velocity interferometer system (ORVIS) can be operated in a line-imaging configuration that effectively combines subnanosecond temporal resolution with high spatial resolution (length scales<10 {mu}m). This technique easily captures very small temporal variations in the onset of motion across the face of a small-scale (400-{mu}m diameter) laser-driven flyer. In another application, line-imaging ORVIS has been used to obtain spatially resolved particle velocity vs. time information at flyer impact on a lithium fluoride witness plate. Subnanosecond differences in flyer arrival time are clearly resolved and the results also show subtle amplitude variations in the pulse delivered at different locations of the acceptor. Observed velocity field variations in laser acceleration of a patterned flyer target demonstrate the feasibility of using line ORVIS in studies of instability formation and growth. These results indicate that this diagnostic can be applied to a wide variety of shock phenomena.

  1. Tangential velocity measurement using interferometric MTI radar

    DOE Patents [OSTI]

    Doerry, Armin W.; Mileshosky, Brian P.; Bickel, Douglas L.

    2006-01-03

    Radar systems use time delay measurements between a transmitted signal and its echo to calculate range to a target. Ranges that change with time cause a Doppler offset in phase and frequency of the echo. Consequently, the closing velocity between target and radar can be measured by measuring the Doppler offset of the echo. The closing velocity is also known as radial velocity, or line-of-sight velocity. Doppler frequency is measured in a pulse-Doppler radar as a linear phase shift over a set of radar pulses during some Coherent Processing Interval (CPI). An Interferometric Moving Target Indicator (MTI) radar can be used to measure the tangential velocity component of a moving target. Multiple baselines, along with the conventional radial velocity measurement, allow estimating the true 3-D velocity of a target.

  2. EXPERIMENTAL STUDY OF SHOCK WAVE DYNAMICS IN MAGNETIZED PLASMAS

    SciTech Connect (OSTI)

    Nirmol K. Podder

    2009-03-17

    In this four-year project (including one-year extension), the project director and his research team built a shock-wave-plasma apparatus to study shock wave dynamics in glow discharge plasmas in nitrogen and argon at medium pressure (1–20 Torr), carried out various plasma and shock diagnostics and measurements that lead to increased understanding of the shock wave acceleration phenomena in plasmas. The measurements clearly show that in the steady-state dc glow discharge plasma, at fixed gas pressure the shock wave velocity increases, its amplitude decreases, and the shock wave disperses non-linearly as a function of the plasma current. In the pulsed discharge plasma, at fixed gas pressure the shock wave dispersion width and velocity increase as a function of the delay between the switch-on of the plasma and shock-launch. In the afterglow plasma, at fixed gas pressure the shock wave dispersion width and velocity decrease as a function of the delay between the plasma switch-off and shock-launch. These changes are found to be opposite and reversing towards the room temperature value which is the initial condition for plasma ignition case. The observed shock wave properties in both igniting and afterglow plasmas correlate well with the inferred temperature changes in the two plasmas.

  3. VELOCITY SELECTOR METHOD FOR THE SEPARATION OF ISOTOPES

    DOE Patents [OSTI]

    Britten, R.J.

    1957-12-31

    A velocity selector apparatus is described for separating and collecting an enriched fraction of the isotope of a particular element. The invention has the advantage over conventional mass spectrometers in that a magnetic field is not used, doing away with the attendant problems of magnetic field variation. The apparatus separates the isotopes by selectively accelerating the ionized constituents present in a beam of the polyisotopic substance that are of uniform kinetic energy, the acceleration being applied intermittently and at spaced points along the beam and in a direction normal to the direction of the propagation of the uniform energy beam whereby a transverse displacement of the isotopic constituents of different mass is obtained.

  4. OBSERVATIONS OF THE INTERACTION OF ACOUSTIC WAVES AND SMALL-SCALE MAGNETIC FIELDS IN A QUIET SUN

    SciTech Connect (OSTI)

    Chitta, Lakshmi Pradeep; Kariyappa, R.; Jain, Rekha; Jefferies, Stuart M. E-mail: rkari@iiap.res.in E-mail: stuartj@ifa.hawaii.edu

    2012-01-10

    The effect of the magnetic field on photospheric intensity and velocity oscillations at the sites of small-scale magnetic fields (SMFs) in a quiet Sun near the solar disk center is studied. We use observations made by the G-band filter in the Solar Optical Telescope on board Hinode for intensity oscillations; Doppler velocity, magnetic field, and continuum intensity are derived from an Ni I photospheric absorption line at 6767.8 A using the Michelson Doppler Imager on board the Solar and Heliospheric Observatory. Our analysis shows that both the high-resolution intensity observed in the G band and velocity oscillations are influenced by the presence of a magnetic field. While intensity oscillations are suppressed at all frequencies in strong magnetic field regions compared to weak magnetic field regions, velocity oscillations show an enhancement of power in the frequency band 5.5-7 mHz. We find that there is a drop of 20%-30% in the p-mode power of velocity oscillations within the SMFs when compared to the regions surrounding them. Our findings indicate that the nature of the interaction of acoustic waves with the quiet Sun SMFs is similar to that of large-scale magnetic fields in active regions. We also report the first results of the center-to-limb variation of such effects using the observations of the quiet Sun from the Helioseismic and Magnetic Imager (HMI) aboard the Solar Dynamics Observatory (SDO). The independent verification of these interactions using SDO/HMI suggests that the velocity power drop of 20%-30% in p-modes is fairly constant across the solar disk.

  5. Numerical modeling of the effects of wave energy converter characteristics on nearshore wave conditions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chang, G.; Ruehl, K.; Jones, C. A.; Roberts, J.; Chartrand, C.

    2015-12-24

    Modeled nearshore wave propagation was investigated downstream of simulated wave energy converters (WECs) to evaluate overall near- and far-field effects of WEC arrays. Model sensitivity to WEC characteristics and WEC array deployment scenarios was evaluated using a modified version of an industry standard wave model, Simulating WAves Nearshore (SWAN), which allows the incorporation of device-specific WEC characteristics to specify obstacle transmission. The sensitivity study illustrated that WEC device type and subsequently its size directly resulted in wave height variations in the lee of the WEC array. Wave heights decreased up to 30% between modeled scenarios with and without WECs formore » large arrays (100 devices) of relatively sizable devices (26 m in diameter) with peak power generation near to the modeled incident wave height. Other WEC types resulted in less than 15% differences in modeled wave height with and without WECs, with lesser influence for WECs less than 10 m in diameter. Wave directions and periods were largely insensitive to changes in parameters. Furthermore, additional model parameterization and analysis are required to fully explore the model sensitivity of peak wave period and mean wave direction to the varying of the parameters.« less

  6. Numerical modeling of the effects of wave energy converter characteristics on nearshore wave conditions

    SciTech Connect (OSTI)

    Chang, G.; Ruehl, K.; Jones, C. A.; Roberts, J.; Chartrand, C.

    2015-12-24

    Modeled nearshore wave propagation was investigated downstream of simulated wave energy converters (WECs) to evaluate overall near- and far-field effects of WEC arrays. Model sensitivity to WEC characteristics and WEC array deployment scenarios was evaluated using a modified version of an industry standard wave model, Simulating WAves Nearshore (SWAN), which allows the incorporation of device-specific WEC characteristics to specify obstacle transmission. The sensitivity study illustrated that WEC device type and subsequently its size directly resulted in wave height variations in the lee of the WEC array. Wave heights decreased up to 30% between modeled scenarios with and without WECs for large arrays (100 devices) of relatively sizable devices (26 m in diameter) with peak power generation near to the modeled incident wave height. Other WEC types resulted in less than 15% differences in modeled wave height with and without WECs, with lesser influence for WECs less than 10 m in diameter. Wave directions and periods were largely insensitive to changes in parameters. Furthermore, additional model parameterization and analysis are required to fully explore the model sensitivity of peak wave period and mean wave direction to the varying of the parameters.

  7. Plane wave method for elastic wave scattering by a heterogeneous...

    Office of Scientific and Technical Information (OSTI)

    Plane wave method for elastic wave scattering by a heterogeneous fracture Citation Details In-Document Search Title: Plane wave method for elastic wave scattering by a ...

  8. Head-on-collision of modulated dust acoustic waves in strongly coupled dusty plasma

    SciTech Connect (OSTI)

    El-Labany, S. K.; El-Depsy, A.; Zedan, N. A.; El-Taibany, W. F.; El-Shamy, E. F.

    2012-10-15

    The derivative expansion perturbation method is applied to a strongly coupled dusty plasma system consisting of negatively charged dust grains, electrons, and ions. The basic equations are reduced to a nonlinear Schroedinger type equation appropriate for describing the modulated dust acoustic (DA) waves. We have examined the modulation (in) stability and the dependence of the system physical parameters (angular frequency and group velocity) on the polarization force variation. Finally, the extended Poincare-Lighthill-Kuo technique is employed to investigate the head-on collision (HoC) between two DA dark solitons. The analytical phase shifts and the trajectories of these dark solitons after the collision are derived. The numerical illustrations show that the polarization effect has strong influence on the nature of the phase shifts and the trajectories of the two DA dark solitons after collision.

  9. Ultra Deep Wave Equation Imaging and Illumination

    SciTech Connect (OSTI)

    Alexander M. Popovici; Sergey Fomel; Paul Sava; Sean Crawley; Yining Li; Cristian Lupascu

    2006-09-30

    In this project we developed and tested a novel technology, designed to enhance seismic resolution and imaging of ultra-deep complex geologic structures by using state-of-the-art wave-equation depth migration and wave-equation velocity model building technology for deeper data penetration and recovery, steeper dip and ultra-deep structure imaging, accurate velocity estimation for imaging and pore pressure prediction and accurate illumination and amplitude processing for extending the AVO prediction window. Ultra-deep wave-equation imaging provides greater resolution and accuracy under complex geologic structures where energy multipathing occurs, than what can be accomplished today with standard imaging technology. The objective of the research effort was to examine the feasibility of imaging ultra-deep structures onshore and offshore, by using (1) wave-equation migration, (2) angle-gathers velocity model building, and (3) wave-equation illumination and amplitude compensation. The effort consisted of answering critical technical questions that determine the feasibility of the proposed methodology, testing the theory on synthetic data, and finally applying the technology for imaging ultra-deep real data. Some of the questions answered by this research addressed: (1) the handling of true amplitudes in the downward continuation and imaging algorithm and the preservation of the amplitude with offset or amplitude with angle information required for AVO studies, (2) the effect of several imaging conditions on amplitudes, (3) non-elastic attenuation and approaches for recovering the amplitude and frequency, (4) the effect of aperture and illumination on imaging steep dips and on discriminating the velocities in the ultra-deep structures. All these effects were incorporated in the final imaging step of a real data set acquired specifically to address ultra-deep imaging issues, with large offsets (12,500 m) and long recording time (20 s).

  10. Stable operating regime for traveling wave devices

    DOE Patents [OSTI]

    Carlsten, Bruce E.

    2000-01-01

    Autophase stability is provided for a traveling wave device (TWD) electron beam for amplifying an RF electromagnetic wave in walls defining a waveguide for said electromagnetic wave. An off-axis electron beam is generated at a selected energy and has an energy noise inherently arising from electron gun. The off-axis electron beam is introduced into the waveguide. The off-axis electron beam is introduced into the waveguide at a second radius. The waveguide structure is designed to obtain a selected detuning of the electron beam. The off-axis electron beam has a velocity and the second radius to place the electron beam at a selected distance from the walls defining the waveguide, wherein changes in a density of the electron beam due to the RF electromagnetic wave are independent of the energy of the electron beam to provide a concomitant stable operating regime relative to the energy noise.

  11. Nonrelativistic QCD factorization and the velocity dependence...

    Office of Scientific and Technical Information (OSTI)

    CONFIGURATION; FACTORIZATION; MATRIX ELEMENTS; QUANTUM CHROMODYNAMICS; QUARKONIUM; SINGULARITY; T QUARKS; VELOCITY Word Cloud More Like This Full Text Journal Articles DOI: ...

  12. 3-D seismic velocity and attenuation structures in the geothermal field

    SciTech Connect (OSTI)

    Nugraha, Andri Dian [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Syahputra, Ahmad [Geophyisical Engineering, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Geophyisical Engineering, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Fatkhan,; Sule, Rachmat [Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)

    2013-09-09

    We conducted delay time tomography to determine 3-D seismic velocity structures (Vp, Vs, and Vp/Vs ratio) using micro-seismic events in the geothermal field. The P-and S-wave arrival times of these micro-seismic events have been used as input for the tomographic inversion. Our preliminary seismic velocity results show that the subsurface condition of geothermal field can be fairly delineated the characteristic of reservoir. We then extended our understanding of the subsurface physical properties through determining of attenuation structures (Qp, Qs, and Qs/Qp ratio) using micro-seismic waveform. We combined seismic velocities and attenuation structures to get much better interpretation of the reservoir characteristic. Our preliminary attanuation structures results show reservoir characterization can be more clearly by using the 3-D attenuation model of Qp, Qs, and Qs/Qp ratio combined with 3-D seismic velocity model of Vp, Vs, and Vp/Vs ratio.

  13. Surface-wave and refraction tomography at the FACT Site, Sandia National

    Office of Scientific and Technical Information (OSTI)

    Laboratories, Albuquerque, New Mexico. (Technical Report) | SciTech Connect Surface-wave and refraction tomography at the FACT Site, Sandia National Laboratories, Albuquerque, New Mexico. Citation Details In-Document Search Title: Surface-wave and refraction tomography at the FACT Site, Sandia National Laboratories, Albuquerque, New Mexico. We present a technique that allows for the simultaneous acquisition and interpretation of both shear-wave and compressive-wave 3-D velocities. The

  14. Dependence of synergy current driven by lower hybrid wave and electron cyclotron wave on the frequency and parallel refractive index of electron cyclotron wave for Tokamaks

    SciTech Connect (OSTI)

    Huang, J.; Chen, S. Y. Tang, C. J.; Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064

    2014-01-15

    The physical mechanism of the synergy current driven by lower hybrid wave (LHW) and electron cyclotron wave (ECW) in tokamaks is investigated using theoretical analysis and simulation methods in the present paper. Research shows that the synergy relationship between the two waves in velocity space strongly depends on the frequency ω and parallel refractive index N{sub //} of ECW. For a given spectrum of LHW, the parameter range of ECW, in which the synergy current exists, can be predicted by theoretical analysis, and these results are consistent with the simulation results. It is shown that the synergy effect is mainly caused by the electrons accelerated by both ECW and LHW, and the acceleration of these electrons requires that there is overlap of the resonance regions of the two waves in velocity space.

  15. Effects of light illumination on electron velocity of AlGaN/GaN heterostructures under high electric field

    SciTech Connect (OSTI)

    Guo, Lei; Yang, Xuelin Cheng, Jianpeng; Sang, Ling; Xu, Fujun; Tang, Ning; Feng, Zhihong; Lv, Yuanjie; Wang, Xinqiang; Shen, B.; Ge, Weikun

    2014-12-15

    We have investigated the variation of electron velocity in AlGaN/GaN heterostructures depending on illuminating light intensity and wavelength. It is shown that the electron velocity at high electric field increases under above-band light illumination. This electron velocity enhancement is found to be related to the photo-generated cold holes which interact with hot electrons and thus accelerate the energy relaxation at high electric field. The results suggest an alternative way to improve the electron energy relaxation rate and hence the electron velocity in GaN based heterostructures.

  16. Wave Energy Scotland

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... Industry outreach: DOE and Wave Energy Scotland co-sponsored WEC technology workshop News, Partnership, Renewable Energy, Water Power, Workshops Industry outreach: DOE and Wave ...

  17. Effects of ion abundances on electromagnetic ion cyclotron wave growth rate in the vicinity of the plasmapause

    SciTech Connect (OSTI)

    Henning, F. D. Mace, R. L.

    2014-04-15

    Electromagnetic ion cyclotron (EMIC) waves in multi-ion species plasmas propagate in branches. Except for the branch corresponding to the heaviest ion species, which has only a resonance at its gyrofrequency, these branches are bounded below by a cutoff frequency and above by a resonant gyrofrequency. The condition for wave growth is determined by the thermal anisotropies of each ion species, j, which sets an upper bound, ?{sub j}{sup ?}, on the wave frequency below which that ion species contributes positively to the growth rate. It follows that the relative positions of the cutoffs and the critical frequencies ?{sub j}{sup ?} play a crucial role in determining whether a particular wave branch will be unstable. The effect of the magnetospheric ion abundances on the growth rate of each branch of the EMIC instability in a model where all the ion species have kappa velocity distributions is investigated by appealing to the above ideas. Using the variation of the cutoff frequencies predicted by cold plasma theory as a guide, optimal ion abundances that maximise the EMIC instability growth rate are sought. When the ring current is comprised predominantly of H{sup +} ions, all branches of the EMIC wave are destabilised, with the proton branch having the maximum growth rate. When the O{sup +} ion abundance in the ring current is increased, a decrease in the growth rate of the proton branch and cyclotron damping of the helium branch are observed. The oxygen branch, on the other hand, experiences an increase in the maximum growth rate with an increase in the O{sup +} ion abundance. When the ring current is comprised predominantly of He{sup +} ions, only the helium and oxygen branches of the EMIC wave are destabilised, with the helium branch having the maximum growth rate.

  18. Wave Energy Converter Effects on Wave Fields: Evaluation of SNL-SWAN and Sensitivity Studies in Monterey Bay CA.

    SciTech Connect (OSTI)

    Roberts, Jesse D.; Chang, Grace; Magalen, Jason; Jones, Craig

    2014-09-01

    A modified version of an indust ry standard wave modeling tool was evaluated, optimized, and utilized to investigate model sensitivity to input parameters a nd wave energy converter ( WEC ) array deployment scenarios. Wave propagation was investigated d ownstream of the WECs to evaluate overall near - and far - field effects of WEC arrays. The sensitivity study illustrate d that wave direction and WEC device type we r e most sensitive to the variation in the model parameters examined in this study . Generally, the changes in wave height we re the primary alteration caused by the presence of a WEC array. Specifically, W EC device type and subsequently their size directly re sult ed in wave height variations; however, it is important to utilize ongoing laboratory studies and future field tests to determine the most appropriate power matrix values for a particular WEC device and configuration in order to improve modeling results .

  19. Seismic Surface-Wave Tomography of Waste Sites - Final Report

    SciTech Connect (OSTI)

    Long, Timothy L.

    2000-09-14

    The objective of this study was to develop analysis programs for surface-wave group-velocity tomography, and apply these to three test areas. We succeeded by obtaining data covering two square areas that were 30 meters on a side, and a third area that was 16 meters on a side, in addition to a collaborative effort wherein we processed data from the Oak Ridge National Laboratory site. At all sites, usable group velocities were obtained for frequencies from 16 to 50 Hz using a sledgehammer source. The resulting tomographic images and velocity anomalies were sufficient to delineate suspected burial trenches (one 4-meters deep) and anomalous velocity structure related to rocks and disturbed soil. The success was not uniform because in portions of one area the inversion for shear-wave structure became unstable. More research is needed to establish a more robust inversion technique.

  20. Temporal evolution of bubble tip velocity in classical Rayleigh-Taylor instability at arbitrary Atwood numbers

    SciTech Connect (OSTI)

    Liu, W. H.; HEDPS and CAPT, Peking University, Beijing 100871 ; Wang, L. F.; Ye, W. H.; Institute of Applied Physics and Computational Mathematics, Beijing 100088; Department of Physics, Zhejiang University, Hangzhou 310027 ; He, X. T.; Institute of Applied Physics and Computational Mathematics, Beijing 100088

    2013-06-15

    In this research, the temporal evolution of the bubble tip velocity in Rayleigh-Taylor instability (RTI) at arbitrary Atwood numbers and different initial perturbation velocities with a discontinuous profile in irrotational, incompressible, and inviscid fluids (i.e., classical RTI) is investigated. Potential models from Layzer [Astrophys. J. 122, 1 (1955)] and perturbation velocity potentials from Goncharov [Phys. Rev. Lett. 88, 134502 (2002)] are introduced. It is found that the temporal evolution of bubble tip velocity [u(t)] depends essentially on the initial perturbation velocity [u(0)]. First, when the u(0)velocity increases smoothly up to the asymptotic velocity (u{sup asp}) or terminal velocity. Second, when C{sup (1)}u{sup asp}?u(0)velocity increases quickly, reaching a maximum velocity and then drops slowly to the u{sup asp}. Third, when C{sup (2)}u{sup asp}?u(0)velocity decays rapidly to a minimum velocity and then increases gradually toward the u{sup asp}. Finally, when u(0)?C{sup (3)}u{sup asp}, the bubble tip velocity decays monotonically to the u{sup asp}. Here, the critical coefficients C{sup (1)},C{sup (2)}, and C{sup (3)}, which depend sensitively on the Atwood number (A) and the initial perturbation amplitude of the bubble tip [h(0)], are determined by a numerical approach. The model proposed here agrees with hydrodynamic simulations. Thus, it should be included in applications where the bubble tip velocity plays an important role, such as the design of the ignition target of inertial confinement fusion where the Richtmyer-Meshkov instability (RMI) can create the seed of RTI with u(0)?u{sup asp}, and stellar formation and evolution in astrophysics where the deflagration wave front propagating outwardly from the star is subject to the combined RMI and RTI.

  1. Landau damping of Langmuir waves in non-Maxwellian plasmas

    SciTech Connect (OSTI)

    Ouazene, M.; Annou, R.

    2011-11-15

    As free electrons move in the nearest neighbour ion's potential well, the equilibrium velocity departs from Maxwell distribution. The effect of the non-Maxwellian velocity distribution function (NMVDF) on many properties of the plasma such as the transport coefficients, the kinetic energy, and the degree of ionization is found to be noticeable. A correction to the Langmuir wave dispersion relation is proved to arise due to the NMVDF as well [Phys. Plasmas 17, 052105 (2010)]. The study is extended hereafter to include the effect of NMVDF on the Landau damping of Langmuir wave.

  2. Finite Difference Modeling of Wave Progpagation in Acoustic TiltedTI...

    Office of Scientific and Technical Information (OSTI)

    Based on an acoustic assumption (shear wave velocity is zero) and a dispersion relation, ... DOE Contract Number: DE-AC02-05CH11231 Resource Type: Journal Article Resource Relation: ...

  3. Quench propagation velocity for highly stabilized conductors

    SciTech Connect (OSTI)

    Mints, R.G. |; Ogitsu, T. |; Devred, A.

    1995-05-01

    Quench propagation velocity in conductors having a large amount of stabilizer outside the multifilamentary area is considered. It is shown that the current redistribution process between the multifilamentary area and the stabilizer can strongly effect the quench propagation. A criterion is derived determining the conditions under which the current redistribution process becomes significant, and a model of effective stabilizer area is suggested to describe its influence on the quench propagation velocity. As an illustration, the model is applied to calculate the adiabatic quench propagation velocity for a conductor geometry with a multifilamentary area embedded inside the stabilizer.

  4. Two-station phase velocity determination for structure in North Africa

    SciTech Connect (OSTI)

    Hazler, S; Pasyanos, M; Sheehan, A; Walter, W

    1999-07-28

    The seismic structure of North Africa is poorly understood due to the relative paucity of stations and seismicity when compared to other continental regions of the world. A better understanding of the velocity structure in this area will allow improved models of travel times and regional phase amplitudes. Such models will improve location and identification capability in this region leading to more effective monitoring of the Comprehensive Nuclear-Test-Ban Treaty. Using regional-to-teleseismic Rayleigh and Love waves that traverse the area we can obtain information about the region's seismic structure by examining phase velocity as a function of period. We utilize earthquakes from the tectonically active regions bounding North Africa (Mediterranean, Red Sea, East African Rift, and Mid-Atlantic Ridge) recorded at broadband seismic stations distributed throughout the region. A two-station method is utilized to determine phase velocity information along the interstation segment of the ray path. The two-station method provides particular advantage in this region as it dramatically increases the number of events available to provide pure North African sampling. Bandpass filters are applied to the seismograms so that peaks and troughs may be correlated. The phase is unwrapped and a difference curve computed. The difference curve is then converted to a phase velocity dispersion curve. Phase velocity curves are constructed in the range of 10 to 120 seconds. Rayleigh and Love waves in this period range are most sensitive to the shear velocity structure of the lithosphere and can be used in combination with additional independent seismic observations (e.g. Pn tomography, surface wave group velocity tomography, receiver functions, etc.) to construct reliable velocity models. We compare velocities computed in this study to those generated from well known models for similar tectonic regions throughout the world in order to better define the tectonic setting of North Africa

  5. Slow wave structures using twisted waveguides for charged particle applications

    DOE Patents [OSTI]

    Kang, Yoon W.; Fathy, Aly E.; Wilson, Joshua L.

    2012-12-11

    A rapidly twisted electromagnetic accelerating structure includes a waveguide body having a central axis, one or more helical channels defined by the body and disposed around a substantially linear central axial channel, with central portions of the helical channels merging with the linear central axial channel. The structure propagates electromagnetic waves in the helical channels which support particle beam acceleration in the central axial channel at a phase velocity equal to or slower than the speed of light in free space. Since there is no variation in the shape of the transversal cross-section along the axis of the structure, inexpensive mechanical fabrication processes can be used to form the structure, such as extrusion, casting or injection molding. Also, because the field and frequency of the resonant mode depend on the whole structure rather than on dimensional tolerances of individual cells, no tuning of individual cells is needed. Accordingly, the overall operating frequency may be varied with a tuning/phase shifting device located outside the resonant waveguide structure.

  6. Coherent cooling of atoms in a frequency-modulated standing laser wave: Wave function and stochastic trajectory approaches

    SciTech Connect (OSTI)

    Argonov, V. Yu.

    2014-11-15

    The wave function of a moderately cold atom in a stationary near-resonant standing light wave delocalizes very fast due to wave packet splitting. However, we show that frequency modulation of the field can suppress packet splitting for some atoms whose specific velocities are in a narrow range. These atoms remain localized in a small space for a long time. We demonstrate and explain this effect numerically and analytically. We also demonstrate that the modulated field can not only trap but also cool the atoms. We perform a numerical experiment with a large atomic ensemble having wide initial velocity and energy distributions. During the experiment, most of atoms leave the wave while the trapped atoms have a narrow energy distribution.

  7. Optically Recording Velocity Interferometer System (ORVIS): Applications

    Office of Scientific and Technical Information (OSTI)

    and Challenges. (Conference) | SciTech Connect Conference: Optically Recording Velocity Interferometer System (ORVIS): Applications and Challenges. Citation Details In-Document Search Title: Optically Recording Velocity Interferometer System (ORVIS): Applications and Challenges. Abstract not provided. Authors: Cooper, Marcia A. Publication Date: 2015-06-01 OSTI Identifier: 1257697 Report Number(s): SAND2015-4721C 590812 DOE Contract Number: AC04-94AL85000 Resource Type: Conference Resource

  8. Seismic Velocity Measurements at Expanded Seismic Network Sites

    SciTech Connect (OSTI)

    Woolery, Edward W; Wang, Zhenming

    2005-01-01

    Structures at the Paducah Gaseous Diffusion Plant (PGDP), as well as at other locations in the northern Jackson Purchase of western Kentucky may be subjected to large far-field earthquake ground motions from the New Madrid seismic zone, as well as those from small and moderate-sized local events. The resultant ground motion a particular structure is exposed from such event will be a consequence of the earthquake magnitude, the structures' proximity to the event, and the dynamic and geometrical characteristics of the thick soils upon which they are, of necessity, constructed. This investigation evaluated the latter. Downhole and surface (i.e., refraction and reflection) seismic velocity data were collected at the Kentucky Seismic and Strong-Motion Network expansion sites in the vicinity of the Paducah Gaseous Diffusion Plant (PGDP) to define the dynamic properties of the deep sediment overburden that can produce modifying effects on earthquake waves. These effects are manifested as modifications of the earthquake waves' amplitude, frequency, and duration. Each of these three ground motion manifestations is also fundamental to the assessment of secondary earthquake engineering hazards such as liquefaction.

  9. Optimization of Gutzwiller wave functions in quantum Monte Carlo

    SciTech Connect (OSTI)

    Koch, E.; Gunnarsson, O.; Martin, R.M.

    1999-06-01

    Gutzwiller functions are popular variational wave functions for correlated electrons in Hubbard models. Following the variational principle, we are interested in the Gutzwiller parameters that minimize, e.g., the expectation value of the energy. Rewriting the expectation value as a rational function in the Gutzwiller parameters, we find a very efficient way for performing that minimization. The method can be used to optimize general Gutzwiller-type wave functions both in variational and in fixed-node diffusion Monte Carlo. {copyright} {ital 1999} {ital The American Physical Society}

  10. Mass-velocity and size-velocity distributions of ejecta cloud from shock-loaded tin surface using atomistic simulations

    SciTech Connect (OSTI)

    Durand, O.; Soulard, L.

    2015-04-28

    The mass (volume and areal densities) versus velocity as well as the size versus velocity distributions of a shock-induced cloud of particles are investigated using large scale molecular dynamics simulations. A generic three-dimensional tin crystal with a sinusoidal free surface roughness (single wavelength) is set in contact with vacuum and shock-loaded so that it melts directly on shock. At the reflection of the shock wave onto the perturbations of the free surface, two-dimensional sheets/jets of liquid metal are ejected. The simulations show that the distributions may be described by an analytical model based on the propagation of a fragmentation zone, from the tip of the sheets to the free surface, in which the kinetic energy of the atoms decreases as this zone comes closer to the free surface on late times. As this kinetic energy drives (i) the (self-similar) expansion of the zone once it has broken away from the sheet and (ii) the average size of the particles which result from fragmentation in the zone, the ejected mass and the average size of the particles progressively increase in the cloud as fragmentation occurs closer to the free surface. Though relative to nanometric scales, our model may help in the analysis of experimental profiles.

  11. Experimental investigation on structures and velocity of liquid jets in a supersonic crossflow

    SciTech Connect (OSTI)

    Wang, Zhen-guo Wu, Liyin; Li, Qinglian; Li, Chun

    2014-09-29

    Particle image velocimetry was applied in the study focusing on the structure and velocity of water jets injected into a Ma?=?2.1 crossflow. The instantaneous structures of the jet, including surface waves in the near-injector region and vortices in the far-field, were visualized clearly. Spray velocity increases rapidly to 66% of the mainstream velocity in the region of x/d?velocity grows slowly in the far-field region, where the liquid inside the spray is accelerated mainly by the continuous driven force provided by the mainstream with the gas-liquid shear. The injection and atomization of liquid jet in a supersonic crossflow serves as a foundation of scramjet combustion process, by affecting the combustion efficiency and some other performances. With various forces acting on the liquid jet (Mashayek et al. [AIAA J. 46, 26742686 (2008)] and Wang et al. [AIAA J. 50, 13601366 (2012)]), the atomization process involves very complex flow physics. These physical processes include strong vortical structures, small-scale wave formation, stripping of small droplets from the jet surface, formations of ligaments, and droplets with a wide range of sizes.

  12. DETERMINATION OF NON-THERMAL VELOCITY DISTRIBUTIONS FROM SERTS LINEWIDTH OBSERVATIONS

    SciTech Connect (OSTI)

    Coyner, Aaron J. [Department of Physics, Catholic University of America, 620 Michigan Avenue, Washington, DC 20064 (United States); Davila, Joseph M., E-mail: aaron.j.coyner@nasa.gov [Code 671, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2011-12-01

    Non-thermal velocities obtained from the measurement of coronal Extreme Ultraviolet (EUV) linewidths have been consistently observed in solar EUV spectral observations and have been theorized to result from many plausible scenarios including wave motions, turbulence, or magnetic reconnection. Constraining these velocities can provide a physical limit for the available energy resulting from unresolved motions in the corona. We statistically determine a series of non-thermal velocity distributions from linewidth measurements of 390 emission lines from a wide array of elements and ionization states observed during the Solar Extreme Ultraviolet Research Telescope and Spectrograph 1991-1997 flights covering the spectral range 174-418 A and a temperature range from 80,000 K to 12.6 MK. This sample includes 248 lines from active regions, 101 lines from quiet-Sun regions, and 41 lines were observed from plasma off the solar limb. We find a strongly peaked distribution corresponding to a non-thermal velocity of 19-22 km s{sup -1} in all three of the quiet-Sun, active region, and off-limb distributions. For the possibility of Alfven wave resonance heating, we find that velocities in the core of these distributions do not provide sufficient energy, given typical densities and magnetic field strengths for the coronal plasma, to overcome the estimated coronal energy losses required to maintain the corona at the typical temperatures working as the sole mechanism. We find that at perfect efficiency 50%-60% of the needed energy flux can be produced from the non-thermal velocities measured.

  13. Gyrokinetic simulation of momentum transport with residual stress from diamagnetic level velocity shears

    SciTech Connect (OSTI)

    Waltz, R. E.; Staebler, G. M.; Solomon, W. M.

    2011-04-15

    Residual stress refers to the remaining toroidal angular momentum (TAM) flux (divided by major radius) when the shear in the equilibrium fluid toroidal velocity (and the velocity itself) vanishes. Previously [Waltz et al., Phys. Plasmas 14, 122507 (2007); errata 16, 079902 (2009)], we demonstrated with GYRO [Candy and Waltz, J. Comp. Phys. 186, 545 (2003)] gyrokinetic simulations that TAM pinching from (ion pressure gradient supported or diamagnetic level) equilibrium ExB velocity shear could provide some of the residual stress needed to support spontaneous toroidal rotation against normal diffusive loss. Here we show that diamagnetic level shear in the intrinsic drift wave velocities (or ''profile shear'' in the ion and electron density and temperature gradients) provides a comparable residual stress. The individual signed contributions of these small (rho-star level) ExB and profile velocity shear rates to the turbulence level and (rho-star squared) ion energy transport stabilization are additive if the rates are of the same sign. However because of the additive stabilization effect, the contributions to the small (rho-star cubed) residual stress is not always simply additive. If the rates differ in sign, the residual stress from one can buck out that from the other (and in some cases reduce the stabilization.) The residual stress from these diamagnetic velocity shear rates is quantified by the ratio of TAM flow to ion energy (power) flow (M/P) in a global GYRO core simulation of a ''null'' toroidal rotation DIII-D [Mahdavi and Luxon, Fusion Sci. Technol. 48, 2 (2005)] discharge by matching M/P profiles within experimental uncertainty. Comparison of global GYRO (ion and electron energy as well as particle) transport flow balance simulations of TAM transport flow in a high-rotation DIII-D L-mode quantifies and isolates the ExB shear and parallel velocity (Coriolis force) pinching components from the larger ''diffusive'' parallel velocity shear driven component and

  14. PHOTOSPHERIC VARIATIONS OF THE SUPERGIANT {gamma} Cyg

    SciTech Connect (OSTI)

    Gray, David F.

    2010-11-15

    New high-resolution spectroscopic observations of the supergiant {gamma} Cyg (F8 Iab) taken between 2000 and 2008 consistently show strongly reversed-C-shaped bisectors for all unblended spectral lines. Small-amplitude variations in radial velocity and line shapes occur in an irregular manner with time scales {approx}100 days and longer. The radial velocities occasionally show changes as large as 2 km s{sup -1}, but much smaller changes are going on continuously. Differential line bisectors show shape changes and Doppler displacement characteristic of radial expansion and contraction. These might arise from non-periodic radial pulsation-like motions or from the appearance of giant convection cells that occupy most of the visible hemisphere of the star. Line-depth ratios are correlated with the line shifts on a seasonal basis and indicate temperature changes ranging up to {approx}15 K, with larger temperature occurring during times of most rapid contraction.

  15. Detonation Wave Profile

    SciTech Connect (OSTI)

    Menikoff, Ralph

    2015-12-14

    The Zel’dovich-von Neumann-Doering (ZND) profile of a detonation wave is derived. Two basic assumptions are required: i. An equation of state (EOS) for a partly burned explosive; P(V, e, λ). ii. A burn rate for the reaction progress variable; d/dt λ = R(V, e, λ). For a steady planar detonation wave the reactive flow PDEs can be reduced to ODEs. The detonation wave profile can be determined from an ODE plus algebraic equations for points on the partly burned detonation loci with a specified wave speed. Furthermore, for the CJ detonation speed the end of the reaction zone is sonic. A solution to the reactive flow equations can be constructed with a rarefaction wave following the detonation wave profile. This corresponds to an underdriven detonation wave, and the rarefaction is know as a Taylor wave.

  16. Catching a Wave: Innovative Wave Energy Device Surfs for Power...

    Office of Environmental Management (EM)

    Catching a Wave: Innovative Wave Energy Device Surfs for Power in Hawaii Catching a Wave: Innovative Wave Energy Device Surfs for Power in Hawaii July 29, 2015 - 12:00pm Addthis...

  17. Property:Maximum Velocity(m/s) | Open Energy Information

    Open Energy Info (EERE)

    Velocity(ms) Jump to: navigation, search Property Name Maximum Velocity(ms) Property Type String Pages using the property "Maximum Velocity(ms)" Showing 25 pages using this...

  18. Property:Velocity(m/s) | Open Energy Information

    Open Energy Info (EERE)

    Velocity(ms) Jump to: navigation, search Property Name Velocity(ms) Property Type String Pages using the property "Velocity(ms)" Showing 21 pages using this property. A Alden...

  19. VELOCITY-SHEAR-INDUCED MODE COUPLING IN THE SOLAR ATMOSPHERE AND SOLAR WIND: IMPLICATIONS FOR PLASMA HEATING AND MHD TURBULENCE

    SciTech Connect (OSTI)

    Hollweg, Joseph V.; Chandran, Benjamin D. G.; Kaghashvili, Edisher Kh. E-mail: ekaghash@aer.com

    2013-06-01

    We analytically consider how velocity shear in the corona and solar wind can cause an initial Alfven wave to drive up other propagating signals. The process is similar to the familiar coupling into other modes induced by non-WKB refraction in an inhomogeneous plasma, except here the refraction is a consequence of velocity shear. We limit our discussion to a low-beta plasma, and ignore couplings into signals resembling the slow mode. If the initial Alfven wave is propagating nearly parallel to the background magnetic field, then the induced signals are mainly a forward-going (i.e., propagating in the same sense as the original Alfven wave) fast mode, and a driven signal propagating like a forward-going Alfven wave but polarized like the fast mode; both signals are compressive and subject to damping by the Landau resonance. For an initial Alfven wave propagating obliquely with respect to the magnetic field, the induced signals are mainly forward- and backward-going fast modes, and a driven signal propagating like a forward-going Alfven wave but polarized like the fast mode; these signals are all compressive and subject to damping by the Landau resonance. A backward-going Alfven wave, thought to be important in the development of MHD turbulence, is also produced, but it is very weak. However, we suggest that for oblique propagation of the initial Alfven wave the induced fast-polarized signal propagating like a forward-going Alfven wave may interact coherently with the initial Alfven wave and distort it at a strong-turbulence-like rate.

  20. Decay of helical Kelvin waves on a quantum vortex filament

    SciTech Connect (OSTI)

    Van Gorder, Robert A.

    2014-07-15

    We study the dynamics of helical Kelvin waves moving along a quantum vortex filament driven by a normal fluid flow. We employ the vector form of the quantum local induction approximation (LIA) due to Schwarz. For an isolated filament, this is an adequate approximation to the full Hall-Vinen-Bekarevich-Khalatnikov dynamics. The motion of such Kelvin waves is both translational (along the quantum vortex filament) and rotational (in the plane orthogonal to the reference axis). We first present an exact closed form solution for the motion of these Kelvin waves in the case of a constant amplitude helix. Such solutions exist for a critical wave number and correspond exactly to the Donnelly-Glaberson instability, so perturbations of such solutions either decay to line filaments or blow-up. This leads us to consider helical Kelvin waves which decay to line filaments. Unlike in the case of constant amplitude helical solutions, the dynamics are much more complicated for the decaying helical waves, owing to the fact that the rate of decay of the helical perturbations along the vortex filament is not constant in time. We give an analytical and numerical description of the motion of decaying helical Kelvin waves, from which we are able to ascertain the influence of the physical parameters on the decay, translational motion along the filament, and rotational motion, of these waves (all of which depend nonlinearly on time). One interesting finding is that the helical Kelvin waves do not decay uniformly. Rather, such waves decay slowly for small time scales, and more rapidly for large time scales. The rotational and translational velocity of the Kelvin waves depend strongly on this rate of decay, and we find that the speed of propagation of a helical Kelvin wave along a quantum filament is large for small time while the wave asymptotically slows as it decays. The rotational velocity of such Kelvin waves along the filament will increase over time, asymptotically reaching a finite

  1. Investigation of Spatial Variation of Sea States Offshore of Humboldt Bay CA Using a Hindcast Model.

    SciTech Connect (OSTI)

    Dallman, Ann Renee; Neary, Vincent Sinclair

    2014-10-01

    Spatial variability of sea states is an important consideration when performing wave resource assessments and wave resource characterization studies for wave energy converter (WEC) test sites and commercial WEC deployments. This report examines the spatial variation of sea states offshore of Humboldt Bay, CA, using the wave model SWAN . The effect of depth and shoaling on bulk wave parameters is well resolved using the model SWAN with a 200 m grid. At this site, the degree of spatial variation of these bulk wave parameters, with shoaling generally perpendicular to the depth contours, is found to depend on the season. The variation in wave height , for example, was higher in the summer due to the wind and wave sheltering from the protruding land on the coastline north of the model domain. Ho wever, the spatial variation within an area of a potential Tier 1 WEC test site at 45 m depth and 1 square nautical mile is almost negligible; at most about 0.1 m in both winter and summer. The six wave characterization parameters recommended by the IEC 6 2600 - 101 TS were compared at several points along a line perpendicular to shore from the WEC test site . As expected, these parameters varied based on depth , but showed very similar seasonal trends.

  2. TOWARD UNBIASED GALAXY CLUSTER MASSES FROM LINE-OF-SIGHT VELOCITY DISPERSIONS

    SciTech Connect (OSTI)

    Saro, Alex; Mohr, Joseph J.; Bazin, Gurvan; Dolag, Klaus

    2013-07-20

    We study the use of red-sequence-selected galaxy spectroscopy for unbiased estimation of galaxy cluster masses by using a publicly available simulated galaxy catalog. We explore the impact of selection using galaxy color, projected separation from the cluster center, galaxy luminosity, and spectroscopic redshift. We identify and characterize each of the following sources of bias and scatter in velocity dispersion at fixed mass: the intrinsic properties of halos in the form of halo triaxiality, sampling noise, the presence of multiple kinematic populations within the cluster, and the effect of interlopers. We show that even in red-sequence and spectroscopically selected galaxy samples, the interloper fraction is significant, and that the variations in the interloper population from cluster to cluster provide the dominant contribution to the velocity dispersion scatter at fixed mass. We present measurements of the total scatter in dispersion at fixed mass as a function of the number of redshifts. Results indicate that improvements in scatter are modest beyond samples of {approx}30 redshifts per cluster. Our results show that while cluster velocity dispersions extracted from a few dozen red-sequence-selected galaxies do not provide precise masses on a single cluster basis, an ensemble of cluster velocity dispersions can be combined to produce a precise calibration of a cluster survey-mass-observable relation. Currently, disagreements in the literature on simulated subhalo velocity dispersion-mass relations place a systematic floor on velocity dispersion mass calibration at the 5% level in dispersion.

  3. PROTOSTELLAR JETS ENCLOSED BY LOW-VELOCITY OUTFLOWS (Journal...

    Office of Scientific and Technical Information (OSTI)

    PROTOSTELLAR JETS ENCLOSED BY LOW-VELOCITY OUTFLOWS Citation Details In-Document Search Title: PROTOSTELLAR JETS ENCLOSED BY LOW-VELOCITY OUTFLOWS A protostellar jet and outflow...

  4. Wave Energy | Open Energy Information

    Open Energy Info (EERE)

    Wave Energy Jump to: navigation, search Contents 1 Description 2 History 3 Technology 4 Current and Possible Wave Farms 5 Pros and Cons Description Wave energy (or wave power) is...

  5. Effect of Resolution on Propagating Detonation Wave

    SciTech Connect (OSTI)

    Menikoff, Ralph

    2014-07-10

    Simulations of the cylinder test are used to illustrate the effect of mesh resolution on a propagating detonation wave. For this study we use the xRage code with the SURF burn model for PBX 9501. The adaptive mesh capability of xRage is used to vary the resolution of the reaction zone. We focus on two key properties: the detonation speed and the cylinder wall velocity. The latter is related to the release isentrope behind the detonation wave. As the reaction zone is refined (2 to 15 cells for cell size of 62 to 8?m), both the detonation speed and final wall velocity change by a small amount; less than 1 per cent. The detonation speed decreases with coarser resolution. Even when the reaction zone is grossly under-resolved (cell size twice the reaction-zone width of the burn model) the wall velocity is within a per cent and the detonation speed is low by only 2 per cent.

  6. Ion-acoustic cnoidal waves in a quantum plasma

    SciTech Connect (OSTI)

    Mahmood, S.; Haas, F.

    2014-10-15

    Nonlinear ion-acoustic cnoidal wave structures are studied in an unmagnetized quantum plasma. Using the reductive perturbation method, a Korteweg-de Vries equation is derived for appropriate boundary conditions and nonlinear periodic wave solutions are obtained. The corresponding analytical solution and numerical plots of the ion-acoustic cnoidal waves and solitons in the phase plane are presented using the Sagdeev pseudo-potential approach. The variations in the nonlinear potential of the ion-acoustic cnoidal waves are studied at different values of quantum parameter H{sub e} which is the ratio of electron plasmon energy to electron Fermi energy defined for degenerate electrons. It is found that both compressive and rarefactive ion-acoustic cnoidal wave structures are formed depending on the value of the quantum parameter. The dependence of the wavelength and frequency on nonlinear wave amplitude is also presented.

  7. AN EXTREME-ULTRAVIOLET WAVE ASSOCIATED WITH A SURGE

    SciTech Connect (OSTI)

    Zheng, Ruisheng; Jiang, Yunchun; Yang, Jiayan; Bi, Yi; Hong, Junchao; Yang, Bo; Yang, Dan

    2013-02-10

    Taking advantage of the high temporal and spatial resolution observations from the Solar Dynamics Observatory, we present an extreme-ultraviolet (EUV) wave associated with a surge on 2010 November 13. Due to the magnetic flux cancelation, some surges formed in the source active region (AR). The strongest surge produced our studied event. The surge was deflected by the nearby loops that connected to another AR, and disrupted the overlying loops that slowly expanded and eventually evolved into a weak coronal mass ejection (CME). The surge was likely associated with the core of the CME. The EUV wave happened after the surge deflected. The wave departed far from the flare center and showed a close location relative to the deflected surge. The wave propagated in a narrow angular extent, mainly in the ejection direction of the surge. The close timing and location relations between the EUV wave and the surge indicate that the wave was closely associated with the CME. The wave had a velocity of 310-350 km s{sup -1}, while the speeds of the surge and the expanding loops were about 130 and 150 km s{sup -1}, respectively. All of the results suggest that the EUV wave was a fast-mode wave and was most likely triggered by the weak CME.

  8. In-Situ Continuous Detonation Velocity Measurements Using Fiber-optic Bragg Grating Sensors

    SciTech Connect (OSTI)

    Benterou, J; Udd, E; Wilkins, P; Roeske, F; Roos, E; Jackson, D

    2007-07-25

    In order to fully calibrate hydrocodes and dynamic chemistry burn models, initiation and detonation research requires continuous measurement of low order detonation velocities as the detonation runs up to full order detonation for a given density and initiation pressure pulse. A novel detector of detonation velocity is presented using a 125 micron diameter optical fiber with an integral chirped fiber Bragg grating as an intrinsic sensor. This fiber is embedded in the explosive under study and interrogated during detonation as the fiber Bragg grating scatters light back along the fiber to a photodiode, producing a return signal dependant on the convolution integral of the grating reflection bandpass, the ASE intensity profile and the photodetector response curve. Detonation velocity is measured as the decrease in reflected light exiting the fiber as the grating is consumed when the detonation reaction zone proceeds along the fiber sensor axis. This small fiber probe causes minimal perturbation to the detonation wave and can measure detonation velocities along path lengths tens of millimeters long. Experimental details of the associated equipment and preliminary data in the form of continuous detonation velocity records within nitromethane and PBX-9502 are presented.

  9. Apparatus and method for laser velocity interferometry

    DOE Patents [OSTI]

    Stanton, Philip L.; Sweatt, William C.; Crump, Jr., O. B.; Bonzon, Lloyd L.

    1993-09-14

    An apparatus and method for laser velocity interferometry employing a fixed interferometer cavity and delay element. The invention permits rapid construction of interferometers that may be operated by those non-skilled in the art, that have high image quality with no drift or loss of contrast, and that have long-term stability even without shock isolation of the cavity.

  10. Realizing bright-matter-wave-soliton collisions with controlled relative phase

    SciTech Connect (OSTI)

    Billam, T. P.; Cornish, S. L.; Gardiner, S. A.

    2011-04-15

    We propose a method to split the ground state of an attractively interacting atomic Bose-Einstein condensate into two bright solitary waves with controlled relative phase and velocity. We analyze the stability of these waves against their subsequent recollisions at the center of a cylindrically symmetric, prolate harmonic trap as a function of relative phase, velocity, and trap anisotropy. We show that the collisional stability is strongly dependent on relative phase at low velocity, and we identify previously unobserved oscillations in the collisional stability as a function of the trap anisotropy. An experimental implementation of our method would determine the validity of the mean-field description of bright solitary waves and could prove to be an important step toward atom interferometry experiments involving bright solitary waves.

  11. P- and S-body wave tomography of the state of Nevada.

    SciTech Connect (OSTI)

    Preston, Leiph

    2010-04-01

    P- and S-body wave travel times collected from stations in and near the state of Nevada were inverted for P-wave velocity and the Vp/Vs ratio. These waves consist of Pn, Pg, Sn and Sg, but only the first arriving P and S waves were used in the inversion. Travel times were picked by University of Nevada Reno colleagues and were culled for inclusion in the tomographic inversion. The resulting tomographic model covers the entire state of Nevada to a depth of {approx}90 km; however, only the upper 40 km indicate relatively good resolution. Several features of interest are imaged including the Sierra Nevada, basin structures, and low velocities at depth below Yucca Mountain. These velocity structure images provide valuable information to aide in the interpretation of geothermal resource areas throughout the state on Nevada.

  12. Propagating and reflecting of spin wave in permalloy nanostrip with 360 domain wall

    SciTech Connect (OSTI)

    Zhang, Senfu; Mu, Congpu; Zhu, Qiyuan; Zheng, Qi; Liu, Xianyin; Wang, Jianbo; Liu, Qingfang

    2014-01-07

    By micromagnetic simulation, we investigated the interaction between propagating spin wave (or magnonic) and a 360 domain wall in a nanostrip. It is found that propagating spin wave can drive a 360 domain wall motion, and the velocity and direction are closely related to the transmission coefficient of the spin wave of the domain wall. When the spin wave passes through the domain wall completely, the 360 domain wall moves toward the spin wave source. When the spin wave is reflected by the domain wall, the 360 domain wall moves along the spin wave propagation direction. Moreover, when the frequency of the spin wave is coincident with that of the 360 domain wall normal mode, the 360 domain wall velocity will be resonantly enhanced no matter which direction the 360 DW moves along. On the other hand, when the spin wave is reflected from the moving 360 domain wall, we observed the Doppler effect clearly. After passing through a 360 domain wall, the phase of the spin wave is changed, and the phase shift is related to the frequency. Nevertheless, phase shift could be manipulated by the number of 360 domain walls that spin wave passing through.

  13. Cycloidal Wave Energy Converter

    SciTech Connect (OSTI)

    Stefan G. Siegel, Ph.D.

    2012-11-30

    This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will

  14. The transverse and rotational motions of magnetohydrodynamic kink waves in the solar atmosphere

    SciTech Connect (OSTI)

    Goossens, M.; Van Doorsselaere, T. [Centre for Mathematical Plasma Astrophysics, Katholieke Universiteit Leuven, Celestijnenlaan 200B, bus 2400, B-3001 Herverlee (Belgium); Soler, R.; Terradas, J. [Departament de Fsica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Verth, G., E-mail: marcel.goossens@wis.kuleuven.be [Solar Physics and Space Plasma Research Centre (SP2RC), The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

    2014-06-10

    Magnetohydrodynamic (MHD) kink waves have now been observed to be ubiquitous throughout the solar atmosphere. With modern instruments, they have now been detected in the chromosphere, interface region, and corona. The key purpose of this paper is to show that kink waves do not only involve purely transverse motions of solar magnetic flux tubes, but the velocity field is a spatially and temporally varying sum of both transverse and rotational motion. Taking this fact into account is particularly important for the accurate interpretation of varying Doppler velocity profiles across oscillating structures such as spicules. It has now been shown that, as well as bulk transverse motions, spicules have omnipresent rotational motions. Here we emphasize that caution should be used before interpreting the particular MHD wave mode/s responsible for these rotational motions. The rotational motions are not necessarily signatures of the classic axisymmetric torsional Alfvn wave alone, because kink motion itself can also contribute substantially to varying Doppler velocity profiles observed across these structures. In this paper, the displacement field of the kink wave is demonstrated to be a sum of its transverse and rotational components, both for a flux tube with a discontinuous density profile at its boundary, and one with a more realistic density continuum between the internal and external plasma. Furthermore, the Doppler velocity profile of the kink wave is forward modeled to demonstrate that, depending on the line of sight, it can either be quite distinct or very similar to that expected from a torsional Alfvn wave.

  15. DIRECT IMAGING OF QUASI-PERIODIC FAST PROPAGATING WAVES OF {approx}2000 km s{sup -1} IN THE LOW SOLAR CORONA BY THE SOLAR DYNAMICS OBSERVATORY ATMOSPHERIC IMAGING ASSEMBLY

    SciTech Connect (OSTI)

    Liu Wei; Title, Alan M.; Schrijver, Carolus J.; Aschwanden, Markus J.; De Pontieu, Bart; Tarbell, Theodore D.; Zhao Junwei; Ofman, Leon

    2011-07-20

    Quasi-periodic propagating fast mode magnetosonic waves in the solar corona were difficult to observe in the past due to relatively low instrument cadences. We report here evidence of such waves directly imaged in EUV by the new Atmospheric Imaging Assembly instrument on board the Solar Dynamics Observatory. In the 2010 August 1 C3.2 flare/coronal mass ejection event, we find arc-shaped wave trains of 1%-5% intensity variations (lifetime {approx}200 s) that emanate near the flare kernel and propagate outward up to {approx}400 Mm along a funnel of coronal loops. Sinusoidal fits to a typical wave train indicate a phase velocity of 2200 {+-} 130 km s{sup -1}. Similar waves propagating in opposite directions are observed in closed loops between two flare ribbons. In the k-{omega} diagram of the Fourier wave power, we find a bright ridge that represents the dispersion relation and can be well fitted with a straight line passing through the origin. This k-{omega} ridge shows a broad frequency distribution with power peaks at 5.5, 14.5, and 25.1 mHz. The strongest signal at 5.5 mHz (period 181 s) temporally coincides with quasi-periodic pulsations of the flare, suggesting a common origin. The instantaneous wave energy flux of (0.1-2.6) x 10{sup 7} erg cm{sup -2} s{sup -1} estimated at the coronal base is comparable to the steady-state heating requirement of active region loops.

  16. Investigation of microscale shock phenomena using a line-imaging optically recording velocity interferometer system

    SciTech Connect (OSTI)

    Trott, W.M.; Asay, J.R.

    1998-07-01

    An optically recording velocity interferometer system (ORVIS) can be operated in a line-imaging configuration that effectively combines subnanosecond temporal resolution with high spatial resolution (length scales{lt}10{mu}m). This technique easily captures very small temporal variations in the onset of motion across the face of a small-scale (400-{mu}m diameter) laser-driven flyer. In another application, line-imaging ORVIS has been used to obtain spatially resolved particle velocity vs. time information at flyer impact on a lithium fluoride witness plate. Subnanosecond differences in flyer arrival time are clearly resolved and the results also show subtle amplitude variations in the pulse delivered at different locations of the acceptor. Observed velocity field variations in laser acceleration of a patterned flyer target demonstrate the feasibility of using line ORVIS in studies of instability formation and growth. These results indicate that this diagnostic can be applied to a wide variety of shock phenomena. {copyright} {ital 1998 American Institute of Physics.}

  17. RADIATION WAVE DETECTION

    DOE Patents [OSTI]

    Wouters, L.F.

    1960-08-30

    Radiation waves can be detected by simultaneously measuring radiation- wave intensities at a plurality of space-distributed points and producing therefrom a plot of the wave intensity as a function of time. To this end. a detector system is provided which includes a plurality of nuclear radiation intensity detectors spaced at equal radial increments of distance from a source of nuclear radiation. Means are provided to simultaneously sensitize the detectors at the instant a wave of radiation traverses their positions. the detectors producing electrical pulses indicative of wave intensity. The system further includes means for delaying the pulses from the detectors by amounts proportional to the distance of the detectors from the source to provide an indication of radiation-wave intensity as a function of time.

  18. Coiled tubing velocity strings keep wells unloaded

    SciTech Connect (OSTI)

    Wesson, H.R.; Shursen, J.L.

    1989-07-01

    Liquid loading is a problem in many older and even some newer gas wells, particularly in pressure depletion type reservoirs. This liquid loading results in decreased production and may even kill the well. The use of coiled tubing as a velocity string (or siphon string) has proved to be an economically viable alternative to allow continued and thus, increased cumulative production for wells experiencing liquid loading problems. Coiled tubing run inside the existing production string reduces the flow area, whether the well is produced up the tubing or up the annulus. This reduction in flow area results in an increase in flow velocity and thus, an increase in the well's ability to unload fluids.

  19. Characteristics of transverse waves in chromospheric mottles

    SciTech Connect (OSTI)

    Kuridze, D.; Mathioudakis, M.; Jess, D. B.; Keenan, F. P. [Astrophysics Research Center, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN (United Kingdom); Verth, G.; Erdlyi, R. [Solar Physics and Space Plasma Research Center (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Morton, R. J. [Mathematics and Information Science, Northumbria University, Camden Street, Newcastle Upon Tyne NE1 8ST (United Kingdom); Christian, D. J., E-mail: dkuridze01@qub.ac.uk [Department of Physics and Astronomy, California State University, Northridge, CA 91330 (United States)

    2013-12-10

    Using data obtained by the high temporal and spatial resolution Rapid Oscillations in the Solar Atmosphere instrument on the Dunn Solar Telescope, we investigate at an unprecedented level of detail transverse oscillations in chromospheric fine structures near the solar disk center. The oscillations are interpreted in terms of propagating and standing magnetohydrodynamic kink waves. Wave characteristics including the maximum transverse velocity amplitude and the phase speed are measured as a function of distance along the structure's length. Solar magnetoseismology is applied to these measured parameters to obtain diagnostic information on key plasma parameters (e.g., magnetic field, density, temperature, flow speed) of these localized waveguides. The magnetic field strength of the mottle along the ?2 Mm length is found to decrease by a factor of 12, while the local plasma density scale height is ?280 80 km.

  20. Radial velocities of southern visual multiple stars

    SciTech Connect (OSTI)

    Tokovinin, Andrei; Pribulla, Theodor; Fischer, Debra E-mail: pribulla@ta3.sk

    2015-01-01

    High-resolution spectra of visual multiple stars were taken in 20082009 to detect or confirm spectroscopic subsystems and to determine their orbits. Radial velocities of 93 late-type stars belonging to visual multiple systems were measured by numerical cross-correlation. We provide the individual velocities, the width, and the amplitude of the Gaussians that approximate the correlations. The new information on the multiple systems resulting from these data is discussed. We discovered double-lined binaries in HD 41742B, HD 56593C, and HD 122613AB, confirmed several other known subsystems, and constrained the existence of subsystems in some visual binaries where both components turned out to have similar velocities. The orbits of double-lined subsystems with periods of 148 and 13 days are computed for HD 104471 Aa,Ab and HD 210349 Aa,Ab, respectively. We estimate individual magnitudes and masses of the components in these triple systems and update the outer orbit of HD 104471 AB.

  1. Radial velocity curves of ellipsoidal red giant binaries in the Large Magellanic Cloud

    SciTech Connect (OSTI)

    Nie, J. D.; Wood, P. R. E-mail: peter.wood@anu.edu.au

    2014-12-01

    Ellipsoidal red giant binaries are close binary systems where an unseen, relatively close companion distorts the red giant, leading to light variations as the red giant moves around its orbit. These binaries are likely to be the immediate evolutionary precursors of close binary planetary nebula and post-asymptotic giant branch and post-red giant branch stars. Due to the MACHO and OGLE photometric monitoring projects, the light variability nature of these ellipsoidal variables has been well studied. However, due to the lack of radial velocity curves, the nature of their masses, separations, and other orbital details has so far remained largely unknown. In order to improve this situation, we have carried out spectral monitoring observations of a large sample of 80 ellipsoidal variables in the Large Magellanic Cloud and we have derived radial velocity curves. At least 12 radial velocity points with good quality were obtained for most of the ellipsoidal variables. The radial velocity data are provided with this paper. Combining the photometric and radial velocity data, we present some statistical results related to the binary properties of these ellipsoidal variables.

  2. Compositional Variation Within Hybrid Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Compositional Variation Within Hybrid Nanostructures Compositional Variation Within Hybrid Nanostructures Print Wednesday, 29 September 2010 00:00 The inherently high surface area...

  3. Three-dimensional P and S waves velocity structures of the Coso...

    Open Energy Info (EERE)

    synthetic modeling of a cross model at critical locations, is estimated to be 0.35 km for V (sub p ) and 0.5 km for V (sub s ) . Model uncertainties are estimated by a jackknife...

  4. FILTER FOR HIGH VELOCITY GAS STREAMS

    DOE Patents [OSTI]

    Heckman, R.A.; Warner, H.F.

    1963-11-01

    An air filter that is particularly useful in air-sampling rockets is presented. The filter comprises a cellulose fiber mat having an evenly disposed thin coating of stearic acid. Protective loose weave fabric covers are stitched to the front and back of the fiber mat, the stitching being in the form of a sine wave spiraled from the midpoint of the mat out to its periphery. (AEC)

  5. In-phase waves: Their behavior, internal stratification and fabric

    SciTech Connect (OSTI)

    Cheel, R.J. (Brock Univ., St. Catharines, Ontario (Canada). Dept. of Earth Sciences); Udri, A. (Freiburg Univ. (Germany). Dept. of Geologie)

    1993-03-01

    Experiments were conducted in 0.305m wide, 9m long recirculating sediment flume on a bed of quartz sand (mean diameter of 0.18mm). The experiments included eight runs over the following range of conditions: 0.0605m [<=] depth [<=] 0.068m, 0.51m/s [<=] mean flow velocity [<=] 0.90m/s and 0.63 [<=] Froze Number (F) [<=] 1.1. For F < 0.83 dunes were the dominant bedform and these became longer and lower as F increased. At F = 0.83 the bed was nominally plane but locally and temporarily developed low in-phase waves or dunes. Post-run bed profiles showed symmetrical bedwaves with average length (L) of 0.26m and average height (H) of 0.005m. A complete cycle was characterized by: increased height of bed and water surface waves [r arrow] upstream migration [r arrow] breaking or decay [r arrow] planing of bed surface [r arrow] growth of new in-phase waves (initially migrating downstream and then remaining stationary during continued vertical growth). Each in-phase wave normally behaved independently of other waves although less commonly a breaking wave would trigger breaking of the next downstream wave. For F > 1.0 in-phase waves behaved as described above but a breaking wave would more commonly cause breaking of other waves. With increasing F it became more common for waves to break and rebuild quickly without complete planing of the bed surface. However, complete cycles occurred frequently with the following significant differences: (1) the upstream-migrating antidune developed upstream slopes that approached 25[degree]; (2) planing was accomplished by the rapid migration of a low, asymmetrical bedform through the antidune trough.

  6. Kinetic Theory of Plasma Waves - Part I: Introduction

    SciTech Connect (OSTI)

    Lamalle, P.U

    2004-03-15

    The kinetic description of linear waves in plasmas is succinctly presented, with emphasis on applications to high-frequency (hf) wave heating and current drive. The Maxwell-Vlasov system of equations is introduced. Its two-timescale analysis yields the linearized Vlasov and the quasilinear Fokker-Planck equations. The standard guiding centre and Hamiltonian formalisms are presented. Two formulations of the hf plasma wave equation are given: as a partial differential equation to hold at each position, and as a global Galerkin ('variational') form.

  7. PROTOSTELLAR JETS ENCLOSED BY LOW-VELOCITY OUTFLOWS

    SciTech Connect (OSTI)

    Machida, Masahiro N.

    2014-11-20

    A protostellar jet and outflow are calculated for ?270yr following the protostar formation using a three-dimensional magnetohydrodynamics simulation, in which both the protostar and its parent cloud are spatially resolved. A high-velocity (?100 km s{sup 1}) jet with good collimation is driven near the disk's inner edge, while a low-velocity (? 10 km s{sup 1}) outflow with a wide opening angle appears in the outer-disk region. The high-velocity jet propagates into the low-velocity outflow, forming a nested velocity structure in which a narrow high-velocity flow is enclosed by a wide low-velocity flow. The low-velocity outflow is in a nearly steady state, while the high-velocity jet appears intermittently. The time-variability of the jet is related to the episodic accretion from the disk onto the protostar, which is caused by gravitational instability and magnetic effects such as magnetic braking and magnetorotational instability. Although the high-velocity jet has a large kinetic energy, the mass and momentum of the jet are much smaller than those of the low-velocity outflow. A large fraction of the infalling gas is ejected by the low-velocity outflow. Thus, the low-velocity outflow actually has a more significant effect than the high-velocity jet in the very early phase of the star formation.

  8. Variational transition state theory

    SciTech Connect (OSTI)

    Truhlar, D.G.

    1993-12-01

    This research program involves the development of variational transition state theory (VTST) and semiclassical tunneling methods for the calculation of gas-phase reaction rates and selected applications. The applications are selected for their fundamental interest and/or their relevance to combustion.

  9. SQUARE WAVE AMPLIFIER

    DOE Patents [OSTI]

    Leavitt, M.A.; Lutz, I.C.

    1958-08-01

    An amplifier circuit is described for amplifying sigmals having an alternating current component superimposed upon a direct current component, without loss of any segnnent of the alternating current component. The general circuit arrangement includes a vibrator, two square wave amplifiers, and recombination means. The amplifier input is connected to the vibrating element of the vibrator and is thereby alternately applied to the input of each square wave amplifier. The detailed circuitry of the recombination means constitutes the novelty of the annplifier and consists of a separate, dual triode amplifier coupled to the output of each square wave amplifier with a recombination connection from the plate of one amplifier section to a grid of one section of the other amplifier. The recombination circuit has provisions for correcting distortion caused by overlapping of the two square wave voltages from the square wave amplifiers.

  10. On the fully nonlinear acoustic waves in a plasma with positrons beam impact and superthermal electrons

    SciTech Connect (OSTI)

    Ali Shan, S.; National Centre For Physics , Shahdra Valley Road, 44000 Islamabad; Pakistan Institute of Engineering and Applied Sciences , Islamabad ; El-Tantawy, S. A.; Moslem, W. M.

    2013-08-15

    Arbitrary amplitude ion-acoustic waves in an unmagnetized plasma consisting of cold positive ions, superthermal electrons, and positrons beam are reported. The basic set of fluid equations is reduced to an energy-balance like equation. The latter is numerically analyzed to examine the existence regions for solitary and shock waves. It is found that only solitary waves can propagate, however, the model cannot support shocks. The effects of superthermality and beam parameters (via, positrons concentration and streaming velocity) on the existence region, as well as solitary wave profile have been discussed.

  11. 1-D seismic velocity model and hypocenter relocation using double difference method around West Papua region

    SciTech Connect (OSTI)

    Sabtaji, Agung E-mail: agung.sabtaji@bmkg.go.id; Nugraha, Andri Dian

    2015-04-24

    West Papua region has fairly high of seismicity activities due to tectonic setting and many inland faults. In addition, the region has a unique and complex tectonic conditions and this situation lead to high potency of seismic hazard in the region. The precise earthquake hypocenter location is very important, which could provide high quality of earthquake parameter information and the subsurface structure in this region to the society. We conducted 1-D P-wave velocity using earthquake data catalog from BMKG for April, 2009 up to March, 2014 around West Papua region. The obtained 1-D seismic velocity then was used as input for improving hypocenter location using double-difference method. The relocated hypocenter location shows fairly clearly the pattern of intraslab earthquake beneath New Guinea Trench (NGT). The relocated hypocenters related to the inland fault are also observed more focus in location around the fault.

  12. Alfven-wave particle interaction in finite-dimensional self-consistent field model

    SciTech Connect (OSTI)

    Padhye, N.; Horton, W.

    1998-10-09

    A low-dimensional Hamiltonian model is derived for the acceleration of ions in finite amplitude Alfven waves in a finite pressure plasma sheet. The reduced low-dimensional wave-particle Hamiltonian is useful for describing the reaction of the accelerated ions on the wave amplitudes and phases through the self-consistent fields within the envelope approximation. As an example, the authors show for a single Alfven wave in the central plasma sheet of the Earth`s geotail, modeled by the linear pinch geometry called the Harris sheet, the time variation of the wave amplitude during the acceleration of fast protons.

  13. Method and apparatus for millimeter-wave detection of thermal waves for materials evaluation

    DOE Patents [OSTI]

    Gopalsami, Nachappa; Raptis, Apostolos C.

    1991-01-01

    A method and apparatus for generating thermal waves in a sample and for measuring thermal inhomogeneities at subsurface levels using millimeter-wave radiometry. An intensity modulated heating source is oriented toward a narrow spot on the surface of a material sample and thermal radiation in a narrow volume of material around the spot is monitored using a millimeter-wave radiometer; the radiometer scans the sample point-by-point and a computer stores and displays in-phase and quadrature phase components of thermal radiations for each point on the scan. Alternatively, an intensity modulated heating source is oriented toward a relatively large surface area in a material sample and variations in thermal radiation within the full field of an antenna array are obtained using an aperture synthesis radiometer technique.

  14. Wave-wave interactions in solar type III radio bursts

    SciTech Connect (OSTI)

    Thejappa, G.; MacDowall, R. J.

    2014-02-11

    The high time resolution observations from the STEREO/WAVES experiment show that in type III radio bursts, the Langmuir waves often occur as localized magnetic field aligned coherent wave packets with durations of a few ms and with peak intensities well exceeding the strong turbulence thresholds. Some of these wave packets show spectral signatures of beam-resonant Langmuir waves, down- and up-shifted sidebands, and ion sound waves, with frequencies, wave numbers, and tricoherences satisfying the resonance conditions of the oscillating two stream instability (four wave interaction). The spectra of a few of these wave packets also contain peaks at f{sub pe}, 2f{sub pe} and 3 f{sub pe} (f{sub pe} is the electron plasma frequency), with frequencies, wave numbers and bicoherences (computed using the wavelet based bispectral analysis techniques) satisfying the resonance conditions of three wave interactions: (1) excitation of second harmonic electromagnetic waves as a result of coalescence of two oppositely propagating Langmuir waves, and (2) excitation of third harmonic electromagnetic waves as a result of coalescence of Langmuir waves with second harmonic electromagnetic waves. The implication of these findings is that the strong turbulence processes play major roles in beam stabilization as well as conversion of Langmuir waves into escaping radiation in type III radio bursts.

  15. Seismic Technology Adapted to Analyzing and Developing Geothermal Systems Below Surface-Exposed High-Velocity Rocks Final Report

    SciTech Connect (OSTI)

    Hardage, Bob A.; DeAngelo, Michael V.; Ermolaeva, Elena; Hardage, Bob A.; Remington, Randy; Sava, Diana; Wagner, Donald; Wei, Shuijion

    2013-02-01

    The objective of our research was to develop and demonstrate seismic data-acquisition and data-processing technologies that allow geothermal prospects below high-velocity rock outcrops to be evaluated. To do this, we acquired a 3-component seismic test line across an area of exposed high-velocity rocks in Brewster County, Texas, where there is high heat flow and surface conditions mimic those found at numerous geothermal prospects. Seismic contractors have not succeeded in creating good-quality seismic data in this area for companies who have acquired data for oil and gas exploitation purposes. Our test profile traversed an area where high-velocity rocks and low-velocity sediment were exposed on the surface in alternating patterns that repeated along the test line. We verified that these surface conditions cause non-ending reverberations of Love waves, Rayleigh waves, and shallow critical refractions to travel across the earth surface between the boundaries of the fast-velocity and slow-velocity material exposed on the surface. These reverberating surface waves form the high level of noise in this area that does not allow reflections from deep interfaces to be seen and utilized. Our data-acquisition method of deploying a box array of closely spaced geophones allowed us to recognize and evaluate these surface-wave noise modes regardless of the azimuth direction to the surface anomaly that backscattered the waves and caused them to return to the test-line profile. With this knowledge of the surface-wave noise, we were able to process these test-line data to create P-P and SH-SH images that were superior to those produced by a skilled seismic data-processing contractor. Compared to the P-P data acquired along the test line, the SH-SH data provided a better detection of faults and could be used to trace these faults upward to the boundaries of exposed surface rocks. We expanded our comparison of the relative value of S-wave and P-wave seismic data for geothermal

  16. Peculiarity of convergence of shock wave generated by underwater electrical explosion of ring-shaped wire

    SciTech Connect (OSTI)

    Shafer, D.; Toker, G. R.; Gurovich, V. Tz.; Gleizer, S.; Krasik, Ya. E.

    2013-05-15

    Nanosecond timescale underwater electrical wire explosions of ring-shaped Cu wires were investigated using a pulsed generator with a current amplitude up to 50 kA. It was shown that this type of wire explosion results in the generation of a toroidal shock wave (SW). Time- and space-resolved optical diagnostics were used to determine azimuthal uniformity of the shock wave front and its velocity. It was found that the shock wave preserves its circular front shape in the range of radii 50?mwave propagates with a constant velocity of v{sub sw}=1.2M, where M is the Mach number. The dynamics of the leading part of the shock wave, based on the oblique shock wave theory, is presented, explaining the constant velocity of the shock wave.

  17. Modeling coiled tubing velocity strings for gas wells

    SciTech Connect (OSTI)

    Martinez, J.; Martinez, A.

    1995-12-31

    Multiphase flowing pressure and velocity prediction models are necessary to coiled tubing velocity string design. A model used by most of the coiled tubing service companies or manufacturers is reviewed. Guidance is provided for selecting a coiled tubing of the proper size. The steps include: (1) Measured data matching; (2) Fluid property adjustment; (3) Pressure, velocity, and holdup selection; (4) Correlation choice; (5) Coiled tubing selection. A velocity range for the lift of liquid is given.

  18. Amplitude variations on the Extreme Adaptive Optics testbed

    SciTech Connect (OSTI)

    Evans, J; Thomas, S; Dillon, D; Gavel, D; Phillion, D; Macintosh, B

    2007-08-14

    High-contrast adaptive optics systems, such as those needed to image extrasolar planets, are known to require excellent wavefront control and diffraction suppression. At the Laboratory for Adaptive Optics on the Extreme Adaptive Optics testbed, we have already demonstrated wavefront control of better than 1 nm rms within controllable spatial frequencies. Corresponding contrast measurements, however, are limited by amplitude variations, including those introduced by the micro-electrical-mechanical-systems (MEMS) deformable mirror. Results from experimental measurements and wave optic simulations of amplitude variations on the ExAO testbed are presented. We find systematic intensity variations of about 2% rms, and intensity variations with the MEMS to be 6%. Some errors are introduced by phase and amplitude mixing because the MEMS is not conjugate to the pupil, but independent measurements of MEMS reflectivity suggest that some error is introduced by small non-uniformities in the reflectivity.

  19. Plane shock wave studies of Westerly granite and Nugget sandstone

    SciTech Connect (OSTI)

    Larson, D.B.; Anderson, G.D.

    1980-12-01

    Plane shock wave experiments were performed by using a light-gas gun on dry and water-saturated Westerly granite and dry Nugget sandstone. Changes in the slopes of the shock velocity versus particle velocity curves at 2 to 3 GPa and 1 to 2 GPa for dry granite and for dry sandstone, respectively, are attributed to the onset of pore collapse. However, there is little apparent loss of shear strength in either dry rock over the stress range of the experiments (i.e., 9.3 GPa in Westerly granite and 9.2 GPa in Nugget sandstone). Agreement between the shock wave data and quasistatic, uniaxial strain data for the dry rock implies the absence of rate-dependence in uniaxial strain. The shock data on saturated granite agree well with those for dry granite, thus suggesting there was no loss in shear strength as a result of pore pressure buildup.

  20. WindWaveFloat

    SciTech Connect (OSTI)

    Weinstein, Alla

    2011-11-01

    Presentation from the 2011 Water Peer Review includes in which principal investigator Alla Weinstein discusses project progress in development of a floating offshore wind structure - the WindFloat - and incorporation therin of a Spherical Wave Energy Device.

  1. Surface-wave and refraction tomography at the FACT Site, Sandia National Laboratories, Albuquerque, New Mexico.

    SciTech Connect (OSTI)

    Abbott, Robert E.; Bartel, Lewis Clark; Pullammanappallil, Satish; Engler, Bruce Phillip

    2006-08-01

    We present a technique that allows for the simultaneous acquisition and interpretation of both shear-wave and compressive-wave 3-D velocities. The technique requires no special seismic sources or array geometries, and is suited to studies with small source-receiver offsets. The method also effectively deals with unwanted seismic arrivals by using the statistical properties of the data itself to discriminate against spurious picks. We demonstrate the technique with a field experiment at the Facility for Analysis, Calibration, and Testing at Sandia National Laboratories, Albuquerque, New Mexico. The resulting 3-D shear-velocity and compressive-velocity distributions are consistent with surface geologic mapping. The averaged velocities and V{sub p}/V{sub s} ratio in the upper 30 meters are also consistent with examples found in the scientific literature.

  2. Wave Propagation Program

    Energy Science and Technology Software Center (OSTI)

    2007-01-08

    WPP is a massively parallel, 3D, C++, finite-difference elastodynamic wave propagation code. Typical applications for wave propagation with WPP include: evaluation of seismic event scenarios and damage from earthquakes, non-destructive evaluation of materials, underground facility detection, oil and gas exploration, predicting the electro-magnetic fields in accelerators, and acoustic noise generation. For more information, see User’s Manual [1].

  3. Gravitational Waves Community Lecture

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Gravitational Waves Community Lecture Gravitational Waves Community Lecture WHEN: Sep 19, 2016 7:30 PM - 8:30 PM WHERE: Grand Ballroom at the Eldorado Hotel 309 W San Francisco St Santa Fe, New Mexico 87501 USA (505) 988-4455 SPEAKER: Gabriela Gonzalez CONTACT: Linda Anderman (505) 665-9196 CATEGORY: Bradbury INTERNAL: Calendar Login Event Description Sponsored by Los Alamos National Laboratory, University of New Mexico, St. John's College and Santa Fe Community College The Los Alamos National

  4. Filament velocity scaling laws for warm ions

    SciTech Connect (OSTI)

    Manz, P.; Max-Planck-Institut fr Plasmaphysik, EURATOM Assoziation, Boltzmannstr. 2, 85748 Garching ; Carralero, D.; Birkenmeier, G.; Mller, H. W.; Scott, B. D.; Mller, S. H.; Fuchert, G.; Stroth, U.; Physik-Department E28, Technische Universitt Mnchen, James-Franck-Str. 1, 85748 Garching

    2013-10-15

    The dynamics of filaments or blobs in the scrape-off layer of magnetic fusion devices are studied by magnitude estimates of a comprehensive drift-interchange-Alfvn fluid model. The standard blob models are reproduced in the cold ion case. Even though usually neglected, in the scrape-off layer, the ion temperature can exceed the electron temperature by an order of magnitude. The ion pressure affects the dynamics of filaments amongst others by adding up to the interchange drive and the polarisation current. It is shown how both effects modify the scaling laws for filament velocity in dependence of its size. Simplifications for experimentally relevant limit regimes are given. These are the sheath dissipation, collisional, and electromagnetic regime.

  5. THE EFFECT OF THE PRE-DETONATION STELLAR INTERNAL VELOCITY PROFILE ON THE NUCLEOSYNTHETIC YIELDS IN TYPE Ia SUPERNOVA

    SciTech Connect (OSTI)

    Kim, Yeunjin; Jordan, G. C. IV; Graziani, Carlo; Lamb, D. Q.; Truran, J. W.; Meyer, B. S.

    2013-07-01

    A common model of the explosion mechanism of Type Ia supernovae is based on a delayed detonation of a white dwarf. A variety of models differ primarily in the method by which the deflagration leads to a detonation. A common feature of the models, however, is that all of them involve the propagation of the detonation through a white dwarf that is either expanding or contracting, where the stellar internal velocity profile depends on both time and space. In this work, we investigate the effects of the pre-detonation stellar internal velocity profile and the post-detonation velocity of expansion on the production of {alpha}-particle nuclei, including {sup 56}Ni, which are the primary nuclei produced by the detonation wave. We perform one-dimensional hydrodynamic simulations of the explosion phase of the white dwarf for center and off-center detonations with five different stellar velocity profiles at the onset of the detonation. In order to follow the complex flows and to calculate the nucleosynthetic yields, approximately 10,000 tracer particles were added to every simulation. We observe two distinct post-detonation expansion phases: rarefaction and bulk expansion. Almost all the burning to {sup 56}Ni occurs only in the rarefaction phase, and its expansion timescale is influenced by pre-existing flow structure in the star, in particular by the pre-detonation stellar velocity profile. We find that the mass fractions of the {alpha}-particle nuclei, including {sup 56}Ni, are tight functions of the empirical physical parameter {rho}{sub up}/v{sub down}, where {rho}{sub up} is the mass density immediately upstream of the detonation wave front and v{sub down} is the velocity of the flow immediately downstream of the detonation wave front. We also find that v{sub down} depends on the pre-detonation flow velocity. We conclude that the properties of the pre-existing flow, in particular the internal stellar velocity profile, influence the final isotopic composition of burned

  6. The circular velocity function of group galaxies

    SciTech Connect (OSTI)

    Abramson, Louis E.; Williams, Rik J.; Benson, Andrew J.; Kollmeier, Juna A.; Mulchaey, John S.

    2014-09-20

    A robust prediction of ΛCDM cosmology is the halo circular velocity function (CVF), a dynamical cousin of the halo mass function. The correspondence between theoretical and observed CVFs is uncertain, however: cluster galaxies are reported to exhibit a power-law CVF consistent with N-body simulations, but that of the field is distinctly Schechter-like, flattened compared to ΛCDM expectations at circular velocities v {sub c} ≲ 200 km s{sup –1}. Groups offer a powerful probe of the role environment plays in this discrepancy as they bridge the field and clusters. Here, we construct the CVF for a large, mass- and multiplicity-complete sample of group galaxies from the Sloan Digital Sky Survey. Using independent photometric v {sub c} estimators, we find no transition from field to ΛCDM-shaped CVF above v {sub c} = 50 km s{sup –1} as a function of group halo mass. All groups with 12.4 ≲ log M {sub halo}/M {sub ☉} ≲ 15.1 (Local Group analogs to rich clusters) display similar Schechter-like CVFs marginally suppressed at low v {sub c} compared to that of the field. Conversely, some agreement with N-body results emerges for samples saturated with late-type galaxies, with isolated late-types displaying a CVF similar in shape to ΛCDM predictions. We conclude that the flattening of the low-v {sub c} slope in groups is due to their depressed late-type fractions—environment affecting the CVF only to the extent that it correlates with this quantity—and that previous cluster analyses may suffer from interloper contamination. These results serve as useful benchmarks for cosmological simulations of galaxy formation.

  7. QUASI-PERIODIC FAST-MODE WAVE TRAINS WITHIN A GLOBAL EUV WAVE AND SEQUENTIAL TRANSVERSE OSCILLATIONS DETECTED BY SDO/AIA

    SciTech Connect (OSTI)

    Liu Wei; Nitta, Nariaki V.; Aschwanden, Markus J.; Schrijver, Carolus J.; Title, Alan M.; Tarbell, Theodore D.; Ofman, Leon

    2012-07-01

    We present the first unambiguous detection of quasi-periodic wave trains within the broad pulse of a global EUV wave (so-called EIT wave) occurring on the limb. These wave trains, running ahead of the lateral coronal mass ejection (CME) front of 2-4 times slower, coherently travel to distances {approx}> R{sub Sun }/2 along the solar surface, with initial velocities up to 1400 km s{sup -1} decelerating to {approx}650 km s{sup -1}. The rapid expansion of the CME initiated at an elevated height of 110 Mm produces a strong downward and lateral compression, which may play an important role in driving the primary EUV wave and shaping its front forwardly inclined toward the solar surface. The wave trains have a dominant 2 minute periodicity that matches the X-ray flare pulsations, suggesting a causal connection. The arrival of the leading EUV wave front at increasing distances produces an uninterrupted chain sequence of deflections and/or transverse (likely fast kink mode) oscillations of local structures, including a flux-rope coronal cavity and its embedded filament with delayed onsets consistent with the wave travel time at an elevated (by {approx}50%) velocity within it. This suggests that the EUV wave penetrates through a topological separatrix surface into the cavity, unexpected from CME-caused magnetic reconfiguration. These observations, when taken together, provide compelling evidence of the fast-mode MHD wave nature of the primary (outer) fast component of a global EUV wave, running ahead of the secondary (inner) slow component of CME-caused restructuring.

  8. Jeans instability of a dusty plasma with dust charge variations

    SciTech Connect (OSTI)

    Hakimi Pajouh, H. Afshari, N.

    2015-09-15

    The effect of the dust charge variations on the stability of a self-gravitating dusty plasma has been theoretically investigated. The dispersion relation for the dust-acoustic waves in a self-gravitating dusty plasma is obtained. It is shown that the dust charge variations have significant effects. It increases the growth rate of instability and the instability cutoff wavenumbers. It is found that by increasing the value of the ions temperature and the absolute value of the equilibrium dust charge, the cutoff wavenumber decreases and the stability region is extended.

  9. Interaction of a nonlinear spin-wave and magnetic soliton in a uniaxial anisotropic ferromagnet

    SciTech Connect (OSTI)

    Li Zaidong Li Qiuyan; He Pengbin; Bai Zhanguo; Sun Yubao

    2007-12-15

    We study the interaction of a nonlinear spin-wave and magnetic soliton in a uniaxial anisotropic ferromagnet. By means of a reasonable assumption and a straightforward Darboux transformation one- and two-soliton solutions in a nonlinear spin-wave background are obtained analytically, and their properties are discussed in detail. On the background of a nonlinear spin-wave the amplitude of the envelope soliton has the spatial and temporal period, and soliton can be trapped only in space. The amplitude and wave number of spin-wave have the different contribution to the width, velocity, and amplitude of soliton solutions. The envelope of solution hold the shape of soliton, and the amplitude of each envelope soliton keeps invariability before and after collision which shows the elastic collision of two envelope soliton on the background of a nonlinear spin-wave.

  10. Numerical wave propagation on non-uniform one-dimensional staggered grids

    SciTech Connect (OSTI)

    Long, D.; Thuburn, J.

    2011-04-01

    The wave propagation behaviour of centered difference schemes on one-dimensional non-uniform staggered grids is investigated. Previous results for the linear advection equation are extended to the case of the shallow water equations on staggered grids. For waves of a given frequency, the wave field is decomposed into right- and left-propagating components, and a wave energy conservation law is derived in terms of these components. For slowly varying grids, separate evolution equations for the right- and left-propagating components are derived, leading to the result that there is asymptotically no reflection in the limit of a slowly varying grid, provided that waves of that frequency are resolvable. However, there will be reflection from any location at which the wave group velocity goes to zero. The possibility for wave energy to tunnel through a narrow region of the grid too coarse for propagation is noted. Grids with an abrupt jump in resolution are also investigated. It is possible to tailor the scheme at the jump to minimize spurious wave reflection over a range of frequencies provided the waves are resolvable on both sides of the jump. However, it does not appear possible to avoid complete reflection, except by introducing extra dissipation terms, if the waves are not resolvable on one side of the jump. An example is presented of a second-order accurate scheme that spontaneously radiates waves from the resolution jump.

  11. System and method to estimate compressional to shear velocity (VP/VS) ratio in a region remote from a borehole

    DOE Patents [OSTI]

    Vu, Cung; Nihei, Kurt T; Schmitt, Denis P; Skelt, Christopher; Johnson, Paul A; Guyer, Robert; TenCate, James A; Le Bas, Pierre-Yves

    2012-10-16

    In some aspects of the disclosure, a method for creating three-dimensional images of non-linear properties and the compressional to shear velocity ratio in a region remote from a borehole using a conveyed logging tool is disclosed. In some aspects, the method includes arranging a first source in the borehole and generating a steered beam of elastic energy at a first frequency; arranging a second source in the borehole and generating a steerable beam of elastic energy at a second frequency, such that the steerable beam at the first frequency and the steerable beam at the second frequency intercept at a location away from the borehole; receiving at the borehole by a sensor a third elastic wave, created by a three wave mixing process, with a frequency equal to a difference between the first and second frequencies and a direction of propagation towards the borehole; determining a location of a three wave mixing region based on the arrangement of the first and second sources and on properties of the third wave signal; and creating three-dimensional images of the non-linear properties using data recorded by repeating the generating, receiving and determining at a plurality of azimuths, inclinations and longitudinal locations within the borehole. The method is additionally used to generate three dimensional images of the ratio of compressional to shear acoustic velocity of the same volume surrounding the borehole.

  12. The preliminary results: Seismic ambient noise Rayleigh wave tomography around Merapi volcano, central Java, Indonesia

    SciTech Connect (OSTI)

    Trichandi, Rahmantara; Yudistira, Tedi; Nugraha, Andri Dian; Zulhan, Zulfakriza; Saygin, Erdinc

    2015-04-24

    Ambient noise tomography is relatively a new method for imaging the shallow structure of the Earth subsurface. We presents the application of this method to produce a Rayleigh wave group velocity maps around the Merapi Volcano, Central Java. Rayleigh waves group velocity maps were reconstructed from the cross-correlation of ambient noise recorded by the DOMERAPI array which consists 43 broadband seismometers. In the processing stage, we first filtered the observation data to separatethe noise from the signal that dominated by the strong volcanic activities. Next, we cross-correlate the filtered data and stack to obtain the Green’s function for all possible station pairs. Then we carefully picked the peak of each Green’s function to estimate the dispersion trend and appliedMultiple Filter Technique to obtain the dispersion curve. Inter-station group velocity curvesare inverted to produceRayleigh wave group velocity maps for periods 1 to 10 s. The resulted Rayleigh group velocity maps show the interesting features around the Merapi Volcano which generally agree with the previous studies. Merapi-Lawu Anomaly (MLA) is emerged as a relatively low anomaly in our group velocity maps.

  13. Scattering of matter waves in spatially inhomogeneous environments

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tsitoura, F.; Krüger, P.; Kevrekidis, P. G.; Frantzeskakis, D. J.

    2015-03-30

    In this article, we study scattering of quasi-one-dimensional matter waves at an interface of two spatial domains, one with repulsive and one with attractive interatomic interactions. It is shown that the incidence of a Gaussian wave packet from the repulsive to the attractive region gives rise to generation of a soliton train. More specifically, the number of emergent solitons can be controlled, e.g., by the variation of the amplitude or the width of the incoming wave packet. Furthermore, we study the reflectivity of a soliton incident from the attractive region to the repulsive one. We find the reflection coefficient numericallymore » and employ analytical methods, which treat the soliton as a particle (for moderate and large amplitudes) or a quasilinear wave packet (for small amplitudes), to determine the critical soliton momentum (as a function of the soliton amplitude) for which total reflection is observed.« less

  14. Scattering of matter waves in spatially inhomogeneous environments

    SciTech Connect (OSTI)

    Tsitoura, F.; Krüger, P.; Kevrekidis, P. G.; Frantzeskakis, D. J.

    2015-03-30

    In this article, we study scattering of quasi-one-dimensional matter waves at an interface of two spatial domains, one with repulsive and one with attractive interatomic interactions. It is shown that the incidence of a Gaussian wave packet from the repulsive to the attractive region gives rise to generation of a soliton train. More specifically, the number of emergent solitons can be controlled, e.g., by the variation of the amplitude or the width of the incoming wave packet. Furthermore, we study the reflectivity of a soliton incident from the attractive region to the repulsive one. We find the reflection coefficient numerically and employ analytical methods, which treat the soliton as a particle (for moderate and large amplitudes) or a quasilinear wave packet (for small amplitudes), to determine the critical soliton momentum (as a function of the soliton amplitude) for which total reflection is observed.

  15. Eulerian simulations of collisional effects on electrostatic plasma waves

    SciTech Connect (OSTI)

    Pezzi, Oreste; Valentini, Francesco; Perrone, Denise; Veltri, Pierluigi [Dipartimento di Fisica and CNISM, Universit della Calabria, 87036 Rende (CS) (Italy)] [Dipartimento di Fisica and CNISM, Universit della Calabria, 87036 Rende (CS) (Italy)

    2013-09-15

    The problem of collisions in a plasma is a wide subject with a huge historical literature. In fact, the description of realistic plasmas is a tough problem to attack, both from the theoretical and the numerical point of view. In this paper, a Eulerian time-splitting algorithm for the study of the propagation of electrostatic waves in collisional plasmas is presented. Collisions are modeled through one-dimensional operators of the Fokker-Planck type, both in linear and nonlinear forms. The accuracy of the numerical code is discussed by comparing the numerical results to the analytical predictions obtained in some limit cases when trying to evaluate the effects of collisions in the phenomenon of wave plasma echo and collisional dissipation of Bernstein-Greene-Kruskal waves. Particular attention is devoted to the study of the nonlinear Dougherty collisional operator, recently used to describe the collisional dissipation of electron plasma waves in a pure electron plasma column [M. W. Anderson and T. M. O'Neil, Phys. Plasmas 14, 112110 (2007)]. Finally, for the study of collisional plasmas, a recipe to set the simulation parameters in order to prevent the filamentation problem can be provided, by exploiting the property of velocity diffusion operators to smooth out small velocity scales.

  16. ENERGY CONTENT AND PROPAGATION IN TRANSVERSE SOLAR ATMOSPHERIC WAVES

    SciTech Connect (OSTI)

    Goossens, M.; Van Doorsselaere, T.; Soler, R.; Verth, G.

    2013-05-10

    Recently, a significant amount of transverse wave energy has been estimated propagating along solar atmospheric magnetic fields. However, these estimates have been made with the classic bulk Alfven wave model which assumes a homogeneous plasma. In this paper, the kinetic, magnetic, and total energy densities and the flux of energy are computed for transverse MHD waves in one-dimensional cylindrical flux tube models with a piecewise constant or continuous radial density profile. There are fundamental deviations from the properties for classic bulk Alfven waves. (1) There is no local equipartition between kinetic and magnetic energy. (2) The flux of energy and the velocity of energy transfer have, in addition to a component parallel to the magnetic field, components in the planes normal to the magnetic field. (3) The energy densities and the flux of energy vary spatially, contrary to the case of classic bulk Alfven waves. This last property has the important consequence that the energy flux computed with the well known expression for bulk Alfven waves could overestimate the real flux by a factor in the range 10-50, depending on the flux tube equilibrium properties.

  17. Optimization of High-order Wave Equations for Multicore CPUs

    Energy Science and Technology Software Center (OSTI)

    2011-11-01

    This is a simple benchmark to guage the performance of a high-order isotropic wave equation grid. The code is optimized for both SSE and AVX and is parallelized using OpenMP (see Optimization section). Structurally, the benchmark begins, reads a few command-line parameters, allocates and pads the four arrays (current, last, next wave fields, and the spatially varying but isotropic velocity), initializes these arrays, then runs the benchmark proper. The code then benchmarks the naive, SSEmore » (if supported), and AVX (if supported implementations) by applying the wave equation stencil 100 times and taking the average performance. Boundary conditions are ignored and would noiminally be implemented by the user. THus, the benchmark measures only the performance of the wave equation stencil and not a full simulation. The naive implementation is a quadruply (z,y,x, radius) nested loop that can handle arbitrarily order wave equations. The optimized (SSE/AVX) implentations are somewhat more complex as they operate on slabs and include a case statement to select an optimized inner loop depending on wave equation order.« less

  18. Out-of-plane ultrasonic velocity measurement

    DOE Patents [OSTI]

    Hall, M.S.; Brodeur, P.H.; Jackson, T.G.

    1998-07-14

    A method for improving the accuracy of measuring the velocity and time of flight of ultrasonic signals through moving web-like materials such as paper, paperboard and the like, includes a pair of ultrasonic transducers disposed on opposing sides of a moving web-like material. In order to provide acoustical coupling between the transducers and the web-like material, the transducers are disposed in fluid-filled wheels. Errors due to variances in the wheel thicknesses about their circumference which can affect time of flight measurements and ultimately the mechanical property being tested are compensated by averaging the ultrasonic signals for a predetermined number of revolutions. The invention further includes a method for compensating for errors resulting from the digitization of the ultrasonic signals. More particularly, the invention includes a method for eliminating errors known as trigger jitter inherent with digitizing oscilloscopes used to digitize the signals for manipulation by a digital computer. In particular, rather than cross-correlate ultrasonic signals taken during different sample periods as is known in the art in order to determine the time of flight of the ultrasonic signal through the moving web, a pulse echo box is provided to enable cross-correlation of predetermined transmitted ultrasonic signals with predetermined reflected ultrasonic or echo signals during the sample period. By cross-correlating ultrasonic signals in the same sample period, the error associated with trigger jitter is eliminated. 20 figs.

  19. Out-of-plane ultrasonic velocity measurement

    DOE Patents [OSTI]

    Hall, Maclin S.; Brodeur, Pierre H.; Jackson, Theodore G.

    1998-01-01

    A method for improving the accuracy of measuring the velocity and time of flight of ultrasonic signals through moving web-like materials such as paper, paperboard and the like, includes a pair of ultrasonic transducers disposed on opposing sides of a moving web-like material. In order to provide acoustical coupling between the transducers and the web-like material, the transducers are disposed in fluid-filled wheels. Errors due to variances in the wheel thicknesses about their circumference which can affect time of flight measurements and ultimately the mechanical property being tested are compensated by averaging the ultrasonic signals for a predetermined number of revolutions. The invention further includes a method for compensating for errors resulting from the digitization of the ultrasonic signals. More particularly, the invention includes a method for eliminating errors known as trigger jitter inherent with digitizing oscilloscopes used to digitize the signals for manipulation by a digital computer. In particular, rather than cross-correlate ultrasonic signals taken during different sample periods as is known in the art in order to determine the time of flight of the ultrasonic signal through the moving web, a pulse echo box is provided to enable cross-correlation of predetermined transmitted ultrasonic signals with predetermined reflected ultrasonic or echo signals during the sample period. By cross-correlating ultrasonic signals in the same sample period, the error associated with trigger jitter is eliminated.

  20. Resonance of relativistic electrons with electromagnetic ion cyclotron waves

    SciTech Connect (OSTI)

    Denton, R. E.; Jordanova, V. K.; Bortnik, J.

    2015-06-29

    Relativistic electrons have been thought to more easily resonate with electromagnetic ion cyclotron EMIC waves if the total density is large. We show that, for a particular EMIC mode, this dependence is weak due to the dependence of the wave frequency and wave vector on the density. A significant increase in relativistic electron minimum resonant energy might occur for the H band EMIC mode only for small density, but no changes in parameters significantly decrease the minimum resonant energy from a nominal value. The minimum resonant energy depends most strongly on the thermal velocity associated with the field line motion of the hot ring current protons that drive the instability. High density due to a plasmasphere or plasmaspheric plume could possibly lead to lower minimum resonance energy by causing the He band EMIC mode to be dominant. We demonstrate these points using parameters from a ring current simulation.

  1. Single crystal metal wedges for surface acoustic wave propagation

    DOE Patents [OSTI]

    Fisher, E.S.

    1980-05-09

    An ultrasonic testing device has been developed to evaluate flaws and inhomogeneities in the near-surface region of a test material. A metal single crystal wedge is used to generate high frequency Rayleigh surface waves in the test material surface by conversion of a slow velocity, bulk acoustic mode in the wedge into a Rayleigh wave at the metal-wedge test material interface. Particular classes of metals have been found to provide the bulk acoustic modes necessary for production of a surface wave with extremely high frequency and angular collimation. The high frequency allows flaws and inhomogeneities to be examined with greater resolution. The high degree of angular collimation for the outgoing ultrasonic beam permits precision angular location of flaws and inhomogeneities in the test material surface.

  2. Langasite Surface Acoustic Wave Gas Sensors: Modeling and Verification

    SciTech Connect (OSTI)

    Zheng, Peng; Greve, David W; Oppenheim, Irving J

    2013-01-01

    We report finite element simulations of the effect of conductive sensing layers on the surface wave velocity of langasite substrates. The simulations include both the mechanical and electrical influences of the conducting sensing layer. We show that three-dimensional simulations are necessary because of the out-of-plane displacements of the commonly used (0, 138.5, 26.7) Euler angle. Measurements of the transducer input admittance in reflective delay-line devices yield a value for the electromechanical coupling coefficient that is in good agreement with the three-dimensional simulations on bare langasite substrate. The input admittance measurements also show evidence of excitation of an additional wave mode and excess loss due to the finger resistance. The results of these simulations and measurements will be useful in the design of surface acoustic wave gas sensors.

  3. Resonance of relativistic electrons with electromagnetic ion cyclotron waves

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Denton, R. E.; Jordanova, V. K.; Bortnik, J.

    2015-06-29

    Relativistic electrons have been thought to more easily resonate with electromagnetic ion cyclotron EMIC waves if the total density is large. We show that, for a particular EMIC mode, this dependence is weak due to the dependence of the wave frequency and wave vector on the density. A significant increase in relativistic electron minimum resonant energy might occur for the H band EMIC mode only for small density, but no changes in parameters significantly decrease the minimum resonant energy from a nominal value. The minimum resonant energy depends most strongly on the thermal velocity associated with the field line motionmore » of the hot ring current protons that drive the instability. High density due to a plasmasphere or plasmaspheric plume could possibly lead to lower minimum resonance energy by causing the He band EMIC mode to be dominant. We demonstrate these points using parameters from a ring current simulation.« less

  4. Single crystal metal wedges for surface acoustic wave propagation

    DOE Patents [OSTI]

    Fisher, Edward S.

    1982-01-01

    An ultrasonic testing device has been developed to evaluate flaws and inhomogeneities in the near-surface region of a test material. A metal single crystal wedge is used to generate high frequency Rayleigh surface waves in the test material surface by conversion of a slow velocity, bulk acoustic mode in the wedge into a Rayleigh wave at the metal-wedge test material interface. Particular classes of metals have been found to provide the bulk acoustic modes necessary for production of a surface wave with extremely high frequency and angular collimation. The high frequency allows flaws and inhomogeneities to be examined with greater resolution. The high degree of angular collimation for the outgoing ultrasonic beam permits precision angular location of flaws and inhomogeneities in the test material surface.

  5. Measurements and modeling of surface waves in drilled shafts in rock

    SciTech Connect (OSTI)

    Kalinski, M.E.; Stokoe, K.H. II; Roesset, J.M.; Cheng, D.S.

    1999-07-01

    Seismic testing was conducted in the WIPP facility in November 1994 by personnel from the Geotechnical Engineering Center at the University of Texas at Austin. Surface wave measurements were made in horizontal drilled shafts in rock salt to characterize the stiffness of the rock around the shafts. The Spectral-Analysis-of-Surface-Waves (SASW) method was used to determine dispersion curves of surface wave velocity versus wavelength. Dispersion curves were measured for surface waves propagating axially and circumferentially in the shafts. Surface wave velocities determined from axial testing increased slightly with increasing wavelength due to the cylindrical geometry of the shafts. On the other hand, surface wave velocities determined from circumferential testing exhibited a completely different type of geometry-induced dispersion. In both instances, finite-element forward modeling of the experimental dispersion curves revealed the presence of a thin, slightly softer disturbed rock zone (DRZ) around the shafts. This phenomenon has been previously confirmed by crosshole and other seismic measurements and is generally associated with relaxation of the individual salt crystals after confirming stress is relieved by excavation.

  6. Asymmetric material impact: Achieving free surfaces velocities nearly double that of the projectile

    SciTech Connect (OSTI)

    Aslam, Tariq; Dattelbaum, Dana; Gustavsen, Richard; Scharff, Robert; Byers, Mark

    2015-05-19

    Hypervelocity impact speeds are often limited by practical considerations in guns and explosive driven systems. In particular, for gas guns (both powder driven and light gas guns), there is the general trend that higher projectile speeds often come at the expense of smaller diameters, and thus less time for examining shock phenomena prior to two dimensional release waves affecting the observed quantities of interest. Similarly, explosive driven systems have their own set of limiting conditions due to limitations in explosive energy and size of devices required as engineering dimensions increase. The focus in this study is to present a methodology of obtaining free surface velocities well in excess of the projectile velocity. The key to this approach is in using a high impedance projectile that impacts a series of progressively lower impedance materials. The free surface velocity (if they were separated) of each of the progressively lower impedance materials would increase for each material. The theory behind this approach, as well as experimental results are presented.

  7. Asymmetric material impact: Achieving free surfaces velocities nearly double that of the projectile

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aslam, Tariq; Dattelbaum, Dana; Gustavsen, Richard; Scharff, Robert; Byers, Mark

    2015-05-19

    Hypervelocity impact speeds are often limited by practical considerations in guns and explosive driven systems. In particular, for gas guns (both powder driven and light gas guns), there is the general trend that higher projectile speeds often come at the expense of smaller diameters, and thus less time for examining shock phenomena prior to two dimensional release waves affecting the observed quantities of interest. Similarly, explosive driven systems have their own set of limiting conditions due to limitations in explosive energy and size of devices required as engineering dimensions increase. The focus in this study is to present a methodologymore » of obtaining free surface velocities well in excess of the projectile velocity. The key to this approach is in using a high impedance projectile that impacts a series of progressively lower impedance materials. The free surface velocity (if they were separated) of each of the progressively lower impedance materials would increase for each material. The theory behind this approach, as well as experimental results are presented.« less

  8. Asymmetric material impact: Achieving free surfaces velocities nearly double that of the projectile

    SciTech Connect (OSTI)

    Aslam, Tariq [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dattelbaum, Dana [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gustavsen, Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Scharff, Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Byers, Mark [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-01-01

    Hypervelocity impact speeds are often limited by practical considerations in guns and explosive driven systems. In particular, for gas guns (both powder driven and light gas guns), there is the general trend that higher projectile speeds often come at the expense of smaller diameters, and thus less time for examining shock phenomena prior to two dimensional release waves affecting the observed quantities of interest. Similarly, explosive driven systems have their own set of limiting conditions due to limitations in explosive energy and size of devices required as engineering dimensions increase. The focus in this study is to present a methodology of obtaining free surface velocities well in excess of the projectile velocity. The key to this approach is in using a high impedance projectile that impacts a series of progressively lower impedance materials. The free surface velocity (if they were separated) of each of the progressively lower impedance materials would increase for each material. The theory behind this approach, as well as experimental results, are presented.

  9. Piezoelectric wave motor

    DOE Patents [OSTI]

    Yerganian, Simon Scott

    2003-02-11

    A piezoelectric motor having a stator in which piezoelectric elements are contained in slots formed in the stator transverse to the desired wave motion. When an electric field is imposed on the elements, deformation of the elements imposes a force perpendicular to the sides of the slot, deforming the stator. Appropriate frequency and phase-shifting of the electric field will produce a wave in the stator and motion in a rotor. In a preferred aspect, the piezoelectric elements are configured so that deformation of the elements in the direction of an imposed electric field, generally referred to as the d.sub.33 direction, is utilized to produce wave motion in the stator. In a further aspect, the elements are compressed into the slots so as to minimize tensile stresses on the elements in use.

  10. Piezoelectric wave motor

    DOE Patents [OSTI]

    Yerganian, Simon Scott

    2001-07-17

    A piezoelectric motor having a stator in which piezoelectric elements are contained in slots formed in the stator transverse to the desired wave motion. When an electric field is imposed on the elements, deformation of the elements imposes a force perpendicular to the sides of the slot, deforming the stator. Appropriate frequency and phase shifting of the electric field will produce a wave in the stator and motion in a rotor. In a preferred aspect, the piezoelectric elements are configured so that deformation of the elements in direction of an imposed electric field, generally referred to as the d.sub.33 direction, is utilized to produce wave motion in the stator. In a further aspect, the elements are compressed into the slots so as to minimize tensile stresses on the elements in use.

  11. TIMING OF SHOCK WAVES

    DOE Patents [OSTI]

    Tuck, J.L.

    1955-03-01

    This patent relates to means for ascertaining the instant of arrival of a shock wave in an exploslve charge and apparatus utilizing this means to coordinate the timing of two operations involving a short lnterval of time. A pair of spaced electrodes are inserted along the line of an explosive train with a voltage applied there-across which is insufficient to cause discharge. When it is desired to initiate operation of a device at the time the explosive shock wave reaches a particular point on the explosive line, the device having an inherent time delay, the electrodes are located ahead of the point such that the ionization of the area between the electrodes caused by the traveling explosive shock wave sends a signal to initiate operation of the device to cause it to operate at the proper time. The operated device may be photographic equipment consisting of an x-ray illuminating tube.

  12. Standing wave compressor

    DOE Patents [OSTI]

    Lucas, Timothy S.

    1991-01-01

    A compressor for compression-evaporation cooling systems, which requires no moving parts. A gaseous refrigerant inside a chamber is acoustically compressed and conveyed by means of a standing acoustic wave which is set up in the gaseous refrigerant. This standing acoustic wave can be driven either by a transducer, or by direct exposure of the gas to microwave and infrared sources, including solar energy. Input and output ports arranged along the chamber provide for the intake and discharge of the gaseous refrigerant. These ports can be provided with optional valve arrangements, so as to increase the compressor's pressure differential. The performance of the compressor in either of its transducer or electromagnetically driven configurations, can be optimized by a controlling circuit. This controlling circuit holds the wavelength of the standing acoustical wave constant, by changing the driving frequency in response to varying operating conditions.

  13. Adaptive multiconfigurational wave functions

    SciTech Connect (OSTI)

    Evangelista, Francesco A.

    2014-03-28

    A method is suggested to build simple multiconfigurational wave functions specified uniquely by an energy cutoff ?. These are constructed from a model space containing determinants with energy relative to that of the most stable determinant no greater than ?. The resulting ?-CI wave function is adaptive, being able to represent both single-reference and multireference electronic states. We also consider a more compact wave function parameterization (?+SD-CI), which is based on a small ?-CI reference and adds a selection of all the singly and doubly excited determinants generated from it. We report two heuristic algorithms to build ?-CI wave functions. The first is based on an approximate prescreening of the full configuration interaction space, while the second performs a breadth-first search coupled with pruning. The ?-CI and ?+SD-CI approaches are used to compute the dissociation curve of N{sub 2} and the potential energy curves for the first three singlet states of C{sub 2}. Special attention is paid to the issue of energy discontinuities caused by changes in the size of the ?-CI wave function along the potential energy curve. This problem is shown to be solvable by smoothing the matrix elements of the Hamiltonian. Our last example, involving the Cu{sub 2}O{sub 2}{sup 2+} core, illustrates an alternative use of the ?-CI method: as a tool to both estimate the multireference character of a wave function and to create a compact model space to be used in subsequent high-level multireference coupled cluster computations.

  14. RADIATION WAVE DETECTOR

    DOE Patents [OSTI]

    Wouters, L.F.

    1958-10-28

    The detection of the shape and amplitude of a radiation wave is discussed, particularly an apparatus for automatically indicating at spaced lntervals of time the radiation intensity at a flxed point as a measure of a radiation wave passing the point. The apparatus utilizes a number of photomultiplier tubes surrounding a scintillation type detector, For obtainlng time spaced signals proportional to radiation at predetermined intervals the photolnultiplier tubes are actuated ln sequence following detector incidence of a predetermined radiation level by electronic means. The time spaced signals so produced are then separately amplified and relayed to recording means.

  15. Quantum positron acoustic waves

    SciTech Connect (OSTI)

    Metref, Hassina; Tribeche, Mouloud

    2014-12-15

    Nonlinear quantum positron-acoustic (QPA) waves are investigated for the first time, within the theoretical framework of the quantum hydrodynamic model. In the small but finite amplitude limit, both deformed Korteweg-de Vries and generalized Korteweg-de Vries equations governing, respectively, the dynamics of QPA solitary waves and double-layers are derived. Moreover, a full finite amplitude analysis is undertaken, and a numerical integration of the obtained highly nonlinear equations is carried out. The results complement our previously published results on this problem.

  16. AnisWave2D: User's Guide to the 2d Anisotropic Finite-DifferenceCode

    SciTech Connect (OSTI)

    Toomey, Aoife

    2005-01-06

    This document describes a parallel finite-difference code for modeling wave propagation in 2D, fully anisotropic materials. The code utilizes a mesh refinement scheme to improve computational efficiency. Mesh refinement allows the grid spacing to be tailored to the velocity model, so that fine grid spacing can be used in low velocity zones where the seismic wavelength is short, and coarse grid spacing can be used in zones with higher material velocities. Over-sampling of the seismic wavefield in high velocity zones is therefore avoided. The code has been implemented to run in parallel over multiple processors and allows large-scale models and models with large velocity contrasts to be simulated with ease.

  17. Property:Current Velocity Range(m/s) | Open Energy Information

    Open Energy Info (EERE)

    Current Velocity Range(ms) Jump to: navigation, search Property Name Current Velocity Range(ms) Property Type String Pages using the property "Current Velocity Range(ms)"...

  18. Property:Maximum Velocity with Constriction(m/s) | Open Energy...

    Open Energy Info (EERE)

    Velocity with Constriction(ms) Jump to: navigation, search Property Name Maximum Velocity with Constriction(ms) Property Type String Pages using the property "Maximum Velocity...

  19. Vlasov simulations of kinetic Alfvén waves at proton kinetic scales

    SciTech Connect (OSTI)

    Vásconez, C. L.; Valentini, F.; Veltri, P.; Camporeale, E.

    2014-11-15

    Kinetic Alfvén waves represent an important subject in space plasma physics, since they are thought to play a crucial role in the development of the turbulent energy cascade in the solar wind plasma at short wavelengths (of the order of the proton gyro radius ρ{sub p} and/or inertial length d{sub p} and beyond). A full understanding of the physical mechanisms which govern the kinetic plasma dynamics at these scales can provide important clues on the problem of the turbulent dissipation and heating in collisionless systems. In this paper, hybrid Vlasov-Maxwell simulations are employed to analyze in detail the features of the kinetic Alfvén waves at proton kinetic scales, in typical conditions of the solar wind environment (proton plasma beta β{sub p} = 1). In particular, linear and nonlinear regimes of propagation of these fluctuations have been investigated in a single-wave situation, focusing on the physical processes of collisionless Landau damping and wave-particle resonant interaction. Interestingly, since for wavelengths close to d{sub p} and β{sub p} ≃ 1 (for which ρ{sub p} ≃ d{sub p}) the kinetic Alfvén waves have small phase speed compared to the proton thermal velocity, wave-particle interaction processes produce significant deformations in the core of the particle velocity distribution, appearing as phase space vortices and resulting in flat-top velocity profiles. Moreover, as the Eulerian hybrid Vlasov-Maxwell algorithm allows for a clean almost noise-free description of the velocity space, three-dimensional plots of the proton velocity distribution help to emphasize how the plasma departs from the Maxwellian configuration of thermodynamic equilibrium due to nonlinear kinetic effects.

  20. Cryogenic Testing of High-Velocity Spoke Cavities

    SciTech Connect (OSTI)

    Hopper, Christopher S.; Delayen, Jean R.; Park, HyeKyoung

    2014-12-01

    Spoke-loaded cavities are being investigated for the high-velocity regime. The relative compactness at low-frequency makes them attractive for applications requiring, or benefiting from, 4 K operation. Additionally, the large velocity acceptance makes them good candidates for the acceleration of high-velocity protons and ions. Here we present the results of cryogenic testing of a 325 MHz, β0= 0.82 single-spoke cavity and a 500 MHz, β0 = 1 double-spoke cavity.

  1. Exact seismic velocities for VTI and HTI media and extendedThomsen Formulas for stronger anisotropies

    SciTech Connect (OSTI)

    Berryman, J.G.

    2007-05-14

    I explore a different type of approximation to the exactanisotropic wave velocities as a function of incidence angle invertically transversely isotropic (VTI) media. This method extends theThomsen weak anisotropy approach to stronger anisotropy withoutsignificantly affecting the simplicity of the formulas. One importantimprovement is that the peak of the quasi-SV-wave speed vsv(theta) islocated at the correct incidence angle theta= theta max, rather thanalways being at the position theta = 45o, which universally holds forThomsen's approximation although max theta = 45o is actually nevercorrect for any VTI anisotropic medium. The magnitudes of all the wavespeeds are also more closely approximated for all values of the incidenceangle. Furthermore, the value of theta max (which is needed in the newformulas) can be deduced from the same data that are typically used inthe weak anisotropy data analysis. The two examples presented are basedon systems having vertical fractures. The first set of model fractureshas their axes of symmetry randomly oriented in the horizontal plane.Such a system is then isotropic in the horizontal plane and, therefore,exhibits vertical transverse isotropic (VTI) symmetry. The second set offractures also has axes of symmetry in the horizontal plane, but it isassumed these axes are aligned so that the system exhibits horizontaltransverse isotropic (HTI) symmetry. Both types of systems are easilytreated with the new wave speed formulation.

  2. Multiple-frequency acoustic wave devices for chemical sensing and materials characterization in both gas and liquid phase

    DOE Patents [OSTI]

    Martin, S.J.; Ricco, A.J.

    1993-08-10

    A chemical or intrinsic physical property sensor is described comprising: (a) a substrate; (b) an interaction region of said substrate where the presence of a chemical or physical stimulus causes a detectable change in the velocity and/or an attenuation of an acoustic wave traversing said region; and (c) a plurality of paired input and output interdigitated electrodes patterned on the surface of said substrate where each of said paired electrodes has a distinct periodicity, where each of said paired electrodes is comprised of an input and an output electrode; (d) an input signal generation means for transmitting an input signal having a distinct frequency to a specified input interdigitated electrode of said plurality so that each input electrode receives a unique input signal, whereby said electrode responds to said input signal by generating an acoustic wave of a specified frequency, thus, said plurality responds by generating a plurality of acoustic waves of different frequencies; (e) an output signal receiving means for determining an acoustic wave velocity and an amplitude of said acoustic waves at several frequencies after said waves transverses said interaction region and comparing these values to an input acoustic wave velocity and an input acoustic wave amplitude to produce values for perturbations in acoustic wave velocities and for acoustic wave attenuation as a function of frequency, where said output receiving means is individually coupled to each of said output interdigitated electrode; (f) a computer means for analyzing a data stream comprising information from said output receiving means and from said input signal generation means to differentiate a specified response due to a perturbation from a subsequent specified response due to a subsequent perturbation to determine the chemical or intrinsic physical properties desired.

  3. Summary of Convective Core Vertical Velocity Properties Using...

    Office of Scientific and Technical Information (OSTI)

    Title: Summary of Convective Core Vertical Velocity Properties Using ARM UHF Wind Profilers in Oklahoma Authors: Giangrande S. E. ; Collis, S. ; Straka, J. ; Protat, A. ; Williams, ...

  4. A novel platform to study magnetized high-velocity collisionless...

    Office of Scientific and Technical Information (OSTI)

    A novel platform to study magnetized high-velocity collisionless shocks This content will become publicly available on March 12, 2017 Title: A novel platform to study magnetized ...

  5. Magnetic Resonance Flow Velocity and Temperature Mapping of a...

    Office of Scientific and Technical Information (OSTI)

    of a Shape Memory Polymer Foam Device Citation Details In-Document Search Title: Magnetic Resonance Flow Velocity and Temperature Mapping of a Shape Memory Polymer Foam ...

  6. Doppler Lidar Vertical Velocity Statistics Value-Added Product...

    Office of Scientific and Technical Information (OSTI)

    Citation Details In-Document Search Title: Doppler Lidar Vertical Velocity Statistics ... Facility operates coherent Doppler lidar systems at several sites around the globe. ...

  7. USING MICRO-SEISMICITY AND SEISMIC VELOCITIES TO MAP SUBSURFACE...

    Open Energy Info (EERE)

    some cases, although a significant portion of seismicity remains diffuse and does not cluster into sharply defined structures. The seismic velocity structure reveals heterogeneous...

  8. Using Micro-Seismicity and Seismic Velocities to Map Subsurface...

    Open Energy Info (EERE)

    some cases, although a significant portion of seismicity remains diffuse and does not cluster into sharply defined structures. The seismic velocity structure reveals heterogeneous...

  9. A novel photonic Doppler velocimetry for transverse velocity measurement

    SciTech Connect (OSTI)

    Chen Guanghua; Wang Detian; Liu Jun; Meng Jianhua; Liu Shouxian; Yang Qingguo

    2013-01-15

    A fiber interferometry for transverse velocity measurement has been developed. This diagnostic is similar to photonic Doppler velocimetry in the way in which laser propagates and couples. The interferometer mainly consists of a fiber coupler, an emitting probe, and two receiving probes. A pair of scattered laser beams mix in the coupler and generates fringes with frequency proportional to transverse velocity. Measurement of transverse velocity is independent of longitudinal velocity. The feasibility of the technique has been verified by rotating wheel experiment and shock loading experiment.

  10. Behavior of Impurity Ion Velocities during the Pulsed Poloidal...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the sudden reduction of both magnetic fluctuations and radiation from neutral ... In order to obtain a toroidal plasma velocity profile, we have measured the Doppler shift ...

  11. Electron acceleration by Z-mode and whistler-mode waves

    SciTech Connect (OSTI)

    Lee, K. H.; Omura, Y.; Lee, L. C.; Institute of Earth Science, Academia Sinica, Nankang, Taiwan

    2013-11-15

    We carried out a series of particle simulations to study electron acceleration by Z-mode and whistler-mode waves generated by an electron ring distribution. The electron ring distribution leads to excitations of X-mode waves mainly in the perpendicular direction, Z-mode waves in the perpendicular and parallel directions, and whistler-mode waves mainly in the parallel direction. The parallel Z- and whistler-mode waves can lead to an effective acceleration of ring electrons. The electron acceleration is mainly determined by the wave amplitude and phase velocity, which in turn is affected by the ratio of electron plasma to cyclotron frequencies. For the initial kinetic energy ranging from 100 to 500 keV, the peak energy of the accelerated electrons is found to reach 28 times the initial kinetic energy. We further study the acceleration process by test-particle calculations in which electrons interact with one, two, or four waves. The electron trajectories in the one-wave case are simple diffusion curves. In the multi-wave cases, electrons are accelerated simultaneously by counter-propagating waves and can have a higher final energy.

  12. Deflagration Wave Profiles

    SciTech Connect (OSTI)

    Menikoff, Ralph

    2012-04-03

    Shock initiation in a plastic-bonded explosives (PBX) is due to hot spots. Current reactive burn models are based, at least heuristically, on the ignition and growth concept. The ignition phase occurs when a small localized region of high temperature (or hot spot) burns on a fast time scale. This is followed by a growth phase in which a reactive front spreads out from the hot spot. Propagating reactive fronts are deflagration waves. A key question is the deflagration speed in a PBX compressed and heated by a shock wave that generated the hot spot. Here, the ODEs for a steady deflagration wave profile in a compressible fluid are derived, along with the needed thermodynamic quantities of realistic equations of state corresponding to the reactants and products of a PBX. The properties of the wave profile equations are analyzed and an algorithm is derived for computing the deflagration speed. As an illustrative example, the algorithm is applied to compute the deflagration speed in shock compressed PBX 9501 as a function of shock pressure. The calculated deflagration speed, even at the CJ pressure, is low compared to the detonation speed. The implication of this are briefly discussed.

  13. Haynes Wave Basin | Open Energy Information

    Open Energy Info (EERE)

    Wave Basin Jump to: navigation, search Basic Specifications Facility Name Haynes Wave Basin Overseeing Organization Texas A&M (Haynes) Hydrodynamic Testing Facility Type Wave Basin...

  14. Microfabricated bulk wave acoustic bandgap device (Patent) |...

    Office of Scientific and Technical Information (OSTI)

    Microfabricated bulk wave acoustic bandgap device Title: Microfabricated bulk wave acoustic bandgap device A microfabricated bulk wave acoustic bandgap device comprises a periodic ...

  15. Wave Star Energy | Open Energy Information

    Open Energy Info (EERE)

    Star Energy Jump to: navigation, search Name: Wave Star Energy Place: Denmark Zip: DK-2920 Product: Denmark-based private wave device developer. References: Wave Star Energy1...

  16. APPROVAL/VARIATION REQUEST (AR/VR)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Register or other documentation being submitted. If Variation Request, describe nature of variation and requirement from which the variation exists. 8. Does this...

  17. Elgen Wave | Open Energy Information

    Open Energy Info (EERE)

    Elgen Wave Jump to: navigation, search Name: Elgen Wave Region: United States Sector: Marine and Hydrokinetic Website: www.elgenwave.com This company is listed in the Marine and...

  18. Density waves in the Calogero model - revisited

    SciTech Connect (OSTI)

    Bardek, V. Feinberg, J. Meljanac, S.

    2010-03-15

    The Calogero model bears, in the continuum limit, collective excitations in the form of density waves and solitary modulations of the density of particles. This sector of the spectrum of the model was investigated, mostly within the framework of collective-field theory, by several authors, over the past 15 years or so. In this work we shall concentrate on periodic solutions of the collective BPS-equation (also known as 'finite amplitude density waves'), as well as on periodic solutions of the full static variational equations which vanish periodically (also known as 'large amplitude density waves'). While these solutions are not new, we feel that our analysis and presentation add to the existing literature, as we explain in the text. In addition, we show that these solutions also occur in a certain two-family generalization of the Calogero model, at special points in parameter space. A compendium of useful identities associated with Hilbert transforms, including our own proofs of these identities, appears in Appendix A. In Appendix B we also elucidate in the present paper some fine points having to do with manipulating Hilbert-transforms, which appear ubiquitously in the collective field formalism. Finally, in order to make this paper self-contained, we briefly summarize in Appendix C basic facts about the collective field formulation of the Calogero model.

  19. Compositional Variation Within Hybrid Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Compositional Variation Within Hybrid Nanostructures Print The inherently high surface area of bimetallic nanoparticles makes them especially attractive materials for heterogeneous...

  20. Measurement of sound speed vs. depth in South Pole ice: pressure waves and shear waves

    SciTech Connect (OSTI)

    IceCube Collaboration; Klein, Spencer

    2009-06-04

    We have measured the speed of both pressure waves and shear waves as a function of depth between 80 and 500 m depth in South Pole ice with better than 1% precision. The measurements were made using the South Pole Acoustic Test Setup (SPATS), an array of transmitters and sensors deployed in the ice at the South Pole in order to measure the acoustic properties relevant to acoustic detection of astrophysical neutrinos. The transmitters and sensors use piezoceramics operating at {approx}5-25 kHz. Between 200 m and 500 m depth, the measured profile is consistent with zero variation of the sound speed with depth, resulting in zero refraction, for both pressure and shear waves. We also performed a complementary study featuring an explosive signal propagating vertically from 50 to 2250 m depth, from which we determined a value for the pressure wave speed consistent with that determined for shallower depths, higher frequencies, and horizontal propagation with the SPATS sensors. The sound speed profile presented here can be used to achieve good acoustic source position and emission time reconstruction in general, and neutrino direction and energy reconstruction in particular. The reconstructed quantities could also help separate neutrino signals from background.

  1. Shock-wave strength properties of boron carbide and silicon carbide

    SciTech Connect (OSTI)

    Grady, D.E.

    1994-02-01

    Time-resolved velocity interferometry measurements have been made on boron carbide and silicon carbide ceramics to assess dynamic equation-of-state and strength properties of these materials. Hugoniot pecursor characteristics, and post-yield shock and release wave properties, indicated markedly different dynamic strength and flow behavior for the two carbides.

  2. MEASUREMENTS OF ANISOTROPIC ION TEMPERATURES, NON-THERMAL VELOCITIES, AND DOPPLER SHIFTS IN A CORONAL HOLE

    SciTech Connect (OSTI)

    Hahn, M.; Savin, D. W.

    2013-02-15

    We present a new diagnostic allowing one to measure the anisotropy of ion temperatures and non-thermal velocities, as well as Doppler shifts with respect to the ambient magnetic field. This method provides new results, as well as an independent test for previous measurements obtained with other techniques. Our spectral data come from observations of a low-latitude, on-disk coronal hole. A potential field source surface model was used to calculate the angle between the magnetic field lines and the line of sight for each spatial bin of the observation. A fit was performed to determine the line widths and Doppler shifts parallel and perpendicular to the magnetic field. For each line width component we derived ion temperatures T {sub i,} and T {sub i, Parallel-To} and non-thermal velocities v {sub nt,} and v {sub nt, Parallel-To }. T {sub i,} was cooler than off-limb polar coronal hole measurements, suggesting increasing collisional cooling with decreasing height. T {sub i, Parallel-To} is consistent with a uniform temperature of (1.8 {+-} 0.2) Multiplication-Sign 10{sup 6} K for each ion. Since parallel ion heating is expected to be weak, this ion temperature should reflect the proton temperature. A comparison between our results and others implies a large proton temperature gradient around 1.02 R {sub Sun }. The non-thermal velocities are thought to be proportional to the amplitudes of various waves. Our results for v {sub nt,} agree with Alfven wave amplitudes inferred from off-limb polar coronal hole line width measurements. Our v {sub nt, Parallel-To} results are consistent with slow magnetosonic wave amplitudes inferred from Fourier analysis of time-varying intensity fluctuations. Doppler shift measurements yield outflows of Almost-Equal-To 5 km s{sup -1} for ions formed over a broad temperature range. This differs from other studies that found a strong Doppler shift dependence on formation temperature.

  3. Hydrocarbon saturation determination using acoustic velocities obtained through casing

    DOE Patents [OSTI]

    Moos, Daniel

    2010-03-09

    Compressional and shear velocities of earth formations are measured through casing. The determined compressional and shear velocities are used in a two component mixing model to provides improved quantitative values for the solid, the dry frame, and the pore compressibility. These are used in determination of hydrocarbon saturation.

  4. SDO/AIA AND HINODE/EIS OBSERVATIONS OF INTERACTION BETWEEN AN EUV WAVE AND ACTIVE REGION LOOPS

    SciTech Connect (OSTI)

    Yang, Liheng; Zhang, Jun; Li, Ting; Liu, Wei; Shen, Yuandeng E-mail: zjun@bao.ac.cn

    2013-09-20

    We present detailed analysis of an extreme-ultraviolet (EUV) wave and its interaction with active region (AR) loops observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly and the Hinode EUV Imaging Spectrometer (EIS). This wave was initiated from AR 11261 on 2011 August 4 and propagated at velocities of 430-910 km s{sup 1}. It was observed to traverse another AR and cross over a filament channel on its path. The EUV wave perturbed neighboring AR loops and excited a disturbance that propagated toward the footpoints of these loops. EIS observations of AR loops revealed that at the time of the wave transit, the original redshift increased by about 3 km s{sup 1}, while the original blueshift decreased slightly. After the wave transit, these changes were reversed. When the EUV wave arrived at the boundary of a polar coronal hole, two reflected waves were successively produced and part of them propagated above the solar limb. The first reflected wave above the solar limb encountered a large-scale loop system on its path, and a secondary wave rapidly emerged 144 Mm ahead of it at a higher speed. These findings can be explained in the framework of a fast-mode magnetosonic wave interpretation for EUV waves, in which observed EUV waves are generated by expanding coronal mass ejections.

  5. Doppler Lidar Vertical Velocity Statistics Value-Added Product

    SciTech Connect (OSTI)

    Newsom, R. K.; Sivaraman, C.; Shippert, T. R.; Riihimaki, L. D.

    2015-07-01

    Accurate height-resolved measurements of higher-order statistical moments of vertical velocity fluctuations are crucial for improved understanding of turbulent mixing and diffusion, convective initiation, and cloud life cycles. The Atmospheric Radiation Measurement (ARM) Climate Research Facility operates coherent Doppler lidar systems at several sites around the globe. These instruments provide measurements of clear-air vertical velocity profiles in the lower troposphere with a nominal temporal resolution of 1 sec and height resolution of 30 m. The purpose of the Doppler lidar vertical velocity statistics (DLWSTATS) value-added product (VAP) is to produce height- and time-resolved estimates of vertical velocity variance, skewness, and kurtosis from these raw measurements. The VAP also produces estimates of cloud properties, including cloud-base height (CBH), cloud frequency, cloud-base vertical velocity, and cloud-base updraft fraction.

  6. Evolution of velocity dispersion along cold collisionless flows

    SciTech Connect (OSTI)

    Banik, Nilanjan; Sikivie, Pierre

    2015-11-17

    We found that the infall of cold dark matter onto a galaxy produces cold collisionless flows and caustics in its halo. If a signal is found in the cavity detector of dark matter axions, the flows will be readily apparent as peaks in the energy spectrum of photons from axion conversion, allowing the densities, velocity vectors and velocity dispersions of the flows to be determined. We also discuss the evolution of velocity dispersion along cold collisionless flows in one and two dimensions. A technique is presented for obtaining the leading behaviour of the velocity dispersion near caustics. The results are used to derive an upper limit on the energy dispersion of the Big Flow from the sharpness of its nearby caustic, and a prediction for the dispersions in its velocity components.

  7. Tracking moving radar targets with parallel, velocity-tuned filters

    DOE Patents [OSTI]

    Bickel, Douglas L.; Harmony, David W.; Bielek, Timothy P.; Hollowell, Jeff A.; Murray, Margaret S.; Martinez, Ana

    2013-04-30

    Radar data associated with radar illumination of a movable target is processed to monitor motion of the target. A plurality of filter operations are performed in parallel on the radar data so that each filter operation produces target image information. The filter operations are defined to have respectively corresponding velocity ranges that differ from one another. The target image information produced by one of the filter operations represents the target more accurately than the target image information produced by the remainder of the filter operations when a current velocity of the target is within the velocity range associated with the one filter operation. In response to the current velocity of the target being within the velocity range associated with the one filter operation, motion of the target is tracked based on the target image information produced by the one filter operation.

  8. Property:Maximum Wave Height(m) at Wave Period(s) | Open Energy...

    Open Energy Info (EERE)

    at Wave Period(s) Jump to: navigation, search Property Name Maximum Wave Height(m) at Wave Period(s) Property Type String Pages using the property "Maximum Wave Height(m) at Wave...

  9. Rotation-induced nonlinear wavepackets in internal waves

    SciTech Connect (OSTI)

    Whitfield, A. J. Johnson, E. R.

    2014-05-15

    The long time effect of weak rotation on an internal solitary wave is the decay into inertia-gravity waves and the eventual formation of a localised wavepacket. Here this initial value problem is considered within the context of the Ostrovsky, or the rotation-modified Korteweg-de Vries (KdV), equation and a numerical method for obtaining accurate wavepacket solutions is presented. The flow evolutions are described in the regimes of relatively-strong and relatively-weak rotational effects. When rotational effects are relatively strong a second-order soliton solution of the nonlinear Schrödinger equation accurately predicts the shape, and phase and group velocities of the numerically determined wavepackets. It is suggested that these solitons may form from a local Benjamin-Feir instability in the inertia-gravity wave-train radiated when a KdV solitary wave rapidly adjusts to the presence of strong rotation. When rotational effects are relatively weak the initial KdV solitary wave remains coherent longer, decaying only slowly due to weak radiation and modulational instability is no longer relevant. Wavepacket solutions in this regime appear to consist of a modulated KdV soliton wavetrain propagating on a slowly varying background of finite extent.

  10. Kinetic transverse dispersion relation for relativistic magnetized electron-positron plasmas with Maxwell-Jttner velocity distribution functions

    SciTech Connect (OSTI)

    Lpez, Rodrigo A.; Moya, Pablo S.; Muoz, Vctor; Vias, Adolfo F.; Valdivia, J. Alejandro

    2014-09-15

    We use a kinetic treatment to study the linear transverse dispersion relation for a magnetized isotropic relativistic electron-positron plasma with finite relativistic temperature. The explicit linear dispersion relation for electromagnetic waves propagating along a constant background magnetic field is presented, including an analytical continuation to the whole complex frequency plane for the case of Maxwell-Jttner velocity distribution functions. This dispersion relation is studied numerically for various temperatures. For left-handed solutions, the system presents two branches, the electromagnetic ordinary mode and the Alfvn mode. In the low frequency regime, the Alfvn branch has two dispersive zones, the normal zone (where ??/?k?>?0) and an anomalous zone (where ??/?k?waves are damped, and there is a maximum wave number for which the Alfvn branch is suppressed. We also study the dependence of the Alfvn velocity and effective plasma frequency with the temperature. We complemented the analytical and numerical approaches with relativistic full particle simulations, which consistently agree with the analytical results.

  11. Overstability of acoustic waves in strongly magnetized anisotropic magnetohydrodynamic shear flows

    SciTech Connect (OSTI)

    Uchava, E. S.; Shergelashvili, B. M.; Tevzadze, A. G.; Poedts, S.

    2014-08-15

    We present a linear stability analysis of the perturbation modes in anisotropic magnetohydrodynamic (MHD) flows with velocity shear and strong magnetic field. Collisionless or weakly collisional plasma is described within the 16-momentum MHD fluid closure model that takes into account not only the effect of pressure anisotropy but also the effect of anisotropic heat fluxes. In this model, the low frequency acoustic wave is revealed into a standard acoustic mode and higher frequency fast thermo-acoustic and lower frequency slow thermo-acoustic waves. It is shown that thermo-acoustic waves become unstable and grow exponentially when the heat flux parameter exceeds some critical value. It seems that velocity shear makes thermo-acoustic waves overstable even at subcritical heat flux parameters. Thus, when the effect of heat fluxes is not profound acoustic waves will grow due to the velocity shear, while at supercritical heat fluxes the flow reveals compressible thermal instability. Anisotropic thermal instability should be also important in astrophysical environments, where it will limit the maximal value of magnetic field that a low density ionized anisotropic flow can sustain.

  12. Charge Density Wave Compounds

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fisher Research Group Layered Chalcogenides 29 February 2008 Controlling the Wave by Brad Plummer, SLAC Communications Stanford University researchers working in part at SSRL have discovered a novel set of properties pertaining to a compound of materials called tritellurides. These compounds, composed of three atoms of tellurium and a single atom of one of the rare earth elements, demonstrate unique electronic properties that can be controlled by altering the temperature of the material. The

  13. ocean wave energy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    wave energy - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced Nuclear Energy

  14. Quasi-Rayleigh waves in butt-welded thick steel plate

    SciTech Connect (OSTI)

    Kamas, Tuncay E-mail: victorg@sc.edu Giurgiutiu, Victor E-mail: victorg@sc.edu Lin, Bin E-mail: victorg@sc.edu

    2015-03-31

    This paper discusses theoretical and experimental analyses of weld guided surface acoustic waves (SAW) through the guided wave propagation (GWP) analyses. The GWP analyses have been carried out by utilizing piezoelectric wafer active sensors (PWAS) for in situ structural inspection of a thick steel plate with butt weld as the weld bead is ground flush. Ultrasonic techniques are commonly used for validation of welded structures in many in-situ monitoring applications, e.g. in off-shore structures, in nuclear and pressure vessel industries and in a range of naval applications. PWAS is recently employed in such ultrasonic applications as a resonator as well as a transducer. Quasi-Rayleigh waves a.k.a. SAW can be generated in relatively thick isotropic elastic plate having the same phase velocity as Rayleigh waves whereas Rayleigh waves are a high frequency approximation of the first symmetric (S0) and anti-symmetric (A0) Lamb wave modes. As the frequency becomes very high the S0 and the A0 wave speeds coalesce, and both have the same value. This value is exactly the Rayleigh wave speed and becomes constant along the frequency i.e. Rayleigh waves are non-dispersive guided surface acoustic waves. The study is followed with weld-GWP tests through the pitch-catch method along the butt weld line. The tuning curves of quasi-Rayleigh wave are determined to show the tuning and trapping effect of the weld bead that has higher thickness than the adjacent plates on producing a dominant quasi-Rayleigh wave mode. The significant usage of the weld tuned and guided quasi-Rayleigh wave mode is essentially discussed for the applications in the in-situ inspection of relatively thick structures with butt weld such as naval offshore structures. The paper ends with summary, conclusions and suggestions for future work.

  15. A statistical study of EMIC waves observed by Cluster. 1. Wave properties. EMIC Wave Properties

    SciTech Connect (OSTI)

    Allen, R. C.; Zhang, J. -C.; Kistler, L. M.; Spence, H. E.; Lin, R. -L.; Klecker, B.; Dunlop, M. W.; Andr, M.; Jordanova, V. K.

    2015-07-23

    Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better understand the effects of these waves on particle dynamics, detailed information about the occurrence rate, wave power, ellipticity, normal angle, energy propagation angle distributions, and local plasma parameters are required. Previous statistical studies have used in situ observations to investigate the distribution of these parameters in the magnetic local time versus L-shell (MLT-L) frame within a limited magnetic latitude (MLAT) range. In our study, we present a statistical analysis of EMIC wave properties using 10 years (20012010) of data from Cluster, totaling 25,431 min of wave activity. Due to the polar orbit of Cluster, we are able to investigate EMIC waves at all MLATs and MLTs. This allows us to further investigate the MLAT dependence of various wave properties inside different MLT sectors and further explore the effects of Shabansky orbits on EMIC wave generation and propagation. Thus, the statistical analysis is presented in two papers. OUr paper focuses on the wave occurrence distribution as well as the distribution of wave properties. The companion paper focuses on local plasma parameters during wave observations as well as wave generation proxies.

  16. A statistical study of EMIC waves observed by Cluster. 1. Wave properties. EMIC Wave Properties

    SciTech Connect (OSTI)

    Allen, R. C.; Zhang, J. -C.; Kistler, L. M.; Spence, H. E.; Lin, R. -L.; Klecker, B.; Dunlop, M. W.; André, M.; Jordanova, V. K.

    2015-07-23

    Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better understand the effects of these waves on particle dynamics, detailed information about the occurrence rate, wave power, ellipticity, normal angle, energy propagation angle distributions, and local plasma parameters are required. Previous statistical studies have used in situ observations to investigate the distribution of these parameters in the magnetic local time versus L-shell (MLT-L) frame within a limited magnetic latitude (MLAT) range. In our study, we present a statistical analysis of EMIC wave properties using 10 years (2001–2010) of data from Cluster, totaling 25,431 min of wave activity. Due to the polar orbit of Cluster, we are able to investigate EMIC waves at all MLATs and MLTs. This allows us to further investigate the MLAT dependence of various wave properties inside different MLT sectors and further explore the effects of Shabansky orbits on EMIC wave generation and propagation. Thus, the statistical analysis is presented in two papers. OUr paper focuses on the wave occurrence distribution as well as the distribution of wave properties. The companion paper focuses on local plasma parameters during wave observations as well as wave generation proxies.

  17. A statistical study of EMIC waves observed by Cluster. 1. Wave properties. EMIC Wave Properties

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Allen, R. C.; Zhang, J. -C.; Kistler, L. M.; Spence, H. E.; Lin, R. -L.; Klecker, B.; Dunlop, M. W.; André, M.; Jordanova, V. K.

    2015-07-23

    Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better understand the effects of these waves on particle dynamics, detailed information about the occurrence rate, wave power, ellipticity, normal angle, energy propagation angle distributions, and local plasma parameters are required. Previous statistical studies have used in situ observations to investigate the distribution of these parameters in the magnetic local time versus L-shell (MLT-L) frame within a limited magnetic latitude (MLAT) range. In our study, we present a statistical analysis of EMIC wave properties using 10 years (2001–2010) of datamore » from Cluster, totaling 25,431 min of wave activity. Due to the polar orbit of Cluster, we are able to investigate EMIC waves at all MLATs and MLTs. This allows us to further investigate the MLAT dependence of various wave properties inside different MLT sectors and further explore the effects of Shabansky orbits on EMIC wave generation and propagation. Thus, the statistical analysis is presented in two papers. OUr paper focuses on the wave occurrence distribution as well as the distribution of wave properties. The companion paper focuses on local plasma parameters during wave observations as well as wave generation proxies.« less

  18. Internal energy relaxation in shock wave structure

    SciTech Connect (OSTI)

    Josyula, Eswar Suchyta, Casimir J.; Boyd, Iain D.; Vedula, Prakash

    2013-12-15

    The Wang Chang-Uhlenbeck (WCU) equation is numerically integrated to characterize the internal structure of Mach 3 and Mach 5 shock waves in a gas with excitation in the internal energy states for the treatment of inelastic collisions. Elastic collisions are modeled with the hard sphere collision model and the transition rates for the inelastic collisions modified appropriately using probabilities based on relative velocities of the colliding particles. The collision integral is evaluated by the conservative discrete ordinate method [F. Tcheremissine, “Solution of the Boltzmann kinetic equation for high-speed flows,” Comput. Math. Math. Phys. 46, 315–329 (2006); F. Cheremisin, “Solution of the Wang Chang-Uhlenbeck equation,” Dokl. Phys. 47, 487–490 (2002)] developed for the Boltzmann equation. For the treatment of the diatomic molecules, the internal energy modes in the Boltzmann equation are described quantum mechanically given by the WCU equation. As a first step in the treatment of the inelastic collisions by the WCU equation, a two- and three-quantum system is considered to study the effect of the varying of (1) the inelastic cross section and (2) the energy gap between the quantum energy states. An alternative method, the direct simulation Monte Carlo method, is used for the Mach 3 shock wave to ensure the consistency of implementation in the two methods and there is an excellent agreement between the two methods. The results from the WCU implementation showed consistent trends for the Mach 3 and Mach5 standing shock waves simulations. Inelastic contributions change the downstream equilibrium state and allow the flow to transition to the equilibrium state further upstream.

  19. Ocean current wave interaction study

    SciTech Connect (OSTI)

    Hayes, J.G.

    1980-09-20

    A numerical model has been developed to incorporate refraction of ocean surface gravity waves by major ocean currents. The model is initialized with directional wave spectra and verified with aircraft synthetic aperture radar X band spectra, laser profilometer spectra, and pitch and roll buoy data. Data collected during the Marineland test experiment are used as surface truth observations for the wave-current study. Evidence of Gulf Stream refraction and trapping of surface waves as well as caustics in the current is shown and modeled assuming a nonuniform Gulf Stream distribution. Frequency and directional resolution of the wave spectral distribution and the current refraction patterns illustrates the need for further study of ocean current-wave interaction in wave refraction studies.

  20. Elimination of a spiral wave pinned at an obstacle by a train of plane waves: Effect of diffusion between obstacles and surrounding media

    SciTech Connect (OSTI)

    Tanaka, Masanobu; Hörning, Marcel; Kitahata, Hiroyuki; Yoshikawa, Kenichi

    2015-10-15

    In excitable media such as cardiac tissue and Belousov-Zhabotinsky reaction medium, spiral waves tend to anchor (pin) to local heterogeneities. In general, such pinned waves are difficult to eliminate and may progress to spatio-temporal chaos. Heterogeneities can be classified as either the absence or presence of diffusive interaction with the surrounding medium. In this study, we investigated the difference in the unpinning of spiral waves from obstacles with and without diffusive interaction, and found a profound difference. The pacing period required for unpinning at fixed obstacle size is larger in case of diffusive obstacles. Further, we deduced a generic theoretical framework that can predict the minimal unpinning period. Our results explain the difference in pacing periods between for the obstacles with and without diffusive interaction, and the difference is interpreted in terms of the local decrease of spiral wave velocity close to the obstacle boundary caused in the case of diffusive interaction.

  1. Influence of the outer-magnetospheric magnetohydrodynamic waveguide on the reflection of hydromagnetic waves from a shear flow at the magnetopause

    SciTech Connect (OSTI)

    Mazur, V. A. Chuiko, D. A.

    2013-12-15

    The coefficient of reflection of a fast magnetosonic wave incident on the magnetosphere from the solar wind is studied analytically in the framework of a plane-stratified model of the medium with allowance for the transverse inhomogeneity of the magnetosphere and a jump of the plasma parameters at the magnetopause. Three factors decisively affecting the properties of reflection are taken into account: the shear flow of the solar wind plasma relative to the magnetosphere; the presence of a magnetospheric magnetohydrodynamic waveguide caused by the transverse plasma inhomogeneity; and the presence of an Alfvn resonance deep in the magnetosphere, where the oscillation energy dissipates. If the solar wind velocity exceeds the wave phase velocity along the magnetopause, then the wave energy in the solar wind is negative and such a wave experiences overreflection. In the opposite case, the wave energy is positive and the wave is reflected only partially. The wave reflection has a pronounced resonant character: the reflection coefficient has deep narrow minima or high narrow maxima at the eigenfrequencies of the magnetospheric waveguide. For other frequencies, the reflection coefficient only slightly differs from unity. The wave energy influx into the magnetosphere is positive for waves with both positive and negative energies. For waves with a negative energy, this is a consequence of their overreflection, because the flux of negative energy carried away by the reflected wave exceeds the incident flux of negative energy.

  2. A millimeter wave relativistic backward wave oscillator operating in TM{sub 03} mode with low guiding magnetic field

    SciTech Connect (OSTI)

    Ye, Hu; Wu, Ping; Teng, Yan; Chen, Changhua; Ning, Hui; Song, Zhimin; Cao, Yibing

    2015-06-15

    A V-band overmoded relativistic backward wave oscillator (RBWO) guided by low magnetic field and operating on a TM{sub 03} mode is presented to increase both the power handling capacity and the wave-beam interaction conversion efficiency. Trapezoidal slow wave structures (SWSs) with shallow corrugations and long periods are adopted to make the group velocity of TM{sub 03} mode at the intersection point close to zero. The coupling impedance and diffraction Q-factor of the RBWO increase, while the starting current decreases owing to the reduction of the group velocity of TM{sub 03} mode. In addition, the TM{sub 03} mode dominates over the other modes in the startup of the oscillation. Via numerical simulation, the generation of the microwave pulse with an output power of 425 MW and a conversion efficiency of 32% are achieved at 60.5 GHz with an external magnetic field of 1.25 T. This RBWO can provide greater power handling capacity when operating on the TM{sub 03} mode than on the TM{sub 01} mode.

  3. Simultaneous sensing of light and sound velocities of fluids in a two-dimensional phoXonic crystal with defects

    SciTech Connect (OSTI)

    Amoudache, Samira; Pennec, Yan Djafari Rouhani, Bahram; Khater, Antoine; Lucklum, Ralf; Tigrine, Rachid

    2014-04-07

    We theoretically investigate the potentiality of dual phononic-photonic (the so-called phoxonic) crystals for liquid sensing applications. We study the transmission through a two-dimensional (2D) crystal made of infinite cylindrical holes in a silicon substrate, where one row of holes oriented perpendicular to the propagation direction is filled with a liquid. The infiltrated holes may have a different radius than the regular holes. We show, in the defect structure, the existence of well-defined features (peaks or dips) in the transmission spectra of acoustic and optical waves and estimate their sensitivity to the sound and light velocity of the analyte. Some of the geometrical requirements behave in opposite directions when searching for an efficient sensing of either sound or light velocities. Hence, a compromise in the choice of the parameters may become necessary in making the phoxonic sensor.

  4. Two-stream instability with time-dependent drift velocity

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Qin, Hong; Davidson, Ronald C.

    2014-06-26

    The classical two-stream instability driven by a constant relative drift velocity between two plasma components is extended to the case with time-dependent drift velocity. A solution method is developed to rigorously define and calculate the instability growth rate for linear perturbations relative to the time-dependent unperturbed two-stream motions. The stability diagrams for the oscillating two-stream instability are presented over a large region of parameter space. It is shown that the growth rate for the classical two-stream instability can be significantly reduced by adding an oscillatory component to the relative drift velocity.

  5. Lower bound on the electroweak wall velocity from hydrodynamic instability

    SciTech Connect (OSTI)

    Mégevand, Ariel; Membiela, Federico Agustín; Sánchez, Alejandro D.

    2015-03-27

    The subsonic expansion of bubbles in a strongly first-order electroweak phase transition is a convenient scenario for electroweak baryogenesis. For most extensions of the Standard Model, stationary subsonic solutions (i.e., deflagrations) exist for the propagation of phase transition fronts. However, deflagrations are known to be hydrodynamically unstable for wall velocities below a certain critical value. We calculate this critical velocity for several extensions of the Standard Model and compare with an estimation of the wall velocity. In general, we find a region in parameter space which gives stable deflagrations as well as favorable conditions for electroweak baryogenesis.

  6. Terahertz wave electro-optic measurements with optical spectral filtering

    SciTech Connect (OSTI)

    Ilyakov, I. E. Shishkin, B. V.; Kitaeva, G. Kh.; Akhmedzhanov, R. A.

    2015-03-23

    We propose electro-optic detection techniques based on variations of the laser pulse spectrum induced during pulse co-propagation with terahertz wave radiation in a nonlinear crystal. Quantitative comparison with two other detection methods is made. Substantial improvement of the sensitivity compared to the standard electro-optic detection technique (at high frequencies) and to the previously shown technique based on laser pulse energy changes is demonstrated in experiment.

  7. WAVE DELAYING STRUCTURE FOR RECTANGULAR WAVE-GUIDES

    DOE Patents [OSTI]

    Robertson-Shersby-Harvie, R.B.; Dain, J.

    1956-11-13

    This patent relates to wave-guides and in particular describes wave delaying structure located within a wave-guide. The disclosed wave-guide has an elongated fiat metal sheet arranged in a central plane of the guide and formed with a series of transverse inductive slots such that each face presents an inductive impedance to the guide. The sheet is thickened in the area between slots to increase the self capacity of the slots. Experimental results indicate that in a wave-guide loaded in accordance with the invention the guided wavelength changes more slowly as the air wavelength is changed than the guided wavelength does in wave-guides loaded by means of corrugations.

  8. Statistics, Uncertainty, and Transmitted Variation

    SciTech Connect (OSTI)

    Wendelberger, Joanne Roth

    2014-11-05

    The field of Statistics provides methods for modeling and understanding data and making decisions in the presence of uncertainty. When examining response functions, variation present in the input variables will be transmitted via the response function to the output variables. This phenomenon can potentially have significant impacts on the uncertainty associated with results from subsequent analysis. This presentation will examine the concept of transmitted variation, its impact on designed experiments, and a method for identifying and estimating sources of transmitted variation in certain settings.

  9. Electron acceleration during the decay of nonlinear Whistler waves in low-beta electron-ion plasma

    SciTech Connect (OSTI)

    Umeda, Takayuki; Saito, Shinji; Nariyuki, Yasuhiro E-mail: saito@stelab.nagoya-u.ac.jp

    2014-10-10

    Relativistic electron acceleration through dissipation of a nonlinear, short-wavelength, and monochromatic electromagnetic whistler wave in low-beta plasma is investigated by utilizing a one-dimensional fully relativistic electromagnetic particle-in-cell code. The nonlinear (large-amplitude) parent whistler wave decays through the parametric instability which enhances electrostatic ion acoustic waves and electromagnetic whistler waves. These waves satisfy the condition of three-wave coupling. Through the decay instability, the energy of electron bulk velocity supporting the parent wave is converted to the thermal energy perpendicular to the background magnetic field. Increase of the perpendicular temperature triggers the electron temperature anisotropy instability which generates broadband whistler waves and heats electrons in the parallel direction. The broadband whistler waves are inverse-cascaded during the relaxation of the electron temperature anisotropy. In lower-beta conditions, electrons with a pitch angle of about 90 are successively accelerated by inverse-cascaded whistler waves, and selected electrons are accelerated to over a Lorentz factor of 10. The result implies that the nonlinear dissipation of a finite-amplitude and short-wavelength whistler wave plays an important role in producing relativistic nonthermal electrons over a few MeV especially at lower beta plasmas.

  10. Spin Wave Genie

    Energy Science and Technology Software Center (OSTI)

    2015-02-16

    The four-dimensional scattering function S(Q,w) obtained by inelastic neutron scattering measurements provides unique "dynamical fingerprints" of the spin state and interactions present in complex magnetic materials. Extracting this information however is currently a slow and complex process that may take an expert -depending on the complexity of the system- up to several weeks of painstaking work to complete. Spin Wave Genie was created to abstract and automate this process. It strives to both reduce themore » time to complete this analysis and make these calculations more accessible to a broader group of scientists and engineers.« less

  11. Spin waves in the (

    SciTech Connect (OSTI)

    Lipscombe, O. J.; Chen, G. F.; Fang, Chen; Perring, T. G.; Abernathy, Douglas L; Christianson, Andrew D; Egami, Takeshi; Wang, Nanlin; Hu, Jiangping; Dai, Pengcheng

    2011-01-01

    We use neutron scattering to show that spin waves in the iron chalcogenide Fe{sub 1.05}Te display novel dispersion clearly different from both the first principles density functional calculations and recent observations in the related iron pnictide CaFe{sub 2}As{sub 2}. By fitting to a Heisenberg Hamiltonian, we find that although the nearest-neighbor exchange couplings in the two systems are quite different, their next-nearest-neighbor (NNN) couplings are similar. This suggests that superconductivity in the pnictides and chalcogenides share a common magnetic origin that is intimately associated with the NNN magnetic coupling between the irons.

  12. The detection of upwardly propagating waves channeling energy from the chromosphere to the low corona

    SciTech Connect (OSTI)

    Freij, N.; Nelson, C. J.; Mumford, S.; Erdlyi, R.; Scullion, E. M.; Wedemeyer, S.

    2014-08-10

    There have been ubiquitous observations of wave-like motions in the solar atmosphere for decades. Recent improvements to space- and ground-based observatories have allowed the focus to shift to smaller magnetic structures on the solar surface. In this paper, high-resolution ground-based data taken using the Swedish 1 m Solar Telescope is combined with co-spatial and co-temporal data from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) satellite to analyze running penumbral waves (RPWs). RPWs have always been thought to be radial wave propagation that occurs within sunspots. Recent research has suggested that they are in fact upwardly propagating field-aligned waves (UPWs). Here, RPWs within a solar pore are observed for the first time and are interpreted as UPWs due to the lack of a penumbra that is required to support RPWs. These UPWs are also observed co-spatially and co-temporally within several SDO/AIA elemental lines that sample the transition region and low corona. The observed UPWs are traveling at a horizontal velocity of around 17 0.5 km s{sup 1} and a minimum vertical velocity of 42 21 km s{sup 1}. The estimated energy of the waves is around 150 W m{sup 2}, which is on the lower bound required to heat the quiet-Sun corona. This is a new, yet unconsidered source of wave energy within the solar chromosphere and low corona.

  13. Vertical wave packets observed in a crystallized hexagonal monolayer complex plasma

    SciTech Connect (OSTI)

    Samsonov, D.; Zhdanov, S.; Morfill, G.

    2005-02-01

    Propagation of vertical wave packets was observed experimentally in a crystallized hexagonal monolayer complex plasma. It was found that the phase velocity exceeded the group velocity by a factor 65 and was directed into the opposite direction as expected for an inverse optical-like dispersion relation. The wave packets propagated keeping their width constant. The explanation of this behavior is based on three-dimensional equations of motion and uses a long-wavelength weak dispersion weak inhomogeneity approximation. While the wave dispersion causes the wave packet to spread, lattice inhomogeneity and neutral gas drag counteract spreading. A plasma diagnostic method was developed that is based on the ratio between vertical and dust-lattice wave speeds. This ratio is very sensitive to the lattice parameter {kappa} (ratio of the particle separation to the screening length) in a very useful range of {kappa} < or approx. 2. It was found that only a two-dimensional lattice model can provide a quantitative description of the vertical waves, while a linear chain model gives only a qualitative agreement.

  14. Wave like signatures in aerosol optical depth and associated radiative impacts over the central Himalayan region

    SciTech Connect (OSTI)

    Shukla, K. K.; Phanikumar, D. V.; Kumar, Niranjan; Reddy, Kishore; Kotamarthi, Veerabhadra R.; Newsom, Rob K.; Ouarda, Taha B.

    2015-10-01

    In this study, we present a case study on 16 October 2011 to show the first observational evidence of the influence of short period gravity waves in aerosol transport during daytime over the central Himalayan region. The Doppler lidar data has been utilized to address the daytime boundary layer evolution and related aerosol dynamics over the site. Mixing layer height is estimated by wavelet covariance transform method and found to be ~ 0.7 km, AGL. Aerosol optical depth observations during daytime revealed an asymmetry showing clear enhancement during afternoon hours as compared to forenoon. Interestingly, Fourier and wavelet analysis of vertical velocity and attenuated backscatter showed similar 50-90 min short period gravity wave signatures during afternoon hours. Moreover, our observations showed that gravity waves are dominant within the boundary layer implying that the daytime boundary layer dynamics is playing a vital role in transporting the aerosols from surface to the top of the boundary layer. Similar modulations are also evident in surface parameters like temperature, relative humidity and wind speed indicating these waves are associated with the dynamical aspects over Himalayan region. Finally, time evolution of range-23 height indicator snapshots during daytime showed strong upward velocities especially during afternoon hours implying that convective processes through short period gravity waves plays a significant role in transporting aerosols from the nearby valley region to boundary layer top over the site. These observations also establish the importance of wave induced daytime convective boundary layer dynamics in the lower Himalayan region.

  15. Wave Energy Converter Effects on Nearshore Wave Propagation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Energy Converter Effects on Nearshore Wave Propagation Jesse Roberts 1 , Grace Chang *2 , Craig Jones *3 Sandia National Laboratories 1515 Eubank SE, Albuquerque, NM 87123 USA 1...

  16. Revisit of the relationship between the elastic properties and sound velocities at high pressures

    SciTech Connect (OSTI)

    Wang, Chenju; Yan, Xiaozhen; Xiang, Shikai Chen, Haiyan; Gu, Jianbing; Yu, Yin; Kuang, Xiaoyu

    2014-09-14

    The second-order elastic constants and stress-strain coefficients are defined, respectively, as the second derivatives of the total energy and the first derivative of the stress with respect to strain. Since the Lagrangian and infinitesimal strain are commonly used in the two definitions above, the second-order elastic constants and stress-strain coefficients are separated into two categories, respectively. In general, any of the four physical quantities is employed to characterize the elastic properties of materials without differentiation. Nevertheless, differences may exist among them at non-zero pressures, especially high pressures. Having explored the confusing issue systemically in the present work, we find that the four quantities are indeed different from each other at high pressures and these differences depend on the initial stress applied on materials. Moreover, the various relations between the four quantities depicting elastic properties of materials and high-pressure sound velocities are also derived from the elastic wave equations. As examples, we calculated the high-pressure sound velocities of cubic tantalum and hexagonal rhenium using these nexus. The excellent agreement of our results with available experimental data suggests the general applicability of the relations.

  17. Study of the Earth's interior using measurements of sound velocities in minerals by ultrasonic interferometry

    SciTech Connect (OSTI)

    Li, Baosheng; Liebermann, Robert C.

    2014-07-29

    This paper reviews the progress of the technology of ultrasonic interferometry from the early 1950s to the present day. During this period of more than 60 years, sound wave velocity measurements have been increased from at pressures less than 1 GPa and temperatures less than 800 K to conditions above 25 GPa and temperatures of 1800 K. This is complimentary to other direct methods to measure sound velocities (such as Brillouin and impulsive stimulated scattering) as well as indirect methods (e.g., resonance ultrasound spectroscopy, static or shock compression, inelastic X-ray scattering). Newly-developed pressure calibration methods and data analysis procedures using a finite strain approach are described and applied to data for the major mantle minerals. The implications for the composition of the Earth’s mantle are discussed. The state-of-the-art ultrasonic experiments performed in conjunction with synchrotron X-radiation can provide simultaneous measurements of the elastic bulk and shear moduli and their pressure and temperature derivatives with direct determination of pressure. The current status and outlook/challenges for future experiments are summarized.

  18. Minimum Velocity Required to Transport Solid Particles from the...

    Office of Scientific and Technical Information (OSTI)

    Required to Transport Solid Particles from the 2H-Evaporator to the Tank Farm Citation Details In-Document Search Title: Minimum Velocity Required to Transport Solid Particles ...

  19. SGP and TWP (Manus) Ice Cloud Vertical Velocities (Dataset) ...

    Office of Scientific and Technical Information (OSTI)

    particle terminal fall velocity (Vter) are given at 10s, 20min and 1hr resolution. Retrieved Vair and Vter follow radar notation, so positive values indicate downward motion. ...

  20. The PDV Velocity History and Shock Arrival Time Analyzer

    Energy Science and Technology Software Center (OSTI)

    2006-08-29

    This software allows the user to analyze heterodyne beat signals generated when a Doppler-shifted laser light interacts with un-shifted laser light. The software analyzes the data in a joint time frequency domain to extract instantaneous velocity.

  1. Prop transport in vertical fractures: settling velocity correlations

    SciTech Connect (OSTI)

    Clark, P.E.; Guler, N.

    1983-03-01

    The settling velocity of propping agents is a critical variable in the calculation of proppant distribution in a fracture. Most computer programs available in the industry today base estimates of settling velocity on a Stokes' Law type calculation. We have found that significant deviations from Stokes' Law settling velocities occur in cross-linked fluids and uncrosslinked fluids (concentrations in excess of 0.48%). This paper discusses experimental results obtained with a dynamic system and the implications which these data have on prop transport calculations. In addition, correlations have been derived which can be used to predict the settling velocities of particles in cross-linked gels. A discussion of these correlations will be included.

  2. Doppler Lidar Vertical Velocity Statistics Value-Added Product

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    49 Doppler Lidar Vertical Velocity Statistics Value-Added Product RK Newsom C Sivaraman TR Shippert LD Riihimaki July 2015 DISCLAIMER This report was prepared as an account of work...

  3. Compositional Variation Within Hybrid Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Compositional Variation Within Hybrid Nanostructures Compositional Variation Within Hybrid Nanostructures Print Wednesday, 29 September 2010 00:00 The inherently high surface area of bimetallic nanoparticles makes them especially attractive materials for heterogeneous catalysis. The ability to selectively grow these and other types of nanoparticles on a desired surface is ideal for the fabrication of higher-order nanoscale architectures. However, the growth mechanism for bimetallic nanoparticles

  4. Noise pair velocity and range echo location system

    DOE Patents [OSTI]

    Erskine, D.J.

    1999-02-16

    An echo-location method for microwaves, sound and light capable of using incoherent and arbitrary waveforms of wide bandwidth to measure velocity and range (and target size) simultaneously to high resolution is disclosed. Two interferometers having very long and nearly equal delays are used in series with the target interposed. The delays can be longer than the target range of interest. The first interferometer imprints a partial coherence on an initially incoherent source which allows autocorrelation to be performed on the reflected signal to determine velocity. A coherent cross-correlation subsequent to the second interferometer with the source determines a velocity discriminated range. Dithering the second interferometer identifies portions of the cross-correlation belonging to a target apart from clutter moving at a different velocity. The velocity discrimination is insensitive to all slowly varying distortions in the signal path. Speckle in the image of target and antenna lobing due to parasitic reflections is minimal for an incoherent source. An arbitrary source which varies its spectrum dramatically and randomly from pulse to pulse creates a radar elusive to jamming. Monochromatic sources which jigger in frequency from pulse to pulse or combinations of monochromatic sources can simulate some benefits of incoherent broadband sources. Clutter which has a symmetrical velocity spectrum will self-cancel for short wavelengths, such as the apparent motion of ground surrounding target from a sidelooking airborne antenna. 46 figs.

  5. Noise pair velocity and range echo location system

    DOE Patents [OSTI]

    Erskine, David J.

    1999-01-01

    An echo-location method for microwaves, sound and light capable of using incoherent and arbitrary waveforms of wide bandwidth to measure velocity and range (and target size) simultaneously to high resolution. Two interferometers having very long and nearly equal delays are used in series with the target interposed. The delays can be longer than the target range of interest. The first interferometer imprints a partial coherence on an initially incoherent source which allows autocorrelation to be performed on the reflected signal to determine velocity. A coherent cross-correlation subsequent to the second interferometer with the source determines a velocity discriminated range. Dithering the second interferometer identifies portions of the cross-correlation belonging to a target apart from clutter moving at a different velocity. The velocity discrimination is insensitive to all slowly varying distortions in the signal path. Speckle in the image of target and antenna lobing due to parasitic reflections is minimal for an incoherent source. An arbitrary source which varies its spectrum dramatically and randomly from pulse to pulse creates a radar elusive to jamming. Monochromatic sources which jigger in frequency from pulse to pulse or combinations of monochromatic sources can simulate some benefits of incoherent broadband sources. Clutter which has a symmetrical velocity spectrum will self-cancel for short wavelengths, such as the apparent motion of ground surrounding target from a sidelooking airborne antenna.

  6. Dual output acoustic wave sensor for molecular identification

    DOE Patents [OSTI]

    Frye, Gregory C.; Martin, Stephen J.

    1991-01-01

    A method of identification and quantification of absorbed chemical species by measuring changes in both the velocity and the attenuation of an acoustic wave traveling through a thin film into which the chemical species is sorbed. The dual output response provides two independent sensor responses from a single sensing device thereby providing twice as much information as a single output sensor. This dual output technique and analysis allows a single sensor to provide both the concentration and the identity of a chemical species or permits the number of sensors required for mixtures to be reduced by a factor of two.

  7. Wave propagation in an epoxy-graphite laminate

    SciTech Connect (OSTI)

    Clements, B.E.; Johnson, J.N.; Addessio, F.L.

    1997-11-01

    The third-order, nonhomogenized, dynamic method of cells is used to calculate the particle velocity for a shock wave experiment involving an epoxy{endash}graphite laminate. Constitutive relations suitable for the various materials are used. This includes linear and nonlinear elasticity and, when appropriate, viscoelasticity. It is found to be beneficial to incorporate artificial viscosity into the analysis. Artificial viscosity successfully removes the unphysical high-frequency ringing in the numerical solutions of the theory, while leaving the physical oscillations, characteristic of wave propagation in a periodic laminate, largely undiminished. It also allows the viscoelastic relaxed moduli to be closer to their unrelaxed counterparts than in a previous calculation, thus making them more acceptable. The results agree well with the corresponding plate-impact experiment, and are compared to the second-order theory of Clements, Johnson, and Hixson [Phys. Rev. E, {bold 54}, 6876 (1996)]. {copyright} {ital 1997 American Institute of Physics.}

  8. Wave energy and intertidal productivity

    SciTech Connect (OSTI)

    Leigh, E.G. Jr.; Paine, R.T.; Quinn, J.F.; Suchanek, T.H.

    1987-03-01

    In the northern Pacific, intertidal zones of the most wave-beaten shores receive more energy from breaking waves than from the sun. Despite severe mortality from winter storms, communities at some wave-beaten sites produce an extraordinary quantity of dry matter per unit area of shore per year. At wave-beaten sites of Tatoosh Island, WA, sea palms, Postelsia palmaeformis, can produce > 10 kg of dry matter, or 1.5 x 10/sup 8/ J, per m/sup 2/ in a good year. Extraordinarily productive organisms such as Postelsia are restricted to wave-beaten sites. Intertidal organisms cannot transform wave energy into chemical energy, as photosynthetic plants transform solar energy, nor can intertidal organisms harness wave energy. Nonetheless, wave energy enhances the productivity of intertidal organisms. On exposed shores, waves increase the capacity of resident algae to acquire nutrients and use sunlight, augment the competitive ability of productive organism, and protect intertidal residents by knocking away their enemies or preventing them from feeding.

  9. Wave | OpenEI Community

    Open Energy Info (EERE)

    Submitted by Ocop(5) Member 15 July, 2014 - 07:07 MHK LCOE Reporting Guidance Draft Cost Current DOE LCOE numerical modeling Performance Tidal Wave To normalize competing...

  10. Wave Basin | Open Energy Information

    Open Energy Info (EERE)

    Basin Jump to: navigation, search Retrieved from "http:en.openei.orgwindex.php?titleWaveBasin&oldid596392" Feedback Contact needs updating Image needs updating Reference...

  11. Guided acoustic wave inspection system

    DOE Patents [OSTI]

    Chinn, Diane J.

    2004-10-05

    A system for inspecting a conduit for undesirable characteristics. A transducer system induces guided acoustic waves onto said conduit. The transducer system detects the undesirable characteristics of the conduit by receiving guided acoustic waves that contain information about the undesirable characteristics. The conduit has at least two sides and the transducer system utilizes flexural modes of propagation to provide inspection using access from only the one side of the conduit. Cracking is detected with pulse-echo testing using one transducer to both send and receive the guided acoustic waves. Thinning is detected in through-transmission testing where one transducer sends and another transducer receives the guided acoustic waves.

  12. Harnessing Energy from Ocean Waves

    SciTech Connect (OSTI)

    Lehmann, Marcus

    2015-05-06

    Berkeley Lab scientist Marcus Lehmann, a member of the Lab's Cyclotron Road cohort, discusses his research on harnessing energy from ocean waves.

  13. The generation and damping of propagating MHD kink waves in the solar atmosphere

    SciTech Connect (OSTI)

    Morton, R. J.; Verth, G.; Erdlyi, R.; Hillier, A. E-mail: g.verth@sheffield.ac.uk

    2014-03-20

    The source of the non-thermal energy required for the heating of the upper solar atmosphere to temperatures in excess of a million degrees and the acceleration of the solar wind to hundreds of kilometers per second is still unclear. One such mechanism for providing the required energy flux is incompressible torsional Alfvn and kink magnetohydrodynamic (MHD) waves, which are magnetically dominated waves supported by the Sun's pervasive and complex magnetic field. In particular, propagating MHD kink waves have recently been observed to be ubiquitous throughout the solar atmosphere, but, until now, critical details of the transport of the kink wave energy throughout the Sun's atmosphere were lacking. Here, the ubiquity of the waves is exploited for statistical studies in the highly dynamic solar chromosphere. This large-scale investigation allows for the determination of the chromospheric kink wave velocity power spectra, a missing link necessary for determining the energy transport between the photosphere and corona. Crucially, the power spectra contain evidence for horizontal photospheric motions being an important mechanism for kink wave generation in the quiescent Sun. In addition, a comparison with measured coronal power spectra is provided for the first time, revealing frequency-dependent transmission profiles, suggesting that there is enhanced damping of kink waves in the lower corona.

  14. Soliton generation via continuous stokes acoustic self-scattering of hypersonic waves in a paramagnetic crystal

    SciTech Connect (OSTI)

    Bugay, A. N.; Sazonov, S. V.

    2008-08-15

    A new mechanism is proposed for continuous frequency down-conversion of acoustic waves propagating in a paramagnetic crystal at a low temperature in an applied magnetic field. A transverse hypersonic pulse generating a carrier-free longitudinal strain pulse via nonlinear effects is scattered by the generated pulse. This leads to a Stokes shift in the transverse hypersonic wave proportional to its intensity, and both pulses continue to propagate in the form of a mode-locked soliton. As the transverse-pulse frequency is Stokes shifted, its spectrum becomes narrower. This process can be effectively implemented only if the linear group velocity of the transverse hypersonic pulse equals the phase velocity of the longitudinal strain wave. These velocities are renormalized by spin-phonon coupling and can be made equal by adjusting the magnitude of the applied magnetic field. The transverse structure of the soliton depends on the sign of the group velocity dispersion of the transverse component. When the dispersion is positive, planar solitons can develop whose transverse component has a topological defect of dark vortex type and longitudinal component has a hole. In the opposite case, the formation of two-component acoustic 'bullets' or vortices localized in all directions is possible.

  15. Effect of parametric resonance on the formation of waves with a broad multiharmonic spectrum during the development of two-stream instability

    SciTech Connect (OSTI)

    Kulish, V. V.; Lysenko, A. V.; Rombovsky, M. Yu.

    2010-07-15

    A cubically nonlinear multiharmonic theory of two-stream instability in a two-velocity relativistic electron beam is constructed with allowance for parametric resonance between harmonics of longitudinal waves of different types, as well as between wave harmonics of the same type. The effect of these two kinds of parametric resonance interaction on the development of two-stream instability is investigated. It is shown that parametric resonance between different types of longitudinal waves excited in a two-velocity beam can substantially affect the development of physical processes in the system under study. It is proposed to use parametric resonance between longitudinal waves of different types to form waves with a prescribed broad multiharmonic spectrum.

  16. Effect of squeeze on electrostatic Trivelpiece-Gould wave damping

    SciTech Connect (OSTI)

    Ashourvan, Arash; Dubin, Daniel H. E.

    2014-05-15

    We present a theory for increased damping of Trivelpiece-Gouid plasma modes on a nonneutral plasma column, due to application of a Debye shielded cylindrically symmetric squeeze potential φ{sub 1}. We present two models of the effect this has on the plasma modes: a 1D model with only axial dependence, and a 2D model that also keeps radial dependence in the squeezed equilibrium and the mode. We study the models using both analytical and numerical methods. For our analytical studies, we assume that φ{sub 1}/T≪1, and we treat the Debye shielded squeeze potential as a perturbation in the equilibrium Hamiltonian. Our numerical simulations solve the 1D Vlasov-Poisson system and obtain the frequency and damping rate for a self-consistent plasma mode, making no assumptions as to the size of the squeeze. In both the 1D and 2D models, damping of the mode is caused by Landau resonances at energies E{sub n} for which the particle bounce frequency ω{sub b}(E{sub n}) and the wave frequency ω satisfy ω=nω{sub b}(E{sub n}). Particles experience a non-sinusoidal wave potential along their bounce orbits due to the squeeze potential. As a result, the squeeze induces bounce harmonics with n > 1 in the perturbed distribution. The harmonics allow resonances at energies E{sub n}≤T that cause substantial damping, even when wave phase velocities are much larger than the thermal velocity. In the regime ω/k≫√(T/m) (k is the wave number) and T≫φ{sub 1}, the resonance damping rate has a |φ{sub 1}|{sup 2} dependence. This dependence agrees with the simulations and experimental results.

  17. Topological horseshoes in travelling waves of discretized nonlinear wave equations

    SciTech Connect (OSTI)

    Chen, Yi-Chiuan; Chen, Shyan-Shiou; Yuan, Juan-Ming

    2014-04-15

    Applying the concept of anti-integrable limit to coupled map lattices originated from space-time discretized nonlinear wave equations, we show that there exist topological horseshoes in the phase space formed by the initial states of travelling wave solutions. In particular, the coupled map lattices display spatio-temporal chaos on the horseshoes.

  18. Surface Wave Simulation and Processing with MatSeis

    SciTech Connect (OSTI)

    THOMPSON,BEVERLY D.; CHAEL,ERIC P.; YOUNG,CHRISTOPHER J.; WALTER,WILLIAM R.; PASYANOS,MICHAEL E.

    2000-08-07

    In order to exploit the information on surface wave propagation that is stored in large seismic event datasets, Sandia and Lawrence Livermore National Laboratories have developed a MatSeis interface for performing phase-matched filtering of Rayleigh arrivals. MatSeis is a Matlab-based seismic processing toolkit which provides graphical tools for analyzing seismic data from a network of stations. Tools are available for spectral and polarization measurements, as well as beam forming and f-k analysis with array data, to name just a few. Additionally, one has full access to the Matlab environment and any functions available there. Previously the authors reported the development of new MatSeis tools for calculating regional discrimination measurements. The first of these performs Lg coda analysis as developed by Mayeda and coworkers at Lawrence Livermore National Laboratory. A second tool measures regional phase amplitude ratios for an event and compares the results to ratios from known earthquakes and explosions. Release 1.5 of MatSeis includes the new interface for the analysis of surface wave arrivals. This effort involves the use of regionalized dispersion models from a repository of surface wave data and the construction of phase-matched filters to improve surface wave identification, detection, and magnitude calculation. The tool works as follows. First, a ray is traced from source to receiver through a user-defined grid containing different group velocity versus period values to determine the composite group velocity curve for the path. This curve is shown along with the upper and lower group velocity bounds for reference. Next, the curve is used to create a phase-matched filter, apply the filter, and show the resultant waveform. The application of the filter allows obscured Rayleigh arrivals to be more easily identified. Finally, after screening information outside the range of the phase-matched filter, an inverse version of the filter is applied to obtain a

  19. Wave energy absorber mountable on wave-facing structure

    SciTech Connect (OSTI)

    Kondo, H.

    1983-09-13

    A wave energy absorber comprising a caisson mountable on the seaside surface of an existing breakwater or coastal embankment, which caisson has a water chamber with an open side and a rear wall facing the open side. The distance from the open side to the rear wall is longer than one quarter of a wavelength L /SUB c/ in the water chamber so as to generate a standing wave in the water chamber with a node of the standing wave at a distance L /SUB c/ /4 from the rear wall toward the open side. A wave power turbine impeller is pivotally supported in the caisson at the node position, the impeller rotating in only one direction, whereby wave energy is absorbed by the impeller for further conversion into electric or thermal energy. The caisson itself can also be utilized as a breakwater or an embankment.

  20. Marine pipeline dynamic response to waves from directional wave spectra

    SciTech Connect (OSTI)

    Lambrakos, K.F.

    1982-07-01

    A methodology has been developed to calculate the dynamic probabilistic movement and resulting stresses for marine pipelines subjected to storm waves. A directional wave spectrum is used with a Fourier series expansion to simulate short-crested waves and calculate their loads on the pipeline. The pipeline displacements resulting from these loads are solutions to the time-dependent beam-column equation which also includes the soil resistance as external loading. The statistics of the displacements for individual waves are combined with the wave statistics for a given period of time, e.g. pipeline lifetime, to generate probabilistic estimates for net pipeline movement. On the basis of displacements for specified probability levels the pipeline configuration is obtained from which pipeline stresses can be estimated using structural considerations, e.g. pipeline stiffness, end restraints, etc.

  1. Relativistic electron scattering by magnetosonic waves: Effects of discrete wave emission and high wave amplitudes

    SciTech Connect (OSTI)

    Artemyev, A. V.; Mourenas, D.; Krasnoselskikh, V. V.

    2015-06-15

    In this paper, we study relativistic electron scattering by fast magnetosonic waves. We compare results of test particle simulations and the quasi-linear theory for different spectra of waves to investigate how a fine structure of the wave emission can influence electron resonant scattering. We show that for a realistically wide distribution of wave normal angles θ (i.e., when the dispersion δθ≥0.5{sup °}), relativistic electron scattering is similar for a wide wave spectrum and for a spectrum consisting in well-separated ion cyclotron harmonics. Comparisons of test particle simulations with quasi-linear theory show that for δθ>0.5{sup °}, the quasi-linear approximation describes resonant scattering correctly for a large enough plasma frequency. For a very narrow θ distribution (when δθ∼0.05{sup °}), however, the effect of a fine structure in the wave spectrum becomes important. In this case, quasi-linear theory clearly fails in describing accurately electron scattering by fast magnetosonic waves. We also study the effect of high wave amplitudes on relativistic electron scattering. For typical conditions in the earth's radiation belts, the quasi-linear approximation cannot accurately describe electron scattering for waves with averaged amplitudes >300 pT. We discuss various applications of the obtained results for modeling electron dynamics in the radiation belts and in the Earth's magnetotail.

  2. Wave-function functionals for the density

    SciTech Connect (OSTI)

    Slamet, Marlina; Pan Xiaoyin; Sahni, Viraht

    2011-11-15

    We extend the idea of the constrained-search variational method for the construction of wave-function functionals {psi}[{chi}] of functions {chi}. The search is constrained to those functions {chi} such that {psi}[{chi}] reproduces the density {rho}(r) while simultaneously leading to an upper bound to the energy. The functionals are thereby normalized and automatically satisfy the electron-nucleus coalescence condition. The functionals {psi}[{chi}] are also constructed to satisfy the electron-electron coalescence condition. The method is applied to the ground state of the helium atom to construct functionals {psi}[{chi}] that reproduce the density as given by the Kinoshita correlated wave function. The expectation of single-particle operators W={Sigma}{sub i}r{sub i}{sup n}, n=-2,-1,1,2, W={Sigma}{sub i}{delta}(r{sub i}) are exact, as must be the case. The expectations of the kinetic energy operator W=-(1/2){Sigma}{sub i}{nabla}{sub i}{sup 2}, the two-particle operators W={Sigma}{sub n}u{sup n}, n=-2,-1,1,2, where u=|r{sub i}-r{sub j}|, and the energy are accurate. We note that the construction of such functionals {psi}[{chi}] is an application of the Levy-Lieb constrained-search definition of density functional theory. It is thereby possible to rigorously determine which functional {psi}[{chi}] is closer to the true wave function.

  3. On the damping of right hand circularly polarized waves in spin quantum plasmas

    SciTech Connect (OSTI)

    Iqbal, Z.; Hussain, A.; Murtaza, G.; Ali, M.

    2014-12-15

    General dispersion relation for the right hand circularly polarized waves has been derived using non-relativistic spin quantum kinetic theory. Employing the derived dispersion relation, temporal and spatial damping of the right hand circularly polarized waves are studied for both the degenerate and non-degenerate plasma regimes for two different frequency domains: (i) k{sub ?}v?(?+?{sub ce}),(?+?{sub cg}) and (ii) k{sub ?}v?(?+?{sub ce}),(?+?{sub cg}). Comparison of the cold and hot plasma regimes shows that the right hand circularly polarized wave with spin-effects exists for larger k-values as compared to the spinless case, before it damps completely. It is also found that the spin-effects can significantly influence the phase and group velocities of the whistler waves in both the degenerate and non-degenerate regimes. The results obtained are also analyzed graphically for some laboratory parameters to demonstrate the physical significance of the present work.

  4. Alfven waves in dusty plasmas with plasma particles described by anisotropic kappa distributions

    SciTech Connect (OSTI)

    Galvao, R. A.; Ziebell, L. F.; Gaelzer, R.; Juli, M. C. de

    2012-12-15

    We utilize a kinetic description to study the dispersion relation of Alfven waves propagating parallelly to the ambient magnetic field in a dusty plasma, taking into account the fluctuation of the charge of the dust particles, which is due to inelastic collisions with electrons and ions. We consider a plasma in which the velocity distribution functions of the plasma particles are modelled as anisotropic kappa distributions, study the dispersion relation for several combinations of the parameters {kappa}{sub Parallel-To} and {kappa}{sub Up-Tack }, and emphasize the effect of the anisotropy of the distributions on the mode coupling which occurs in a dusty plasma, between waves in the branch of circularly polarized waves and waves in the whistler branch.

  5. Crustal Structure of Iraq from Receiver Functions and Surface Wave Dispersion

    SciTech Connect (OSTI)

    Gok, R; Mahdi, H; Al-Shukri, H; Rodgers, A J

    2006-08-31

    We report the crustal structure of Iraq, located in the northeastern Arabian plate, estimated by joint inversion of P-wave receiver functions and surface wave group velocity dispersion. Receiver functions were computed from teleseismic recordings at two temporary broadband seismic stations in Mosul (MSL) and Baghdad (BHD), separated by approximately 360 km. Group velocity dispersion curves at the sites were derived from continental-scale tomography of Pasyanos (2006). The inversion results show that the crustal thicknesses are 39 km at MSL and 43 km at BHD. Both sites reveal low velocity surface layers consistent with sedimentary thickness of about 3 km at station MSL and 7 km at BHD, agreeing well with the existing models. Ignoring the sediments, the crustal velocities and thicknesses are remarkably similar between the two stations, suggesting that the crustal structure of the proto-Arabian Platform in northern Iraq was uniform before subsidence and deposition of the sediments in the Cenozoic. Deeper low velocity sediments at BHD are expected to result in higher ground motions for earthquakes.

  6. Compressive passive millimeter wave imager

    DOE Patents [OSTI]

    Gopalsami, Nachappa; Liao, Shaolin; Elmer, Thomas W; Koehl, Eugene R; Heifetz, Alexander; Raptis, Apostolos C

    2015-01-27

    A compressive scanning approach for millimeter wave imaging and sensing. A Hadamard mask is positioned to receive millimeter waves from an object to be imaged. A subset of the full set of Hadamard acquisitions is sampled. The subset is used to reconstruct an image representing the object.

  7. Full wave simulations of fast wave heating losses in the scrape...

    Office of Scientific and Technical Information (OSTI)

    Full wave simulations of fast wave heating losses in the scrape-off layer of NSTX and NSTX-U Citation Details In-Document Search Title: Full wave simulations of fast wave heating...

  8. Symmetries of the triple degenerate DNLS equations for weakly nonlinear dispersive MHD waves

    SciTech Connect (OSTI)

    Webb, G. M.; Brio, M.; Zank, G. P.

    1996-07-20

    A formulation of Hamiltonian and Lagrangian variational principles, Lie point symmetries and conservation laws for the triple degenerate DNLS equations describing the propagation of weakly nonlinear dispersive MHD waves along the ambient magnetic field, in {beta}{approx}1 plasmas is given. The equations describe the interaction of the Alfven and magnetoacoustic modes near the triple umbilic point, where the fast magnetosonic, slow magnetosonic and Alfven speeds coincide and a{sub g}{sup 2}=V{sub A}{sup 2} where a{sub g} is the gas sound speed and V{sub A} is the Alfven speed. A discussion is given of the travelling wave similarity solutions of the equations, which include solitary wave and periodic traveling waves. Strongly compressible solutions indicate the necessity for the insertion of shocks in the flow, whereas weakly compressible, near Alfvenic solutions resemble similar, shock free travelling wave solutions of the DNLS equation.

  9. Ion velocities in a micro-cathode arc thruster

    SciTech Connect (OSTI)

    Zhuang Taisen; Shashurin, Alexey; Keidar, Michael; Beilis, Isak

    2012-06-15

    Ion velocities in the plasma jet generated by the micro-cathode arc thruster are studied by means of time-of-flight method using enhanced ion detection system (EIDS). The EIDS triggers perturbations (spikes) on arc current waveform, and the larger current in the spike generates denser plasma bunches propagating along with the mainstream plasma. The EIDS utilizes double electrostatic probes rather than single probes. The average Ti ion velocity is measured to be around 2 Multiplication-Sign 10{sup 4} m/s without a magnetic field. It was found that the application of a magnetic field does not change ion velocities in the interelectrode region while leads to ion acceleration in the free expanding plasma plume by a factor of about 2. Ion velocities of about 3.5 Multiplication-Sign 10{sup 4} m/s were detected for the magnetic field of about 300 mT at distance of about 100-200 mm from the cathode. It is proposed that plasma is accelerated due to Lorentz force. The average thrust is calculated using the ion velocity measurements and the cathode mass consumption rate, and its increase with the magnetic field is demonstrated.

  10. Optic-microwave mixing velocimeter for superhigh velocity measurement

    SciTech Connect (OSTI)

    Weng Jidong; Wang Xiang; Tao Tianjiong; Liu Cangli; Tan Hua

    2011-12-15

    The phenomenon that a light beam reflected off a moving object experiences a Doppler shift in its frequency underlies practical interferometric techniques for remote velocity measurements, such as velocity interferometer system for any reflector (VISAR), displacement interferometer system for any reflector (DISAR), and photonic Doppler velocimetry (PDV). While VISAR velocimeters are often bewildered by the fringe loss upon high-acceleration dynamic process diagnosis, the optic-fiber velocimeters such as DISAR and PDV, on the other hand, are puzzled by high velocity measurement over 10 km/s, due to the demand for the high bandwidth digitizer. Here, we describe a new optic-microwave mixing velocimeter (OMV) for super-high velocity measurements. By using currently available commercial microwave products, we have constructed a simple, compact, and reliable OMV device, and have successfully obtained, with a digitizer of bandwidth 6 GH only, the precise velocity history of an aluminum flyer plate being accelerated up to 11.2 km/s in a three stage gas-gun experiment.

  11. Effects of increasing tip velocity on wind turbine rotor design.

    SciTech Connect (OSTI)

    Resor, Brian Ray; Maniaci, David Charles; Berg, Jonathan Charles; Richards, Phillip William

    2014-05-01

    A reduction in cost of energy from wind is anticipated when maximum allowable tip velocity is allowed to increase. Rotor torque decreases as tip velocity increases and rotor size and power rating are held constant. Reduction in rotor torque yields a lighter weight gearbox, a decrease in the turbine cost, and an increase in the capacity for the turbine to deliver cost competitive electricity. The high speed rotor incurs costs attributable to rotor aero-acoustics and system loads. The increased loads of high speed rotors drive the sizing and cost of other components in the system. Rotor, drivetrain, and tower designs at 80 m/s maximum tip velocity and 100 m/s maximum tip velocity are created to quantify these effects. Component costs, annualized energy production, and cost of energy are computed for each design to quantify the change in overall cost of energy resulting from the increase in turbine tip velocity. High fidelity physics based models rather than cost and scaling models are used to perform the work. Results provide a quantitative assessment of anticipated costs and benefits for high speed rotors. Finally, important lessons regarding full system optimization of wind turbines are documented.

  12. Exceptional Ground Accelerations and Velocities Caused by Earthquakes

    SciTech Connect (OSTI)

    Anderson, John

    2008-01-17

    This project aims to understand the characteristics of the free-field strong-motion records that have yielded the 100 largest peak accelerations and the 100 largest peak velocities recorded to date. The peak is defined as the maximum magnitude of the acceleration or velocity vector during the strong shaking. This compilation includes 35 records with peak acceleration greater than gravity, and 41 records with peak velocities greater than 100 cm/s. The results represent an estimated 150,000 instrument-years of strong-motion recordings. The mean horizontal acceleration or velocity, as used for the NGA ground motion models, is typically 0.76 times the magnitude of this vector peak. Accelerations in the top 100 come from earthquakes as small as magnitude 5, while velocities in the top 100 all come from earthquakes with magnitude 6 or larger. Records are dominated by crustal earthquakes with thrust, oblique-thrust, or strike-slip mechanisms. Normal faulting mechanisms in crustal earthquakes constitute under 5% of the records in the databases searched, and an even smaller percentage of the exceptional records. All NEHRP site categories have contributed exceptional records, in proportions similar to the extent that they are represented in the larger database.

  13. Integrated coherent matter wave circuits

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ryu, C.; Boshier, M. G.

    2015-09-21

    An integrated coherent matter wave circuit is a single device, analogous to an integrated optical circuit, in which coherent de Broglie waves are created and then launched into waveguides where they can be switched, divided, recombined, and detected as they propagate. Applications of such circuits include guided atom interferometers, atomtronic circuits, and precisely controlled delivery of atoms. We report experiments demonstrating integrated circuits for guided coherent matter waves. The circuit elements are created with the painted potential technique, a form of time-averaged optical dipole potential in which a rapidly moving, tightly focused laser beam exerts forces on atoms through theirmoreelectric polarizability. Moreover, the source of coherent matter waves is a BoseEinstein condensate (BEC). Finally, we launch BECs into painted waveguides that guide them around bends and form switches, phase coherent beamsplitters, and closed circuits. These are the basic elements that are needed to engineer arbitrarily complex matter wave circuitry.less

  14. Tube-wave seismic imaging

    DOE Patents [OSTI]

    Korneev, Valeri A [LaFayette, CA

    2009-05-05

    The detailed analysis of cross well seismic data for a gas reservoir in Texas revealed two newly detected seismic wave effects, recorded approximately 2000 feet above the reservoir. A tube-wave (150) is initiated in a source well (110) by a source (111), travels in the source well (110), is coupled to a geological feature (140), propagates (151) through the geological feature (140), is coupled back to a tube-wave (152) at a receiver well (120), and is and received by receiver(s) (121) in either the same (110) or a different receiving well (120). The tube-wave has been shown to be extremely sensitive to changes in reservoir characteristics. Tube-waves appear to couple most effectively to reservoirs where the well casing is perforated, allowing direct fluid contact from the interior of a well case to the reservoir.

  15. Tube-wave seismic imaging

    DOE Patents [OSTI]

    Korneev, Valeri A.; Bakulin, Andrey

    2009-10-13

    The detailed analysis of cross well seismic data for a gas reservoir in Texas revealed two newly detected seismic wave effects, recorded approximately 2000 feet above the reservoir. A tube-wave (150) is initiated in a source well (110) by a source (111), travels in the source well (110), is coupled to a geological feature (140), propagates (151) through the geological feature (140), is coupled back to a tube-wave (152) at a receiver well (120), and is and received by receiver(s) (121) in either the same (110) or a different receiving well (120). The tube-wave has been shown to be extremely sensitive to changes in reservoir characteristics. Tube-waves appear to couple most effectively to reservoirs where the well casing is perforated, allowing direct fluid contact from the interior of a well case to the reservoir.

  16. Two-dimensional Vlasov simulation of electron plasma wave trapping, wavefront bowing, self-focusing, and sideloss

    SciTech Connect (OSTI)

    Banks, J. W.; Berger, R. L.; Cohen, B. I.; Hittinger, J. A. F.; Brunner, S.

    2011-05-15

    Two-dimensional Vlasov simulations of nonlinear electron plasma waves are presented, in which the interplay of linear and nonlinear kinetic effects is evident. The plasma wave is created with an external traveling wave potential with a transverse envelope of width {Delta}y such that thermal electrons transit the wave in a ''sideloss'' time, t{sub sl{approx}{Delta}}y/v{sub e}. Here, v{sub e} is the electron thermal velocity. The quasisteady distribution of trapped electrons and its self-consistent plasma wave are studied after the external field is turned off. In cases of particular interest, the bounce frequency, {omega}{sub be}=k{radical}(e{phi}/m{sub e}), satisfies the trapping condition {omega}{sub be}t{sub sl}>2{pi} such that the wave frequency is nonlinearly downshifted by an amount proportional to the number of trapped electrons. Here, k is the wavenumber of the plasma wave and {phi} is its electric potential. For sufficiently short times, the magnitude of the negative frequency shift is a local function of {phi}. Because the trapping frequency shift is negative, the phase of the wave on axis lags the off-axis phase if the trapping nonlinearity dominates linear wave diffraction. In this case, the phasefronts are curved in a focusing sense. In the opposite limit, the phasefronts are curved in a defocusing sense. Analysis and simulations in which the wave amplitude and transverse width are varied establish criteria for the development of each type of wavefront. The damping and trapped-electron-induced focusing of the finite-amplitude electron plasma wave are also simulated. The damping rate of the field energy of the wave is found to be about the sideloss rate, {nu}{sub e{approx}}t{sub sl}{sup -1}. For large wave amplitudes or widths {Delta}y, a trapping-induced self-focusing of the wave is demonstrated.

  17. Multiple plates subducting beneath Colombia, as illuminated by seismicity and velocity from the joint inversion of seismic and gravity data

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Syracuse, Ellen M.; Maceira, Monica; Prieto, German A.; Zhang, Haijiang; Ammon, Charles J.

    2016-04-12

    Subduction beneath the northernmost Andes in Colombia is complex. Based on seismicity distributions, multiple segments of slab appear to be subducting, and arc volcanism ceases north of 5° N. Here, we illuminate the subduction system through hypocentral relocations and Vp and Vs models resulting from the joint inversion of local body wave arrivals, surface wave dispersion measurements, and gravity data. The simultaneous use of multiple data types takes advantage of the differing sensitivities of each data type, resulting in velocity models that have improved resolution at both shallower and deeper depths than would result from traditional travel time tomography alone.more » The relocated earthquake dataset and velocity model clearly indicate a tear in the Nazca slab at 5° N, corresponding to a 250-km shift in slab seismicity and the termination of arc volcanism. North of this tear, the slab is flat, and it comprises slabs of two sources: the Nazca and Caribbean plates. The Bucaramanga nest, a small region of among the most intense intermediate-depth seismicity globally, is associated with the boundary between these two plates and possibly with a zone of melting or elevated water content, based on reduced Vp and increased Vp/Vs. As a result, we also use relocated seismicity to identify two new faults in the South American plate, one related to plate convergence and one highlighted by induced seismicity.« less

  18. MHK Technologies/C Wave | Open Energy Information

    Open Energy Info (EERE)

    homepage C Wave.jpg Technology Profile Primary Organization C Wave Technology Resource Click here Wave Technology Type Click here Attenuator Technology Description The C Wave...

  19. Property:Wind Velocity Range(m/s) | Open Energy Information

    Open Energy Info (EERE)

    Velocity Range(ms) Jump to: navigation, search Property Name Wind Velocity Range(ms) Property Type String Pages using the property "Wind Velocity Range(ms)" Showing 10 pages...

  20. Mixing between high velocity clouds and the galactic halo

    SciTech Connect (OSTI)

    Gritton, Jeffrey A.; Shelton, Robin L.; Kwak, Kyujin E-mail: rls@physast.uga.edu

    2014-11-01

    In the Galactic halo, metal-bearing Galactic halo material mixes into high velocity clouds (HVCs) as they hydrodynamically interact. This interaction begins long before the clouds completely dissipate and long before they slow to the velocity of the Galactic material. In order to make quantitative estimates of the mixing efficiency and resulting metal enrichment of HVCs, we made detailed two- and three-dimensional simulations of cloud-interstellar medium interactions. Our simulations track the hydrodynamics and time-dependent ionization levels. They assume that the cloud originally has a warm temperature and extremely low metallicity while the surrounding medium has a high temperature, low density, and substantial metallicity, but our simulations can be generalized to other choices of initial metallicities. In our simulations, mixing between cloud and halo gas noticeably raises the metallicity of the high velocity material. We present plots of the mixing efficiency and metal enrichment as a function of time.

  1. C Wave Ltd | Open Energy Information

    Open Energy Info (EERE)

    Ltd Jump to: navigation, search Name: C-Wave Ltd Place: England, United Kingdom Zip: SO17 1BJ Product: C-Wave is developing an innovative wave power technology using a unique...

  2. Clutter in the GMTI range-velocity map.

    SciTech Connect (OSTI)

    Doerry, Armin Walter

    2009-04-01

    Ground Moving Target Indicator (GMTI) radar maps echo data to range and range-rate, which is a function of a moving target's velocity and its position within the antenna beam footprint. Even stationary clutter will exhibit an apparent motion spectrum and can interfere with moving vehicle detections. Consequently it is very important for a radar to understand how stationary clutter maps into radar measurements of range and velocity. This mapping depends on a wide variety of factors, including details of the radar motion, orientation, and the 3-D topography of the clutter.

  3. SGP and TWP (Manus) Ice Cloud Vertical Velocities

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Kalesse, Heike

    Daily netcdf-files of ice-cloud dynamics observed at the ARM sites at SGP (Jan1997-Dec2010) and Manus (Jul1999-Dec2010). The files include variables at different time resolution (10s, 20min, 1hr). Profiles of radar reflectivity factor (dbz), Doppler velocity (vel) as well as retrieved vertical air motion (V_air) and reflectivity-weighted particle terminal fall velocity (V_ter) are given at 10s, 20min and 1hr resolution. Retrieved V_air and V_ter follow radar notation, so positive values indicate downward motion. Lower level clouds are removed, however a multi-layer flag is included.

  4. SGP and TWP (Manus) Ice Cloud Vertical Velocities

    SciTech Connect (OSTI)

    Kalesse, Heike

    2013-06-27

    Daily netcdf-files of ice-cloud dynamics observed at the ARM sites at SGP (Jan1997-Dec2010) and Manus (Jul1999-Dec2010). The files include variables at different time resolution (10s, 20min, 1hr). Profiles of radar reflectivity factor (dbz), Doppler velocity (vel) as well as retrieved vertical air motion (V_air) and reflectivity-weighted particle terminal fall velocity (V_ter) are given at 10s, 20min and 1hr resolution. Retrieved V_air and V_ter follow radar notation, so positive values indicate downward motion. Lower level clouds are removed, however a multi-layer flag is included.

  5. Edge Turbulence Velocity Changes with Lithium Coating on NSTX

    SciTech Connect (OSTI)

    Cao, A.; Zweben, S. J.; Stotler, D. P.; Bell, M.; Diallo, A.; Kaye, S. M.; LeBlanc, B.

    2012-08-10

    Lithium coating improves energy confinement and eliminates edge localized modes in NSTX, but the mechanism of this improvement is not yet well understood. We used the gas-puff-imaging (GPI) diagnostic on NSTX to measure the changes in edge turbulence which occurred during a scan with variable lithium wall coating, in order to help understand the reason for the confinement improvement with lithium. There was a small increase in the edge turbulence poloidal velocity and a decrease in the poloidal velocity fluctuation level with increased lithium. The possible effect of varying edge neutral density on turbulence damping was evaluated for these cases in NSTX. __________________________________________________

  6. Surface plasma wave assisted second harmonic generation of laser over a metal film

    SciTech Connect (OSTI)

    Chauhan, Santosh; Parashar, J.

    2015-01-15

    Second harmonic generation of laser mode converted surface plasma wave (SPW) over a corrugated metal film is studied. The laser, impinged on the metal film, under attenuated total reflection configuration, excites SPW over the metal–vacuum interface. The excited SPW extends over a much wider surface area than the laser spot cross-section. It exerts a second harmonic ponderomotive force on metal electrons, imparting them velocity that beats with the surface ripple to produce a nonlinear current, driving resonant second harmonic surface plasma wave.

  7. Kinetic Wave Power | Open Energy Information

    Open Energy Info (EERE)

    Wave Power Jump to: navigation, search Name: Kinetic Wave Power Address: 2861 N Tupelo St Place: Midland Zip: 48642 Region: United States Sector: Marine and Hydrokinetic Phone...

  8. Triton Sea Wave Technologies | Open Energy Information

    Open Energy Info (EERE)

    Triton Sea Wave Technologies Jump to: navigation, search Name: Triton Sea Wave Technologies Address: 22 A Thrakis Zip: 15669 Region: Greece Sector: Marine and Hydrokinetic Year...

  9. Clean Wave Ventures | Open Energy Information

    Open Energy Info (EERE)

    Wave Ventures Jump to: navigation, search Name: Clean Wave Ventures Place: Indianapolis, Indiana Zip: 46204 Product: Midwest-based venture capital firm specializing in high growth...

  10. Euro Wave Energy | Open Energy Information

    Open Energy Info (EERE)

    Wave Energy Jump to: navigation, search Name: Euro Wave Energy Region: Norway Sector: Marine and Hydrokinetic Website: www.eurowaveenergy.com This company is listed in the Marine...

  11. Dartmouth Wave Energy Searaser | Open Energy Information

    Open Energy Info (EERE)

    Energy Searaser Jump to: navigation, search Name: Dartmouth Wave Energy (Searaser) Place: United Kingdom Product: British firm developing the wave energy converter, Searaser....

  12. Leancon Wave Energy | Open Energy Information

    Open Energy Info (EERE)

    Leancon Wave Energy Jump to: navigation, search Name: Leancon Wave Energy Address: Alpedalsvej 37 Place: Kolding Zip: 6000 Region: Denmark Sector: Marine and Hydrokinetic Phone...

  13. Green Ocean Wave Energy | Open Energy Information

    Open Energy Info (EERE)

    Ocean Wave Energy Jump to: navigation, search Name: Green Ocean Wave Energy Region: United States Sector: Marine and Hydrokinetic Website: http: This company is listed in the...

  14. Millimeter Wave Sensor Technologies Track Biometrics; Detect...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Argonne's millimeter wave (mmW) sensor technologies measure a wide range of threat ... Argonne's millimeter wave (mmW) sensor technologies measure a wide range of threat ...

  15. Wave Wind LLC | Open Energy Information

    Open Energy Info (EERE)

    Wave Wind LLC Jump to: navigation, search Name: Wave Wind LLC Place: Sun Prairie, Wisconsin Zip: 53590 Sector: Services, Wind energy Product: Wisconsin-based wind developer and...

  16. Wind Waves and Sun | Open Energy Information

    Open Energy Info (EERE)

    Wind Waves and Sun Jump to: navigation, search Name: Wind Waves and Sun Region: United States Sector: Marine and Hydrokinetic Website: www.windwavesandsun.com This company is...

  17. Wave Energy Basics | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Ocean » Wave Energy Basics Wave Energy Basics August 16, 2013 - 4:30pm Addthis Photo of a large wave. Wave energy technologies extract energy directly from surface waves or from pressure fluctuations below the surface. Renewable energy analysts believe there is enough energy in ocean waves to provide up to 2 terawatts of electricity. (A terawatt is equal to a trillion watts.) However, wave energy cannot be harnessed everywhere. Wave power-rich areas of the world include the western coasts of

  18. Motor Wave Group | Open Energy Information

    Open Energy Info (EERE)

    Wave Group Jump to: navigation, search Name: Motor Wave Group Place: Hong Kong Region: China Sector: Marine and Hydrokinetic Website: www.motorwavegroup.com This company is listed...

  19. Mirror force induced wave dispersion in Alfvn waves

    SciTech Connect (OSTI)

    Damiano, P. A.; Johnson, J. R.

    2013-06-15

    Recent hybrid MHD-kinetic electron simulations of global scale standing shear Alfvn waves along the Earth's closed dipolar magnetic field lines show that the upward parallel current region within these waves saturates and broadens perpendicular to the ambient magnetic field and that this broadening increases with the electron temperature. Using resistive MHD simulations, with a parallel Ohm's law derived from the linear Knight relation (which expresses the current-voltage relationship along an auroral field line), we explore the nature of this broadening in the context of the increased perpendicular Poynting flux resulting from the increased parallel electric field associated with mirror force effects. This increased Poynting flux facilitates wave energy dispersion across field lines which in-turn allows for electron acceleration to carry the field aligned current on adjacent field lines. This mirror force driven dispersion can dominate over that associated with electron inertial effects for global scale waves.

  20. Recirculation in multiple wave conversions

    SciTech Connect (OSTI)

    Kaufman, A. N.; Brizard, A.J.; Kaufman, A.N.; Tracy, E.R.

    2008-07-30

    A one-dimensional multiple wave-conversion model is constructed that allows energy recirculation in ray phase space. Using a modular eikonal approach, the connection coefficients for this model are calculated by ray phase-space methods. Analytical results (confirmed numerically) show that all connection coefficients exhibit interference effects that depend on an interference phase, calculated from the coupling constants and the area enclosed by the intersecting rays. This conceptual model, which focuses on the topology of intersecting rays in phase space, is used to investigate how mode conversion between primary and secondary waves is modified by the presence of a tertiary wave.

  1. Low inlet gas velocity high throughput biomass gasifier

    DOE Patents [OSTI]

    Feldmann, Herman F.; Paisley, Mark A.

    1989-01-01

    The present invention discloses a novel method of operating a gasifier for production of fuel gas from carbonaceous fuels. The process disclosed enables operating in an entrained mode using inlet gas velocities of less than 7 feet per second, feedstock throughputs exceeding 4000 lbs/ft.sup.2 -hr, and pressures below 100 psia.

  2. Measurement of turbulent wind velocities using a rotating boom apparatus

    SciTech Connect (OSTI)

    Sandborn, V.A.; Connell, J.R.

    1984-04-01

    The present report covers both the development of a rotating-boom facility and the evaluation of the spectral energy of the turbulence measured relative to the rotating boom. The rotating boom is composed of a helicopter blade driven through a pulley speed reducer by a variable speed motor. The boom is mounted on a semiportable tower that can be raised to provide various ratios of hub height to rotor diameter. The boom can be mounted to rotate in either the vertical or horizontal plane. Probes that measure the three components of turbulence can be mounted at any location along the radius of the boom. Special hot-film sensors measured two components of the turbulence at a point directly in front of the rotating blade. By using the probe rotated 90/sup 0/ about its axis, the third turbulent velocity component was measured. Evaluation of the spectral energy distributions for the three components of velocity indicates a large concentration of energy at the rotational frequency. At frequencies slightly below the rotational frequency, the spectral energy is greatly reduced over that measured for the nonrotating case measurements. Peaks in the energy at frequencies that are multiples of the rotation frequency were also observed. We conclude that the rotating boom apparatus is suitable and ready to be used in experiments for developing and testing sensors for rotational measurement of wind velocity from wind turbine rotors. It also can be used to accurately measure turbulent wind for testing theories of rotationally sampled wind velocity.

  3. Velocity Autocorrelation Functions and Diffusion of Dusty Plasma

    SciTech Connect (OSTI)

    Ramazanov, T. S.; Dzhumagulova, K. N.; Daniyarov, T. T.; Dosbolayev, M. K.; Jumabekov, A. N.

    2008-09-07

    The velocity autocorrelation functions and square displacements were calculated on the basis of experimental data obtained on experimental setup with dc discharge. Computer simulation of the system of dust particles by the method of the Langevin dynamics was performed. The comparisons of experimental and theoretical results are given.

  4. Brady 1D seismic velocity model ambient noise prelim

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Mellors, Robert J.

    2013-10-25

    Preliminary 1D seismic velocity model derived from ambient noise correlation. 28 Green's functions filtered between 4-10 Hz for Vp, Vs, and Qs were calculated. 1D model estimated for each path. The final model is a median of the individual models. Resolution is best for the top 1 km. Poorly constrained with increasing depth.

  5. Effect of Dust Grains on Solitary Kinetic Alfven Wave

    SciTech Connect (OSTI)

    Li Yangfang; Wu, D. J.; Morfill, G. E.

    2008-09-07

    Solitary kinetic Alfven wave has been studied in dusty plasmas. The effect of the dust charge-to-mass ratio is considered. We derive the Sagdeev potential for the soliton solutions based on the hydrodynamic equations. A singularity in the Sagdeev potential is found and this singularity results in a bell-shaped soliton. The soliton solutions comprise two branches. One branch is sub-Alfvenic and the soliton velocities are much smaller than the Alfven speed. The other branch is super-Alfvenic and the soliton velocities are very close to or greater than the Alfven speed. Both compressive and rarefactive solitons can exist in each branch. For the sub-Alfvenic branch, the rarefactive soliton is a bell shape curve which is much narrower than the compressive one. In the super-Alfvenic branch, however, the compressive soliton is bell-shaped and the rarefactive one is broadened. We also found that the super-Alfvenic solitons can develop to other structures. When the charge-to-mass ratio of the dust grains is sufficiently high, the width of the rarefactive soliton will increase extremely and an electron density depletion will be observed. When the velocity is much higher than the Alfven speed, the bell-shaped soliton will transit to a cusped structure.

  6. Forging of compressor blades: Temperature and ram velocity effects

    SciTech Connect (OSTI)

    Saigal, A.; Zhen, K.; Chan, T.S.

    1995-07-01

    Forging is one of the most widely used manufacturing process for making high-strength, structurally integrated, impact and creep-resistant Ti-6Al-4V compressor blades for jet engines. In addition, in modern metal forming technology, finite element analysis method and computer modeling are being extensively employed for initial evaluation and optimization of various processes, including forging. In this study, DEFORM, a rigid viscoplastic two-dimensional finite element code was used to study the effects of initial die temperature and initial ram velocity on the forging process. For a given billet, die temperature and ram velocity influence the strain rate, temperature distribution,and thus the flow stress of the material. The die temperature and the ram velocity were varied over the range 300 to 700 F and 15--25 in./sec, respectively, to estimate the maximum forging load and the total energy required to forge compressor blades. The ram velocity was assumed to vary linearly as a function of stroke. Based on the analysis,it was found the increasing the die temperature from 300 to 700 F decreases the forging loads by 19.9 percent and increases the average temperature of the workpiece by 43 F. Similarly, increasing the initial ram velocity from 15 to 25 in./sec decreases the forging loads by 25.2 percent and increases the average temperature of the workpiece by 36 F. The nodal temperature distribution is bimodal in each case. The forging energy required to forge the blades is approximately 18 kips *in./in.

  7. The interaction of katabatic winds and mountain waves

    SciTech Connect (OSTI)

    Poulos, G.S.

    1997-01-01

    The variation in the oft-observed, thermally-forced, nocturnal katabatic winds along the east side of the Rocky Mountains can be explained by either internal variability or interactions with various other forcings. Though generally katabatic flows have been studied as an entity protected from external forcing by strong thermal stratification, this work investigates how drainage winds along the Colorado Front Range interact with, in particular, topographically forced mountain waves. Previous work has shown, based on measurements taken during the Atmospheric Studies in Complex Terrain 1993 field program, that the actual dispersion in katabatic flows is often greater than reflected in models of dispersion. The interaction of these phenomena is complicated and non-linear since the amplitude, wavelength and vertical structure of mountain waves developed by flow over the Rocky Mountain barrier are themselves partly determined by the evolving atmospheric stability in which the drainage flows develop. Perturbations to katabatic flow by mountain waves, relative to their more steady form in quiescent conditions, are found to be caused by both turbulence and dynamic pressure effects. The effect of turbulent interaction is to create changes to katabatic now depth, katabatic flow speed, katabatic jet height and, vertical thermal stratification. The pressure effect is found to primarily influence the variability of a given katabatic now through the evolution of integrated column wave forcing on surface pressure. Variability is found to occur on two scales, on the mesoscale due to meso-gamma scale mountain wave evolution, and on the microscale, due to wave breaking. Since existing parameterizations for the statically stable case are predominantly based on nearly flat terrain atmospheric measurements under idealized or nearly quiescent conditions, it is no surprise that these parameterizations often contribute to errors in prediction, particularly in complex terrain.

  8. HIGH-RESOLUTION OBSERVATIONS AND THE PHYSICS OF HIGH-VELOCITY CLOUD A0

    SciTech Connect (OSTI)

    Verschuur, Gerrit L.

    2013-04-01

    The neutral hydrogen structure of high-velocity cloud A0 (at about -180 km s{sup -1}) has been mapped with a 9.'1 resolution. Gaussian decomposition of the profiles is used to separately map families of components defined by similarities in center velocities and line widths. About 70% of the H I gas is in the form of a narrow, twisted filament whose typical line widths are of the order of 24 km s{sup -1}. Many bright features with narrow line widths of the order of 6 km s{sup -1}, clouds, are located in and near the filament. A third category with properties between those of the filament and clouds appears in the data. The clouds are not always co-located with the broader line width filament emission as seen projected on the sky. Under the assumption that magnetic fields underlie the presence of the filament, a theorem is developed for its stability in terms of a toroidal magnetic field generated by the flow of gas along field lines. It is suggested that the axial magnetic field strength may be derived from the excess line width of the H I emission over and above that due to kinetic temperature by invoking the role of Alfven waves that create what is in essence a form of magnetic turbulence. At a distance of 200 pc the axial and the derived toroidal magnetic field strengths in the filament are then about 6 {mu}G while for the clouds they are about 4 {mu}G. The dependence of the derived field strength on distance is discussed.

  9. Wave-operated power plant

    SciTech Connect (OSTI)

    Ghesquiere, H.

    1980-08-12

    This wave-operated power plant comprises a perforated caisson breakwater in which propellers, or turbines, are mounted in the perforations or openings and drives hydraulic pumps connected thereto, which in turn drives a hydraulic motor coupled to an electric generator. One-way flap valves are mounted in the openings. Some of said flap valves allow the rushing waves to enter the caisson, while the other flap valves allow the water to flow out of the caisson.

  10. Direct Drive Wave Energy Buoy

    SciTech Connect (OSTI)

    Rhinefrank, Kenneth E.; Lenee-Bluhm, Pukha; Prudell, Joseph H.; Schacher, Alphonse A.; Hammagren, Erik J.; Zhang, Zhe

    2013-07-29

    The most prudent path to a full-scale design, build and deployment of a wave energy conversion (WEC) system involves establishment of validated numerical models using physical experiments in a methodical scaling program. This Project provides essential additional rounds of wave tank testing at 1:33 scale and ocean/bay testing at a 1:7 scale, necessary to validate numerical modeling that is essential to a utility-scale WEC design and associated certification.

  11. Effect of magnetic field on the wave dispersion relation in three-dimensional dusty plasma crystals

    SciTech Connect (OSTI)

    Yang Xuefeng [School of Mathematical Sciences, Dalian University of Technology, Dalian 116024 (China); Wang Zhengxiong [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2012-07-15

    Three-dimensional plasma crystals under microgravity condition are investigated by taking into account an external magnetic field. The wave dispersion relations of dust lattice modes in the body centered cubic (bcc) and the face centered cubic (fcc) plasma crystals are obtained explicitly when the magnetic field is perpendicular to the wave motion. The wave dispersion relations of dust lattice modes in the bcc and fcc plasma crystals are calculated numerically when the magnetic field is in an arbitrary direction. The numerical results show that one longitudinal mode and two transverse modes are coupled due to the Lorentz force in the magnetic field. Moreover, three wave modes, i.e., the high frequency phonon mode, the low frequency phonon mode, and the optical mode, are obtained. The optical mode and at least one phonon mode are hybrid modes. When the magnetic field is neither parallel nor perpendicular to the primitive wave motion, all the three wave modes are hybrid modes and do not have any intersection points. It is also found that with increasing the magnetic field strength, the frequency of the optical mode increases and has a cutoff at the cyclotron frequency of the dust particles in the limit of long wavelength, and the mode mixings for both the optical mode and the high frequency phonon mode increase. The acoustic velocity of the low frequency phonon mode is zero. In addition, the acoustic velocity of the high frequency phonon mode depends on the angle of the magnetic field and the wave motion but does not depend on the magnetic field strength.

  12. Compositional Variation Within Hybrid Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Compositional Variation Within Hybrid Nanostructures Print The inherently high surface area of bimetallic nanoparticles makes them especially attractive materials for heterogeneous catalysis. The ability to selectively grow these and other types of nanoparticles on a desired surface is ideal for the fabrication of higher-order nanoscale architectures. However, the growth mechanism for bimetallic nanoparticles on a surface is expected to be quite different than that for free particles in

  13. Compositional Variation Within Hybrid Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Compositional Variation Within Hybrid Nanostructures Print The inherently high surface area of bimetallic nanoparticles makes them especially attractive materials for heterogeneous catalysis. The ability to selectively grow these and other types of nanoparticles on a desired surface is ideal for the fabrication of higher-order nanoscale architectures. However, the growth mechanism for bimetallic nanoparticles on a surface is expected to be quite different than that for free particles in

  14. Compositional Variation Within Hybrid Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Compositional Variation Within Hybrid Nanostructures Print The inherently high surface area of bimetallic nanoparticles makes them especially attractive materials for heterogeneous catalysis. The ability to selectively grow these and other types of nanoparticles on a desired surface is ideal for the fabrication of higher-order nanoscale architectures. However, the growth mechanism for bimetallic nanoparticles on a surface is expected to be quite different than that for free particles in

  15. Clock asynchrony and mass variation

    SciTech Connect (OSTI)

    Gruber, R.P.; Brahm, D.E.

    1993-04-01

    Many theories have been proposed in which particle masses vary with time. In a world with varying particle masses, clocks become asynchronous and metersticks inconsistent. By combining two or more clocks with different known dependences on mass, one can construct a nearly invariant clock, and measure the rate of mass variation. If the proton and electron masses vary differently, then certain equations must be applied to predict a clock's dependence on each. 8 refs.

  16. Compositional Variation Within Hybrid Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Compositional Variation Within Hybrid Nanostructures Print The inherently high surface area of bimetallic nanoparticles makes them especially attractive materials for heterogeneous catalysis. The ability to selectively grow these and other types of nanoparticles on a desired surface is ideal for the fabrication of higher-order nanoscale architectures. However, the growth mechanism for bimetallic nanoparticles on a surface is expected to be quite different than that for free particles in

  17. Compositional Variation Within Hybrid Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Compositional Variation Within Hybrid Nanostructures Print The inherently high surface area of bimetallic nanoparticles makes them especially attractive materials for heterogeneous catalysis. The ability to selectively grow these and other types of nanoparticles on a desired surface is ideal for the fabrication of higher-order nanoscale architectures. However, the growth mechanism for bimetallic nanoparticles on a surface is expected to be quite different than that for free particles in

  18. Compositional Variation Within Hybrid Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Compositional Variation Within Hybrid Nanostructures Print The inherently high surface area of bimetallic nanoparticles makes them especially attractive materials for heterogeneous catalysis. The ability to selectively grow these and other types of nanoparticles on a desired surface is ideal for the fabrication of higher-order nanoscale architectures. However, the growth mechanism for bimetallic nanoparticles on a surface is expected to be quite different than that for free particles in

  19. Compositional Variation Within Hybrid Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Compositional Variation Within Hybrid Nanostructures Print The inherently high surface area of bimetallic nanoparticles makes them especially attractive materials for heterogeneous catalysis. The ability to selectively grow these and other types of nanoparticles on a desired surface is ideal for the fabrication of higher-order nanoscale architectures. However, the growth mechanism for bimetallic nanoparticles on a surface is expected to be quite different than that for free particles in

  20. Compositional Variation Within Hybrid Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Compositional Variation Within Hybrid Nanostructures Print The inherently high surface area of bimetallic nanoparticles makes them especially attractive materials for heterogeneous catalysis. The ability to selectively grow these and other types of nanoparticles on a desired surface is ideal for the fabrication of higher-order nanoscale architectures. However, the growth mechanism for bimetallic nanoparticles on a surface is expected to be quite different than that for free particles in

  1. Laser generation and detection of longitudinal and shear acoustic waves in a diamond anvil cell

    SciTech Connect (OSTI)

    Chigarev, Nikolay; Zinin, Pavel; Ming Lichung; Amulele, George; Bulou, Alain; Gusev, Vitalyi

    2008-11-03

    Laser ultrasonics in a point-source-point-receiver configuration is applied for the evaluation of elastic properties of nontransparent materials in a diamond anvil cell at high pressures. Measurement of both longitudinal and shear acoustic wave velocities in an iron foil at pressures up to 23 GPa does not require any information in addition to the one obtained by all-optical pump-probe technique.

  2. Apparatus and method for measuring and imaging traveling waves

    DOE Patents [OSTI]

    Telschow, Kenneth L.; Deason, Vance A.

    2001-01-01

    An apparatus is provided for imaging traveling waves in a medium. The apparatus includes a vibration excitation source configured to impart traveling waves within a medium. An emitter is configured to produce two or more wavefronts, at least one wavefront modulated by a vibrating medium. A modulator is configured to modulate another wavefront in synchronization with the vibrating medium. A sensing media is configured to receive in combination the modulated one wavefront and the another wavefront and having a detection resolution within a limited bandwidth. The another wavefront is modulated at a frequency such that a difference frequency between the one wavefront and the another wavefront is within a response range of the sensing media. Such modulation produces an image of the vibrating medium having an output intensity that is substantially linear with small physical variations within the vibrating medium for all vibration frequencies above the sensing media's response bandwidth. A detector is configured to detect an image of traveling waves in the vibrating medium resulting from interference between the modulated one wavefront and the another wavefront when combined in association with the sensing media. The traveling wave can be used to characterize certain material properties of the medium. Furthermore, a method is provided for imaging and characterizing material properties according to the apparatus.

  3. Collisionless damping of dust-acoustic waves in a charge varying dusty plasma with nonextensive ions

    SciTech Connect (OSTI)

    Amour, Rabia; Tribeche, Mouloud

    2014-12-15

    The charge variation induced nonlinear dust-acoustic wave damping in a charge varying dusty plasma with nonextensive ions is considered. It is shown that the collisionless damping due to dust charge fluctuation causes the nonlinear dust acoustic wave propagation to be described by a damped Korteweg-de Vries (dK-dV) equation the coefficients of which depend sensitively on the nonextensive parameter q. The damping term, solely due to the dust charge variation, is affected by the ion nonextensivity. For the sake of completeness, the possible effects of nonextensivity and collisionless damping on weakly nonlinear wave packets described by the dK-dV equation are succinctly outlined by deriving a nonlinear Schrödinger-like equation with a complex nonlinear coefficient.

  4. Vertical dispersion of inertial waves in the upper ocean

    SciTech Connect (OSTI)

    Rubenstein, D.M.

    1983-05-20

    A linear model of the vertical dispersion of near-inertial waves is developed. A porosity distribution near the bottom of the computational domain minimizes bottom reflections and simulates an ocean of the infinite depth. The model is used to show that the vertical dispersion of near-inertial waves in the upper ocean may, under certain conditions, contribute significanlty to the observed rapid decay of inertial oscillations in the surface layer. The kinetic energy of inertial oscillations at mid-latitudes decays with an e folding time scale of 10 days or less, when the parameter lambda(km)/N(cph)d(m) is less than or of the order of unity, where lambda is the wavelength of the wind-generated near-inertial waves, N is the Vaeisaelae frequency in the upper pycnocline, and d is the surface layer thickness. At the top of the pycnocline the model predicts a velocity maximum, which develops as energy propagates downward, out of the surface layer. However, when the upper pycnocline is sufficiently peaked, a resonant frequency interference effect is predicted. This effect modulates the dissipation of surface layer inertial oscillations, and their magnitude after a storm need not decay monotonically. We also make qualitative comparisons with deep-ocean current meter observations taken during the Mixed Layer Experiment (MILE) and with shallow water (105 m) observations taken in the Baltic Sea.

  5. Wave Energy Resource Assessment | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Wave Energy Resource Assessment Wave Energy Resource Assessment Wave Energy Resource Assessment 52_wave_resource_assessment_epri_jacobson.ppt (308.5 KB) More Documents & Publications OTEC resource assessment OTEC Cold Water Pipe-Platform Sub-System Dynamic Interaction Validation (OPPSDIV) Whitestone Power & Communications (TRL 1 2 3 System) - Whitestone Poncelet RISEC Project

  6. Dust-acoustic waves and stability in the permeating dusty plasma. II. Power-law distributions

    SciTech Connect (OSTI)

    Gong Jingyu; Du Jiulin; Liu Zhipeng

    2012-08-15

    The dust-acoustic waves and the stability theory for the permeating dusty plasma with power-law distributions are studied by using nonextensive q-statistics. In two limiting physical cases, when the thermal velocity of the flowing dusty plasma is much larger than, and much smaller than the phase velocity of the waves, we derived the dust-acoustic wave frequency, the instability growth rate, and the instability critical flowing velocity. As compared with the formulae obtained in part I [Gong et al., Phys. Plasmas 19, 043704 (2012)], all formulae of the present cases and the resulting plasma characteristics are q-dependent, and the power-law distribution of each plasma component of the permeating dusty plasma has a different q-parameter and thus has a different nonextensive effect. Further, we make numerical analyses of an example that a cometary plasma tail is passing through the interplanetary space dusty plasma and we show that these power-law distributions have significant effects on the plasma characteristics of this kind of plasma environment.

  7. Rayleigh surface wave interaction with the 2D exciton Bose-Einstein condensate

    SciTech Connect (OSTI)

    Boev, M. V.; Kovalev, V. M.

    2015-06-15

    We describe the interaction of a Rayleigh surface acoustic wave (SAW) traveling on the semiconductor substrate with the excitonic gas in a double quantum well located on the substrate surface. We study the SAW attenuation and its velocity renormalization due to the coupling to excitons. Both the deformation potential and piezoelectric mechanisms of the SAW-exciton interaction are considered. We focus on the frequency and excitonic density dependences of the SAW absorption coefficient and velocity renormalization at temperatures both above and well below the critical temperature of Bose-Einstein condensation of the excitonic gas. We demonstrate that the SAW attenuation and velocity renormalization are strongly different below and above the critical temperature.

  8. Experimental determination of radiated internal wave power without pressure field data

    SciTech Connect (OSTI)

    Lee, Frank M.; Morrison, P. J. [Physics Department and Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 787121192 (United States)] [Physics Department and Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 787121192 (United States); Paoletti, M. S.; Swinney, Harry L. [Physics Department, The University of Texas at Austin, Austin, Texas 787121192 (United States)] [Physics Department, The University of Texas at Austin, Austin, Texas 787121192 (United States)

    2014-04-15

    We present a method to determine, using only velocity field data, the time-averaged energy flux (J) and total radiated power P for two-dimensional internal gravity waves. Both (J) and P are determined from expressions involving only a scalar function, the stream function ?. We test the method using data from a direct numerical simulation for tidal flow of a stratified fluid past a knife edge. The results for the radiated internal wave power given by the stream function method agree to within 0.5% with results obtained using pressure and velocity data from the numerical simulation. The results for the radiated power computed from the stream function agree well with power computed from the velocity and pressure if the starting point for the stream function computation is on a solid boundary, but if a boundary point is not available, care must be taken to choose an appropriate starting point. We also test the stream function method by applying it to laboratory data for tidal flow past a knife edge, and the results are found to agree with the direct numerical simulation. The supplementary material includes a Matlab code with a graphical user interface that can be used to compute the energy flux and power from two-dimensional velocity field data.

  9. Shear wave transducer for boreholes

    DOE Patents [OSTI]

    Mao, N.H.

    1984-08-23

    A technique and apparatus is provided for estimating in situ stresses by measuring stress-induced velocity anisotropy around a borehole. Two sets each of radially and tangentially polarized transducers are placed inside the hole with displacement directions either parallel or perpendicular to the principal stress directions. With this configuration, relative travel times are measured by both a pulsed phase-locked loop technique and a cross correlation of digitized waveforms. The biaxial velocity data are used to back-calculate the applied stress.

  10. THE RADIAL VELOCITY EXPERIMENT (RAVE): FOURTH DATA RELEASE

    SciTech Connect (OSTI)

    Kordopatis, G.; Gilmore, G.; Steinmetz, M.; Williams, M. E. K.; Piffl, T.; Enke, H.; Carrillo, I.; Boeche, C.; Roeser, S.; Seabroke, G. M.; Siebert, A.; Zwitter, T.; Binney, J.; De Laverny, P.; Recio-Blanco, A.; Bijaoui, A.; Wyse, R. F. G.; Freeman, K.; Munari, U.; Anguiano, B.; and others

    2013-11-01

    We present the stellar atmospheric parameters (effective temperature, surface gravity, overall metallicity), radial velocities, individual abundances, and distances determined for 425,561 stars, which constitute the fourth public data release of the RAdial Velocity Experiment (RAVE). The stellar atmospheric parameters are computed using a new pipeline, based on the algorithms of MATISSE and DEGAS. The spectral degeneracies and the Two Micron All Sky Survey photometric information are now better taken into consideration, improving the parameter determination compared to the previous RAVE data releases. The individual abundances for six elements (magnesium, aluminum, silicon, titanium, iron, and nickel) are also given, based on a special-purpose pipeline that is also improved compared to that available for the RAVE DR3 and Chemical DR1 data releases. Together with photometric information and proper motions, these data can be retrieved from the RAVE collaboration Web site and the Vizier database.

  11. Low velocity ion stopping in binary ionic mixtures

    SciTech Connect (OSTI)

    Tashev, Bekbolat; Baimbetov, Fazylkhan; Deutsch, Claude; Fromy, Patrice

    2008-10-15

    Attention is focused on the low ion velocity stopping mechanisms in multicomponent and dense target plasmas built of quasiclassical electron fluids neutralizing binary ionic mixtures, such as, deuterium-tritium of current fusion interest, proton-heliumlike iron in the solar interior or proton-helium ions considered in planetology, as well as other mixtures of fiducial concern in the heavy ion beam production of warm dense matter at Bragg peak conditions. The target plasma is taken in a multicomponent dielectric formulation a la Fried-Conte. The occurrence of projectile ion velocities (so-called critical) for which target electron slowing down equals that of given target ion components is also considered. The corresponding multiquadrature computations, albeit rather heavy, can be monitored analytical through a very compact code operating a PC cluster. Slowing down results are systematically scanned with respect to target temperature and electron density, as well as ion composition.

  12. GLOBULAR CLUSTERS AND DARK SATELLITE GALAXIES THROUGH THE STREAM VELOCITY

    SciTech Connect (OSTI)

    Naoz, Smadar; Narayan, Ramesh

    2014-08-10

    The formation of purely baryonic globular clusters with no gravitationally bound dark matter is still a theoretical challenge. We show that these objects might form naturally whenever there is a relative stream velocity between baryons and dark matter. The stream velocity causes a phase shift between linear modes of baryonic and dark matter perturbations, which translates to a spatial offset between the two components when they collapse. For a 2σ (3σ) density fluctuation, baryonic clumps with masses in the range 10{sup 5}-2.5 × 10{sup 6} M {sub ☉} (10{sup 5}-4 × 10{sup 6} M {sub ☉}) collapse outside the virial radii of their counterpart dark matter halos. These objects could survive as long-lived, dark-matter-free objects and might conceivably become globular clusters. In addition, their dark matter counterparts, which were deprived of gas, might become dark satellite galaxies.

  13. What are Gravitational Waves? | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    are Gravitational Waves? What are Gravitational Waves? June 27, 2016 - 1:03pm Addthis Einstein was right! Gravitational Waves exist. Find out how they work. | Graphic courtesy of California Institute of Technology. Einstein was right! Gravitational Waves exist. Find out how they work. | Graphic courtesy of California Institute of Technology. Daniel Holz University of Chicago Albert Einstein first predicted gravitational waves almost a century ago, but only since September 15, 2015, have

  14. Vertical Velocities in Continental Boundary Layer Stratocumulus Clouds

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Velocities in Continental Boundary Layer Stratocumulus Clouds Virendra Ghate Bruce Albrecht and Pavlos Kollias Why BL Stratocumulus?? * Extensive Coverage - Cover ~24% of earth's surface - Persist of long time-scales * Impact on radiation budget - High SW albedo compared to land or ocean Klein and Hartmann 1993 But Why Continental Clouds? * They do exist - Monthly cloud fraction can vary from 10% to 23% * Impact on pollution & Diurnal Cycle - Affect pollutant venting out of BL & Aerosol

  15. Homogeneous charge engines -- Basis of cyclic variations. Final report

    SciTech Connect (OSTI)

    Whitelaw, J.H.

    1997-06-30

    The objectives of the Grant required investigations of cyclic variations in a homogeneous-charge engine initially with gas combustion and the air from ranging from near quiescent to the incorporation of swirl and tumble by valve inserts. Later experiments were performed with unleaded gasoline. The measurements included local velocity and cylinder pressure through the four strokes of a single-cylinder engine, under motored and firing conditions and with examination of the flame kernel growth by combinations of photography and flame-ionization gauges. In all cases, the measurements of in-cylinder characteristics were linked to performance as measured in terms of speed and its variability, load and emissions. The experiments progressed to consider deviations from homogeneous charge and included consideration of stratified charge with local injection of a rich mixture in the vicinity of the spark gap so as to establish a flame kernel which would propagate securely into an overall weak mixture.

  16. Creating unstable velocity-space distributions with barium injections

    SciTech Connect (OSTI)

    Pongratz, M.B.

    1983-01-01

    Large Debye lengths relative to detector dimensions and the absence of confining walls makes space an attractive laboratory for studying fundamental theories of plasma instabilities. However, natural space plasmas are rarely found displaced from equilibrium enough to permit isolation and diagnosis of the controlling parameters and driving conditions. Furthermore, any plasma or field response to the departure from equilibrium can be masked by noise in the natural system. Active experiments provide a technique for addressing the chicken or egg dilemma. Early thermite barium releases were generally conducted at low altitudes from sounding rockets to trace electric fields passively or to study configuration-space instabilities. One can also study velocity-space instabilities with barium releases. Neutral barium vapor releases wherein a typical speed greatly exceeds the thermal speed can be used to produce barium ion velocity-space distributions that should be subject to a number of microinstabilities. We examine the ion velocity-space distributions resulting from barium injections from orbiting spacecraft and shaped-charges.

  17. VELOCITY AND MAGNETIC FIELD DISTRIBUTION IN A FORMING PENUMBRA

    SciTech Connect (OSTI)

    Romano, P.; Guglielmino, S. L.; Frasca, D.; Zuccarello, F.; Ermolli, I.; Tritschler, A.; Reardon, K. P.

    2013-07-01

    We present results from the analysis of high-resolution spectropolarimetric and spectroscopic observations of the solar photosphere and chromosphere, obtained shortly before the formation of a penumbra in one of the leading polarity sunspots of NOAA active region 11490. The observations were performed at the Dunn Solar Telescope of the National Solar Observatory on 2012 May 28, using the Interferometric Bidimensional Spectrometer. The data set is comprised of a 1 hr time sequence of measurements in the Fe I 617.3 nm and Fe I 630.25 nm lines (full Stokes polarimetry) and in the Ca II 854.2 nm line (Stokes I only). We perform an inversion of the Fe I 630.25 nm Stokes profiles to derive magnetic field parameters and the line-of-sight (LOS) velocity at the photospheric level. We characterize chromospheric LOS velocities by the Doppler shift of the centroid of the Ca II 854.2 nm line. We find that, before the formation of the penumbra, an annular zone of 3''-5'' width is visible around the sunspot. In the photosphere, we find that this zone is characterized by an uncombed structure of the magnetic field although no visible penumbra has formed yet. We also find that the chromospheric LOS velocity field shows several elongated structures characterized by downflow and upflow motions in the inner and outer parts of the annular zone, respectively.

  18. A restoration model of distorted electron density in wave-cutoff probe measurement

    SciTech Connect (OSTI)

    Jun, Hyun-Su Lee, Yun-Seong

    2014-02-15

    This study investigates the problem of electron density distortion and how the density can be restored in a wave-cutoff probe. Despite recent plasma diagnostics research using a wave-cutoff probe, the problem of electron density distortion caused by plasma conditions has not been resolved. Experimental results indicate that electron density measured using the wave-cutoff method is highly susceptible to variations in the probe tip gap. This electron density distortion is caused by the bulk plasma disturbance between probe tips, and it must be removed for calculating the absolute electron density. To do this, a detailed analytic model was developed using the power balance equation near probe tips. This model demonstrates the characteristics of plasma distortion in wave-cutoff probe measurement and successfully restored the absolute value of electron density with varying probe tip gaps.

  19. Two-dimensional cylindrical ion-acoustic solitary and rogue waves in ultrarelativistic plasmas

    SciTech Connect (OSTI)

    Ata-ur-Rahman; National Centre for Physics at QAU Campus, Shahdrah Valley Road, Islamabad 44000 ; Ali, S.; Moslem, W. M.; Mushtaq, A.; Department of Physics, Abdul Wali Khan University, Mardan 23200

    2013-07-15

    The propagation of ion-acoustic (IA) solitary and rogue waves is investigated in a two-dimensional ultrarelativistic degenerate warm dense plasma. By using the reductive perturbation technique, the cylindrical KadomtsevPetviashvili (KP) equation is derived, which can be further transformed into a Kortewegde Vries (KdV) equation. The latter admits a solitary wave solution. However, when the frequency of the carrier wave is much smaller than the ion plasma frequency, the KdV equation can be transferred to a nonlinear Schrdinger equation to study the nonlinear evolution of modulationally unstable modified IA wavepackets. The propagation characteristics of the IA solitary and rogue waves are strongly influenced by the variation of different plasma parameters in an ultrarelativistic degenerate dense plasma. The present results might be helpful to understand the nonlinear electrostatic excitations in astrophysical degenerate dense plasmas.

  20. Mixing of two collinear Rayleigh waves in an isotropic nonlinear elastic half-space

    SciTech Connect (OSTI)

    Morlock, Merlin B.; Kim, Jin-Yeon; Jacobs, Laurence J.; Qu, Jianmin

    2014-02-18

    Nonlinear mixing of two collinear, initially monochromatic, Rayleigh waves propagating in the same direction in an isotropic, nonlinear elastic solid is investigated analytically. A system of coupled ordinary differential equations is derived based on the Lagrange equations of the second kind to predict the evolution of the higher harmonic and combination frequency components of the fundamentals waves. Numerical results show that the energy transfer is larger for higher frequencies, and that the oscillation of the energy between the different frequency components depends on the amplitudes and frequencies of the fundamental waves. Furthermore, it is illustrated that the horizontal velocity component can form a shock wave while the vertical velocity component can form a pulse. The occurrence of these effects is independent of the specific fundamental frequencies and amplitudes that are mixed. However, the nonlinear interaction is more efficient when the mixing frequencies are close to each other which increases both effects. The analytical model is then extended by implementing diffraction effects in the parabolic approximation.

  1. Imaging shock waves in diamond with both high temporal and spatial resolution at an XFEL

    SciTech Connect (OSTI)

    Schropp, Andreas; Hoppe, Robert; Meier, Vivienne; Patommel, Jens; Seiboth, Frank; Ping, Yuan; Hicks, Damien G.; Beckwith, Martha A.; Collins, Gilbert W.; Higginbotham, Andrew; Wark, Justin S.; Lee, Hae Ja; Nagler, Bob; Galtier, Eric C.; Arnold, Brice; Zastrau, Ulf; Hastings, Jerome B.; Schroer, Christian G.

    2015-06-18

    The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range, and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnified x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width, and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions.

  2. Arbitrary amplitude dust ion acoustic solitary waves in a magnetized suprathermal dusty plasma

    SciTech Connect (OSTI)

    Shahmansouri, M.; Alinejad, H.

    2012-12-15

    The linear and nonlinear dust-ion-acoustic (DIA) wave propagating obliquely with respect to an external magnetic field is studied in a magnetized complex plasma which consists of a cold ion fluid, superthermal electrons, and static dust particles. The propagation properties of two possible modes (in the linear regime) are investigated. It is found that the electron suprathermality and the electron population decrease the phase velocities of both modes, while obliqueness leads to increase of separation between two modes. An energy-like equation derived to describe the nonlinear evolution of DIA solitary waves. The influences of electron suprathermality, obliqueness, and electron population on the existence domain of solitary waves and the soliton characteristics are examined. It is shown that the existence domain of the DIA soliton and its profile are significantly depending on the deviation of electrons from thermodynamic equilibrium, electrons population, and obliqueness. It is also found that the suprathermal plasma supports the DIA solitons with larger amplitude.

  3. Propagating Structure Of A Microwave Driven Shock wave Inside A Tube

    SciTech Connect (OSTI)

    Shimada, Yutaka; Shibata, Teppei; Yamaguchi, Toshikazu; Komurasaki, Kimiya; Oda, Yasuhisa; Kajiwara, Ken; Takahashi, Koji; Kasugai, Atsushi; Sakamoto, Keishi; Arakawa, Yoshihiro

    2010-05-06

    The thrust generation process of a microwave rocket is similar to a pulse detonation engine, and understanding the interactions between microwave plasma and shock waves is important. Shadowgraph images of the microwave plasma generated in a tube under atmospheric air were taken. The observed plasma and shock wave were propagating one-dimensionally at constant velocity inside the tube. In order to understand the flow field inside the rocket, one-dimensional CFD analysis was conducted. With the change of microwave power density, the structure of the flow field was classified into two regimes: Microwave Supported Combustion (MSC), and Microwave Supported Detonation (MSD). The structure of the MSD was different from the structure of a chemical detonation, which implied the existence of a preheating in front of the shock wave. Furthermore, the flight performance was estimated by calculating the momentum coupling coefficient. It was confirmed that the efficiency was nearly constant in the MSD regime, with the increase of microwave power density.

  4. Gravitational waves from gravitational collapse

    SciTech Connect (OSTI)

    Fryer, Christopher L; New, Kimberly C

    2008-01-01

    Gravitational wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.

  5. Effects of alpha beam on the parametric decay of a parallel propagating circularly polarized Alfven wave: Hybrid simulations

    SciTech Connect (OSTI)

    Gao, Xinliang; Lu, Quanming; Tao, Xin; Hao, Yufei; Wang, Shui

    2013-09-15

    Alfven waves with a finite amplitude are found to be unstable to a parametric decay in low beta plasmas. In this paper, the parametric decay of a circularly polarized Alfven wave in a proton-electron-alpha plasma system is investigated with one-dimensional (1-D) hybrid simulations. In cases without alpha particles, with the increase of the wave number of the pump Alfven wave, the growth rate of the decay instability increases and the saturation amplitude of the density fluctuations slightly decrease. However, when alpha particles with a sufficiently large bulk velocity along the ambient magnetic field are included, at a definite range of the wave numbers of the pump wave, both the growth rate and the saturation amplitude of the parametric decay become much smaller and the parametric decay is heavily suppressed. At these wave numbers, the resonant condition between the alpha particles and the daughter Alfven waves is satisfied, therefore, their resonant interactions might play an important role in the suppression of the parametric decay instability.

  6. Supernova 2010as: the lowest-velocity member of a family of flat-velocity type IIb supernovae

    SciTech Connect (OSTI)

    Folatelli, Gastn; Bersten, Melina C.; Nomoto, Ken'ichi [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Kuncarayakti, Hanindyo; Hamuy, Mario [Departamento de Astronoma, Universidad de Chile, Casilla 36-D, Santiago (Chile); Olivares Estay, Felipe; Pignata, Giuliano [Departamento de Ciencias Fisicas, Universidad Andres Bello, Avda. Republica 252, Santiago (Chile); Anderson, Joseph P. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago (Chile); Holmbo, Simon; Stritzinger, Maximilian [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Morrell, Nidia; Contreras, Carlos; Phillips, Mark M. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Frster, Francisco [Center for Mathematical Modelling, Universidad de Chile, Avenida Blanco Encalada 2120 Piso 7, Santiago (Chile); Prieto, Jos Luis [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Peyton Hall, Princeton, NJ 08544 (United States); Valenti, Stefano [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Afonso, Paulo; Altenmller, Konrad; Elliott, Jonny, E-mail: gaston.folatelli@ipmu.jp [Max-Planck-Institut fr extraterrestrische Physik, Giessenbachstrae 1, D-85740 Garching (Germany); and others

    2014-09-01

    We present extensive optical and near-infrared photometric and spectroscopic observations of the stripped-envelope supernova SN 2010as. Spectroscopic peculiarities such as initially weak helium features and low expansion velocities with a nearly flat evolution place this object in the small family of events previously identified as transitional Type Ib/c supernovae (SNe). There is ubiquitous evidence of hydrogen, albeit weak, in this family of SNe, indicating that they are in fact a peculiar kind of Type IIb SNe that we name 'flat-velocity' Type IIb. The flat-velocity evolutionwhich occurs at different levels between 6000 and 8000 km s{sup 1} for different SNesuggests the presence of a dense shell in the ejecta. Despite the spectroscopic similarities, these objects show surprisingly diverse luminosities. We discuss the possible physical or geometrical unification picture for such diversity. Using archival Hubble Space Telescope images, we associate SN 2010as with a massive cluster and derive a progenitor age of ?6 Myr, assuming a single star-formation burst, which is compatible with a Wolf-Rayet progenitor. Our hydrodynamical modeling, on the contrary, indicates that the pre-explosion mass was relatively low, ?4 M {sub ?}. The seeming contradiction between a young age and low pre-SN mass may be solved by a massive interacting binary progenitor.

  7. Diversity waves in collapse-driven population dynamics

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Maslov, Sergei; Sneppen, Kim

    2015-09-14

    Populations of species in ecosystems are often constrained by availability of resources within their environment. In effect this means that a growth of one population, needs to be balanced by comparable reduction in populations of others. In neutral models of biodiversity all populations are assumed to change incrementally due to stochastic births and deaths of individuals. Here we propose and model another redistribution mechanism driven by abrupt and severe collapses of the entire population of a single species freeing up resources for the remaining ones. This mechanism may be relevant e.g. for communities of bacteria, with strain-specific collapses caused e.g.more » by invading bacteriophages, or for other ecosystems where infectious diseases play an important role. The emergent dynamics of our system is cyclic ‘‘diversity waves’’ triggered by collapses of globally dominating populations. The population diversity peaks at the beginning of each wave and exponentially decreases afterwards. Species abundances are characterized by a bimodal time-aggregated distribution with the lower peak formed by populations of recently collapsed or newly introduced species while the upper peak - species that has not yet collapsed in the current wave. In most waves both upper and lower peaks are composed of several smaller peaks. This self-organized hierarchical peak structure has a long-term memory transmitted across several waves. It gives rise to a scale-free tail of the time-aggregated population distribution with a universal exponent of 1.7. We show that diversity wave dynamics is robust with respect to variations in the rules of our model such as diffusion between multiple environments, species-specific growth and extinction rates, and bet-hedging strategies.« less

  8. Diversity waves in collapse-driven population dynamics

    SciTech Connect (OSTI)

    Maslov, Sergei; Sneppen, Kim

    2015-09-14

    Populations of species in ecosystems are often constrained by availability of resources within their environment. In effect this means that a growth of one population, needs to be balanced by comparable reduction in populations of others. In neutral models of biodiversity all populations are assumed to change incrementally due to stochastic births and deaths of individuals. Here we propose and model another redistribution mechanism driven by abrupt and severe collapses of the entire population of a single species freeing up resources for the remaining ones. This mechanism may be relevant e.g. for communities of bacteria, with strain-specific collapses caused e.g. by invading bacteriophages, or for other ecosystems where infectious diseases play an important role. The emergent dynamics of our system is cyclic ‘‘diversity waves’’ triggered by collapses of globally dominating populations. The population diversity peaks at the beginning of each wave and exponentially decreases afterwards. Species abundances are characterized by a bimodal time-aggregated distribution with the lower peak formed by populations of recently collapsed or newly introduced species while the upper peak - species that has not yet collapsed in the current wave. In most waves both upper and lower peaks are composed of several smaller peaks. This self-organized hierarchical peak structure has a long-term memory transmitted across several waves. It gives rise to a scale-free tail of the time-aggregated population distribution with a universal exponent of 1.7. We show that diversity wave dynamics is robust with respect to variations in the rules of our model such as diffusion between multiple environments, species-specific growth and extinction rates, and bet-hedging strategies.

  9. Global coherence of dust density waves

    SciTech Connect (OSTI)

    Killer, Carsten; Melzer, Andr

    2014-06-15

    The coherence of self-excited three-dimensional dust density waves has been experimentally investigated by comparing global and local wave properties. For that purpose, three-dimensional dust clouds have been confined in a radio frequency plasma with thermophoretic levitation. Global wave properties have been measured from the line-of-sight integrated dust density obtained from homogenous light extinction measurements. Local wave properties have been obtained from thin, two-dimensional illuminated laser slices of the cloud. By correlating the simultaneous global and local wave properties, the spatial coherence of the waves has been determined. We find that linear waves with small amplitudes tend to be fragmented, featuring an incoherent wave field. Strongly non-linear waves with large amplitudes, however, feature a strong spatial coherence throughout the dust cloud, indicating a high level of synchronization.

  10. Surface wave chemical detector using optical radiation

    DOE Patents [OSTI]

    Thundat, Thomas G.; Warmack, Robert J.

    2007-07-17

    A surface wave chemical detector comprising at least one surface wave substrate, each of said substrates having a surface wave and at least one measurable surface wave parameter; means for exposing said surface wave substrate to an unknown sample of at least one chemical to be analyzed, said substrate adsorbing said at least one chemical to be sensed if present in said sample; a source of radiation for radiating said surface wave substrate with different wavelengths of said radiation, said surface wave parameter being changed by said adsorbing; and means for recording signals representative of said surface wave parameter of each of said surface wave substrates responsive to said radiation of said different wavelengths, measurable changes of said parameter due to adsorbing said chemical defining a unique signature of a detected chemical.

  11. GRAVITATIONAL WAVES FROM STELLAR COLLAPSE

    SciTech Connect (OSTI)

    C. L. FRYER

    2001-01-01

    Stellar core-collapse plays an important role in nearly all facets of astronomy: cosmology (as standard candles), formation of compact objects, nucleosynthesis and energy deposition in galaxies. In addition, they release energy in powerful explosions of light over a range of energies, neutrinos, and the subject of this meeting, gravitational waves. Because of this broad range of importance, astronomers have discovered a number of constraints which can be used to help them understand the importance of stellar core-collapse as gravitational wave sources.

  12. Pulse Wave Well Development Demonstration

    SciTech Connect (OSTI)

    Burdick, S.

    2001-02-23

    Conventional methods of well development at the Savannah River Site generate significant volumes of investigative derived waste (IDW) which must be treated and disposed of at a regulated Treatment, Storage, or Disposal (TSD) facility. Pulse Wave technology is a commercial method of well development utilizing bursts of high pressure gas to create strong pressure waves through the well screen zone, extending out into the formation surrounding the well. The patented process is intended to reduce well development time and the amount of IDW generated as well as to micro-fracture the formation to improve well capacity.

  13. Radial distribution of compressive waves in the solar corona revealed by Akatsuki radio occultation observations

    SciTech Connect (OSTI)

    Miyamoto, Mayu; Imamura, Takeshi; Ando, Hiroki; Toda, Tomoaki; Nakamura, Masato; Tokumaru, Munetoshi; Shiota, Daikou; Isobe, Hiroaki; Asai, Ayumi; Husler, Bernd; Ptzold, Martin; Nabatov, Alexander

    2014-12-10

    Radial variations of the amplitude and the energy flux of compressive waves in the solar corona were explored for the first time using a spacecraft radio occultation technique. By applying wavelet analysis to the frequency time series taken at heliocentric distances of 1.5-20.5 R{sub S} (solar radii), quasi-periodic density disturbances were detected at almost all distances. The period ranges from 100 to 2000 s. The amplitude of the fractional density fluctuation increases with distance and reaches ?30% around 5 R{sub S} , implying that nonlinearity of the wave field is potentially important. We further estimate the wave energy flux on the assumption that the observed periodical fluctuations are manifestations of acoustic waves. The energy flux increases with distance below ?6 R{sub S} and seems to saturate above this height, suggesting that the acoustic waves do not propagate from the low corona but are generated in the extended corona, probably through nonlinear dissipation of Alfvn waves. The compressive waves should eventually dissipate through shock generation to heat the corona.

  14. Nonlinear dust acoustic waves in inhomogeneous four-component dusty plasma with opposite charge polarity dust grains

    SciTech Connect (OSTI)

    El-Taibany, W. F.

    2013-09-15

    The reductive perturbation technique is employed to investigate the propagation properties of nonlinear dust acoustic (DA) waves in a four-component inhomogeneous dusty plasma (4CIDP). The 4CIDP consists of both positive- and negative-charge dust grains, characterized by different mass, temperature, and density, in addition to a background of Maxwellian electrons and ions. The inhomogeneity caused by nonuniform equilibrium values of particle densities, fluid velocities, and electrostatic potential leads to a significant modification to the nature of nonlinear DA solitary waves. It is found that this model reveals two DA wave velocities, one slow, λ{sub s}, and the other is fast, λ{sub f}. The nonlinear wave evolution is governed by a modified Kortweg-de Vries equation, whose coefficients are space dependent. Both the two soliton types; compressive and rarefactive are allowed corresponding to λ{sub s}. However, only compressive soliton is created corresponding to λ{sub f}. The numerical investigations illustrate the dependence of the soliton amplitude, width, and velocity on the plasma inhomogeneities in each case. The relevance of these theoretical results with 4CIDPs observed in a multi-component plasma configurations in the polar mesosphere is discussed.

  15. Nonlinear dissipation of circularly polarized Alfven waves due to the beam-induced obliquely propagating waves

    SciTech Connect (OSTI)

    Nariyuki, Y.; Hada, T.; Tsubouchi, K.

    2012-08-15

    In the present study, the dissipation processes of circularly polarized Alfven waves in solar wind plasmas including beam components are numerically discussed by using a 2-D hybrid simulation code. Numerical results suggest that the parent Alfven waves are rapidly dissipated due to the presence of the beam-induced obliquely propagating waves, such as kinetic Alfven waves. The nonlinear wave-wave coupling is directly evaluated by using the induction equation for the parent wave. It is also observed both in the 1-D and 2-D simulations that the presence of large amplitude Alfven waves strongly suppresses the beam instabilities.

  16. Nonlocal theory of electromagnetic wave decay into two electromagnetic waves in a rippled density plasma channel

    SciTech Connect (OSTI)

    Sati, Priti; Tripathi, V. K.

    2012-12-15

    Parametric decay of a large amplitude electromagnetic wave into two electromagnetic modes in a rippled density plasma channel is investigated. The channel is taken to possess step density profile besides a density ripple of axial wave vector. The density ripple accounts for the momentum mismatch between the interacting waves and facilitates nonlinear coupling. For a given pump wave frequency, the requisite ripple wave number varies only a little w.r.t. the frequency of the low frequency decay wave. The radial localization of electromagnetic wave reduces the growth rate of the parametric instability. The growth rate decreases with the frequency of low frequency electromagnetic wave.

  17. Plasma wave aided two photon decay of an electromagnetic wave in a plasma

    SciTech Connect (OSTI)

    Kumar, K. K. Magesh; Singh, Rohtash; Krishan, Vinod

    2014-11-15

    The presence of a Langmuir wave in an unmagnetized plasma is shown to allow parametric decay of an electromagnetic wave into two electromagnetic waves, which is otherwise not allowed due to wave number mismatch. The decay occurs at plasma densities below one ninth the critical density and the decay waves propagate at finite angles to the pump laser. Above the threshold, the growth rate scales linearly with the amplitude of the Langmuir wave and the amplitude of the pump electromagnetic wave. The frequency ω of the lower frequency decay wave increases with the angle its propagation vector makes with that of the pump. The growth rate, however, decreases with ω.

  18. Low Velocity Sphere Impact of a Borosilicate Glass

    SciTech Connect (OSTI)

    Morrissey, Timothy G; Ferber, Mattison K; Wereszczak, Andrew A; Fox, Ethan E

    2012-05-01

    This report summarizes US Army TARDEC sponsored work at Oak Ridge National Laboratory (ORNL) involving low velocity (< 30 m/s or < 65 mph) ball impact testing of Borofloat borosilicate glass, and is a follow-up to a similar study completed by the authors on Starphire soda-lime silicate glass last year. The response of the borosilicate glass to impact testing at different angles was also studied. The Borofloat glass was supplied by the US Army Research Laboratory and its tin-side was impacted or indented. The intent was to better understand low velocity impact response in the Borofloat. Seven sphere materials were used whose densities bracket that of rock: borosilicate glass, soda-lime silicate glass, silicon nitride, aluminum oxide, zirconium oxide, carbon steel, and a chrome steel. A gas gun or a ball-drop test setup was used to produce controlled velocity delivery of the spheres against the glass tile targets. Minimum impact velocities to initiate fracture in the Borofloat were measured and interpreted in context to the kinetic energy of impact and the elastic property mismatch between the seven sphere-Borofloat-target combinations. The primary observations from this low velocity (< 30 m/s or < 65 mph) testing were: (1) BS glass responded similarly to soda-lime silicate glass when spherically indented but quite differently under sphere impact conditions; (2) Frictional effects contributed to fracture initiation in BS glass when it spherically indented. This effect was also observed with soda-lime silicate glass; (3) The force necessary to initiate fracture in BS glass under spherical impact decreases with increasing elastic modulus of the sphere material. This trend is opposite to what was observed with soda-lime silicate glass. Friction cannot explain this trend and the authors do not have a legitimate explanation for it yet; (4) The force necessary to initiate contact-induced fracture is higher under dynamic conditions than under quasi-static conditions. That

  19. Cloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Shupe, Matthew

    Time-height fields of retrieved in-cloud vertical wind velocity and turbulent dissipation rate, both retrieved primarily from vertically-pointing, Ka-band cloud radar measurements. Files are available for manually-selected, stratiform, mixed-phase cloud cases observed at the North Slope of Alaska (NSA) site during periods covering the Mixed-Phase Arctic Cloud Experiment (MPACE, late September through early November 2004) and the Indirect and Semi-Direct Aerosol Campaign (ISDAC, April-early May 2008). These time periods will be expanded in a future submission.

  20. Velocities as a probe of dark sector interactions

    SciTech Connect (OSTI)

    Koyama, Kazuya; Maartens, Roy; Song, Yong-Seon E-mail: Roy.Maartens@port.ac.uk

    2009-10-01

    Dark energy in General Relativity is typically non-interacting with other matter. However, it is possible that the dark energy interacts with the dark matter, and in this case, the dark matter can violate the universality of free fall (the weak equivalence principle). We show that some forms of the dark sector interaction do not violate weak equivalence. For those interactions that do violate weak equivalence, there are no available laboratory experiments to probe this violation for dark matter. But cosmology provides a test for violations of the equivalence principle between dark matter and baryons—via a test for consistency of the observed galaxy velocities with the Euler equation.

  1. HTPD2016_VelocityDetector_v4c

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    P.J. Fimognari T.P. Crowley, D.R. Demers Xantho Technologies, Madison, WI DEVELOPMENT OF A BEAM ION VELOCITY DETECTOR FOR THE HEAVY ION BEAM PROBE X XA AN NT TH HO O The ability to measure the current density in a toroidal magnetic con�inement plasma experiment with a spatial resolution of order 1 cm and a temporal resolution of 1 μs will be invaluable to stability and transport studies. In an axisymmetric plasma, canonical angular momentum conservation constrains heavy ion beam probe (HIBP)

  2. Method and apparatus for measuring flow velocity using matched filters

    DOE Patents [OSTI]

    Raptis, A.C.

    1983-09-06

    An apparatus and method for measuring the flow velocities of individual phase flow components of a multiphase flow utilizes matched filters. Signals arising from flow noise disturbance are extracted from the flow, at upstream and downstream locations. The signals are processed through pairs of matched filters which are matched to the flow disturbance frequency characteristics of the phase flow component to be measured. The processed signals are then cross-correlated to determine the transit delay time of the phase flow component between sensing positions. 8 figs.

  3. Method and apparatus for measuring flow velocity using matched filters

    DOE Patents [OSTI]

    Raptis, Apostolos C.

    1983-01-01

    An apparatus and method for measuring the flow velocities of individual phase flow components of a multiphase flow utilizes matched filters. Signals arising from flow noise disturbance are extracted from the flow, at upstream and downstream locations. The signals are processed through pairs of matched filters which are matched to the flow disturbance frequency characteristics of the phase flow component to be measured. The processed signals are then cross-correlated to determine the transit delay time of the phase flow component between sensing positions.

  4. Cloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals

    SciTech Connect (OSTI)

    Shupe, Matthew

    2013-05-22

    Time-height fields of retrieved in-cloud vertical wind velocity and turbulent dissipation rate, both retrieved primarily from vertically-pointing, Ka-band cloud radar measurements. Files are available for manually-selected, stratiform, mixed-phase cloud cases observed at the North Slope of Alaska (NSA) site during periods covering the Mixed-Phase Arctic Cloud Experiment (MPACE, late September through early November 2004) and the Indirect and Semi-Direct Aerosol Campaign (ISDAC, April-early May 2008). These time periods will be expanded in a future submission.

  5. ELLIPSOIDAL VARIABLE V1197 ORIONIS: ABSOLUTE LIGHT-VELOCITY ANALYSIS FOR KNOWN DISTANCE

    SciTech Connect (OSTI)

    Wilson, R. E.; Chochol, D.; KomzIk, R.; Van Hamme, W.; Pribulla, T.; Volkov, I.

    2009-09-01

    V1197 Orionis light curves from a long-term observing program for red giant binaries show ellipsoidal variation of small amplitude in the V and R{sub C} bands, although not clearly in U and B. Eclipses are not detected. All four bands show large irregular intrinsic variations, including fleeting quasi-periodicities identified by power spectra, that degrade analysis and may be caused by dynamical tides generated by orbital eccentricity. To deal with the absence of eclipses and consequent lack of astrophysical and geometrical information, direct use is made of the Hipparcos parallax distance while the V and R{sub C} light curves and (older) radial velocity curves are analyzed simultaneously in terms of absolute flux. The red giant's temperature is estimated from new spectra. This type of analysis, called Inverse Distance Estimation for brevity, is new and can also be applied to other ellipsoidal variables. Advantages gained by utilization of definite distance and temperature are discussed in regard to how radius, fractional lobe filling, and mass ratio information are expressed in the observations. The advantages were tested in solutions of noisy synthetic data. Also discussed and tested by simulations are ideas on the optimal number of light curves to be solved simultaneously under various conditions. The dim companion has not been observed or discussed in the literature but most solutions find its mass to be well below that of the red giant. Solutions show red giant masses that are too low for evolution to the red giant stage within the age of the Galaxy, although that result is probably an artifact of the intrinsic brightness fluctuations.

  6. A chain of winking (oscillating) filaments triggered by an invisible extreme-ultraviolet wave

    SciTech Connect (OSTI)

    Shen, Yuandeng; Tian, Zhanjun; Zhao, Ruijuan; Ichimoto, Kiyoshi; Ishii, Takako T.; Shibata, Kazunari

    2014-05-10

    Winking (oscillating) filaments have been observed for many years. However, observations of successive winking filaments in one event have not yet been reported. In this paper, we present the observations of a chain of winking filaments and a subsequent jet that are observed right after the X2.1 flare in AR11283. The event also produced an extreme-ultraviolet (EUV) wave that has two components: an upward dome-like wave (850 km s{sup 1}) and a lateral surface wave (554 km s{sup 1}) that was very weak (or invisible) in imaging observations. By analyzing the temporal and spatial relationships between the oscillating filaments and the EUV waves, we propose that all the winking filaments and the jet were triggered by the weak (or invisible) lateral surface EUV wave. The oscillation of the filaments last for two or three cycles, and their periods, Doppler velocity amplitudes, and damping times are 11-22 minutes, 6-14 km s{sup 1}, and 25-60 minutes, respectively. We further estimate the radial component magnetic field and the maximum kinetic energy of the filaments, and they are 5-10 G and ?10{sup 19} J, respectively. The estimated maximum kinetic energy is comparable to the minimum energy of ordinary EUV waves, suggesting that EUV waves can efficiently launch filament oscillations on their path. Based on our analysis results, we conclude that the EUV wave is a good agent for triggering and connecting successive but separated solar activities in the solar atmosphere, and it is also important for producing solar sympathetic eruptions.

  7. Confinement effects of shock waves on laser-induced plasma from a graphite target

    SciTech Connect (OSTI)

    Huang, Feiling; Liang, Peipei; Yang, Xu; Cai, Hua; Wu, Jiada; Xu, Ning; Ying, Zhifeng; Sun, Jian

    2015-06-15

    The spatial confinement effects of shock waves on the laser-induced plasma (LIP) from a graphite target in air were studied by probe beam deflection (PBD) measurements and optical emission spectroscopy (OES). A clear relationship between the confinement of the LIP by the shock wave and the effects on the LIP emission was observed, and the underlying mechanisms are discussed. PBD monitoring revealed that the laser-ablation induced shock wave could be well analogized to the shock wave generated by a point explosion and would be reflected by a block. OES measurements indicated that the optical emission of the LIP exhibited significant variations with the block placement. A first enhancement and then a fast decay of CN molecular emission as well as a suppression of carbon atomic emission were observed in the presence of the block. The results revealed that the reflected shock wave spatially confined the expansion of the LIP and compressed the LIP after encountering it, pushing back the species of the LIP and changing the density of the LIP species including luminous carbon atoms and CN molecules. It is suggested that the change of the LIP emission is attributed to the density variation of the LIP species due to the compression of the LIP and the reactions occurring in the plasma.

  8. Sandia Energy - WEC-Sim (Wave Energy Converter SIMulator)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    WEC-Sim (Wave Energy Converter SIMulator) Home Stationary Power Energy Conversion Efficiency Water Power WEC-Sim (Wave Energy Converter SIMulator) WEC-Sim (Wave Energy Converter...

  9. MHK Technologies/Ocean Wave Air Piston | Open Energy Information

    Open Energy Info (EERE)

    Ocean Wave Air Piston.jpg Technology Profile Primary Organization Green Ocean Wave Energy Technology Resource Click here Wave Technology Type Click here Attenuator...

  10. Oregon Wave Energy Trust OWET | Open Energy Information

    Open Energy Info (EERE)

    Wave Energy Trust OWET Jump to: navigation, search Name: Oregon Wave Energy Trust (OWET) Place: Portland, Oregon Zip: 97207 Product: String representation "The Oregon Wave ... rgy...

  11. Circulating heat exchangers for oscillating wave engines and...

    Office of Scientific and Technical Information (OSTI)

    heat exchangers for oscillating wave engines and refrigerators Title: Circulating heat exchangers for oscillating wave engines and refrigerators An oscillating-wave engine or ...

  12. WETGen (Wave Energy Turbine GENerator) | Open Energy Information

    Open Energy Info (EERE)

    WETGen (Wave Energy Turbine GENerator) Jump to: navigation, search Logo: WETGen (Wave Energy Turbine GENerator) Name WETGen (Wave Energy Turbine GENerator) Place Coos Bay, Oregon...

  13. Characterizing the convective velocity fields in massive stars

    SciTech Connect (OSTI)

    Chatzopoulos, Emmanouil; Graziani, Carlo; Couch, Sean M.

    2014-11-01

    We apply the mathematical formalism of vector spherical harmonics decomposition to convective stellar velocity fields from multidimensional hydrodynamics simulations and show that the resulting power spectra furnish a robust and stable statistical description of stellar convective turbulence. Analysis of the power spectra helps identify key physical parameters of the convective process such as the dominant scale of the turbulent motions that influence the structure of massive evolved pre-supernova stars. We introduce the numerical method that can be used to calculate vector spherical harmonics power spectra from two-dimensional (2D) and three-dimensional (3D) convective shell simulation data. Using this method we study the properties of oxygen shell burning and convection for a 15 M {sub ☉} star simulated by the hydrodynamics code FLASH in 2D and 3D. We discuss the importance of realistic initial conditions to achieving successful core-collapse supernova explosions in multidimensional simulations. We show that the calculated power spectra can be used to generate realizations of the velocity fields of presupernova convective shells. We find that the slope of the solenoidal mode power spectrum remains mostly constant throughout the evolution of convection in the oxygen shell in both 2D and 3D simulations. We also find that the characteristic radial scales of the convective elements are smaller in 3D than in 2D, while the angular scales are larger in 3D.

  14. DETECTION OF LOW-VELOCITY COLLISIONS IN SATURN'S F RING

    SciTech Connect (OSTI)

    Attree, N. O.; Murray, C. D.; Cooper, N. J.; Williams, G. A.

    2012-08-20

    Jets of material extending several hundred kilometers from Saturn's F ring are thought to be caused by collisions at speeds of several tens of ms{sup -1} between {approx}10 km diameter objects such as S/2004 S 6 and the core of the ring. The subsequent effects of Keplerian shear give rise to the multi-stranded nature of the F ring. Observations of the ring by the Imaging Science Subsystem experiment on the Cassini spacecraft have provided evidence that some smaller protrusions from the ring's core are the result of low-velocity collisions with nearby objects. We refer to these protrusions as 'mini-jets' and one such feature has been observed for {approx}7.5 hr as its length changed from {approx}75 km to {approx}250 km while it simultaneously appeared to collapse into the core. Orbit determinations suggest that such mini-jets consist of ring material displaced by a {approx}1 ms{sup -1} collision with a nearby moonlet, resulting in paths relative to the core that are due to a combination of Keplerian shear and epicyclic motion. Detections of mini-jets in the Cassini images suggest that it may now be possible to understand most small-scale F ring structure as the result of such collisions. A study of these mini-jets will therefore put constraints on the properties of the colliding population as well as improve our understanding of low-velocity collisions between icy objects.

  15. Discretising the velocity distribution for directional dark matter experiments

    SciTech Connect (OSTI)

    Kavanagh, Bradley J.

    2015-07-13

    Dark matter (DM) direct detection experiments which are directionally-sensitive may be the only method of probing the full velocity distribution function (VDF) of the Galactic DM halo. We present an angular basis for the DM VDF which can be used to parametrise the distribution in order to mitigate astrophysical uncertainties in future directional experiments and extract information about the DM halo. This basis consists of discretising the VDF in a series of angular bins, with the VDF being only a function of the DM speed v within each bin. In contrast to other methods, such as spherical harmonic expansions, the use of this basis allows us to guarantee that the resulting VDF is everywhere positive and therefore physical. We present a recipe for calculating the event rates corresponding to the discrete VDF for an arbitrary number of angular bins N and investigate the discretisation error which is introduced in this way. For smooth, Standard Halo Model-like distribution functions, only N=3 angular bins are required to achieve an accuracy of around 10–30% in the number of events in each bin. Shortly after confirmation of the DM origin of the signal with around 50 events, this accuracy should be sufficient to allow the discretised velocity distribution to be employed reliably. For more extreme VDFs (such as streams), the discretisation error is typically much larger, but can be improved with increasing N. This method paves the way towards an astrophysics-independent analysis framework for the directional detection of dark matter.

  16. Rene Wave Ltd | Open Energy Information

    Open Energy Info (EERE)

    Rene Wave Ltd Jump to: navigation, search Name: Rene Wave Ltd Address: 85 Emmett Ave Suite 2508 Place: Toronto Zip: M6M 5A2 Region: Canada Sector: Marine and Hydrokinetic Phone...

  17. Wave Energy Centre | Open Energy Information

    Open Energy Info (EERE)

    Centre Jump to: navigation, search Name: Wave Energy Centre Address: Wave Energy Centre Av Manuela da Maia 36 R C Dto Place: Lisboa Zip: 1000-201 Region: Portugal Sector: Marine...

  18. Next Wave Energy Inc | Open Energy Information

    Open Energy Info (EERE)

    Inc Jump to: navigation, search Name: Next Wave Energy Inc Place: Denver,CO, Colorado Zip: 80202 Sector: Renewable Energy Product: NextWave Energy was a consulting firm focused...

  19. Antiferromagnetic Spin Wave Field-Effect Transistor

    Office of Scientific and Technical Information (OSTI)

    ... Assume that the spin wave is generated at one end of the chain by an oscillating magnetic field along the y-direction at 1.4 THz. tte spin wave is subsequently modulated by a 20 ...

  20. Property:Wave Direction | Open Energy Information

    Open Energy Info (EERE)

    Wave Basin + Uni-Directional + Lakefront Tow Tank + Uni-Directional + Los Angeles and Long Beach Harbors Model + Uni-Directional + M MHL 2D WindWave + Uni-Directional + MHL...

  1. On quantization of nondispersive wave packets

    SciTech Connect (OSTI)

    Altaisky, M. V.

    2013-10-15

    Nondispersive wave packets are widely used in optics and acoustics. We found it interesting that such packets could be also a subject of quantum field theory. Canonical commutation relations for the nondispersive wave packets are constructed.

  2. The Role of Gravity Waves in the Formation and Organization of Clouds during TWPICE

    SciTech Connect (OSTI)

    Reeder, Michael J.; Lane, Todd P.; Hankinson, Mai Chi Nguyen

    2013-09-27

    . The wave activity is strongest in the lower stratosphere below 22 km and, during the suppressed monsoon period, is modulated with a 3-4-day period. The concentration of the wave activity in the lower stratosphere is consistent with the properties of the environment in which these waves propagate, whereas its 3-4-day modulation is explained by the variation of the convection activity in the TWP-ICE domain. At low rainfall intensity the wave activity increases as rainfall intensity increases. At high values of rainfall intensity, however, the wave activity associated with deep convective clouds is independent of the rainfall intensity. The convection and gravity waves observed during TWP-ICE are simulated with the Weather Research and Forecasting (WRF) Model. These simulations are compared with radiosonde observations described above and are used to determine some of the properties of convectively generated gravity waves. The gravity waves appear to be well simulated by the model. The model is used to explore the relationships between the convection, the gravity waves and cirrus.

  3. Initial Examination of Low Velocity Sphere Impact of Glass Ceramics

    SciTech Connect (OSTI)

    Morrissey, Timothy G; Fox, Ethan E; Wereszczak, Andrew A; Ferber, Mattison K

    2012-06-01

    This report summarizes US Army TARDEC sponsored work at Oak Ridge National Laboratory (ORNL) involving low velocity (< 30 m/s or < 65 mph) sphere impact testing of two materials from the lithium aluminosilicate family reinforced with different amounts of ceramic particulate, i.e., glass-ceramic materials, SCHOTT Resistan{trademark}-G1 and SCHOTT Resistan{trademark}-L. Both materials are provided by SCHOTT Glass (Duryea, PA). This work is a follow-up to similar sphere impact studies completed by the authors on PPG's Starphire{reg_sign} soda-lime silicate glass and SCHOTT BOROFLOAT{reg_sign} borosilicate glass. A gas gun or a sphere-drop test setup was used to produce controlled velocity delivery of silicon nitride (Si{sub 3}N{sub 4}) spheres against the glass ceramic tile targets. Minimum impact velocities to initiate fracture in the glass-ceramics were measured and interpreted in context to the kinetic energy of impact and the elastic property mismatch between sphere and target material. Quasistatic spherical indentation was also performed on both glass ceramics and their contact damage responses were compared to those of soda-lime silicate and borosilicate glasses. Lastly, variability of contact damage response was assessed by performing spherical indentation testing across the area of an entire glass ceramic tile. The primary observations from this low velocity (< 30 m/s or < 65 mph) testing were: (1) Resistan{trademark}-L glass ceramic required the highest velocity of sphere impact for damage to initiate. Starphire{reg_sign} soda-lime silicate glass was second best, then Resistan{trademark}-G1 glass ceramic, and then BOROFLOAT{reg_sign} borosilicate glass. (2) Glass-ceramic Resistan{trademark}-L also required the largest force to initiate ring crack from quasi-static indentation. That ranking was followed, in descending order, by Starphire{reg_sign} soda-lime silicate glass, Resistan{trademark}-G1 glass ceramic, and BOROFLOAT{reg_sign} borosilicate glass. (3

  4. Method for estimation of ocean current velocity from satellite images

    SciTech Connect (OSTI)

    Mollo-Christensen, E.; Cornillon, P.; Da S. Mascarenhas, A. Jr.

    1981-05-08

    Barotropic instability waves on a shear interface propagate at the average speed of the water on the two sides. Assuming the instability to be excited by tidal oscillations, the phase speed is the wavelength divided by the tidal period. If the water is at rest on one side of the shear layer the current speed on the other side can be calculated. This method, applied to the Gulf Stream beyond Cape Hatteras as seen in satellite images, gives estimates of current speed in general agreement with in situ observations.

  5. Wave-driven Countercurrent Plasma Centrifuge

    SciTech Connect (OSTI)

    A.J. Fetterman and N.J. Fisch

    2009-03-20

    A method for driving rotation and a countercurrent flow in a fully ionized plasma centrifuge is described. The rotation is produced by radiofrequency waves near the cyclotron resonance. The wave energy is transferred into potential energy in a manner similar to the ? channeling effect. The countercurrent flow may also be driven by radiofrequency waves. By driving both the rotation and the flow pattern using waves instead of electrodes, physical and engineering issues may be avoided.

  6. THE ORIGIN OF NON-MAXWELLIAN SOLAR WIND ELECTRON VELOCITY DISTRIBUTION FUNCTION: CONNECTION TO NANOFLARES IN THE SOLAR CORONA

    SciTech Connect (OSTI)

    Che, H.; Goldstein, M. L.

    2014-11-10

    The formation of the observed core-halo feature in the solar wind electron velocity distribution function is a long-time puzzle. In this Letter, based on the current knowledge of nanoflares, we show that the nanoflare-accelerated electron beams are likely to trigger a strong electron two-stream instability that generates kinetic Alfvn wave and whistler wave turbulence, as we demonstrated in a previous paper. We further show that the core-halo feature produced during the origin of kinetic turbulence is likely to originate in the inner corona and can be preserved as the solar wind escapes to space along open field lines. We formulate a set of equations to describe the heating processes observed in the simulation and show that the core-halo temperature ratio of the solar wind is insensitive to the initial conditions in the corona and is related to the core-halo density ratio of the solar wind and to the quasi-saturation property of the two-stream instability at the time when the exponential decay ends. This relation can be extended to the more general core-halo-strahl feature in the solar wind. The temperature ratio between the core and hot components is nearly independent of the heliospheric distance to the Sun. We show that the core-halo relative drift previously reported is a relic of the fully saturated two-stream instability. Our theoretical results are consistent with the observations while new tests for this model are provided.

  7. Multi-reflective acoustic wave device

    DOE Patents [OSTI]

    Andle, Jeffrey C.

    2006-02-21

    An acoustic wave device, which utilizes multiple localized reflections of acoustic wave for achieving an infinite impulse response while maintaining high tolerance for dampening effects, is disclosed. The device utilized a plurality of electromechanically significant electrodes disposed on most of the active surface. A plurality of sensors utilizing the disclosed acoustic wave mode device are also described.

  8. 3D Elastic Seismic Wave Propagation Code

    Energy Science and Technology Software Center (OSTI)

    1998-09-23

    E3D is capable of simulating seismic wave propagation in a 3D heterogeneous earth. Seismic waves are initiated by earthquake, explosive, and/or other sources. These waves propagate through a 3D geologic model, and are simulated as synthetic seismograms or other graphical output.

  9. Pump and probe spectroscopy with continuous wave quantum cascade lasers

    SciTech Connect (OSTI)

    Kirkbride, James M. R.; Causier, Sarah K.; Dalton, Andrew R.; Ritchie, Grant A. D.; Weidmann, Damien

    2014-02-07

    This paper details infra-red pump and probe studies on nitric oxide conducted with two continuous wave quantum cascade lasers both operating around 5 μm. The pump laser prepares a velocity selected population in a chosen rotational quantum state of the v = 1 level which is subsequently probed using a second laser tuned to a rotational transition within the v = 2 ← v = 1 hot band. The rapid frequency scan of the probe (with respect to the molecular collision rate) in combination with the velocity selective pumping allows observation of marked rapid passage signatures in the transient absorption profiles from the polarized vibrationally excited sample. These coherent transient signals are influenced by the underlying hyperfine structure of the pump and probe transitions, the sample pressure, and the coherent properties of the lasers. Pulsed pump and probe studies show that the transient absorption signals decay within 1 μs at 50 mTorr total pressure, reflecting both the polarization and population dephasing times of the vibrationally excited sample. The experimental observations are supported by simulation based upon solving the optical Bloch equations for a two level system.

  10. THE EFFECTS OF WAVE ESCAPE ON FAST MAGNETOSONIC WAVE TURBULENCE IN SOLAR FLARES

    SciTech Connect (OSTI)

    Pongkitiwanichakul, Peera; Chandran, Benjamin D. G.; Karpen, Judith T.; DeVore, C. Richard E-mail: benjamin.chandran@unh.edu E-mail: devore@nrl.navy.mil

    2012-09-20

    One of the leading models for electron acceleration in solar flares is stochastic acceleration by weakly turbulent fast magnetosonic waves ({sup f}ast waves{sup )}. In this model, large-scale flows triggered by magnetic reconnection excite large-wavelength fast waves, and fast-wave energy then cascades from large wavelengths to small wavelengths. Electron acceleration by large-wavelength fast waves is weak, and so the model relies on the small-wavelength waves produced by the turbulent cascade. In order for the model to work, the energy cascade time for large-wavelength fast waves must be shorter than the time required for the waves to propagate out of the solar-flare acceleration region. To investigate the effects of wave escape, we solve the wave kinetic equation for fast waves in weak turbulence theory, supplemented with a homogeneous wave-loss term. We find that the amplitude of large-wavelength fast waves must exceed a minimum threshold in order for a significant fraction of the wave energy to cascade to small wavelengths before the waves leave the acceleration region. We evaluate this threshold as a function of the dominant wavelength of the fast waves that are initially excited by reconnection outflows.

  11. Traveling wave device for combining or splitting symmetric and asymmetric waves

    DOE Patents [OSTI]

    Möbius, Arnold; Ives, Robert Lawrence

    2005-07-19

    A traveling wave device for the combining or splitting of symmetric and asymmetric traveling wave energy includes a feed waveguide for traveling wave energy, the feed waveguide having an input port and a launching port, a reflector for coupling wave energy between the feed waveguide and a final waveguide for the collection and transport of wave energy to or from the reflector. The power combiner has a launching port for symmetrical waves which includes a cylindrical section coaxial to the feed waveguide, and a launching port for asymmetric waves which includes a sawtooth rotated about a central axis.

  12. Acceleration of soliton by nonlinear Landau damping of dust-helical waves

    SciTech Connect (OSTI)

    Ehsan, Zahida; Tsintsadze, Nodar L.; Vranjes, J.; Poedts, S.

    2009-05-15

    The problem of nonlinear Landau damping of helicon waves in dusty plasma in particular emphasis to the acceleration of soliton is presented here. This in the framework of a collisionless, anisotropic homogeneous dusty plasma in one dimension, can be well described by two coupled dynamical equations of the generalized Zakharov type, with one extra nonlocal term coming from Landau damping. Nonlinear-nonlocal term gives rise to essential contributions relative to the local term. Then under different conditions, kinetic nonlinear Schroedinger equation is constructed and nonlinear decrement is obtained for two cases. It is noticed that the time dependant term in the ponderomotive force plays a significant role for this kind of damping. Additionally, it is shown that nonlinear Landau damping leads to the amplitude modulation of dust helicon waves, further modulational instability, and maximal growth rate is obtained when the group velocity of the helicon wave reaches the dust-acoustic speed. It is demonstrated that how the nonlinear Landau damping leads to the acceleration of soliton, which is eventually slowed down after transferring some of its energy to the wave. Emission of dust-acoustic wave by accelerated soliton is discussed briefly.

  13. Reconstruction of nonlinear wave propagation

    DOE Patents [OSTI]

    Fleischer, Jason W; Barsi, Christopher; Wan, Wenjie

    2013-04-23

    Disclosed are systems and methods for characterizing a nonlinear propagation environment by numerically propagating a measured output waveform resulting from a known input waveform. The numerical propagation reconstructs the input waveform, and in the process, the nonlinear environment is characterized. In certain embodiments, knowledge of the characterized nonlinear environment facilitates determination of an unknown input based on a measured output. Similarly, knowledge of the characterized nonlinear environment also facilitates formation of a desired output based on a configurable input. In both situations, the input thus characterized and the output thus obtained include features that would normally be lost in linear propagations. Such features can include evanescent waves and peripheral waves, such that an image thus obtained are inherently wide-angle, farfield form of microscopy.

  14. Millimeter-wave active probe

    DOE Patents [OSTI]

    Majidi-Ahy, Gholamreza; Bloom, David M.

    1991-01-01

    A millimeter-wave active probe for use in injecting signals with frequencies above 50GHz to millimeter-wave and ultrafast devices and integrated circuits including a substrate upon which a frequency multiplier consisting of filter sections and impedance matching sections are fabricated in uniplanar transmission line format. A coaxial input and uniplanar 50 ohm transmission line couple an approximately 20 GHz input signal to a low pass filter which rolls off at approximately 25 GHz. An input impedance matching section couples the energy from the low pass filter to a pair of matched, antiparallel beam lead diodes. These diodes generate odd-numberd harmonics which are coupled out of the diodes by an output impedance matching network and bandpass filter which suppresses the fundamental and third harmonics and selects the fifth harmonic for presentation at an output.

  15. A 2.5D boundary element formulation for modeling damped waves in arbitrary cross-section waveguides and cavities

    SciTech Connect (OSTI)

    Mazzotti, M.; Civil, Architectural and Environmental Engineering Department, Drexel University, 3141 Chestnut St., Philadelphia, PA 19104 ; Bartoli, I.; Marzani, A.; Viola, E.

    2013-09-01

    Highlights: Dispersive properties of viscoelastic waveguides and cavities are computed using a regularized 2.5D BEM. Linear viscoelasticity is introduced at the constitutive level by means of frequency dependent complex moduli. A contour integral algorithm is used to solve the nonlinear eigenvalue problem. The Sommerfeld radiation condition is used to select the permissible Riemann sheets. Attenuation of surface waves in cavities approaches the attenuation of Rayleigh waves. -- Abstract: A regularized 2.5D boundary element method (BEM) is proposed to predict the dispersion properties of damped stress guided waves in waveguides and cavities of arbitrary cross-section. The wave attenuation, induced by material damping, is introduced using linear viscoelastic constitutive relations and described in a spatial manner by the imaginary component of the axial wavenumber. The discretized dispersive wave equation results in a nonlinear eigenvalue problem, which is solved obtaining complex axial wavenumbers for a fixed frequency using a contour integral algorithm. Due to the singular characteristics and the multivalued feature of the wave equation, the requirement of holomorphicity inside the contour region over the complex wavenumber plane is fulfilled by the introduction of the Sommerfeld branch cuts and by the choice of the permissible Riemann sheets. A post processing analysis is developed for the extraction of the energy velocity of propagative guided waves. The reliability of the method is demonstrated by comparing the results obtained for a rail and a bar with square cross-section with those obtained from a 2.5D Finite Element formulation also known in literature as Semi Analytical Finite Element (SAFE) method. Next, to show the potential of the proposed numerical framework, dispersion properties are predicted for surface waves propagating along cylindrical cavities of arbitrary cross-section. It is demonstrated that the attenuation of surface waves approaches

  16. Progress in measuring detonation wave profiles in PBX9501

    SciTech Connect (OSTI)

    Gustavsen, R.L.; Sheffield, S.A.; Alcon, R.R.

    1998-12-31

    The authors have measured detonation wave profiles in PBX9501 (95 wt% HMX and 5 wt% binders) using VISAR. Planar detonations were produced by impacting the explosive with projectiles launched in a 72 mm bore gas gun. Particle velocity wave profiles were measured at the explosive/window interface using two VISARs with different fringe constants. Windows with very thin vapor deposited aluminum mirrors were used for all experiments. PMMA windows provided an undermatch, and LiF (Lithium Fluoride) windows provided an overmatch to the explosive, reacted and unreacted. While the present experiments do not have adequate time resolution to adequately resolve the ZND spike condition, they do constrain it to lie between 38.7 and 53.4 Gpa or 2.4 and 3.3 km/s. Accurate knowledge of the CJ state places the reaction zone length at 35 {+-} 12 ns ({approx} 0.3 mm). The present experiments do not show any effect of the window on the reaction zone; both window materials result in the same reaction zone length.

  17. Microsoft Word - S08364_SeasonalVariation

    Office of Legacy Management (LM)

    Groundwater Constituents and Seasonal Variation at the Riverton, Wyoming, Processing Site February 2012 LMS/RVT/S08364 This page intentionally left blank U.S. Department of Energy Evaluation of Groundwater Constituents and Seasonal Variation, Riverton, Wyoming February 2012 Doc. No. S08364 Page 1 Evaluation of Groundwater Constituents and Seasonal Variation at the Riverton, Wyoming, Processing Site Executive Summary Historical groundwater monitoring at the Riverton site included collecting

  18. Sequentially pulsed traveling wave accelerator

    DOE Patents [OSTI]

    Caporaso, George J.; Nelson, Scott D.; Poole, Brian R.

    2009-08-18

    A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

  19. advanced wave energy control design

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    wave energy control design - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced

  20. Low velocity impact of inclined CSM composite laminates

    SciTech Connect (OSTI)

    Arnold, W.S.; Madjidi, S.; Marshall, I.H.; Robb, M.D.

    1993-12-31

    The damage tolerance of composite laminates subject to low velocity impact is an important aspect of current design philosophies required to ensure the integrity of primary load bearing structures. To the authors knowledge, no work published in the open literature has addressed the damage tolerance of composites subject to impacts at non-perpendicular inclinations, which in practical situations is the most common form of impact. This paper describes an experimental study, devised to assess the influence of inclined impact on the residual strength characteristics of CSM laminates. Preliminary experimental results and comparisons with previous work on flat plate impact tests are presented. The influence of the degree of inclination and impact energy are correlated with the laminates damage area and residual tensile properties.

  1. Visualizing 3D velocity fields near contour surfaces. Revision 1

    SciTech Connect (OSTI)

    Max, N.; Crawfis, R.; Grant, C.

    1994-08-08

    Vector field rendering is difficult in 3D because the vector icons overlap and hide each other. We propose four different techniques for visualizing vector fields only near surfaces. The first uses motion blurred particles in a thickened region around the surface. The second uses a voxel grid to contain integral curves of the vector field. The third uses many antialiased lines through the surface, and the fourth uses hairs sprouting from the surface and then bending in the direction of the vector field. All the methods use the graphics pipeline, allowing real time rotation and interaction, and the first two methods can animate the texture to move in the flow determined by the velocity field.

  2. Acoustic-velocity measurements in materials using a regenerative method

    DOE Patents [OSTI]

    Laine, E.F.

    1982-09-30

    Acoustic energy is propatated through earth material between an electro-acoustic generator and a receiver which converts the received acoustic energy into electrical signals. A closed loop is formed by a variable gain amplifier system connected between the receiver and the generator. The gain of the amplifier system is increased until sustained oscillations are produced in the closed loop. The frequency of the oscillations is measured as an indication of the acoustic propagation velocity through the earth material. The amplifier gain is measured as an indication of the acoustic attenuation through the earth materials. The method is also applicable to the non-destructive testing of structural materials, such as steel, aluminum and concrete.

  3. Acoustic velocity measurements in materials using a regenerative method

    DOE Patents [OSTI]

    Laine, Edwin F.

    1986-01-01

    Acoustic energy is propagated through earth material between an electro-acoustic generator and a receiver which converts the received acoustic energy into electrical signals. A closed loop is formed by a variable gain amplifier system connected between the receiver and the generator. The gain of the amplifier system is increased until sustained oscillations are produced in the closed loop. The frequency of the oscillations is measured as an indication of the acoustic propagation velocity through the earth material. The amplifier gain is measured as an indication of the acoustic attenuation through the earth materials. The method is also applicable to the non-destructive testing of structural materials, such as steel, aluminum and concrete.

  4. Analytical estimate of phase mixing time of longitudinal Akhiezer-Polovin waves

    SciTech Connect (OSTI)

    Mukherjee, Arghya Sengupta, Sudip

    2014-11-15

    Phase mixing of a longitudinal Akhiezer-Polovin wave subjected to a small amplitude longitudinal perturbation and its eventual breaking is studied analytically. It is well known that longitudinal Akhiezer-Polovin wave subjected to arbitrarily small longitudinal perturbation breaks via the process of phase mixing at an amplitude well below its limiting amplitude [Verma et al., Phys. Rev. Lett. 108, 125005 (2012)]. We analytically show that the phase mixing time (breaking time, ω{sub p}τ{sub mix}) scales with β (phase velocity) and u{sub m}(maximum fluid velocity) as ω{sub p}τ{sub mix}∼(2πβ)/(3δ) [1/u{sub m}{sup 2}−1/4], where δ is the amplitude of velocity perturbation and ω{sub p} is the non-relativistic plasma frequency. This analytical dependence of phase mixing time on β, u{sub m}, and δ is further verified using numerical simulations based on Dawson sheet model.

  5. Nonlinear interaction of plane elastic waves

    SciTech Connect (OSTI)

    Korneev, V.A.; Nihei, K.T.; Myer, L.R.

    1998-06-01

    The paper presents basic first order results of nonlinear elastic theory by Murnaghan for elastic wave propagation in isotropic solids. The authors especially address the problem of resonant scattering of two collimated beams and present analytical solutions for amplitudes of all possible types of resonant interactions for elastic plane waves. For estimation of nonlinear scattered waves they use measured elastic parameters for sandstone. The most profound nonlinear effect is expected for interactions of two SH waves generating compressional P wave at sum frequency. Estimations show that nonlinear phenomena is likely to be observed in seismic data. Basic equations of nonlinear five-constant theory by Murnaghan are also presented.

  6. Ponderomotive Forces On Waves In Modulated Media

    SciTech Connect (OSTI)

    Dodin, I.Y; Fisch, Nathaniel

    2014-02-28

    Nonlinear interactions of waves via instantaneous cross-phase modulation can be cast in the same way as ponderomotive wave-particle interactions in high-frequency electromagnetic fi eld. The ponderomotive effect arises when rays of a probe wave scatter off perturbations of the underlying medium produced by a second, modulation wave, much like charged particles scatter off a quasiperiodic field. Parallels with the point-particle dynamics, which itself is generalized by this theory, lead to new methods of wave manipulation, including asymmetric barriers for light.

  7. Evolution of rogue waves in dusty plasmas

    SciTech Connect (OSTI)

    Tolba, R. E. El-Bedwehy, N. A.; Moslem, W. M.; El-Labany, S. K.

    2015-04-15

    The evolution of rogue waves associated with the dynamics of positively charged dust grains that interact with streaming electrons and ions is investigated. Using a perturbation method, the basic set of fluid equations is reduced to a nonlinear Schrdinger equation (NLSE). The rational solution of the NLSE is presented, which proposed as an effective tool for studying the rogue waves in Jupiter. It is found that the existence region of rogue waves depends on the dust-acoustic speed and the streaming densities of the ions and electrons. Furthermore, the supersonic rogue waves are much taller than the subsonic rogue waves by ?25 times.

  8. Two-dimensional Imaging Velocity Interferometry: Technique and Data Analysis

    SciTech Connect (OSTI)

    Erskine, D J; Smith, R F; Bolme, C; Celliers, P; Collins, G

    2011-03-23

    We describe the data analysis procedures for an emerging interferometric technique for measuring motion across a two-dimensional image at a moment in time, i.e. a snapshot 2d-VISAR. Velocity interferometers (VISAR) measuring target motion to high precision have been an important diagnostic in shockwave physics for many years Until recently, this diagnostic has been limited to measuring motion at points or lines across a target. We introduce an emerging interferometric technique for measuring motion across a two-dimensional image, which could be called a snapshot 2d-VISAR. If a sufficiently fast movie camera technology existed, it could be placed behind a traditional VISAR optical system and record a 2d image vs time. But since that technology is not yet available, we use a CCD detector to record a single 2d image, with the pulsed nature of the illumination providing the time resolution. Consequently, since we are using pulsed illumination having a coherence length shorter than the VISAR interferometer delay ({approx}0.1 ns), we must use the white light velocimetry configuration to produce fringes with significant visibility. In this scheme, two interferometers (illuminating, detecting) having nearly identical delays are used in series, with one before the target and one after. This produces fringes with at most 50% visibility, but otherwise has the same fringe shift per target motion of a traditional VISAR. The 2d-VISAR observes a new world of information about shock behavior not readily accessible by traditional point or 1d-VISARS, simultaneously providing both a velocity map and an 'ordinary' snapshot photograph of the target. The 2d-VISAR has been used to observe nonuniformities in NIF related targets (polycrystalline diamond, Be), and in Si and Al.

  9. Multiple-frequency acoustic wave devices for chemical sensing and materials characterization in both gas and liquid phase

    DOE Patents [OSTI]

    Martin, Stephen J.; Ricco, Antonio J.

    1993-01-01

    A chemical sensor (1) includes two or more pairs of interdigital electrodes (10) having different periodicities. Each pair is comprised of a first electrode (10a) and a second electrode (10b). The electrodes are patterned on a surface of a piezoelectric substrate (12). Each pair of electrodes may launch and receive various acoustic waves (AW), including a surface acoustic wave (SAW), and may also launch and receive several acoustic plate modes (APMs). The frequencies associated with each are functions of the transducer periodicity as well as the velocity of the particular AW in the chosen substrate material. An AW interaction region (13) exists between each pair of electrodes. Circuitry (20, 40) is used to launch, receive, and monitor the propagation characteristics of the AWs and may be configured in an intermittent measurement fashion or in a continuous measurement fashion. Perturbations to the AW velocity and attenuation are recorded at several frequencies and provide the sensor response.

  10. Freak waves in white dwarfs and magnetars

    SciTech Connect (OSTI)

    Sabry, R.; Moslem, W. M.; Shukla, P. K.

    2012-12-15

    We report properties of ion acoustic freak waves that propagate in a plasma composed of warm ions and ultrarelativistic electrons and positrons. The dynamics of the nonlinear freak waves is governed by the nonlinear Schroedinger equation. The possible region for the freak waves to exist is defined precisely for typical parameters of white dwarfs and magnetars corona. It is found that for low wave number, the nonlinear ion-acoustic wave packets are structurally stable in magnetars corona than in white dwarfs. However, for large wave numbers the situation is opposite. The critical wave number threshold (k{sub c}), which indicates where the modulational instability sets in, is defined for both applications. It is seen that near to k{sub c} the freak wave amplitude becomes high, but it decreases whenever we stepped away from k{sub c}. For the wave numbers close to k{sub c}, the increase of the unperturbed density ratio of positrons-to-electrons ({beta}) would lead to increase the freak wave amplitude, but for larger wave numbers the amplitude decreases with the increase of {beta}.

  11. [Investigation of ultrasonic wave interactions with fluid-saturated porous rocks]. [Annual report

    SciTech Connect (OSTI)

    Adler, L.

    1992-07-01

    During the last two years we have continued our investigation of ultrasonic wave propagation in fluid-filled porous materials. First, we studied the feasibility of using different surface modes to characterize both synthetic and natural rocks. We introduced a novel experimental technique based on the direct generation of surface waves by edge excitation. We used two low-frequency (100--500 kHz) shear transducers in pitch-catch mode to launch and receive the ultrasonic surface wave. The contact transducers were coupled to the opposite edges of the porous specimens with normal polarization relative to the surface. The same technique was successfully used to generate Rayleigh-type surface modes on the free surface of both dry and water-saturated specimens, as well as Stoneley-type interface modes on the fluid-loaded surfaces of immersed samples. Our main achievement in this area is the realization that, due to surface tension, practically closed-pore boundary conditions can prevail on the free surface of a water-saturated rock for completely open pores. As a result, the velocity of the true surface mode might be much lower than the Rayleigh velocity of the dry skeleton.

  12. (Investigation of ultrasonic wave interactions with fluid-saturated porous rocks)

    SciTech Connect (OSTI)

    Adler, L.

    1992-01-01

    During the last two years we have continued our investigation of ultrasonic wave propagation in fluid-filled porous materials. First, we studied the feasibility of using different surface modes to characterize both synthetic and natural rocks. We introduced a novel experimental technique based on the direct generation of surface waves by edge excitation. We used two low-frequency (100--500 kHz) shear transducers in pitch-catch mode to launch and receive the ultrasonic surface wave. The contact transducers were coupled to the opposite edges of the porous specimens with normal polarization relative to the surface. The same technique was successfully used to generate Rayleigh-type surface modes on the free surface of both dry and water-saturated specimens, as well as Stoneley-type interface modes on the fluid-loaded surfaces of immersed samples. Our main achievement in this area is the realization that, due to surface tension, practically closed-pore boundary conditions can prevail on the free surface of a water-saturated rock for completely open pores. As a result, the velocity of the true surface mode might be much lower than the Rayleigh velocity of the dry skeleton.

  13. Wave processes in dusty plasma near the Moon’s surface

    SciTech Connect (OSTI)

    Morozova, T. I.; Kopnin, S. I.; Popel, S. I.

    2015-10-15

    A plasma—dust system in the near-surface layer on the illuminated side of the Moon is described. The system involves photoelectrons, solar-wind electrons and ions, neutrals, and charged dust grains. Linear and nonlinear waves in the plasma near the Moon’s surface are discussed. It is noticed that the velocity distribution of photoelectrons can be represented as a superposition of two distribution functions characterized by different electron temperatures: lower energy electrons are knocked out of lunar regolith by photons with energies close to the work function of regolith, whereas higher energy electrons are knocked out by photons corresponding to the peak at 10.2 eV in the solar radiation spectrum. The anisotropy of the electron velocity distribution function is distorted due to the solar wind motion with respect to photoelectrons and dust grains, which leads to the development of instability and excitation of high-frequency oscillations with frequencies in the range of Langmuir and electromagnetic waves. In addition, dust acoustic waves can be excited, e.g., near the lunar terminator. Solutions in the form of dust acoustic solitons corresponding to the parameters of the dust—plasma system in the near-surface layer of the illuminated Moon’s surface are found. Ranges of possible Mach numbers and soliton amplitudes are determined.

  14. Argonoxygen dc magnetron discharge plasma probed with ion acoustic waves

    SciTech Connect (OSTI)

    Saikia, Partha, E-mail: partha.008@gmail.com; Saikia, Bipul Kumar; Goswami, Kalyan Sindhu [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur, Kamrup, Assam 782 402 (India); Phukan, Arindam [Madhabdev College, Narayanpur, Lakhimpur, Assam 784164 (India)

    2014-05-15

    The precise determination of the relative concentration of negative ions is very important for the optimization of magnetron sputtering processes, especially for those undertaken in a multicomponent background produced by adding electronegative gases, such as oxygen, to the discharge. The temporal behavior of an ion acoustic wave excited from a stainless steel grid inside the plasma chamber is used to determine the relative negative ion concentration in the magnetron discharge plasma. The phase velocity of the ion acoustic wave in the presence of negative ions is found to be faster than in a pure argon plasma, and the phase velocity increases with the oxygen partial pressure. Optical emission spectroscopy further confirms the increase in the oxygen negative ion density, along with a decrease in the argon positive ion density under the same discharge conditions. The relative negative ion concentration values measured by ion acoustic waves are compared with those measured by a single Langmuir probe, and a similarity in the results obtained by both techniques is observed.

  15. Mechanisms of amplification of ultrashort electromagnetic pulses in gyrotron traveling wave tube with helically corrugated waveguide

    SciTech Connect (OSTI)

    Ginzburg, N. S. Zaslavsky, V. Yu.; Zotova, I. V.; Sergeev, A. S.; Zheleznov, I. V.; Samsonov, S. V.; Mishakin, S. V.

    2015-11-15

    A time-domain self consistent theory of a gyrotron traveling wave tube with a helically corrugated operating waveguide has been developed. Based on this model, the process of short pulse amplification was studied in regimes of grazing and intersection of the dispersion curves of the electromagnetic wave and the electron beam. In the first case, the possibility of amplification without pulse form distortion was demonstrated for the pulse spectrum width of the order of the gain bandwidth. In the second case, when the electrons' axial velocity was smaller than the wave's group velocity, it was shown that the slippage of the incident signal with respect to the electron beam provides feeding of the signal by “fresh” electrons without initial modulation. As a result, the amplitude of the output pulse can exceed the amplitude of its saturated value for the case of the grazing regime, and, for optimal parameters, the peak output power can be even larger than the kinetic power of the electron beam.

  16. Prospecting with pressures, temperatures, and velocities in the northwest Gulf of Mexico

    SciTech Connect (OSTI)

    Enciso, G. ); Griffith, D.P. )

    1993-09-01

    In the northwest Gulf of Mexico, an empirical relationship exists between subsurface pressure, bottom-hole temperature, and seismic velocity. The pressure, velocity, and temperature patterns are controlled by sedimentation and faulting. Hydrologic fluid pressures and resulting fluid flow can be predicted and mapped by making use of mud weights, seismic velocities, and bottom-hole temperatures. Pressure, velocity, and temperature data have been compiled into extensive computer databases. This has allowed us to manipulate the data for the preparation of regional hydrodynamic head, seismic interval velocity, and isotherm maps. The application of this pressure-velocity-temperature relationship has led to the detection of an underpressured reservoir in the Oligocene's clastic section of southwest Louisiana. The prediction of the sandy underpressured zone with interval velocity analysis provides a useful tool to explore seismically for the fluviodeltaic sands in this area.

  17. Interferometric millimeter wave and THz wave doppler radar

    DOE Patents [OSTI]

    Liao, Shaolin; Gopalsami, Nachappa; Bakhtiari, Sasan; Raptis, Apostolos C.; Elmer, Thomas

    2015-08-11

    A mixerless high frequency interferometric Doppler radar system and methods has been invented, numerically validated and experimentally tested. A continuous wave source, phase modulator (e.g., a continuously oscillating reference mirror) and intensity detector are utilized. The intensity detector measures the intensity of the combined reflected Doppler signal and the modulated reference beam. Rigorous mathematics formulas have been developed to extract bot amplitude and phase from the measured intensity signal. Software in Matlab has been developed and used to extract such amplitude and phase information from the experimental data. Both amplitude and phase are calculated and the Doppler frequency signature of the object is determined.

  18. GLOBAL CORONAL SEISMOLOGY IN THE EXTENDED SOLAR CORONA THROUGH FAST MAGNETOSONIC WAVES OBSERVED BY STEREO SECCHI COR1

    SciTech Connect (OSTI)

    Kwon, Ryun-Young; Kramar, Maxim; Wang, Tongjiang; Ofman, Leon; Davila, Joseph M.; Chae, Jongchul; Zhang, Jie

    2013-10-10

    We present global coronal seismology for the first time, which allows us to determine inhomogeneous magnetic field strength in the extended corona. From the measurements of the propagation speed of a fast magnetosonic wave associated with a coronal mass ejection (CME) and the coronal background density distribution derived from the polarized radiances observed by the STEREO SECCHI COR1, we determined the magnetic field strengths along the trajectories of the wave at different heliocentric distances. We found that the results have an uncertainty less than 40%, and are consistent with values determined with a potential field model and reported in previous works. The characteristics of the coronal medium we found are that (1) the density, magnetic field strength, and plasma ? are lower in the coronal hole region than in streamers; (2) the magnetic field strength decreases slowly with height but the electron density decreases rapidly so that the local fast magnetosonic speed increases while plasma ? falls off with height; and (3) the variations of the local fast magnetosonic speed and plasma ? are dominated by variations in the electron density rather than the magnetic field strength. These results imply that Moreton and EIT waves are downward-reflected fast magnetosonic waves from the upper solar corona, rather than freely propagating fast magnetosonic waves in a certain atmospheric layer. In addition, the azimuthal components of CMEs and the driven waves may play an important role in various manifestations of shocks, such as type II radio bursts and solar energetic particle events.

  19. NONLINEAR WAVE INTERACTIONS AS EMISSION PROCESS OF TYPE II RADIO BURSTS

    SciTech Connect (OSTI)

    Ganse, Urs; Kilian, Patrick; Spanier, Felix; Vainio, Rami

    2012-06-01

    The emission of fundamental and harmonic frequency radio waves of type II radio bursts are assumed to be products of three-wave interaction processes of beam-excited Langmuir waves. Using a particle-in-cell code, we have performed simulations of the assumed emission region, a coronal mass ejection foreshock with two counterstreaming electron beams. Analysis of wavemodes within the simulation shows self-consistent excitation of beam-driven modes, which yield interaction products at both fundamental and harmonic emission frequencies. Through variation of the beam strength, we have investigated the dependence of energy transfer into electrostatic and electromagnetic modes, confirming the quadratic dependence of electromagnetic emission on electron beam strength.

  20. Alfvn wave coupled with flow-driven fluid instability in interpenetrating plasmas

    SciTech Connect (OSTI)

    Vranjes, J.

    2015-05-15

    The Alfvn wave is analyzed in case of one quasineutral plasma propagating with some constant speed v{sub 0} through another static quasineutral plasma. A dispersion equation is derived describing the Alfvn wave coupled with the flow driven mode ?=kv{sub 0} and solutions are discussed analytically and numerically. The usual solutions for two oppositely propagating Alfvn waves are substantially modified due to the flowing plasma. More profound is modification of the solution propagating in the negative direction with respect to the magnetic field and the plasma flow. For a large enough flow speed (exceeding the Alfvn speed in the static plasma), this negative solution may become non-propagating, with frequency equal to zero. In this case, it represents a spatial variation of the electromagnetic field. For greater flow speed it becomes a forward mode, and it may merge with the positive one. This merging of the two modes represents the starting point for a flow-driven instability, with two complex-conjugate solutions. The Alfvn wave in interpenetrating plasmas is thus modified and coupled with the flow-driven mode and this coupled mode is shown to be growing when the flow speed is large enough. The energy for the instability is macroscopic kinetic energy of the flowing plasma. The dynamics of plasma particles caused by such a coupled wave still remains similar to the ordinary Alfvn wave. This means that well-known stochastic heating by the Alfvn wave may work, and this should additionally support the potential role of the Alfvn wave in the coronal heating.

  1. NONLINEAR DYNAMICS OF MAGNETOHYDRODYNAMIC ROSSBY WAVES AND THE CYCLIC NATURE OF SOLAR MAGNETIC ACTIVITY

    SciTech Connect (OSTI)

    Raphaldini, Breno; Raupp, Carlos F. M. E-mail: carlos.raupp@iag.usp.br

    2015-01-20

    The solar dynamo is known to be associated with several periodicities, with the nearly 11/22 yr cycle being the most pronounced one. Even though these quasiperiodic variations of solar activity have been attributed to the underlying dynamo action in the Sun's interior, a fundamental theoretical description of these cycles is still elusive. Here, we present a new possible direction in understanding the Sun's cycles based on resonant nonlinear interactions among magnetohydrodynamic (MHD) Rossby waves. The WKB theory for dispersive waves is applied to magnetohydrodynamic shallow-water equations describing the dynamics of the solar tachocline, and the reduced dynamics of a resonant triad composed of MHD Rossby waves embedded in constant toroidal magnetic field is analyzed. In the conservative case, the wave amplitudes evolve periodically in time, with periods on the order of the dominant solar activity timescale (∼11 yr). In addition, the presence of linear forcings representative of either convection or instabilities of meridionally varying background states appears to be crucial in balancing dissipation and thus sustaining the periodic oscillations of wave amplitudes associated with resonant triad interactions. Examination of the linear theory of MHD Rossby waves embedded in a latitudinally varying mean flow demonstrates that MHD Rossby waves propagate toward the equator in a waveguide from –35° to 35° in latitude, showing a remarkable resemblance to the structure of the butterfly diagram of the solar activity. Therefore, we argue that resonant nonlinear magnetohydrodynamic Rossby wave interactions might significantly contribute to the observed cycles of magnetic solar activity.

  2. ANALYTIC MODELING OF THE MORETON WAVE KINEMATICS

    SciTech Connect (OSTI)

    Temmer, M.; Veronig, A. M.

    2009-09-10

    The issue whether Moreton waves are flare-ignited or coronal mass ejection (CME)-driven, or a combination of both, is still a matter of debate. We develop an analytical model describing the evolution of a large-amplitude coronal wave emitted by the expansion of a circular source surface in order to mimic the evolution of a Moreton wave. The model results are confronted with observations of a strong Moreton wave observed in association with the X3.8/3B flare/CME event from 2005 January 17. Using different input parameters for the expansion of the source region, either derived from the real CME observations (assuming that the upward moving CME drives the wave), or synthetically generated scenarios (expanding flare region, lateral expansion of the CME flanks), we calculate the kinematics of the associated Moreton wave signature. Those model input parameters are determined which fit the observed Moreton wave kinematics best. Using the measured kinematics of the upward moving CME as the model input, we are not able to reproduce the observed Moreton wave kinematics. The observations of the Moreton wave can be reproduced only by applying a strong and impulsive acceleration for the source region expansion acting in a piston mechanism scenario. Based on these results we propose that the expansion of the flaring region or the lateral expansion of the CME flanks is more likely the driver of the Moreton wave than the upward moving CME front.

  3. Electron acoustic wave driven vortices with non-Maxwellian hot electrons in magnetoplasmas

    SciTech Connect (OSTI)

    Haque, Q.; Mirza, Arshad M.; Zakir, U.

    2014-07-15

    Linear dispersion characteristics of the Electron Acoustic Wave (EAW) and the corresponding vortex structures are investigated in a magnetoplasma in the presence of non-Maxwellian hot electrons. In this regard, kappa and Cairns distributed hot electrons are considered. It is noticed that the nonthermal distributions affect the phase velocity of the EAW. Further, it is found that the phase velocity of EAW increases for Cairns and decreases for kappa distributed hot electrons. Nonlinear solutions in the form of dipolar vortices are also obtained for both stationary and non-stationary ions in the presence of kappa distributed hot electrons and dynamic cold electrons. It is found that the amplitude of the nonlinear vortex structures also reduces with kappa factor like the electron acoustic solitons.

  4. Low inlet gas velocity high throughput biomass gasifier

    SciTech Connect (OSTI)

    Feldmann, H.F.; Paisley, M.A.

    1989-05-09

    A method is described for operating a gasifier which comprises: introducing inlet gas at a velocity of about 0.5 to 7 ft/sec to fluidize a bed in a gasifier vessel; forming the bed into a fluidized bed in a first space region by means of the inlet gas, the fluidized bed containing a circulating hot relatively fine and inert solid bed particle component; inputting and throughputting carbonaceous material into and through the first space region with fluidized bed at a rate from 500-4400 lbs/ft/sup 2/-hr; endothermally pyrolyzing the carbonaceous material by means of the circulating hot inert particle component so as to form a product gas; forming contiguous to and above the fluidized bed a lower average density entrained space region containing an entrained mixture of inert solid particles, char, and carbonaceous material and the product gas; gradually and continuously removing the entrained mixture and the product gas from the lower average density entrained space region of the gasifier to a separator, residence time of the carbonaceous material in the gasifier not exceeding 3 minutes on average; separating the entrained mixture from the product gas; passing the entrained mixture containing inert solid particles, char, and carbonaceous material through an exothermic reaction zone to add heat; and returning at least the inert solid particles to the first space region.

  5. Coiled tubing velocity string hangoff method and apparatus

    SciTech Connect (OSTI)

    Gipson, T.C.

    1991-07-02

    This patent describes a method for hanging off a coiled tube velocity string in an active gas production well tubing run, the run having at least a master valve and a first line valve. It includes installing a hangoff assembly in the production well tubing run between the master valve and the first line valve the hangoff assembly comprising a hangoff head, a second line valve, an upper valve, and a hydraulic packoff valve, the hangoff head further comprising a threaded body member, a slip bowl and a threaded cap; inserting through the hydraulic packoff valve, the upper valve, and the hangoff head, coiled tubing for fluid communication with well gases and fluids in the production well tubing run, the coiled tubing having a first downhole end being open to immediately receive and conduct the gases and fluids; opening gas and fluid communication between the production well tubing run and the open end of the coiled tubing whereby the well gases and fluid may pass up through the coiled tubing, the hangoff head sealing the gases and fluids from passing to the hydraulic packoff valve, the upper valve and the second line valve; further inserting the coiled tubing to a desired depth in the production well tubing run; and rotating the cap of the hangoff head to expose the slip bowl.

  6. Relative ion expansion velocity in laser-produced plasmas

    SciTech Connect (OSTI)

    Goldsmith, S.; Moreno, J.C.; Griem, H.R.; Cohen, L.; Richardson, M.C.

    1988-07-15

    The spectra of highly ionized titanium, TiXIII through TiXXI, and CVI Lyman lines were excited in laser-produced plasmas. The plasma was produced by uniformly irradiating spherical glass microballoons coated with thin layers of titanium and parylene. The 24-beam Omega laser system produced short, 0.6 ns, and high intensity, 4 x 10/sup 14/ W/cm,/sup 2/ laser pulses at a wavelength of 351 nm. The measured wavelength for the 2p-3s TiXIII resonance lines had an average shift of +0.023 A relative to the CVI and TiXX spectral lines. No shift was found between the CVI, TiXIX, and TiXX lines. The shift is attributed to a Doppler effect, resulting from a difference of (2.6 +- 0.2) x 10/sup 7/ cm/s in the expansion velocities of TiXIX and TiXX ions compared to TiXIII ions.

  7. Radiation Hydrodynamics Test Problems with Linear Velocity Profiles

    SciTech Connect (OSTI)

    Hendon, Raymond C.; Ramsey, Scott D.

    2012-08-22

    As an extension of the works of Coggeshall and Ramsey, a class of analytic solutions to the radiation hydrodynamics equations is derived for code verification purposes. These solutions are valid under assumptions including diffusive radiation transport, a polytropic gas equation of state, constant conductivity, separable flow velocity proportional to the curvilinear radial coordinate, and divergence-free heat flux. In accordance with these assumptions, the derived solution class is mathematically invariant with respect to the presence of radiative heat conduction, and thus represents a solution to the compressible flow (Euler) equations with or without conduction terms included. With this solution class, a quantitative code verification study (using spatial convergence rates) is performed for the cell-centered, finite volume, Eulerian compressible flow code xRAGE developed at Los Alamos National Laboratory. Simulation results show near second order spatial convergence in all physical variables when using the hydrodynamics solver only, consistent with that solver's underlying order of accuracy. However, contrary to the mathematical properties of the solution class, when heat conduction algorithms are enabled the calculation does not converge to the analytic solution.

  8. Emergent cosmological constant from colliding electromagnetic waves

    SciTech Connect (OSTI)

    Halilsoy, M.; Mazharimousavi, S. Habib; Gurtug, O. E-mail: habib.mazhari@emu.edu.tr

    2014-11-01

    In this study we advocate the view that the cosmological constant is of electromagnetic (em) origin, which can be generated from the collision of em shock waves coupled with gravitational shock waves. The wave profiles that participate in the collision have different amplitudes. It is shown that, circular polarization with equal amplitude waves does not generate cosmological constant. We also prove that the generation of the cosmological constant is related to the linear polarization. The addition of cross polarization generates no cosmological constant. Depending on the value of the wave amplitudes, the generated cosmological constant can be positive or negative. We show additionally that, the collision of nonlinear em waves in a particular class of Born-Infeld theory also yields a cosmological constant.

  9. Refrigeration system having standing wave compressor

    DOE Patents [OSTI]

    Lucas, Timothy S.

    1992-01-01

    A compression-evaporation refrigeration system, wherein gaseous compression of the refrigerant is provided by a standing wave compressor. The standing wave compressor is modified so as to provide a separate subcooling system for the refrigerant, so that efficiency losses due to flashing are reduced. Subcooling occurs when heat exchange is provided between the refrigerant and a heat pumping surface, which is exposed to the standing acoustic wave within the standing wave compressor. A variable capacity and variable discharge pressure for the standing wave compressor is provided. A control circuit simultaneously varies the capacity and discharge pressure in response to changing operating conditions, thereby maintaining the minimum discharge pressure needed for condensation to occur at any time. Thus, the power consumption of the standing wave compressor is reduced and system efficiency is improved.

  10. Width dependent transition of quantized spin-wave modes in Ni{sub 80}Fe{sub 20} square nanorings

    SciTech Connect (OSTI)

    Banerjee, Chandrima; Saha, Susmita; Barman, Saswati; Barman, Anjan, E-mail: abarman@bose.res.in [Thematic Unit of Excellence on Nanodevice Technology, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700098 (India); Rousseau, Olivier [CEMS-RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Otani, YoshiChika [CEMS-RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan)

    2014-10-28

    We investigated optically induced ultrafast magnetization dynamics in square shaped Ni{sub 80}Fe{sub 20} nanorings with varying ring width. Rich spin-wave spectra are observed whose frequencies showed a strong dependence on the ring width. Micromagnetic simulations showed different types of spin-wave modes, which are quantized upto very high quantization number. In the case of widest ring, the spin-wave mode spectrum shows quantized modes along the applied field direction, which is similar to the mode spectrum of an antidot array. As the ring width decreases, additional quantization in the azimuthal direction appears causing mixed modes. In the narrowest ring, the spin-waves exhibit quantization solely in azimuthal direction. The different quantization is attributed to the variation in the internal field distribution for different ring width as obtained from micromagnetic analysis and supported by magnetic force microscopy.

  11. ARM - Lesson Plans: Moving Water and Waves

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Moving Water and Waves Outreach Home Room News Publications Traditional Knowledge Kiosks Barrow, Alaska Tropical Western Pacific Site Tours Contacts Students Study Hall About ARM Global Warming FAQ Just for Fun Meet our Friends Cool Sites Teachers Teachers' Toolbox Lesson Plans Lesson Plans: Moving Water and Waves Objective The objective of this activity is to enable students to demonstrate how wind causes water to move and generate waves and how water pressure causes water to move from higher

  12. Ocean floor mounting of wave energy converters

    DOE Patents [OSTI]

    Siegel, Stefan G

    2015-01-20

    A system for mounting a set of wave energy converters in the ocean includes a pole attached to a floor of an ocean and a slider mounted on the pole in a manner that permits the slider to move vertically along the pole and rotate about the pole. The wave energy converters can then be mounted on the slider to allow adjustment of the depth and orientation of the wave energy converters.

  13. Regional Wave Field Modeling and Array Effects

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    1C Marine and Hydrokinetic Instrumentation, Measurement & Computer Modeling Workshop - Broomfield, CO July 9 th , 2012 Regional Wave Field Modeling and Array Effects Outline  Overview of SNL's Large-Scale Wave and WEC Array Modeling Activities * WEC Farm Modeling on Roadmap * SNL Current Modeling Capabilities * SNL WEC Farm Model Tool Development WEC Farm Modeling  WEC Farms * Currently focused on improving large scale wave models for environmental assessments WEC Farm Modeling: WEC

  14. Space-frequency coupling, conical waves, and small-scale filamentation in water

    SciTech Connect (OSTI)

    Liu Jiansheng; Schroeder, Hartmut; Chin, S. L.; Li Ruxin; Yu Wei; Xu Zhizhan

    2005-11-15

    Numerical simulations of fs laser propagation in water have been made to explain the small-scale filaments in water we have observed by a nonlinear fluorescence technique. Some analytical descriptions combined with numerical simulations show that a space-frequency coupling mainly from the interplay among self-phase modulation, dispersion and phase mismatching will reshape the laser beam into a conical wave which plays a major role of energy redistribution and can prevent laser beam from self-guiding over a long distance. An effective group velocity dispersion is introduced to explain the pulse broadening and compression in the filamentation.

  15. HELICAL BLOWOUT JETS IN THE SUN: UNTWISTING AND PROPAGATION OF WAVES

    SciTech Connect (OSTI)

    Lee, E. J.; Archontis, V.; Hood, A. W.

    2015-01-01

    We report on a numerical experiment of the recurrent onset of helical ''blowout'' jets in an emerging flux region. We find that these jets are running with velocities of ?100-250 km s{sup 1} and they transfer a vast amount of heavy plasma into the outer solar atmosphere. During their emission, they undergo an untwisting motion as a result of reconnection between the twisted emerging and the non-twisted pre-existing magnetic field in the solar atmosphere. For the first time in the context of blowout jets, we provide direct evidence that their untwisting motion is associated with the propagation of torsional Alfvn waves in the corona.

  16. Approval/Variation Request Comment Sheet

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    EA15PC3041-3-0 Mar. 25, 2003 Rev. 0 Page 1 of 2 Approval/Variation Request Comment Sheet 1. Page of 2. G APPROVAL REQUEST 3. G VARIATION REQUEST 4. AR/VR No. 5. PO/Subcontract No. 6. Organization 7. Reviewer 8. Comment: 9. Disposition: Working Copy EA15PC3041-3-0 Mar. 25, 2003 Rev. 0 Page 2 of 2 Instructions for Filling Out Approval/Variation Request Comment Sheet Block 1. Technical Reviewer - Enter the total number of pages upon completion of the review. 2. Technical Reviewer - Check the

  17. NO TRANSIT TIMING VARIATIONS IN WASP-4

    SciTech Connect (OSTI)

    Petrucci, R.; Schwartz, M.; Buccino, A. P.; Mauas, P. J. D.; Jofr, E.; Cneo, V.; Gmez, M.; Martnez, C.

    2013-12-20

    We present six new transits of the system WASP-4. Together with 28 light curves published in the literature, we perform a homogeneous study of its parameters and search for variations in the transits' central times. The final values agree with those previously reported, except for a slightly lower inclination. We find no significant long-term variations in i or R{sub P} /R {sub *}. The O-C mid-transit times do not show signs of transit timing variations greater than 54s.

  18. New experimental capabilities and theoretical insights of high pressure compression waves

    SciTech Connect (OSTI)

    Orlikowski, D; Nguyen, J; Patterson, J R; Minich, R; Martin, L P; Holmes, N

    2007-07-20

    Currently there are three platforms that offer quasi-isentropic compression or ramp-wave compression (RWC): light-gas gun, magnetic flux (Z-pinch), and laser. We focus here on the light-gas gun technique and on some current theoretical insights from experimental data. A gradient impedance through the length of the impactor provides the pressure pulse upon impactor to the subject material. Applications and results are given concerning high-pressure strength and liquid to solid, phase transition of water plus its associated phase fraction history. We also introduce the Korteweg-deVries-Burgers equation as a means to understand the evolution these RWC waves that propagate through the thickness of the subject material. This equation has the necessary competition between non-linear, dispersion, and dissipation processes, which is shown through observed structures that are manifested in the experimental particle velocity histories. Such methodology points towards a possible quantifiable dissipation, through which RWC experiments may be analyzed.

  19. Lower Hybrid to Whistler Wave Conversion

    SciTech Connect (OSTI)

    Winske, Dan

    2012-07-16

    In this presentation we discuss recent work concerning the conversion of whistler waves to lower hybrid waves (as well as the inverse process). These efforts have been motivated by the issue of attenuation of upward propagating whistler waves in the ionosphere generated by VLF transmitters on the ground, i.e., the 'Starks 20 db' problem, which affects the lifetimes of energetic electrons trapped in the geomagnetic field at low magnetic altitude (L). We discuss recent fluid and kinetic plasma simulations as well as ongoing experiments at UCLA to quantify linear and nonlinear mode conversion of lower hybrid to whistler waves.

  20. European Wave and Tidal Energy Conference

    Broader source: Energy.gov [DOE]

    The European Wave and Tidal Energy Conference (EWTEC) series are international, technical and scientific conferences, focussed on ocean renewable energy and widely respected for their commitment to...