Wave-wave interactions in solar type III radio bursts
Thejappa, G. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); MacDowall, R. J. [NASA/Goddard Space Flight Center, Greenbelt MD 20771 (United States)
2014-02-11T23:59:59.000Z
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.
Nonreciprocal wave scattering on nonlinear string-coupled oscillators
Stefano Lepri; Arkady Pikovsky
2014-10-29T23:59:59.000Z
We study scattering of a periodic wave in a string on two lumped oscillators attached to it. The equations can be represented as a driven (by the incident wave) dissipative (due to radiation losses) system of delay differential equations of neutral type. Nonlinearity of oscillators makes the scattering non-reciprocal: the same wave is transmitted differently in two directions. Periodic regimes of scattering are analysed approximately, using amplitude equation approach. We show that this setup can act as a nonreciprocal modulator via Hopf bifurcations of the steady solutions. Numerical simulations of the full system reveal nontrivial regimes of quasiperiodic and chaotic scattering. Moreover, a regime of a "chaotic diode", where transmission is periodic in one direction and chaotic in the opposite one, is reported.
Interactions Between Membrane Conductances Underlying Thalamocortical Slow-Wave Oscillations
Destexhe, Alain
or oscillations can be explained by interactions between calcium- and voltage-dependent channels. At the networkInteractions Between Membrane Conductances Underlying Thalamocortical Slow-Wave Oscillations A: Oscillations and Bursts Emerging From the Interplay of Intrinsic Conductances in Single Neurons 1404 A
Grilli, Stéphan T.
Experimental and Numerical Study of Spar Buoy-magnet/spring Oscillators Used as Wave Energy.g., latching) of the SSLG, in order to further improve power generation. KEYWORDS : Wave energy systems networks), based on captur- ing renewable wave energy. To do so, we design and optimize a new type
Decoherence by wave packet separation and collective neutrino oscillations
Akhmedov, Evgeny; Lindner, Manfred
2014-01-01T23:59:59.000Z
In dense neutrino backgrounds present in supernovae and in the early Universe, neutrino oscillations may exhibit complex collective phenomena, such as synchronized oscillations, bipolar oscillations and spectral splits and swaps. In this Letter we consider for the first time the effects of decoherence by wave packet separation on these phenomena. We derive the evolution equations that govern neutrino oscillations in a dense medium in the presence of decoherence and consider the evolution of several simple neutrino systems in detail. We show that decoherence may modify the oscillation pattern significantly and lead to qualitatively new effects. In particular, contrary to the no-decoherence case, strong flavor conversion becomes possible even in the case of constant or nearly constant density of the neutrino background.
Wave kernels for the Dirac, Euler operators and the harmonic oscillator
Mohameden, Ahmedou Yahya Ould, E-mail: ahmeddou2011@yahoo.fr; Moustapha, Mohamed Vall Ould, E-mail: khames@univ-nkc.mr [Université des Sciences, de Technologie et de la Medécine (USTM) Faculté des Sciences et Techniques. Département de Mathématiques et Informatique, Unité de Recherche: Analyse, EDP et Modélisation: (AEDPM) B.P: 5026, Nouakchott-Mauritanie (United States)
2014-03-15T23:59:59.000Z
Explicit solutions for the wave equations associated to the Dirac, Euler operators and the harmonic oscillator are given.
On the Production of Dissipation by Interaction of Forced Oscillating Waves
Paris-Sud XI, UniversitÃ© de
and parabolic type, oscillations, BKW Calculus, sta- bility. 1 Introduction In Section 1, we introduce
Circulating heat exchangers for oscillating wave engines and refrigerators
Swift, Gregory W.; Backhaus, Scott N.
2003-10-28T23:59:59.000Z
An oscillating-wave engine or refrigerator having a regenerator or a stack in which oscillating flow of a working gas occurs in a direction defined by an axis of a trunk of the engine or refrigerator, incorporates an improved heat exchanger. First and second connections branch from the trunk at locations along the axis in selected proximity to one end of the regenerator or stack, where the trunk extends in two directions from the locations of the connections. A circulating heat exchanger loop is connected to the first and second connections. At least one fluidic diode within the circulating heat exchanger loop produces a superimposed steady flow component and oscillating flow component of the working gas within the circulating heat exchanger loop. A local process fluid is in thermal contact with an outside portion of the circulating heat exchanger loop.
D. Kuridze; T. V. Zaqarashvili
2007-03-19T23:59:59.000Z
Nonlinear coupling between 3-minute oscillations and Alfven waves in the solar lower atmosphere is studied. 3-minute oscillations are considered as acoustic waves trapped in a chromospheric cavity and oscillating along transversally inhomogeneous vertical magnetic field. It is shown that under the action of the oscillations the temporal dynamics of Alfven waves is governed by Mathieu equation. Consequently, the harmonics of Alfven waves with twice period and wavelength of 3-minute oscillations grow exponentially in time near the layer where the sound and Alfven speeds equal. Thus the 3-minute oscillations are resonantly absorbed by pure Alfven waves near this resonant layer. The resonant Alfven waves may penetrate into the solar corona taking energy from the chromosphere. Therefore the layer c_s=v_A may play a role of energy channel for otherwise trapped acoustic oscillations.
A powerful reflector in relativistic backward wave oscillator
Cao, Yibing, E-mail: caoyibing@nint.ac.cn; Sun, Jun; Teng, Yan; Zhang, Yuchuan; Zhang, Lijun; Shi, Yanchao; Ye, Hu; Chen, Changhua [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024 (China)
2014-09-15T23:59:59.000Z
An improved TM{sub 021} resonant reflector is put forward. Similarly with most of the slow wave structures used in relativistic backward wave oscillator, the section plane of the proposed reflector is designed to be trapezoidal. Compared with the rectangular TM{sub 021} resonant reflector, such a structure can depress RF breakdown more effectively by weakening the localized field convergence and realizing good electrostatic insulation. As shown in the high power microwave (HPM) generation experiments, with almost the same output power obtained by the previous structure, the improved structure can increase the pulse width from 25?ns to over 27?ns and no obvious surface damage is observed even if the generated HPM pulses exceed 1000 shots.
Chen, Changhua; Xiao, Renzhen; Sun, Jun; Song, Zhimin; Huo, Shaofei; Bai, Xianchen; Shi, Yanchao; Liu, Guozhi [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)] [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)
2013-11-15T23:59:59.000Z
This paper provides a fresh insight into the effect of non-uniform slow wave structure (SWS) used in a relativistic backward wave oscillator (RBWO) with a resonant reflector. Compared with the uniform SWS, the reflection coefficient of the non-uniform SWS is higher, leading to a lower modulating electric field in the resonant reflector and a larger distance to maximize the modulation current. Moreover, for both types of RBWOs, stronger standing-wave field takes place at the rear part of the SWS. In addition, besides Cerenkov effects, the energy conversion process in the RBWO strongly depends on transit time effects. Thus, the matching condition between the distributions of harmonic current and standing wave field provides a profound influence on the beam-wave interaction. In the non-uniform RBWO, the region with a stronger standing wave field corresponds to a higher fundamental harmonic current distribution. Particle-in-cell simulations show that with a diode voltage of 1.02 MV and beam current of 13.2 kA, a microwave power of 4 GW has been obtained, compared to that of 3 GW in the uniform RBWO.
Asymmetric modes decomposition in an overmoded relativistic backward wave oscillator
Zhang, Dian; Zhang, Jun, E-mail: zhangjun@nudt.edu.cn; Zhong, Huihuang; Jin, Zhenxing; Ju, Jinchuan [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)
2014-09-15T23:59:59.000Z
Most of the investigated overmoded relativistic backward wave oscillators (RBWOs) are azimuthally symmetric; thus, they are designed through two dimensional (2-D) particle-in-cell (PIC) simulations. However, 2-D PIC simulations cannot reveal the effect of asymmetric modes on beam-wave interaction. In order to investigate whether asymmetric mode competition needs to be considered in the design of overmoded RBWOs, a numerical method of determining the composition of both symmetric and asymmetric modes in three dimensional (3-D) PIC simulations is introduced in this paper. The 2-D and 3-D PIC simulation results of an X-band overmoded RBWO are analyzed. Our analysis indicates that the 2-D and 3-D PIC simulation results of our device are quite different due to asymmetric mode competition. In fact, asymmetric surface waves, especially EH{sub 11} mode, can lead to serious mode competition when electron beam propagates near the surface of slow wave structures (SWSs). Therefore, additional method of suppressing asymmetric mode competition, such as adjusting the reflections at both ends of SWSs to decrease the Q-factor of asymmetric modes, needs to be utilized in the design of overmoded RBWOs. Besides, 3-D PIC simulation and modes decomposition are essential for designing overmoded RBWOs.
Reference Model 6 (RM6): Oscillating Wave Energy Converter.
Bull, Diana L; Smith, Chris; Jenne, Dale Scott; Jacob, Paul; Copping, Andrea; Willits, Steve; Fontaine, Arnold; Brefort, Dorian; Gordon, Margaret Ellen; Copeland, Robert; Jepsen, Richard A.
2014-10-01T23:59:59.000Z
This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter reference model design in a complementary manner to Reference Models 1-4 contained in the above report. In this report, a conceptual design for an Oscillating Water Column Wave Energy Converter (WEC) device appropriate for the modeled reference resource site was identified, and a detailed backward bent duct buoy (BBDB) device design was developed using a combination of numerical modeling tools and scaled physical models. Our team used the methodology in SAND2013-9040 for the economic analysis that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays, up to 100 devices. The methodology was applied to identify key cost drivers and to estimate levelized cost of energy (LCOE) for this RM6 Oscillating Water Column device in dollars per kilowatt-hour (%24/kWh). Although many costs were difficult to estimate at this time due to the lack of operational experience, the main contribution of this work was to disseminate a detailed set of methodologies and models that allow for an initial cost analysis of this emerging technology. This project is sponsored by the U.S. Department of Energy's (DOE) Wind and Water Power Technologies Program Office (WWPTO), within the Office of Energy Efficiency & Renewable Energy (EERE). Sandia National Laboratories, the lead in this effort, collaborated with partners from National Laboratories, industry, and universities to design and test this reference model.
Reference Model 5 (RM5): Oscillating Surge Wave Energy Converter
Yu, Y. H.; Jenne, D. S.; Thresher, R.; Copping, A.; Geerlofs, S.; Hanna, L. A.
2015-01-01T23:59:59.000Z
This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter (OSWEC) reference model design in a complementary manner to Reference Models 1-4 contained in the above report. A conceptual design for a taut moored oscillating surge wave energy converter was developed. The design had an annual electrical power of 108 kilowatts (kW), rated power of 360 kW, and intended deployment at water depths between 50 m and 100 m. The study includes structural analysis, power output estimation, a hydraulic power conversion chain system, and mooring designs. The results were used to estimate device capital cost and annual operation and maintenance costs. The device performance and costs were used for the economic analysis, following the methodology presented in SAND2013-9040 that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays up to 100 devices. The levelized cost of energy estimated for the Reference Model 5 OSWEC, presented in this report, was for a single device and arrays of 10, 50, and 100 units, and it enabled the economic analysis to account for cost reductions associated with economies of scale. The baseline commercial levelized cost of energy estimate for the Reference Model 5 device in an array comprised of 10 units is $1.44/kilowatt-hour (kWh), and the value drops to approximately $0.69/kWh for an array of 100 units.
Viktor Szaszko-Bogar; Peter Foldi; F. M. Peeters
2014-03-18T23:59:59.000Z
Ballistic transport through nanoscale devices with time-dependent Rashba-type spin-orbit interaction (SOI) can lead to spin-polarized wave packets that appear even for completely unpolarized input. The SOI that oscillates in a finite domain generates density and spin polarization fluctuations that leave the region as propagating waves. Particularly, spin polarization has space and time dependence even in regions without SOI. Our results are based on an analytic solution of the time-dependent Schr\\"odinger equation. The relevant Floquet quasi-energies that are obtained appear in the energy spectrum of both the transmitted and reflected waves.
Voinigescu, Sorin Petre
SiGe BiCMOS Topologies for Low-Voltage Millimeter-Wave Voltage Controlled Oscillators and Frequency-mail: tod@eecg.toronto.edu Abstract -- BiCMOS topologies for mm-wave voltage- controlled oscillators operation for mm-wave applications. II. BICMOS VOLTAGE-CONTROLLED OSCILLATOR The Colpitts topology
Multiscale modeling of oscillations and spiral waves in Dictyostelium populations
Javad Noorbakhsh; David Schwab; Allyson Sgro; Thomas Gregor; Pankaj Mehta
2014-09-12T23:59:59.000Z
Unicellular organisms exhibit elaborate collective behaviors in response to environmental cues. These behaviors are controlled by complex biochemical networks within individual cells and coordinated through cell-to-cell communication. Describing these behaviors requires new mathematical models that can bridge scales -- from biochemical networks within individual cells to spatially structured cellular populations. Here, we present a family of multiscale models for the emergence of spiral waves in the social amoeba Dictyostelium discoideum. Our models exploit new experimental advances that allow for the direct measurement and manipulation of the small signaling molecule cAMP used by Dictyostelium cells to coordinate behavior in cellular populations. Inspired by recent experiments, we model the Dictyostelium signaling network as an excitable system coupled to various pre-processing modules. We use this family of models to study spatially unstructured populations by constructing phase diagrams that relate the properties of population-level oscillations to parameters in the underlying biochemical network. We then extend our models to include spatial structure and show how they naturally give rise to spiral waves. Our models exhibit a wide range of novel phenomena including a density dependent frequency change, bistability, and dynamic death due to slow cAMP dynamics. Our modeling approach provides a powerful tool for bridging scales in modeling of Dictyostelium populations.
Tian Hui; McIntosh, Scott W. [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States); Wang, Tongjiang; Ofman, Leon [Department of Physics, Catholic University of America, Washington, DC 20064 (United States); De Pontieu, Bart [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover St., Org. ADBS, Bldg. 252, Palo Alto, CA 94304 (United States); Innes, Davina E.; Peter, Hardi, E-mail: htian@ucar.edu [Max Planck Institute for Solar System Research, 37191 Katlenburg-Lindau (Germany)
2012-11-10T23:59:59.000Z
Using data obtained by the EUV Imaging Spectrometer on board Hinode, we have performed a survey of obvious and persistent (without significant damping) Doppler shift oscillations in the corona. We have found mainly two types of oscillations from February to April in 2007. One type is found at loop footpoint regions, with a dominant period around 10 minutes. They are characterized by coherent behavior of all line parameters (line intensity, Doppler shift, line width, and profile asymmetry), and apparent blueshift and blueward asymmetry throughout almost the entire duration. Such oscillations are likely to be signatures of quasi-periodic upflows (small-scale jets, or coronal counterpart of type-II spicules), which may play an important role in the supply of mass and energy to the hot corona. The other type of oscillation is usually associated with the upper part of loops. They are most clearly seen in the Doppler shift of coronal lines with formation temperatures between one and two million degrees. The global wavelets of these oscillations usually peak sharply around a period in the range of three to six minutes. No obvious profile asymmetry is found and the variation of the line width is typically very small. The intensity variation is often less than 2%. These oscillations are more likely to be signatures of kink/Alfven waves rather than flows. In a few cases, there seems to be a {pi}/2 phase shift between the intensity and Doppler shift oscillations, which may suggest the presence of slow-mode standing waves according to wave theories. However, we demonstrate that such a phase shift could also be produced by loops moving into and out of a spatial pixel as a result of Alfvenic oscillations. In this scenario, the intensity oscillations associated with Alfvenic waves are caused by loop displacement rather than density change. These coronal waves may be used to investigate properties of the coronal plasma and magnetic field.
Noncommutative quantum mechanics of a harmonic oscillator under linearized gravitational waves
Anirban Saha; Sunandan Gangopadhyay; Swarup Saha
2011-06-09T23:59:59.000Z
We consider the quantum dynamics of a harmonic oscillator in noncommutative space under the influence of linearized gravitational waves (GW) in the long wave-length and low-velocity limit. Following the prescription in \\cite{ncgw1} we quantize the system. The Hamiltonian of the system is solved by using standard algebraic iterative methods. The solution shows signatures of the coordinate noncommutativity via alterations in the oscillation frequency of the harmonic oscillator system from its commutative counterpart. Moreover, it is found that the response of the harmonic oscillator to periodic GW, when their frequencies match, will oscillate with a time scale imposed by the NC parameter. We expect this noncommutative signature to show up as some noise source in the GW detection experiments since the recent phenomenological upper-bounds set on spatial noncommutative parameter implies a length-scale comparable to the length-variations due to the passage of gravitational waves, detectable in the present day GW detectors.
Stochastic excitation and damping of solar-type oscillations
G. Houdek
2006-12-01T23:59:59.000Z
A review on acoustic mode damping and excitation in solar-type stars is presented. Current models for linear damping rates are discussed in the light of recent low-degree solar linewidth measurements with emphasis on the frequency-dependence of damping rates of low-order modes. Recent developments in stochastic excitation models are reviewed and tested against the latest high-quality data of solar-like oscillations, such as from alpha Cen A, and against results obtained from hydrodynamical simulations.
Wave Energy Extraction from an Oscillating Water Column in a Truncated Circular Cylinder
Wang, Hao
2013-07-19T23:59:59.000Z
Oscillating Water Column (OWC) device is a relatively practical and convenient way that converts wave energy to a utilizable form, which is usually electricity. The OWC is kept inside a fixed truncated vertical cylinder, which is a hollow structure...
A new type of surface waves in a fully degenerate quantum plasma
Yuriy Tyshetskiy; Roman Kompaneets; Sergey V. Vladimirov
2014-04-06T23:59:59.000Z
We study the response of a semi-bounded one-component fully degenerate electron plasma to an initial perturbation in the electrostatic limit. We show that the part of the electric potential corresponding to surface waves in such plasma can be represented, at large times, as the sum of two terms, one term corresponding to "conventional" (Langmuir) surface waves and the other term representing a new type of surface waves resulting from specific analytic properties of degenerate plasma's dielectric response function. These two terms are characterized by different oscillation frequencies (for a given wave number), and, while the "conventional" term's amplitude decays exponentially with time, the new term is characterized by a slower, power-law decay of the oscillation amplitude and is therefore dominant at large times.
Covariant asymmetric wave packet for a field-theoretical description of neutrino oscillations
V. A. Naumov; D. S. Shkirmanov
2014-09-16T23:59:59.000Z
We consider a class of models for the relativistic covariant wave packets which can be used as asymptotically free in and out states in the quantum field theoretical formalisms for description of the neutrino flavor oscillation phenomenon. We demonstrate that the new "asymmetric" wave packet (AWP) is an appropriate alternative for the more convenient "symmetric" wave packets, like the so-called relativistic Gaussian packet (RGP) widely used in the QFT-based approaches to neutrino oscillations. We show that RGP is not a particular case of AWP, although many properties of these models are almost identical in the quasistable regime. We discuss some features of AWP distinguishing it from RGP.
Covariant asymmetric wave packet for a field-theoretical description of neutrino oscillations
Naumov, V A
2014-01-01T23:59:59.000Z
We consider a class of models for the relativistic covariant wave packets which can be used as asymptotically free in and out states in the quantum field theoretical formalisms for description of the neutrino flavor oscillation phenomenon. We demonstrate that the new "asymmetric" wave packet (AWP) is an appropriate alternative for the more convenient "symmetric" wave packets, like the so-called relativistic Gaussian packet (RGP) widely used in the QFT-based approaches to neutrino oscillations. We show that RGP is not a particular case of AWP, although many properties of these models are almost identical in the quasistable regime. We discuss some features of AWP distinguishing it from RGP.
Reference Model 5 (RM5): Oscillating Surge Wave Energy Converter
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
has a gently sloping seabed, free of irregularities that could disturb the local wave field. Thus, it is likely that the wave field is homogeneous over the deployment area of...
A PLL Design Based on a Standing Wave Resonant Oscillator
Karkala, Vinay
2011-10-21T23:59:59.000Z
with a plurality of wires connected in a mobius configuration, with a cross coupled inverter pair connected across the wires. The oscillation frequency can be modulated by coarse and fine tuning. Coarse modification is achieved by altering the number...
Cosmological implications of two types of baryon acoustic oscillation data
Hu, Yazhou; Li, Nan; Wang, Shuang
2015-01-01T23:59:59.000Z
Aims: We explore the cosmological implications of two types of baryon acoustic oscillation (BAO) data that are extracted by using the spherically averaged one-dimensional galaxy clustering (GC) statistics (hereafter BAO1) and the anisotropic two-dimensional GC statistics (hereafter BAO2), respectively. Methods: Firstly, making use of the BAO1 and the BAO2 data, as well as the SNLS3 type Ia supernovae sample and the Planck distance priors data, we constrain the parameter spaces of the $\\Lambda$CDM, the $w$CDM, and the Chevallier-Polarski-Linder (CPL) model. Then, we discuss the impacts of different BAO data on parameter estimation, equation of state $w$, figure of merit and deceleration-acceleration transition redshift. At last, we use various dark energy diagnosis, including Hubble diagram $H(z)$, deceleration diagram $q(z)$, statefinder hierarchy $\\{S^{(1)}_3, S^{(1)}_4\\}$, composite null diagnosic (CND) $\\{S^{(1)}_3, \\epsilon(z)\\}$ and $\\{S^{(1)}_4, \\epsilon(z)\\}$, to distinguish the differences between the...
Vacuum Rabi oscillation of an atom without rotating-wave approximation
Fa-Qiang Wang; Wei-Ci Liu; Rui-Sheng Liang
2008-07-16T23:59:59.000Z
We have investigated vacuum Rabi oscillation of an atom coupled with single-mode cavity field exactly, and compared the results with that of J-C model. The results show that, there is damping Rabi oscillation for an atom, even in strong coupling regime. For small detuning and weak coupling case, the probability for the atom in excited state oscillates against time with different frequency and amplitude from that of J-C model. It exhibits the counter-rotating wave interaction could significantly effect the dynamic behavior of the atom, even under the condition in which the RWA is considered to be justified. On the other hand, the results also reveal that the counter-rotating wave interaction could obviously modify the decay rate in strong coupling regime. And there is Rabi oscillation for initially unexcited atom, which is contrary to that of J-C model.
A watt-class 1-THz backward-wave oscillator based on sine waveguide
Xu Xiong; Wei Yanyu; Shen Fei; Yin Hairong; Xu Jin; Gong Yubin; Wang Wenxiang
2012-01-15T23:59:59.000Z
A novel backward wave oscillator was proposed by utilizing a concise sine waveguide slow-wave structure combined with sheet electron beam to operate at terahertz frequency band. First, the design method was described, and the dispersion curve and interaction impedance of the sine waveguide were calculated, then the device oscillation frequency and operating voltage were determined. Next, the circuit transmission losses were learned over the tunable frequency range. Finally, the particle-in-cell simulation method was applied to predict its signal generation performance. The investigation results show that, the backward wave oscillator can produce over 1.9 -W peak power output at the central operating frequency of 1-THz under 27-kV operating voltage and 5-mA beam current. And the interaction efficiency at 1-THz is more than 1.4% with a circuit length of 7.2-mm. It, therefore, will be considered as a promising watt-class terahertz radiation source.
Iye, Yasuhiro
Resistance Fluctuations and AharonovBohm-Type Oscillations in Antidot Arrays in the Quantum Hall fluctuations (RFs) and the other is the AharonovBohm (AB)-type oscillations. Their dependences on the magnetic field and the gate voltage are quite distinct. While the aperiodic RFs are attributed to the complex
Bulaevskii, L. N.; Kosehlev, A. E.; Tachiki, M.; Materials Science Division; LANL; Univ. of Tokyo
2008-01-01T23:59:59.000Z
Single crystals of layered high-temperature superconductors intrinsically behave as stacks of Josephson junctions. We analyze response of current-biased stack of intrinsic junctions to irradiation by the external electromagnetic (em) wave. In addition to well-known Shapiro steps in the current-voltage characteristics, irradiation promotes stimulated radiation which adds with spontaneous Josephson radiation from the crystal. Such enhancement of radiation from current-biased crystal may be used for amplification of em waves. Irradiation also facilitates synchronization of Josephson oscillations in all intrinsic Josephson junctions of a single crystal as well as oscillations in intrinsic junctions of different crystals.
Duffing-type oscillators with amplitude-independent period
Rand, Richard H.
, Faculty of Technical Sciences, University of Novi Sad, 21125 Novi Sad, Serbia, e-mail: ivanakov], in which the kinetic energy Ek and potential energy Ep of nonlinear oscillators are made equal to the one/2, obtaining X = 2Ep. (6) Then, we also make the kinetic energy Ek of nonlinear oscillators equal to the one
Annular wave packets at Dirac points and probability oscillation in graphene
Ji Luo; Junqiang Lu; Daniel Valencia
2011-08-12T23:59:59.000Z
Wave packets in graphene whose central wave vector is at Dirac points are investigated by numerical calculations. Starting from an initial Gaussian function, these wave packets form into annular peaks that propagate to all directions like ripple-rings on water surface. At the beginning, electronic probability alternates between the central peak and the ripple-rings and transient oscillation occurs at the center. As time increases, the ripple-rings propagate at the fixed Fermi speed, and their widths remain unchanged. The axial symmetry of the energy dispersion leads to the circular symmetry of the wave packets. The fixed speed and widths, however, are attributed to the linearity of the energy dispersion. Interference between states that respectively belong to two branches of the energy dispersion leads to multiple ripple-rings and the probability-density oscillation. In a magnetic field, annular wave packets become confined and no longer propagate to infinity. If the initial Gaussian width differs greatly from the magnetic length, expanding and shrinking ripple-rings form and disappear alternatively in a limited spread, and the wave packet resumes the Gaussian form frequently. The probability thus oscillates persistently between the central peak and the ripple-rings. If the initial Gaussian width is close to the magnetic length, the wave packet retains the Gaussian form and its height and width oscillate with a period determined by the first Landau energy. The wave-packet evolution is determined jointly by the initial state and the magnetic field, through the electronic structure of graphene in a magnetic field.
Natural Wave Control in Lattices of Linear Oscillators Denis V. Efimov, Alexander L. Fradkov
Boyer, Edmond
biological tissues regulation [3], [5], [8], [40], Frenkel- Kontorova models [11] have been controlled as "Cybernetical Physics" [11]. Design and application of control strategies to manipulation of complex oscillatoryNatural Wave Control in Lattices of Linear Oscillators Denis V. Efimov, Alexander L. Fradkov
Biswanath Rath
2015-05-19T23:59:59.000Z
For the first time in the literature of Quantum Physics, we present complex energy eigenvalues of non-Hermitian Harmonic Oscillator $H=\\frac{(p+iLx)}^{2}}{2} + W^{2} \\frac{x^{2}}{2}$ with real wave function having positive frequency of vibration $(w)$ under some selective choice of $L$ and $W$ .Interestingly for the same values of $L$ and $W$, if the frequency of vibration $w$ in the real wave function is (some how) related as $w=L\\pmW$ or $w=W-L$ then the same oscillator can reflect either pure positive or negative energy eigenvalues.The real energy levels are in conformity with the perturbative calculation. PACS :03.65.Db;11.39.Er. Key words: Positive frequency, real wave function, complex energy, real positive energy,negative energy.
The mechanism and realization of a band-agile coaxial relativistic backward-wave oscillator
Ge, Xingjun; Zhang, Jun; Zhong, Huihuang; Qian, Baoliang; Wang, Haitao [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)
2014-11-03T23:59:59.000Z
The mechanism and realization of a band-agile coaxial relativistic backward-wave oscillator (RBWO) are presented. The operation frequency tuning can be easily achieved by merely altering the inner-conductor length. The key effects of the inner-conductor length contributing to the mechanical frequency tunability are investigated theoretically and experimentally. There is a specific inner-conductor length where the operation frequency can jump from one mode to another mode, which belongs to a different operation band. In addition, the operation frequency is tunable within each operation band. During simulation, the L-band microwave with a frequency of 1.61 GHz is radiated when the inner-conductor length is 39?cm. Meanwhile, the S-band microwave with a frequency of 2.32 GHz is radiated when the inner-conductor length is 5?cm. The frequency adjustment bandwidths of L-band and S-band are about 8.5% and 2%, respectively. Moreover, the online mechanical tunability process is described in detail. In the initial experiment, the generated microwave frequencies remain approximately 1.59 GHz and 2.35?GHz when the inner-conductor lengths are 39?cm and 5?cm. In brief, this technical route of the band-agile coaxial RBWO is feasible and provides a guide to design other types of band-agile high power microwaves sources.
5-minute Solar Oscillations and Ion Cyclotron Waves in the Solar Wind
Guglielmi, Anatol; Dovbnya, Boris
2015-01-01T23:59:59.000Z
In the present paper we study impact of the photospheric 5-minute oscillations on the ion cyclotron waves in the solar wind. We proceed from the assumption that the ion cyclotron waves in solar wind are experiencing modulation with a characteristic period of 5 minutes under the influence of Alfven waves driven by photospheric motions. The theory presented in our paper predicts a deep frequency modulation of the ion cyclotron waves. The frequency modulation is expected mainly from variations in orientation of the IMF lines. In turn, the variations in orientation are caused by the Alfven waves, propagating from the Sun. To test the theoretical predictions we have analyzed records of the ultra-low-frequency (ULF) geoelectromagnetic waves in order to find the permanent quasi-monochromatic oscillations of natural origin in the Pc1-2 frequency band (0.1-5 Hz), the carrier frequency of which varies with time in a wide range. As a result we found the so-called "serpentine emission" (SE), which was observed in Antarct...
Nonlinear oscillations and waves in an arbitrary mass ratio cold plasma
Verma, Prabal Singh [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India)
2011-12-15T23:59:59.000Z
It is well known that nonlinear standing oscillations in an arbitrary mass ratio cold plasma always phase mix away. However, there exist nonlinear electron-ion traveling wave solutions, which do not exhibit phase mixing because they have zero ponderomotive force. The existence of these waves has been demonstrated using a perturbation method. Moreover, it is shown that cold plasma BGK waves [Albritton et al., Nucl. Fusion 15, 1199 (1975)] phase mix away if ions are allowed to move and the scaling of phase mixing is found to be different from earlier work [Sengupta et al., Phys. Rev. Lett. 82, 1867 (1999)]. Phase mixing of these waves has been further verified in 1-D particle in cell simulation.
Multi-pulse operation of a super-radiant backward-wave oscillator
Bandurkin, I. V. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod, 603950 (Russian Federation); Savilov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod, 603950 (Russian Federation); Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod (Russian Federation)
2014-08-15T23:59:59.000Z
Theory of a backward-wave electron oscillator operating in the non-stationary regime of super-radiation of short powerful rf pulses is developed. It is shown that there exist multi-frequency regimes of generation of either two-peak or three-peak output signal with different characteristic frequencies in every peak. The use of such regimes allows increasing the duration, the peak power, and the total energy of the output super-radiation rf pulse.
D. Matrasulov
1998-04-17T23:59:59.000Z
Schr\\"odinger equation for two center Coulomb plus harmonic oscillator potential is solved by the method of ethalon equation at large intercenter separations. Asymptotical expansions for energy term and wave function are obtained in the analytical form.
Gonzalez-Rodriguez, David
Experimental studies of sediment transport rates due to near shore waves are often conducted in oscillating water tunnels (OWTs). In an OWT, the oscillatory motion produced by the piston propagates almost instantaneously ...
The role of linear and voltage-dependent ionic currents in the generation of slow wave oscillations
Bose, Amitabha
The role of linear and voltage-dependent ionic currents in the generation of slow wave oscillations voltages, re- spectively. Oscillations are created by inward currents driving the cell away from rest voltages and one outward current that repolarizes the cell. Such currents have traditionally been assumed
Design and Analysis for a Floating Oscillating Surge Wave Energy Converter: Preprint
Yu, Y. H.; Li, Y.; Hallett, K.; Hotimsky, C.
2014-03-01T23:59:59.000Z
This paper presents a recent study on the design and analysis of an oscillating surge wave energy converter. A successful wave energy conversion design requires the balance between the design performance and cost. The cost of energy is often used as the metric to judge the design of the wave energy conversion system. It is often determined based on the device power performance, the cost for manufacturing, deployment, operation and maintenance, as well as the effort to ensure the environmental compliance. The objective of this study is to demonstrate the importance of a cost driven design strategy and how it can affect a WEC design. Three oscillating surge wave energy converter (OSWEC) designs were used as the example. The power generation performance of the design was modeled using a time-domain numerical simulation tool, and the mass properties of the design were determined based on a simple structure analysis. The results of those power performance simulations, the structure analysis and a simple economic assessment were then used to determine the cost-efficiency of selected OSWEC designs. Finally, a discussion on the environmental barrier, integrated design strategy and the key areas that need further investigation is also presented.
Resonant behaviour of an oscillating wave energy converter in a channel
E. Renzi; F. Dias
2012-04-10T23:59:59.000Z
A mathematical model is developed to study the behaviour of an oscillating wave energy converter in a channel. During recent laboratory tests in a wave tank, peaks in the hydrodynamic actions on the converter occurred at certain frequencies of the incident waves. This resonant mechanism is known to be generated by the transverse sloshing modes of the channel. Here the influence of the channel sloshing modes on the performance of the device is further investigated. Within the framework of a linear inviscid potential-flow theory, application of the Green theorem yields a hypersingular integral equation for the velocity potential in the fluid domain. The solution is found in terms of a fast-converging series of Chebyshev polynomials of the second kind. The physical behaviour of the system is then analysed, showing sensitivity of the resonant sloshing modes to the geometry of the device, that concurs in increasing the maximum efficiency. Analytical results are validated with available numerical and experimental data.
Resonant behaviour of an oscillating wave energy converter in a channel
Renzi, E
2012-01-01T23:59:59.000Z
A mathematical model is developed to study the behaviour of an oscillating wave energy converter in a channel. During recent laboratory tests in a wave tank, peaks in the hydrodynamic actions on the converter occurred at certain frequencies of the incident waves. This resonant mechanism is known to be generated by the transverse sloshing modes of the channel. Here the influence of the channel sloshing modes on the performance of the device is further investigated. Within the framework of a linear inviscid potential-flow theory, application of the Green theorem yields a hypersingular integral equation for the velocity potential in the fluid domain. The solution is found in terms of a fast-converging series of Chebyshev polynomials of the second kind. The physical behaviour of the system is then analysed, showing sensitivity of the resonant sloshing modes to the geometry of the device, that concurs in increasing the maximum efficiency. Analytical results are validated with available numerical and experimental d...
Effects of Shock Waves on Neutrino Oscillations in Three Supernova Models
Xu, Jing; Li, Rui-Cheng; Guo, Xin-Heng; Young, Bing-Lin
2014-01-01T23:59:59.000Z
It has been realized that the shock wave effects play an important role in neutrino oscillations during the supernova explosion. In recent years, with the development of simulations about supernova explosion, we have a better understanding about the density profiles and the shock waves in supernovae than before. It has been shown that the appearance of shock waves not only varies with time, but is also affected by the mass of the supernova. When the mass of the supernova happens to be in a certain range (e.g. it equals 10.8 times the mass of the sun), there might be a reverse shock wave, another sudden change of density except the forward shock wave, emerging in the supernova. In addition, there are some other time-dependent changes of density profiles in different supernova models. Because of these complex density profiles, the expression of the crossing probability at the high resonance, $P_H$, which we used previously would be no longer applicable. In order to get more accurate and reasonable results, we u...
Stable coaxial-waveguide gyrotron backward-wave oscillator with distributed losses
Hung, C. L. [Department of Communication Engineering, National Penghu University of Science and Technology, Penghu 880, Taiwan (China)
2010-10-15T23:59:59.000Z
This study analyzes the performance of a coaxial-waveguide gyrotron backward-wave oscillator (gyro-BWO) operating at the fundamental harmonic by considering mode competition, which may be attributed to higher-order axial modes and competing transverse modes. In the coaxial waveguide with a short length and uniform cross section, the threshold currents of the higher-order axial modes are substantially higher than the operating current. Additionally, when the beam voltage or the magnetic field is adjusted, the oscillation that neighbors the minimum start-oscillation current of a transverse mode has a positive-k{sub z} field profile, and is excited near the cutoff frequency. As a result, the distributed wall losses at the downstream end of the interaction structure effectively damp the positive-k{sub z} field, and raise significantly the minimum start-oscillation currents of the competing transverse modes. This study also investigates how the parameters, including lossy section length, outer wall resistivity, inner wall resistivity, and ratio of the outer radius to the inner radius, affect the start-oscillation currents of the competing transverse modes in order to obtain stable operation conditions in the frequency tuning range. As is forecasted, when using a 15 A electron beam, the Ka-band coaxial gyro-BWO produces an output power of 137 kW and 3 dB bandwidth of 4.2% by magnetic tuning and an output power of 145 kW and 3dB bandwidth of 2.0% by beam voltage tuning.
Harmonic-oscillator excitations of precise few-body wave functions
W. Horiuchi; Y. Suzuki
2014-08-21T23:59:59.000Z
A method for calculating the occupation probability of the number of harmonic oscillator (HO) quanta is developed for a precise few-body wave function obtained in a correlated Gaussian basis. The probability distributions of two- to four-nucleon wave functions obtained using different nucleon- nucleon (NN) interactions are analyzed to gain insight into the characteristic behavior of the various interactions. Tensor correlations as well as short-range correlations play a crucial role in enhancing the probability of high HO excitations. For the excited states of 4He, the interaction dependence is much less because high HO quanta are mainly responsible for describing the relative motion function between the 3N+N (3H+p and 3He+n) clusters.
An overmoded relativistic backward wave oscillator with efficient dual-mode operation
Xiao, Renzhen; Li, Jiawei; Bai, Xianchen; Song, Zhimin; Teng, Yan; Ye, Hu; Li, Xiaoze; Sun, Jun; Chen, Changhua [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Zhang, Xiaowei [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi'an Jiaotong University, Xi'an 710049 (China)
2014-03-03T23:59:59.000Z
A dual-mode operation mechanism in an overmoded relativistic backward wave oscillator is presented. The electron beam interacts with the ?1st space harmonic of TM{sub 01} mode synchronously in the slow wave structure. Then the backward propagating TM{sub 01} mode is converted to the forward propagating TM{sub 02} mode. As the phase velocity of the volume harmonic of TM{sub 02} mode is about twice that of the surface harmonic of TM{sub 01} mode, the TM{sub 02} mode also plays an important role in the high-power microwave generation. Particle-in-cell simulation shows that an efficiency of 48% and a significant improvement of the power capacity have been obtained.
On The Harmonic Oscillator Group
Raquel M. Lopez; Sergei K. Suslov; Jose M. Vega-Guzman
2011-12-04T23:59:59.000Z
We discuss the maximum kinematical invariance group of the quantum harmonic oscillator from a view point of the Ermakov-type system. A six parameter family of the square integrable oscillator wave functions, which seems cannot be obtained by the standard separation of variables, is presented as an example. The invariance group of generalized driven harmonic oscillator is shown to be isomorphic to the corresponding Schroedinger group of the free particle.
Investigation of an improved relativistic backward wave oscillator in efficiency and power capacity
Song, W.; Chen, C. H.; Sun, J.; Zhang, X. W.; Shao, H.; Song, Z. M.; Huo, S. F.; Shi, Y. C.; Li, X. Z. [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024 (China)
2012-10-15T23:59:59.000Z
Investigation of relativistic backward wave oscillator with high efficiency and power capacity is presented in this paper. To obtain high power and high efficiency, a TM{sub 021} mode resonant reflector is used to reduce the pulse shortening and increase power capacity to about 1.7 times. Meanwhile, an extraction cavity at the end of slow wave structure is employed to improve the efficiency from less than 30% to over 40%, through the beam-wave interaction intensification and better energy conversion from modulated electron beam to the electromagnetic field. Consistent with the numerical results, microwave with a power of 3.2 GW, a frequency of 9.75 GHz, and a pulse width of 27 ns was obtained in the high power microwave generation experiment, where the electron beam energy was configured to be {approx}910 kV and its current to be {approx}8.6 kA. The efficiency of the RBWO exceeds 40% at a voltage range of 870 kV-1000 kV.
Harmonic mode competition in a terahertz gyrotron backward-wave oscillator
Kao, S. H.; Chiu, C. C.; Chang, P. C.; Wu, K. L.; Chu, K. R. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)
2012-10-15T23:59:59.000Z
Electron cyclotron maser interactions at terahertz (THz) frequencies require a high-order-mode structure to reduce the wall loss to a tolerable level. To generate THz radiation, it is also essential to employ cyclotron harmonic resonances to reduce the required magnetic field strength to a value within the capability of the superconducting magnets. However, much weaker harmonic interactions in a high-order-mode structure lead to serious mode competition problems. The current paper addresses harmonic mode competition in the gyrotron backward wave oscillator (gyro-BWO). We begin with a comparative study of the mode formation and oscillation thresholds in the gyro-BWO and gyromonotron. Differences in linear features result in far fewer 'windows' for harmonic operation of the gyro-BWO. Nonlinear consequences of these differences are examined in particle simulations of the multimode competition processes in the gyro-BWO, which shed light on the competition criteria between modes of different as well as the same cyclotron harmonic numbers. The viability of a harmonic gyro-BWO is assessed on the basis of the results obtained.
Christian, Eric
ULYSSES DETECTS LONG-SOUGHT WAVE MOTIONS OF THE SUN Periodic oscillations originating from deep within the Sun's interior have been detected for the first time in interplanetary space by the Ulysses mission to the poles of the Sun. The discovery was reported in this week's issue of Nature magazine
Millimeter-Wave Absorption as a Quality Control Tool for M-Type...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Millimeter-Wave Absorption as a Quality Control Tool for M-Type Hexaferrite Nanopowders. Millimeter-Wave Absorption as a Quality Control Tool for M-Type Hexaferrite Nanopowders....
Ginzburg, N. S.; Zaslavsky, V. Yu. [Nizhny Novgorod State University, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation) [Nizhny Novgorod State University, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation); Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Malkin, A. M.; Sergeev, A. S. [Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation)] [Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation)
2013-11-15T23:59:59.000Z
Within the framework of a quasi-optical approach, we develop 2D and 3D self-consistent theory of relativistic surface-wave oscillators. Presenting the radiation field as a sum of two counter-propagating wavebeams coupled on a shallow corrugated surface, we describe formation of an evanescent slow wave. Dispersion characteristics of the evanescent wave following from this method are in good compliance with those found from the direct cst simulations. Considering excitation of the slow wave by a sheet electron beam, we simulate linear and nonlinear stages of interaction, which allows us to determine oscillation threshold conditions, electron efficiency, and output coupling. The transition from the model of surface-wave oscillator operating in the ?-mode regime to the canonical model of relativistic backward wave oscillator is considered. We also described a modified scheme of planar relativistic surface-wave oscillators exploiting two-dimensional periodic gratings. Additional transverse propagating waves emerging on these gratings synchronize the emission from a wide sheet rectilinear electron beam allowing realization of a Cherenkov millimeter-wave oscillators with subgigawatt output power level.
On the wave equation in spacetimes of Goedel type
P. Marecki
2012-01-24T23:59:59.000Z
We analyze the d'Alembert equation in the Goedel-type spacetimes with spherical and Lobachevsky sections (with sufficiently rapid rotation). By separating the $t$ and $x_3$ dependence we reduce the problem to a group-theoretical one. In the spherical case solutions have discrete frequencies, and involve spin-weighted spherical harmonics. In the Lobachevsky case we give simple formulas for obtaining all the solutions belonging to the $D^\\pm_\\la$ sectors of the irreducible unitary representations of the reduced Lorentz group. The wave equation enforces restrictions on $\\la$ and the allowed (here: continuous) spectrum of frequencies.
Liu Wei; Nitta, Nariaki V.; Aschwanden, Markus J.; Schrijver, Carolus J.; Title, Alan M.; Tarbell, Theodore D. [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Ofman, Leon, E-mail: weiliu@lmsal.com [Department of Physics, Catholic University of America, Washingtom, DC 20064 (United States)
2012-07-01T23:59:59.000Z
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.
Inhibitory coupling specifically generates emergent gamma oscillations in diverse cell types
Huguenard, John R.
phase-locked action potentials during gamma oscillations in entorhinal cortex slices (11). However3). Isolated networks of FS cells generate emergent gamma oscillations in response to tonic excitation at particular phases of gamma oscillations and or intrinsically oscillate at gamma frequencies and may
Wavelength-doubling optical parametric oscillator
Armstrong, Darrell J. (Albuquerque, NM); Smith, Arlee V. (Albuquerque, NM)
2007-07-24T23:59:59.000Z
A wavelength-doubling optical parametric oscillator (OPO) comprising a type II nonlinear optical medium for generating a pair of degenerate waves at twice a pump wavelength and a plurality of mirrors for rotating the polarization of one wave by 90 degrees to produce a wavelength-doubled beam with an increased output energy by coupling both of the degenerate waves out of the OPO cavity through the same output coupler following polarization rotation of one of the degenerate waves.
PHYSICS CURRICULUM PH 101: Introductory Physics I -Mechanics, oscillations and waves (2:1)
Srinivasan, N.
:1) Temperature, The First Law of Thermodynamics, Kinetic Theory of Gases and Maxwell -Boltzmann Statistics, Heat and Charged Particles, Momentum and Angular Momentum, Two Body Central Force Problems, Collision Theory, Small Oscillations, Coupled Oscillators and Normal Modes, Continuum Mechanics of solids and fluids
Tian, H.; DeLuca, E.; Reeves, K. K.; McKillop, S.; Golub, L.; Saar, S.; Testa, P.; Weber, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); De Pontieu, B.; Martínez-Sykora, J.; Kleint, L.; Cheung, M.; Lemen, J.; Title, A.; Boerner, P.; Hurlburt, N.; Tarbell, T. D.; Wuelser, J. P. [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street, Org. ADBS, Bldg. 252, Palo Alto, CA 94304 (United States); Carlsson, M.; Hansteen, V., E-mail: hui.tian@cfa.harvard.edu [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway); and others
2014-05-10T23:59:59.000Z
We present the first results of sunspot oscillations from observations by the Interface Region Imaging Spectrograph. The strongly nonlinear oscillation is identified in both the slit-jaw images and the spectra of several emission lines formed in the transition region and chromosphere. We first apply a single Gaussian fit to the profiles of the Mg II 2796.35 Å, C II 1335.71 Å, and Si IV 1393.76 Å lines in the sunspot. The intensity change is ?30%. The Doppler shift oscillation reveals a sawtooth pattern with an amplitude of ?10 km s{sup –1} in Si IV. The Si IV oscillation lags those of C II and Mg II by ?6 and ?25 s, respectively. The line width suddenly increases as the Doppler shift changes from redshift to blueshift. However, we demonstrate that this increase is caused by the superposition of two emission components. We then perform detailed analysis of the line profiles at a few selected locations on the slit. The temporal evolution of the line core is dominated by the following behavior: a rapid excursion to the blue side, accompanied by an intensity increase, followed by a linear decrease of the velocity to the red side. The maximum intensity slightly lags the maximum blueshift in Si IV, whereas the intensity enhancement slightly precedes the maximum blueshift in Mg II. We find a positive correlation between the maximum velocity and deceleration, a result that is consistent with numerical simulations of upward propagating magnetoacoustic shock waves.
Biswanath Rath
2015-02-27T23:59:59.000Z
We notice that PT symmetric non-Hermitian one dimensional simple Harmonic Oscillator under simultaneous transformation of co-ordinate and momentum with proper selection of wave function can also reflect real negative energy eigen spectra provided the associated wave function is well behaved, square integrable and normalised to unity. PACS: 03.65Db, 11.30.Pb, 11.30.Er, 03.65-w Key words: P T symmetry, Non-Hermitian Harmonic oscillator, Negative energy, wave function, simultaneous transformation, co-ordinate, momentum. Perturbation theory.
A continuous-wave second harmonic gyrotron oscillator at 460 GHz
Hornstein, Melissa K. (Melissa Kristen), 1977-
2005-01-01T23:59:59.000Z
We report the short pulse and CW operation of a 460 GHz gyrotron oscillator both at the fundamental (near 230 GHz) and second harmonic (near 460 GHz) of electron cyclotron resonance. During operation in a complete CW regime ...
Wu, Ping; Deng, Yuqun [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Fan, Juping; Teng, Yan; Shi, Yanchao; Sun, Jun [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)
2014-10-15T23:59:59.000Z
This paper presents an efficient approach to realizing the frequency tunability of a relativistic backward wave oscillator (RBWO) over three frequency bands by mode transition without changing the slow wave structure (SWS). It is figured out that the transition of the operation mode in the RBWO can be efficiently achieved by using the strong end reflection of the SWS. This mode transition results in the tunability of the RBWO over three frequency bands at high power and high efficiency without changing the SWS. In numerical simulation, the output frequency of the RBWO can jump over 7.9?GHz in C-band, 9.9?GHz in X-band, and 12.4?GHz in Ku-band with output power exceeding 3.0?GW and conversion efficiency higher than 35% by just reasonably transforming the structures of the front and post resonant reflectors which provide the strong end reflection for the SWS.
Banerjee, Pratyay; Basu-Mallick, B. [Theory Group, Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700 064 (India)
2011-05-15T23:59:59.000Z
We solve the eigenvalue problem of the D{sub N}-type of Calogero model by mapping it to a set of decoupled quantum harmonic oscillators through a similarity transformation. In particular, we construct the eigenfunctions of this Calogero model from those of bosonic harmonic oscillators having either all even parity or all odd parity. It turns out that the eigenfunctions of this model are orthogonal with respect to a nontrivial inner product, which can be derived from the quasi-Hermiticity property of the corresponding conserved quantities.
D. Martinez; J. C. Flores-Urbina; R. D. Mota; V. D. Granados
2010-05-21T23:59:59.000Z
We apply the Schr\\"odinger factorization to construct the ladder operators for hydrogen atom, Mie-type potential, harmonic oscillator and pseudo-harmonic oscillator in arbitrary dimensions. By generalizing these operators we show that the dynamical algebra for these problems is the $su(1,1)$ Lie algebra.
Maity, Chandan; Chakrabarti, Nikhil [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Sengupta, Sudip [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
2012-10-15T23:59:59.000Z
In a fluid description, we study space-time evolution of lower hybrid modes in a cold quasi-neutral homogeneous plasma in presence of a background inhomogeneous magnetic field. Within a linear analysis, a dispersion relation with inhomogeneous magnetic field shows 'phase mixing' of such oscillations. A manifestation of 'phase mixing' is shown in 'mode coupling.' By using Lagrangian variables, an exact solution is presented in parametric form of this nonlinear time dependent problem. It is demonstrated that initially excited lower hybrid modes always break via phase mixing phenomenon in presence of an inhomogeneous magnetic field. Breaking of such oscillations is revealed by the appearance of spikes in the plasma density profile.
Model of Thalamocortical Slow-Wave Sleep Oscillations and Transitions to Activated States
Bazhenov, Maxim
) in nonanesthetized cats, silent (down) states alternate with active (up) states; the down states are absent during of SWS oscillation activated the persistent sodium current and depolarized the membrane of cortical py- ramidal (PY) cells sufficiently for spike generation. In the model, this triggered the active phase, which
Yacob Ben-Aryeh
2008-07-29T23:59:59.000Z
The general theory of time-dependent frequency and time-dependent mass ('effective mass') is described.The general theory for time-dependent harmonic- oscillator is applied in the present research for studying certain quantum effects in the interferometers for detecting gravitational waves.When an astronomical binary system approaches its point of coalescence the gravitational wave intensity and frequency are increasing and this can lead to strong deviations from the simple description of harmonic-oscillations for the interferometric masses on which the mirrors are placed.It is shown that under such condtions the harmonic-oscillations of these masses can be described by mechanical harmonic-oscillators with time-dependent frequency and effective-mass. In the present theoretical model the effective-mass is decreasing with time describing pumping phenomena in which the oscillator amplitude is increasing with time . The quantization of this system is analyzed by the use of the adiabatic approximation. It is found that the increase of the gravitational wave intensity, within the adiabatic approximation, leads to squeezing phenomena where the quantum noise in one quadrature is increased and in the other quadrature is decreased.
Copping, Andrea E.; Geerlofs, Simon H.; Hanna, Luke A.
2013-09-30T23:59:59.000Z
Responsible deployment of marine and hydrokinetic (MHK) devices in estuaries, coastal areas, and major rivers requires that biological resources and ecosystems be protected through siting and permitting (consenting) processes. Scoping appropriate deployment locations, collecting pre-installation (baseline) and post-installation data all add to the cost of developing MHK projects, and hence to the cost of energy. Under the direction of the U.S. Department of Energy, Pacific Northwest National Laboratory scientists have developed logic models that describe studies and processes for environmental siting and permitting. Each study and environmental permitting process has been assigned a cost derived from existing and proposed tidal, wave, and riverine MHK projects, as well as expert opinion of marine environmental research professionals. Cost estimates have been developed at the pilot and commercial scale. The reference model described in this document is an oscillating water column device deployed in Northern California at approximately 50 meters water depth.
Excitation of non-radial stellar oscillations by gravitational waves: a first model
D. M. Siegel; M. Roth
2010-10-17T23:59:59.000Z
The excitation of solar and solar-like g modes in non-relativistic stars by arbitrary external gravitational wave fields is studied starting from the full field equations of general relativity. We develop a formalism that yields the mean-square amplitudes and surface velocities of global normal modes excited in such a way. The isotropic elastic sphere model of a star is adopted to demonstrate this formalism and for calculative simplicity. It is shown that gravitational waves solely couple to quadrupolar spheroidal eigenmodes and that normal modes are only sensitive to the spherical component of the gravitational waves having the same azimuthal order. The mean-square amplitudes in case of stationary external gravitational waves are given by a simple expression, a product of a factor depending on the resonant properties of the star and the power spectral density of the gravitational waves' spherical accelerations. Both mean-square amplitudes and surface velocities show a characteristic R^8-dependence (effective R^2-dependence) on the radius of the star. This finding increases the relevance of this excitation mechanism in case of stars larger than the Sun.
Fast Traveling-Wave Reactor of the Channel Type
Vitaliy D. Rusov; Victor A. Tarasov; Volodymyr N. Vashchenko; Sergei A. Chernezhenko; Andrei A. Kakaev; Oksana I. Pantak
2015-04-06T23:59:59.000Z
The main aim of this paper is to solve the technological problems of the TWR based on the technical concept described in our priority of invention reference, which makes it impossible, in particular, for the fuel claddings damaging doses of fast neutrons to excess the ~200 dpa limit. Thus the essence of the technical concept is to provide a given neutron flux at the fuel claddings by setting the appropriate speed of the fuel motion relative to the nuclear burning wave. The basic design of the fast uranium-plutonium nuclear traveling-wave reactor with a softened neutron spectrum is developed, which solves the problem of the radiation resistance of the fuel claddings material.
Fast Traveling-Wave Reactor of the Channel Type
Rusov, Vitaliy D; Vashchenko, Volodymyr N; Chernezhenko, Sergei A; Kakaev, Andrei A; Pantak, Oksana I
2015-01-01T23:59:59.000Z
The main aim of this paper is to solve the technological problems of the TWR based on the technical concept described in our priority of invention reference, which makes it impossible, in particular, for the fuel claddings damaging doses of fast neutrons to excess the ~200 dpa limit. Thus the essence of the technical concept is to provide a given neutron flux at the fuel claddings by setting the appropriate speed of the fuel motion relative to the nuclear burning wave. The basic design of the fast uranium-plutonium nuclear traveling-wave reactor with a softened neutron spectrum is developed, which solves the problem of the radiation resistance of the fuel claddings material.
Relations for a periodic array of flap-type wave energy converters
Renzi, Emiliano
2012-01-01T23:59:59.000Z
This paper investigates the interaction of plane incident waves with a wave farm in the open ocean. The farm consists of a periodic array of large flap-type wave energy converters. A linear inviscid potential-flow model, already developed by the authors for a single flap in a channel, is considered. Asymptotic analysis of the wave field allows to obtain new expressions of the reflection, transmission and radiation coefficients of the system. It is shown that, unlike a line of heaving buoys, an array of flap-type converters is able to exploit resonance of the system transverse modes in order to attain high capture factor levels. Relations between the hydrodynamic coefficients are derived and applied for optimising the power output of the wave farm.
Novel type of chimera spiral waves arising from decoupling of a diffusible component
Tang, Xiaodong; Yang, Tao; Liu, Yang; Zhao, Yuemin; Gao, Qingyu, E-mail: epstein@brandeis.edu, E-mail: gaoqy@cumt.edu.cn [College of Chemical Engineering, China University of Mining and Technology, Xuzhou 221008 (China); Epstein, Irving R., E-mail: epstein@brandeis.edu, E-mail: gaoqy@cumt.edu.cn [Department of Chemistry and Volen Center for Complex Systems, MS 015, Brandeis University, Waltham, Massachusetts 02454-9110 (United States)
2014-07-14T23:59:59.000Z
Spiral waves composed of coherent traveling waves surrounding a core containing stochastically distributed stationary areas are found in numerical simulations of a three-variable reaction-diffusion system with one diffusible species. In the spiral core, diffusion of this component (w) mediates transitions between dynamic states of the subsystem formed by the other two components, whose dynamics is more rapid than that of w. Diffusive coupling between adjacent sites can be “on” or “off” depending on the subsystem state. The incoherent structures in the spiral core are produced by this decoupling of the slow diffusive component from the fast non-diffusing subsystem. The phase diagram reveals that the region of incoherent behavior in chimera spirals grows drastically, leading to modulation and breakup of the spirals, in the transition zones between 1{sup n-1} and 1{sup n} local mixed-mode oscillations.
Kinematics of ICMEs/shocks: blast wave reconstruction using type II emissions
Corona-Romero, P; Aguilar-Rodriguez, E; de-la-Luz, V; Mejia-Ambriz, J C
2015-01-01T23:59:59.000Z
We present a physical methodology to reconstruct the trajectory of interplanetary shocks using type II radio emission data. This technique calculates the shock trajectory assuming that the disturbance propagates as a blast wave in the interplanetary medium. We applied this Blast Wave Reconstruction (BWR) technique to analyze eight fast Earth-directed ICMEs/shocks associated with type II emissions. The technique deduces a shock trajectory that reproduces the type II frequency drifts, and calculates shock onset speed, shock transit time and shock speed at 1~AU. There were good agreements comparing the BWR results with the type II spectra, with data from coronagraph images, {\\it in situ} measurements, and interplanetary scintillation (IPS) observations. Perturbations on the type II data affect the accuracy of the BWR technique. This methodology could be applied to track interplanetary shocks causing TII emissions in real-time, to predict the shock arrival time and shock speed at 1~AU.
Pani, Paolo [Dipartimento di Fisica, Universita di Cagliari, and INFN sezione di Cagliari, Cittadella Universitaria 09042 Monserrato (Italy); Berti, Emanuele [Department of Physics and Astronomy, The University of Mississippi, University, Mississippi 38677-1848 (United States); Theoretical Astrophysics 350-17, California Institute of Technology, Pasadena, California 91125 (United States); Cardoso, Vitor [Department of Physics and Astronomy, The University of Mississippi, University, Mississippi 38677-1848 (United States); Centro Multidisciplinar de Astrofisica - CENTRA, Departamento de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Chen Yanbei; Norte, Richard [Theoretical Astrophysics 350-17, California Institute of Technology, Pasadena, California 91125 (United States)
2009-12-15T23:59:59.000Z
Gravitational waves from compact objects provide information about their structure, probing deep into strong-gravity regions. Here we illustrate how the presence or absence of an event horizon can produce qualitative differences in the gravitational waves emitted by ultracompact objects. In order to set up a straw-man ultracompact object with no event horizon, but which is otherwise almost identical to a black hole, we consider a nonrotating thin-shell model inspired by Mazur and Mottola's gravastar, which has a Schwarzschild exterior, a de Sitter interior and an infinitely thin shell with finite tension separating the two regions. As viewed from the external space-time, the shell can be located arbitrarily close to the Schwarzschild radius, so a gravastar might seem indistinguishable from a black hole when tests are only performed on its external metric. We study the linearized dynamics of the system, and, in particular, the junction conditions connecting internal and external gravitational perturbations. As a first application of the formalism we compute polar and axial oscillation modes of a thin-shell gravastar. We show that the quasinormal mode spectrum is completely different from that of a black hole, even in the limit when the surface redshift becomes infinite. Polar quasinormal modes depend on the equation of state of matter on the shell and can be used to distinguish between different gravastar models. Our calculations suggest that low-compactness gravastars could be unstable when the sound speed on the shell v{sub s}/c > or approx. 0.92.
Reginald T Cahill
2013-12-02T23:59:59.000Z
Amaldi et al. in 1981 reported two key discoveries from the Frascati and Rome gravitational wave cryogenic bar detectors: (a) Rome events delayed by within a few seconds to tens of seconds from the Frascati events, and (b) the Frascati Fourier-analysed data frequency peaks being the same as the earth oscillation frequencies from seismology. The time delay effects have been dismissed as being inconsistent with gravitational waves having speed c. However using data from zener diode quantum detectors, from Perth and London, for January 1-3, 2013, we report the same effects, and in excellent agreement with the Amaldi results. The time delay effects appear to be gravitational wave reverberations, recently observed, and for gravitational wave speeds of some 500km/s, as detected in numerous experiments. We conclude that the Amaldi et al. discoveries were very significant.
Tian, Hui; Wang, Tongjiang; Ofman, Leon; De Pontieu, Bart; Innes, Davina E; Peter, Hardi
2012-01-01T23:59:59.000Z
Using data obtained by the EUV Imaging Spectrometer (EIS) onboard Hinode, we have per- formed a survey of obvious and persistent (without significant damping) Doppler shift oscillations in the corona. We have found mainly two types of oscillations from February to April in 2007. One type is found at loop footpoint regions, with a dominant period around 10 minutes. They are characterized by coherent behavior of all line parameters (line intensity, Doppler shift, line width and profile asymmetry), apparent blue shift and blueward asymmetry throughout almost the en- tire duration. Such oscillations are likely to be signatures of quasi-periodic upflows (small-scale jets, or coronal counterpart of type-II spicules), which may play an important role in the supply of mass and energy to the hot corona. The other type of oscillation is usually associated with the upper part of loops. They are most clearly seen in the Doppler shift of coronal lines with forma- tion temperatures between one and two million degrees. The ...
Magnetoatmospheric oscillations in sunspot umbrae
Hasan, S.S. (Indian Institute of Astrophysics, Bangalore (India))
1991-01-01T23:59:59.000Z
The nature of umbral oscillations is investigated using an empirical model for the sunspot umbra, based on the model of Maltby et al. (1986). Approximating the sunspot as a thick flux tube of circular cross section, the axisymmetric normal modes of magnetoatmospheric waves were determined, and a diagnostic diagram was generated for different field strengths. The diagram shows the existence of avoided crossings in the solution of magnetoatmospheric modes in a sunspot atmosphere. It was found that, for low values of the radial wavenumber k, corresponding to observed oscillations, a simple global classification is not possible. The oscillations in the low photosphere and below are of either fast or mixed type, but tend to acquire a slow or acoustic character above the temperature minimum. 61 refs.
Zhang, Hua; Shu, Ting, E-mail: mrtingshu@qq.com; Ju, Jinchuan; Wu, Dapeng; Bai, Zhen [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)
2014-08-15T23:59:59.000Z
We present the analysis and suppression of asymmetric modes in a Ku-band Cerenkov-type oscillator numerically and experimentally. The asymmetric modes generated in the initial experiments were identified to be HE{sub 11}, HE{sub 21}, and HE{sub 31} modes, respectively, by analyzing of the dispersion relationships, the simulation results and the experiment phenomenon. The factors, such as the cathode emission uniformity, the diode voltage, guiding magnetic field, and the concentricity play key roles in the excitation and suppression of these asymmetric modes. In the improved experiments, the asymmetric modes were suppressed effectively. In the improved experiments the asymmetric modes are suppressed effectively, and the designed TM{sub 01} mode microwave is generated at a frequency of 13.76 GHz with a power of 1.1 GW, which is in good agreement with numerically predications.
The giant star of the symbiotic system YY Her: Rotation, Tidal wave, Solar-type cycle and Spots
Liliana Formiggini; Elia M. Leibowitz
2006-09-17T23:59:59.000Z
We analyze the historical light curve of the symbiotic star YY Her, from 1890 up to December 2005. A secular declining trend is detected, at a rate of ~.01 magn in 1000 d, suggesting that the system could belong to the sub-class of symbiotic novae. Several outburst events are superposed on this slow decline. Three independent periodicities are identified in the light curve. A quasi-periodicity of 4650.7 d is detected for the outburst occurrence. We suggest that it is a signature of a solar-type magnetic dynamo cycle in the giant component. A period of 593.2 d modulates the quiescent light curve and it is identified as the binary period of the system. During outburst events the system shows a stable periodic oscillation of 551.4 d. We suggest that it is the rotation period of the giant.The secondary minima detected at some epochs of quiescence are probably due to dark spots on the surface of the rotating giant. The difference between the frequencies of these two last periods is the frequency of a tidal wave in the outer layers of the giant. A period which is a beat between the magnetic cycle and the tidal wave period is also apparent in the light curve. YY Her is a third symbiotic system exhibiting these cycles in their light curve, suggesting that a magnetic dynamo process is prevalent in the giant components of symbiotic stars, playing an important role in the outburst mechanism of some of these systems.
Development and performance evaluation of an electromagnetic-type shock wave generator for lipolysis
Liang, S. M., E-mail: liangsm@cc.feu.edu.tw; Yang, Z. Y. [Department of Industrial Design, Far East University, No. 49, Zhonghua Road, Xinshi District, Tainan City 744, Taiwan (China)] [Department of Industrial Design, Far East University, No. 49, Zhonghua Road, Xinshi District, Tainan City 744, Taiwan (China); Chang, M. H. [Department of Aeronautics and Astronautics, National Cheng Kung University, No. 1, University Road, East District, Tainan City 701, Taiwan (China)] [Department of Aeronautics and Astronautics, National Cheng Kung University, No. 1, University Road, East District, Tainan City 701, Taiwan (China)
2014-01-15T23:59:59.000Z
This study aims at the design and development of electromagnetic-type intermittent shock wave generation in a liquid. The shock wave generated is focused at a focal point through an acoustic lens. This hardware device mainly consists of a full-wave bridge rectifier, 6 capacitors, a spark gap, and a flat coil. A metal disk is mounted in a liquid-filled tube and is placed in close proximity to the flat coil. Due to the repulsive force existing between the coil and disk shock waves are generated, while an eddy current is induced in the metal disk. Some components and materials associated with the device are also described. By increasing the capacitance content to enhance electric energy level, a highly focused pressure can be achieved at the focal point through an acoustic lens in order to lyse fat tissue. Focused pressures were measured at the focal point and its vicinity for different operation voltages. The designed shock wave generator with an energy intensity of 0.0016 mJ/mm{sup 2} (at 4 kV) and 2000 firings or higher energy intensities with 1000 firings is found to be able to disrupt pig fat tissue.
J. H. Field
2005-03-02T23:59:59.000Z
Feynman's laws of quantum dynamics are concisely stated, discussed in comparison with other formulations of quantum mechanics and applied to selected problems in the physical optics of photons and massive particles as well as flavour oscillations. The classical wave theory of light is derived from these laws for the case in which temporal variation of path amplitudes may be neglected, whereas specific experiments, sensitive to the temporal properties of path amplitudes, are suggested. The reflection coefficient of light from the surface of a transparent medium is found to be markedly different to that predicted by the classical Fresnel formula. Except for neutrino oscillations, good agreement is otherwise found with previous calculations of spatially dependent quantum interference effects.
Reflection type of terahertz imaging system using a high-T{sub c} superconducting oscillator
Kashiwagi, T.; Minami, H.; Kadowaki, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Nakade, K.; Saiwai, Y.; Kitamura, T.; Watanabe, C.; Ishida, K.; Sekimoto, S.; Asanuma, K.; Yasui, T.; Shibano, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Markovi?, B.; Mirkovi?, J. [Faculty of Sciences, University of Montenegro, George Washington Str., 81000 Podgorica (Montenegro); Tsujimoto, M. [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Yamamoto, T. [National Institute for Materials Science, Wide Bandgap Materials Group, Optical and Electronic Materials Unit, Environment and Energy Materials Division, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)
2014-01-13T23:59:59.000Z
A reflection type of imaging system is shown at sub-terahertz frequencies generated from high-T{sub c} superconducting intrinsic Josephson junction mesa structures fabricated by single crystalline Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+?} to demonstrate how the sub-terahertz imaging technique using monochromatic radiation is powerful and unique for the variety of practical applications. Several examples are discussed in detail and are compared to other terahertz imaging systems.
Quantum Mechanics of Neutrino Oscillations
C. Giunti; C. W. Kim
2000-11-06T23:59:59.000Z
We present a simple but general treatment of neutrino oscillations in the framework of quantum mechanics using plane waves and intuitive wave packet principles when necessary. We attempt to clarify some confusing statements that have recently appeared in the literature.
Neutrino Oscillations and Cosmology
A. D. Dolgov
2000-04-04T23:59:59.000Z
Phenomenology of neutrino oscillations in vacuum and in cosmological plasma is considered. Neutrino oscillations in vacuum are usually described in plane wave approximation. In this formalism there is an ambiguity if one should assume $\\delta p =0$ and correspondingly $\\delta E\
Secret of Neutrino Oscillations
Dmitry Zhuridov
2012-03-08T23:59:59.000Z
The new effect of partial and full destruction of the neutrino oscillation pattern due to the neutrino wave packets separation in the transverse plane to the direction of the neutrino propagation is investigated. It is shown that this effect is significant in the real oscillation data, in particular, for the solar neutrinos, and dramatically changes the extracted physical properties of neutrinos.
Acoustic wave front reversal in a three-phase media
N. I. Pushkina
2015-03-05T23:59:59.000Z
Acoustic wave front conjugation is studied in a sandy marine sediment that contains air bubbles in its fluid fraction. The considered phase conjugation is a four-wave nonlinear parametric sound interaction process caused by nonlinear bubble oscillations which are known to be dominant in acoustic nonlinear interactions in three-phase marine sediments. Two various mechanisms of phase conjugation are studied. One of them is based on the stimulated Raman-type sound scattering on resonance bubble oscillations. The second one is associated with sound interactions with bubble oscillations which frequencies are far from resonance bubble frequencies. Nonlinear equations to solve the wave-front conjugation problem are derived, expressions for acoustic wave amplitudes with a reversed wave front are obtained and compared for various frequencies of the excited bubble oscillations.
Acoustic wave front conjugation in a three-phase media
Pushkina, N I
2015-01-01T23:59:59.000Z
Acoustic wave front reversal is studied in a sandy marine sediment that contains air bubbles in its fluid fraction. The considered phase conjugation is a four-wave nonlinear parametric sound interaction process caused by nonlinear bubble oscillations which are known to be dominant in acoustic nonlinear interactions in three-phase marine sediments. Two various mechanisms of phase conjugation are studied. One of them is based on the stimulated Raman-type sound scattering on resonance bubble oscillations. The second one is associated with sound interactions with bubble oscillations which frequencies are far from resonance bubble frequencies. Nonlinear equations to solve the wave-front conjugation problem are derived, expressions for acoustic wave amplitudes with a reversed wave front are obtained and compared for various frequencies of the excited bubble oscillations.
Gravitational waves emitted by solar-type stars excited by orbiting planets
Emanuele Berti; Valeria Ferrari
2000-11-30T23:59:59.000Z
The possibility of exciting the g-modes of a solar-type star as a consequence of the gravitational interaction with a close companion (a planet or a brown dwarf) is studied by a perturbative approach. The amplitude of the emitted gravitational wave is computed and compared with the quadrupole emission of the system, showing that in some cases it can be considerably larger. The effects of radiation reaction are considered to evaluate the timescale of the emission process, and a Roche lobe analysis is used to establish the region where the companion can orbit without being disrupted by tidal interactions with the star.
Potter, B.M.
1980-05-13T23:59:59.000Z
An alien liquid detector employs a monitoring element and an oscillatory electronic circuit for maintaining the temperature of the monitoring element substantially above ambient temperature. The output wave form, eg., frequency of oscillation or wave shape, of the oscillatory circuit depends upon the temperaturedependent electrical characteristic of the monitoring element. A predetermined change in the output waveform allows water to be discriminated from another liquid, eg., oil. Features of the invention employing two thermistors in two oscillatory circuits include positioning one thermistor for contact with water and the other thermistor above the oil-water interface to detect a layer of oil if present. Unique oscillatory circuit arrangements are shown that achieve effective thermistor action with an economy of parts and energizing power. These include an operational amplifier employed in an astable multivibrator circuit, a discrete transistor-powered tank circuit, and use of an integrated circuit chip.
Dynamics of a horizontal cylinder oscillating as a wave energy converter about an off-centred axis.
Lucas, Jorge
2011-11-22T23:59:59.000Z
The hydrodynamic properties of a horizontal cylinder which is free to pitch about an off-centred axis are studied and used to derive the equations of motion of a wave energy converter which extracts energy from incoming ...
Acoustic waves in a Biot-type porous snow model: The fast slow wave in light snow
Sidler, Rolf
2015-01-01T23:59:59.000Z
Wave velocities, attenuation and reflection coefficients in snow can not be explained by the widely used elastic or viscoelastic models for wave propagation. Instead, Biot's model of wave propagation in porous materials should be used. However, the application of Biot's model is difficult due to the large property space of the underlying porous material. Here we use the properties of ice and air as well as empirical relationships to define the properties of snow as a function of porosity. This reduction allows to predict phase velocities and attenuation of the shear- and compressional-waves as functions of porosity or density. For light snow the peculiarity was found that the velocity of the compressional wave of the first kind is lower than the compressional wave of the second kind that is commonly referred to as the "slow" wave. The reversal of the velocities comes with an increase of attenuation for the first compressional wave. This is in line with the common observation that sound is strongly absorbed af...
Phenomenology of Neutrino Oscillations
S. M. Bilenky; C. Giunti; W. Grimus
1999-06-04T23:59:59.000Z
This review is focused on neutrino mixing and neutrino oscillations in the light of the recent experimental developments. After discussing possible types of neutrino mixing for Dirac and Majorana neutrinos and considering in detail the phenomenology of neutrino oscillations in vacuum and matter, we review all existing evidence and indications in favour of neutrino oscillations that have been obtained in the atmospheric, solar and LSND experiments. We present the results of the analyses of the neutrino oscillation data in the framework of mixing of three and four massive neutrinos and investigate possibilities to test the different neutrino mass and mixing schemes obtained in this way. We also discuss briefly future neutrino oscillation experiments.
Quantum Noise in Differential-type Gravitational-wave Interferometer and Signal Recycling
Atsushi Nishizawa; Seiji Kawamura; Masa-aki Sakagami
2007-06-03T23:59:59.000Z
There exists the standard quantum limit (SQL), derived from Heisenberg's uncertainty relation, in the sensitivity of laser interferometer gravitational-wave detectors. However, in the context of a full quantum-mechanical approach, SQL can be overcome using the correlation of shot noise and radiation-pressure noise. So far, signal recycling, which is one of the methods to overcome SQL, is considered only in a recombined-type interferometer such as Advanced-LIGO, LCGT, and GEO600. In this paper, we investigated quantum noise and the possibility of signal recycling in a differential-type interferometer. As a result, we found that signal recycling is possible and creates at most three dips in the sensitivity curve of the detector. Then, taking advantage of the third additional dip and comparing the sensitivity of a differential-type interferometer with that of a next-generation Japanese GW interferometer, LCGT, we found that SNR of inspiral binary is improved by a factor of 1.43 for neutron star binary, 2.28 for 50 M_sun black hole binary, and 2.94 for 100 M_sun black hole binary. We also found that power recycling to increase laser power is possible in our signal-recycling configuration of a detector.
LaCure, Mari Mae
2010-04-29T23:59:59.000Z
Waves is the supporting document to the Master of Fine Arts thesis exhibition of the same title. Exhibited March 7-12 2010 in the Art and Design Gallery at the University of Kansas, Waves was comprised of a series of mixed media drawings...
Epstein, Irving R.
Wave propagation in a FitzHugh-Nagumo-type model with modified excitability E. P. Zemskov1 I. INTRODUCTION Wave propagation and pattern formation in a variety of excitable media can-Lecar equations for neuronal activity. We obtain exact analytic solutions in the form of traveling waves using
Sandia National Laboratories: Floating Oscillating Water Column
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
This model has ... Joint Sandia-DOE-HMRC Testing of a Floating Oscillating Water Column Wave Energy Converter Device On November 11, 2013, in Energy, News, News & Events,...
Boris V. Gisin
2014-05-13T23:59:59.000Z
The Dirac equation, in the field of a traveling circularly polarized electromagnetic wave and a constant magnetic field, has singular solutions, corresponding the expansion of energy in vicinity of some singular point. These solutions described relativistic fermions. States relating to these solutions are not stationary. The temporal change of average energy, momentum and spin for single and mixed states is studied in the paper. A distinctive feature of the states is the disappearance of the longitudinal component of the average spin. Another feature is the equivalence of the condition of fermion minimal energy and the classical condition of the magnetic resonance. Finding such solutions assumes the use of a transformation for rotating and co-moving frames of references. Comparison studies of solutions obtained with the Galilean and non-Galilean transformation shown that some parameters of the non-Galilean transformation may be measured in high-energy physics.
Epstein, Irving R.
Novel type of chimera spiral waves arising from decoupling of a diffusible component Xiaodong Tang (2014) Novel type of chimera spiral waves arising from decoupling of a diffusible component Xiaodong in chimera spirals grows drastically, leading to modulation and breakup of the spirals, in the transition
The Phase of Neutrino Oscillations
C. Giunti
2002-02-07T23:59:59.000Z
Using an analogy with the well-known double-slit experiment, we show that the standard phase of neutrino oscillations is correct, refuting recent claims of a factor of two correction. We also improve the wave packet treatment of neutrino oscillations taking into account explicitly the finite coherence time of the detection process.
LSND neutrino oscillation results
Louis, W.C.
1996-06-01T23:59:59.000Z
In the past several years, a number of experiments have searched for neutrino oscillations, where a neutrino of one type (say {bar {nu}}{sub {mu}}) spontaneously transforms into a neutrino of another type (say {bar {nu}}{sub e}). For this phenomenon to occur, neutrinos must be massive and the apparent conservation law of lepton families must be violated. In 1995 the LSND experiment published data showing candidate events that are consistent with {bar {nu}}{sub {mu}} oscillations. Additional data are reported here which provide stronger evidence for neutrino oscillations.
Weijgaert, Rien van de
;14/03/2014 6 H L H L L Phase & Group Velocity #12;14/03/2014 7 Doppler Effect #12;14/03/2014 8 Shock Waves #12;14/03/2014 14 Supernova Remnant Cassiopeia A Supernova blast waves #12;14/03/2014 15 Tycho's Remnant (SN 1572AD A SNR flythrough Theory of Supernova Blast Waves Supernovae: Type Ia Subsonic deflagration wave turning
On zero-point energy, stability and Hagedorn behavior of Type IIB strings on pp-waves
F. Bigazzi; A. L. Cotrone
2003-09-09T23:59:59.000Z
Type IIB strings on many pp-wave backgrounds, supported either by 5-form or 3-form fluxes, have negative light-cone zero-point energy. This raises the question of their stability and poses possible problems in the definition of their thermodynamic properties. After having pointed out the correct way of calculating the zero-point energy, an issue not fully discussed in literature, we show that these Type IIB strings are classically stable and have well defined thermal properties, exhibiting a Hagedorn behavior.
Houze Jr., Robert A.
1 Precipitation Hydrometeor Type Relative to the Mesoscale Airflow in Oceanic Deep located relative to mesoscale air motions Heavy rain and riming occur downstream of mesoscale Abstract Composite analysis of near-equatorial oceanic mesoscale convective systems (MCSs
A 76GHz PLL for mm-wave imaging applications
Nguyen, Khoa M.
A 76 GHz phase-locked loop (PLL) was designed in 0.13 ?m IBM BiCMOS8HP technology with the intended application of millimeter-wave imaging. The PLL has a type II second order loop filter. The voltage-controlled oscillator ...
Ilya Mandel; Carl-Johan Haster; Michal Dominik; Krzysztof Belczynski
2015-05-04T23:59:59.000Z
We analyze the distinguishability of populations of coalescing binary neutron stars, neutron-star black-hole binaries, and binary black holes, whose gravitational-wave signatures are expected to be observed by the advanced network of ground-based interferometers LIGO and Virgo. We consider population-synthesis predictions for plausible merging binary distributions in mass space, along with measurement accuracy estimates from the main gravitational-wave parameter-estimation pipeline. We find that for our model compact-object binary mass distribution, we can always distinguish binary neutron stars and black-hole--neutron-star binaries, but not necessarily black-hole--neutron-star binaries and binary black holes; however, with a few tens of detections, we can accurately identify the three subpopulations and measure their respective rates.
Torsional oscillations of longitudinally inhomogeneous coronal loops
T. V. Zaqarashvili; K Murawski
2007-04-03T23:59:59.000Z
We explore the effect of an inhomogeneous mass density field on frequencies and wave profiles of torsional Alfven oscillations in solar coronal loops. Dispersion relations for torsional oscillations are derived analytically in limits of weak and strong inhomogeneities. These analytical results are verified by numerical solutions, which are valid for a wide range of inhomogeneity strength. It is shown that the inhomogeneous mass density field leads to the reduction of a wave frequency of torsional oscillations, in comparison to that of estimated from mass density at the loop apex. This frequency reduction results from the decrease of an average Alfven speed as far as the inhomogeneous loop is denser at its footpoints. The derived dispersion relations and wave profiles are important for potential observations of torsional oscillations which result in periodic variations of spectral line widths. Torsional oscillations offer an additional powerful tool for a development of coronal seismology.
SPECTROSCOPIC OBSERVATIONS OF A CORONAL MORETON WAVE
Harra, Louise K. [UCL-Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey, RH5 6NT (United Kingdom); Sterling, Alphonse C. [Space Science Office, VP62, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Goemoery, Peter [Astronomical Institute, Slovak Academy of Sciences, SK-05960 Tatranska Lomnica (Slovakia); Veronig, Astrid, E-mail: lkh@mssl.ucl.ac.uk, E-mail: alphonse.sterling@nasa.gov, E-mail: gomory@astro.s, E-mail: astrid.veronig@uni-graz.at [Institute of Physics, University of Graz, Universitaetsplatz 5, A-8010 Graz (Austria)
2011-08-10T23:59:59.000Z
We observed a coronal wave (EIT wave) on 2011 February 16, using EUV imaging data from the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA) and EUV spectral data from the Hinode/EUV Imaging Spectrometer (EIS). The wave accompanied an M1.6 flare that produced a surge and a coronal mass ejection (CME). EIS data of the wave show a prominent redshifted signature indicating line-of-sight velocities of {approx}20 km s{sup -1} or greater. Following the main redshifted wave front, there is a low-velocity period (and perhaps slightly blueshifted), followed by a second redshift somewhat weaker than the first; this progression may be due to oscillations of the EUV atmosphere set in motion by the initial wave front, although alternative explanations may be possible. Along the direction of the EIS slit the wave front's velocity was {approx}500 km s{sup -1}, consistent with its apparent propagation velocity projected against the solar disk as measured in the AIA images, and the second redshifted feature had propagation velocities between {approx}200 and 500 km s{sup -1}. These findings are consistent with the observed wave being generated by the outgoing CME, as in the scenario for the classic Moreton wave. This type of detailed spectral study of coronal waves has hitherto been a challenge, but is now possible due to the availability of concurrent AIA and EIS data.
Coherent states for the nonlinear harmonic oscillator
Ghosh, Subir [Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 B. T. Road, Kolkata 700108 (India)
2012-06-15T23:59:59.000Z
Wave packets for the quantum nonlinear oscillator are considered in the generalized coherent state framework. To first order in the nonlinearity parameter the coherent state behaves very similar to its classical counterpart. The position expectation value oscillates in a simple harmonic manner. The energy-momentum uncertainty relation is time independent as in a harmonic oscillator. Various features (such as the squeezed state nature) of the coherent state have been discussed.
Gitsevich, Aleksandr (Montgomery Village, MD)
2001-01-01T23:59:59.000Z
An oscillator includes an amplifier having an input and an output, and an impedance transformation network connected between the input of the amplifier and the output of the amplifier, wherein the impedance transformation network is configured to provide suitable positive feedback from the output of the amplifier to the input of the amplifier to initiate and sustain an oscillating condition, and wherein the impedance transformation network is configured to protect the input of the amplifier from a destructive feedback signal. One example of the oscillator is a single active element device capable of providing over 70 watts of power at over 70% efficiency. Various control circuits may be employed to match the driving frequency of the oscillator to a plurality of tuning states of the lamp.
Neutrino optics and oscillations in gravitational fields
G. Lambiase; G. Papini; R. Punzi; G. Scarpetta
2005-03-07T23:59:59.000Z
We study the propagation of neutrinos in gravitational fields using wave functions that are exact to first order in the metric deviation. For illustrative purposes, the geometrical background is represented by the Lense-Thirring metric. We derive explicit expressions for neutrino deflection, helicity transitions, flavor oscillations and oscillation Hamiltonian.
Dirac oscillators and the relativistic R matrix
J. Grineviciute; Dean Halderson
2014-04-17T23:59:59.000Z
The Dirac oscillators are shown to be an excellent expansion basis for solutions of the Dirac equation by $R$-matrix techniques. The combination of the Dirac oscillator and the $R$-matrix approach provides a convenient formalism for reactions as well as bound state problems. The utility of the $R$-matrix approach is demonstrated in relativistic impulse approximation calculations where exchange terms can be calculated exactly, and scattering waves made orthogonal to bound state wave functions.
Autoresonant Excitation of Diocotron Waves
Wurtele, Jonathan
of the wave, the pump and the wave will phase lock at very low wave amplitude. When the pump reachesAutoresonant Excitation of Diocotron Waves J. Fajans E. Gilson U.C. Berkeley L. Friedland Hebrew of phase with the oscillator, and the os- cillator's amplitude will decrease, eventually reaching zero
Moreton Waves and EIT Waves Related to the Flare Events of June 3, 2012 and July 6, 2012
Admiranto, A G; Yus'an, U; Puspitaningrum, E
2015-01-01T23:59:59.000Z
We present geometrical and kinematical analysis of Moreton waves and EIT waves observed on June 3, 2012 and Moreton waves observed on July 6, 2012. The Moreton waves were recorded in H$\\alpha$ images of Global Oscillation Network Group (GONG) archive and EIT waves obtained from SDO/AIA observations, especially in 193 nm channel. The observed wave of June 3 has angular span of about $70^{\\circ}$ with a broad wave front associated to NOAA active region 11496. It was found that the speed of the wave that started propagating at 17.53 UT is between 950 to 1500 km/s. Related to this wave occurrence, there was solar type II and III radio bursts. The speed of the EIT in this respect about 247 km/sec. On the other hand, the wave of July 6 may be associated to X1.1 class flare that occurred at 23.01 UT around the 11514 active region. From the kinematical analysis, the wave propagated with the initial velocity of about 1180 km/s which is in agreement with coronal shock velocity derived from type II radio burst observati...
Ebrahimi, V.; Esfandyari-Kalejahi, A. [Department of Physics, Faculty of Sciences, Azarbaijan Shahid Madani University, 53714-161 Tabriz (Iran, Islamic Republic of)
2014-09-15T23:59:59.000Z
In this paper, first we represent the differences between spatial and temporal dispersions and their dependence on the measurement techniques for electrostatic waves in unmagnetized collisionless plasma. Then, three different experimental data are compared to the solutions of exact nonextensive dispersion relations for electron-ion and pair plasma. The results confirm the existence of new acoustic plasma waves. Furthermore, these comparisons yield a Maxwellian and a nonextensive plasma with nonextensive parameter q larger than one, and a Maxwellian plasma with some abnormal dispersion properties.
>300GHz Fixed-Frequency and Voltage-Controlled Fundamental Oscillators in an InP DHBT Process
Rodwell, Mark J. W.
>300GHz Fixed-Frequency and Voltage-Controlled Fundamental Oscillators in an InP DHBT Process, 93106, USA Abstract -- We report fundamental fixed-frequency and voltage-controlled oscillators bandwidth. Index Terms -- Millimeter-wave oscillators, voltage-controlled oscillators, MMIC oscillators. I
Secondary dust density waves excited by nonlinear dust acoustic waves
Heinrich, J. R.; Kim, S.-H.; Meyer, J. K.; Merlino, R. L. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States); Rosenberg, M. [Department of Electrical and Computer Engineering, University of California, San Diego, California 92093 (United States)
2012-08-15T23:59:59.000Z
Secondary dust density waves were observed in conjunction with high amplitude (n{sub d}/n{sub d0}>2) dust acoustic waves (DAW) that were spontaneously excited in a dc glow discharge dusty plasma in the moderately coupled, {Gamma}{approx}1, state. The high amplitude dust acoustic waves produced large dust particle oscillations, displacements, and trapping. Secondary dust density waves were excited in the wave troughs of the high amplitude DAWs. The waveforms, amplitudes, wavelengths, and wave speeds of the primary DAWs and the secondary waves were measured. A dust-dust streaming instability is discussed as a possible mechanism for the production of the secondary waves.
Kashiwagi, T., E-mail: kashiwagi@ims.tsukuba.ac.jp; Minami, H.; Kadowaki, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Nakade, K.; Saiwai, Y.; Kitamura, T.; Watanabe, C.; Ishida, K.; Sekimoto, S.; Asanuma, K.; Yasui, T.; Shibano, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Tsujimoto, M. [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Yamamoto, T. [Wide Bandgap Materials Group, Optical and Electronic Materials Unit, Environment and Energy Materials Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Markovi?, B. [Faculty of Sciences, University of Montenegro, George Washington Str., 81000 Podgorica (Montenegro); Mirkovi?, J. [Faculty of Science, University of Montenegro, and CETI, Put Radomira Ivanovica, 81000 Podgorica (Montenegro); Klemm, R. A. [Department of Physics, University of Central Florida, 4000 Central Florida Blvd., Orlando, Florida 32816-2385 (United States)
2014-02-24T23:59:59.000Z
A computed tomography (CT) imaging system using monochromatic sub-terahertz coherent electromagnetic waves generated from a device constructed from the intrinsic Josephson junctions in a single crystalline mesa structure of the high-T{sub c} superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+?} was developed and tested on three samples: Standing metallic rods supported by styrofoam, a dried plant (heart pea) containing seeds, and a plastic doll inside an egg shell. The images obtained strongly suggest that this CT imaging system may be useful for a variety of practical applications.
Magnetically insulated transmission line oscillator
Bacon, Larry D. (Albuquerque, NM); Ballard, William P. (Albuquerque, NM); Clark, M. Collins (Albuquerque, NM); Marder, Barry M. (Albuquerque, NM)
1988-01-01T23:59:59.000Z
A magnetically insulated transmission line oscillator employs self-generated magnetic fields to generate microwave energy. An anode of the oscillator includes slow-wave structures which are formed of a plurality of thin conductive vanes defining cavities therebetween, and a gap is formed between the anode and a cathode of the oscillator. In response to a pulsed voltage applied to the anode and cathode, self-generated magnetic fields arfe produced in a cross-field orientation with respect to the orientation of the electric field between the anode and the cathode. The cross-field magnetic fields insulate the flow of electrons in the gap and confine the flow of electrons within the gap.
Jin and Zhang 1 PARAMICS SIMULATION OF PERIODIC OSCILLATIONS CAUSED BY
Mease, Kenneth D.
and global. Finally, consistencies between a macroscopic kinematic wave model and Paramics are discussed-based kinematic wave model, the mechanism of such oscillations is revealed as follows: (i) When two traffic and Zhang 2 ABSTRACT Traffic oscillations such as stop-and-go waves in a traffic system can be caused
Dust-Acoustic Waves: Visible Sound Waves Robert L. Merlino
Merlino, Robert L.
Dust-Acoustic Waves: Visible Sound Waves Robert L. Merlino Department of Physics and Astronomy with their announcement that: "We find that a new type of sound wave, namely, the dust-acoustic waves, can appear" [1 and experimental work on dust acoustic waves is given. The basic physics of the dust acoustic wave and some
Angular momentum extraction by gravity waves in the Sun
Suzanne Talon; Pawan Kumar; Jean-Paul Zahn
2002-06-27T23:59:59.000Z
We review the behavior of the oscillating shear layer produced by gravity waves below the surface convection zone of the Sun. We show that, under asymmetric filtering produced by this layer, gravity waves of low spherical order, which are stochastically excited at the base of the convection zone of late type stars, can extract angular momentum from their radiative interior. The time-scale for this momentum extraction in a Sun-like star is of the order of 10^7 years. The process is particularly efficient in the central region, and it could produce there a slowly rotating core.
Chiral oscillations in terms of the zitterbewegung effect
Alex E. Bernardini
2014-10-22T23:59:59.000Z
We seek the {\\em immediate} description of chiral oscillations in terms of the trembling motion described by the velocity (Dirac) operator {\\boldmath$\\alpha$}. By taking into account the complete set of Dirac equation solutions which results in a free propagating Dirac wave packet composed by positive and negative frequency components, we report about the well-established {\\em zitterbewegung} results and indicate how chiral oscillations can be expressed in terms of the well know quantum oscillating variables. We conclude with the interpretation of chiral oscillations as position very rapid oscillation projections onto the longitudinally decomposed direction of the motion.
Shalaby, M.; Khaled, M. A. [Department of Physics, Faculty of Science, Ain Shams University, Cairo, 11566 (Egypt); EL-Labany, S. K.; EL-Shamy, E. F. [Department of Physics, Faculty of Science, Mansoura University, Damietta Branch, Damietta El-Gedida 34517 (Egypt)
2010-11-15T23:59:59.000Z
The nonlinear propagation of dust ion-acoustic solitary waves (DIASWs) in a magnetized dusty plasma which consists of two different types of nonisothermal electrons, hot adiabatic inertial ions fluid and immobile negatively charged dust particles is studied. The modified Zakharov-Kuznetsov (MZK) equation, describing the small but finite amplitude DIASWs, is derived using a reductive perturbation method. The combined effects of the external magnetic field, obliqueness (i.e., the propagation angle), and the two-temperature nonisothermal electrons, which are found to significantly modify the basic properties of DIASWs, are explicitly examined. The three-dimensional instability of DIASWs is also analyzed using the small-k (long wavelength plane wave) perturbation expansion technique. The results show that the external magnetic field, the propagation angle, and the two-temperature nonisothermal electrons have strong effects on the instability criterion as well as the growth rate.
attached non-linear oscillators: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
for a finite number of oscillators confirm this and, when alpha <0, show the propagation of waves, reminiscent of metachronal coordination. M. Leoni; T. B. Liverpool...
Antoine, Xavier - Institut de MathÃ©matiques Ã?lie Cartan, UniversitÃ© Henri PoincarÃ©
Keywords: Acoustic scattering Finite element Plane wave Pollution High-frequency Artificial boundary condition in acoustic scattering R. Kechroud a , A. Soulaimani a , X. Antoine b,c,* a Ã?cole de Technologie are found. Indeed, it is well known that pollution effects [10Â12] arise in the standard FEM, limiting its
Umbral oscillations as a probe of sunspot
Abdelatif, T.E.H.
1985-01-01T23:59:59.000Z
The interaction of the solar five-minute oscillations with a sunspot is thoroughly explored, both on observational and theoretical grounds. Simple theoretical models are developed in order to understand the observations of umbral oscillations. Observations made at the National Solar Observatory detected both the three-minute and five-minute umbral oscillations at photospheric heights. The three-minute oscillations were found to have a kinetic energy density six times higher in the photosphere than in the chromosphere and to be concentrated in the central part of the umbra, supporting the photospheric resonance theory for the three-minute umbral oscillations. The five-minute oscillations are attenuated in the umbra, which appears to act as a filter in selecting some of the peaks in the power spectrum of five-minute oscillations in the surrounding photosphere. The k-omega power spectrum of the umbral oscillations shows a shift of power to longer wavelengths. Theoretical models of the transmission of acoustic waves into a magnetic region explain both observed effects.
Nobukawa, Hisashi; Kitamura, Mitsuru [Hiroshima Univ., Higashi-Hiroshima (Japan); Swilem, S.A.M. [Univ. of Alexandria (Egypt); Ishibashi, Kozo [Marine Technology Inst. Co., Ltd., Imari (Japan)
1994-12-31T23:59:59.000Z
The concept of a system for extracting uranium from seawater utilizing sea current and wave power is presented in this paper. The uranium absorption tests using model bed units whose size is 1/4 of the real absorbent system were carried out based on the concept design of the system. The model units are towed in the seawater with the velocity of about 2 knots for 30 hours. After the towing, the units were moored for 36 days in Imari Bay. Another absorption test, hanging the model bed units from a mooring ship in an open sea, was performed for 40 hours for assessing the effect of wave power in the uranium absorption. Based on the data obtained from the above tests, the production cost of uranium extraction was also calculated. It becomes about 34,000 yen/kg-uranium for extraction period of 60 days.
Propagating waves mediate information transfer in the motor cortex
Hatsopoulos, Nicholas
Propagating waves mediate information transfer in the motor cortex Doug Rubino1, Kay A Robbins2-delay reaching task, we found that these oscillations propagated as waves across the surface of the motor cortex oscillations propagated as waves across the primary motor (MI) and premotor (PMd) cortices as monkeys planned
Influence of flavor oscillations on neutrino beam instabilities
Mendonça, J. T., E-mail: titomend@ist.utl.pt [Instituto de Física, Universidade de São Paulo, 05508-090 São Paulo SP (Brazil); Haas, F. [Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre RS (Brazil); Bret, A. [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain and Instituto de Investigaciones Energeticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain)
2014-09-15T23:59:59.000Z
We consider the collective neutrino plasma interactions and study the electron plasma instabilities produced by a nearly mono-energetic neutrino beam in a plasma. We describe the mutual interaction between neutrino flavor oscillations and electron plasma waves. We show that the neutrino flavor oscillations are not only perturbed by electron plasmas waves but also contribute to the dispersion relation and the growth rates of neutrino beam instabilities.
Influence of flavor oscillations on neutrino beam instabilities
Mendonça, José Tito; Bret, Antoine
2014-01-01T23:59:59.000Z
We consider the collective neutrino plasma interactions, and study the electron plasma instabilities produced by a nearly mono-energetic neutrino beam in a plasma. We describe the mutual influence of neutrino flavor oscillations and electron plasma waves. We show that the neutrino flavor oscillations are not only perturbed by electron plasmas waves, but also contribute to the dispersion relation and the growth rates of neutrino beam instabilities.
alfven wave resonances: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
2 Resonant energy conversion of 3-minute intensity oscillations into Alfven waves in the solar atmosphere Astrophysics (arXiv) Summary: Nonlinear coupling between 3-minute...
One-way, real time wave front converters
Kwong, S.; Yariv, A.
1986-03-03T23:59:59.000Z
Optical one-way, real time wave front cleanup by means of photorefractively pumped oscillators is reported. A factor of 4000 increase in beam brightness has been achieved.
Holographic Charge Oscillations
Mike Blake; Aristomenis Donos; David Tong
2014-12-05T23:59:59.000Z
The Reissner-Nordstrom black hole provides the prototypical description of a holographic system at finite density. We study the response of this system to the presence of a local, charged impurity. Below a critical temperature, the induced charge density, which screens the impurity, exhibits oscillations. These oscillations can be traced to the singularities in the density-density correlation function moving in the complex momentum plane. At finite temperature, the oscillations are very similar to the Friedel oscillations seen in Fermi liquids. However, at zero temperature the oscillations in the black hole background remain exponentially damped, while Friedel oscillations relax to a power-law
Pota, Himanshu Roy
Voltage Oscillations in Power Distribution Networks in the Presence of DFIGs and Induction Motor of oscillation between the electromechanical and subsynchronous oscillations of power systems. Time for the types of oscillations that occur in distribution systems. Finally, significant parameters of the system
Pulsar kicks from neutrino oscillations
Alexander Kusenko
2004-09-27T23:59:59.000Z
Neutrino oscillations in a core-collapse supernova may be responsible for the observed rapid motions of pulsars. Given the present bounds on the neutrino masses, the pulsar kicks require a sterile neutrino with mass 2-20 keV and a small mixing with active neutrinos. The same particle can be the cosmological dark matter. Its existence can be confirmed the by the X-ray telescopes if they detect a 1-10 keV photon line from the decays of the relic sterile neutrinos. In addition, one may be able to detect gravity waves from a pulsar being accelerated by neutrinos in the event of a nearby supernova.
Quasi-Periodic Oscillations from Magnetorotational Turbulence
Phil Arras; Omer Blaes; Neal J. Turner
2006-02-13T23:59:59.000Z
Quasi-periodic oscillations (QPOs) in the X-ray lightcurves of accreting neutron star and black hole binaries have been widely interpreted as being due to standing wave modes in accretion disks. These disks are thought to be highly turbulent due to the magnetorotational instability (MRI). We study wave excitation by MRI turbulence in the shearing box geometry. We demonstrate that axisymmetric sound waves and radial epicyclic motions driven by MRI turbulence give rise to narrow, distinct peaks in the temporal power spectrum. Inertial waves, on the other hand, do not give rise to distinct peaks which rise significantly above the continuum noise spectrum set by MRI turbulence, even when the fluid motions are projected onto the eigenfunctions of the modes. This is a serious problem for QPO models based on inertial waves.
V. N. Zirakashvili; F. Aharonian
2007-10-26T23:59:59.000Z
%context {Recent observations of hard X-rays and very high energy gamma-rays from a number of young shell type supernova remnants indicate the importance of detailed quantitative studies of energy spectra of relativistic electrons formed via diffusive shock acceleration accompanied by intense nonthermal emission through synchrotron radiation and inverse Compton scattering.} %aim {The aim of this work was derivation of exact asymptotic solutions of the kinetic equation which describes the energy distribution of shock-accelerated electrons for an arbitrary energy-dependence of the diffusion coefficient.} %method {The asymptotic solutions at low and very high energy domains coupled with numerical calculations in the intermediate energy range allow analytical presentations of energy spectra of electrons for the entire energy region.} %results {Under the assumption that the energy losses of electrons are dominated by synchrotron cooling, we derived the exact asymptotic spectra of electrons without any restriction on the diffusion coefficient. We also obtained simple analytical approximations which describe, with accuracy better than ten percent, the energy spectra of nonthermal emission of shock-accelerated electrons due to the synchrotron radiation and inverse Compton scattering.} %conclusions {The results can be applied for interpretation of X-ray and gamma-ray observations of shell type supernova remnants, as well as other nonthermal high energy source populations like microquasars and large scale synchrotron jets of active galactic nuclei.
Non-linear Langmuir waves in a warm quantum plasma
Dubinov, Alexander E., E-mail: dubinov-ae@yandex.ru; Kitaev, Ilya N. [Russian Federal Nuclear Center—All-Russia Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), 37 Mira Ave., Nizhny Novgorod region, Sarov 607188 (Russian Federation); Sarov State Institute of Physics and Technology (SarFTI), National Research Nuclear University MEPhI, 607186 Sarov, Nizhny Novgorod region (Russian Federation)
2014-10-15T23:59:59.000Z
A non-linear differential equation describing the Langmuir waves in a warm quantum electron-ion plasma has been derived. Its numerical solutions of the equation show that ordinary electronic oscillations, similar to the classical oscillations, occur along with small-scale quantum Langmuir oscillations induced by the Bohm quantum force.
Mercier, Matthieu J; Mathur, Manikandan; Gostiaux, Louis; Peacock, Thomas; Dauxois, Thierry
2015-01-01T23:59:59.000Z
We present the results of a combined experimental and numerical study of the generation of internal waves using the novel internal wave generator design of Gostiaux et al. (2007). This mechanism, which involves a tunable source comprised of oscillating plates, has so far been used for a few fundamental studies of internal waves, but its full potential has yet to be realized. Our studies reveal that this approach is capable of producing a wide variety of two-dimensional wave fields, including plane waves, wave beams and discrete vertical modes in finite-depth stratifications. The effects of discretization by a finite number of plates, forcing amplitude and angle of propagation are investigated, and it is found that the method is remarkably efficient at generating a complete wave field despite forcing only one velocity component in a controllable manner. We furthermore find that the nature of the radiated wave field is well predicted using Fourier transforms of the spatial structure of the wave generator.
Longitudinal magnetohydrodynamics oscillations in dissipative, cooling coronal loops
Al-Ghafri, K. S.; Ruderman, M. S.; Williamson, A.; Erdélyi, R., E-mail: app08ksa@sheffield.ac.uk, E-mail: m.s.ruderman@sheffield.ac.uk, E-mail: app09aw@sheffield.ac.uk, E-mail: robertus@sheffield.ac.uk [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)
2014-05-01T23:59:59.000Z
This paper investigates the effect of cooling on standing slow magnetosonic waves in coronal magnetic loops. The damping mechanism taken into account is thermal conduction that is a viable candidate for dissipation of slow magnetosonic waves in coronal loops. In contrast to earlier studies, here we assume that the characteristic damping time due to thermal conduction is not small, but arbitrary, and can be of the order of the oscillation period, i.e., a temporally varying plasma is considered. The approximation of low-beta plasma enables us to neglect the magnetic field perturbation when studying longitudinal waves and consider, instead, a one-dimensional motion that allows a reliable first insight into the problem. The background plasma temperature is assumed to be decaying exponentially with time, with the characteristic cooling timescale much larger than the oscillation period. This assumption enables us to use the WKB method to study the evolution of the oscillation amplitude analytically. Using this method we obtain the equation governing the oscillation amplitude. The analytical expressions determining the wave properties are evaluated numerically to investigate the evolution of the oscillation frequency and amplitude with time. The results show that the oscillation period increases with time due to the effect of plasma cooling. The plasma cooling also amplifies the amplitude of oscillations in relatively cool coronal loops, whereas, for very hot coronal loop oscillations the damping rate is enhanced by the cooling. We find that the critical point for which the amplification becomes dominant over the damping is in the region of 4 MK. These theoretical results may serve as impetus for developing the tools of solar magneto-seismology in dynamic plasmas.
THE RESPONSE OF A THREE-DIMENSIONAL SOLAR ATMOSPHERE TO WAVE-DRIVEN JETS
Scullion, E. [Institute of Theoretical Astrophysics, University of Oslo (Norway); Erdelyi, R.; Fedun, V. [Solar Physics and Space Plasma Research Centre (SP2RC), Department of Applied Mathematics, University of Sheffield, Sheffield S3 7RH (United Kingdom); Doyle, J. G., E-mail: eamonms@astro.uio.no, E-mail: robertus@sheffield.ac.uk, E-mail: v.fedun@sheffield.ac.uk, E-mail: jgd@arm.ac.uk [Armagh Observatory, College Hill, Armagh BT61 9DG (United Kingdom)
2011-12-10T23:59:59.000Z
Global oscillations from the solar interior are, mainly, pressure-driven (p-modes) oscillations with a peak power of a five-minute period. These oscillations are considered to manifest in many phenomena in the lower solar atmosphere, most notably, in spicules. These small-scale jets may provide the key to understanding the powering mechanisms of the transition region (TR) and lower corona. Here, we simulate the formation of wave-driven (type-I) spicule phenomena in three dimensions and the transmission of acoustic waves from the lower chromosphere and into the corona. The outer atmosphere oscillates in response to the jet formation, and in turn, we reveal the formation of a circular seismic surface wave, which we name as a Transition Region Quake (TRQ). The TRQ forms as a consequence of an upward propelling spicular wave train that repeatedly punctures and energizes the TR. The steep density gradient enables the TRQ to develop and radially fan outward from the location where the spicular plasma column impinges the TR. We suggest the TRQ formation as a formidable mechanism in continuously sustaining part of the energy budget of the TR. We present a supporting numerical model which allow us to determine the level of energy dumping at the TR by upward-propagating p-modes. Upon applying a wavelet analysis on our simulations we identify the presence of a chromospheric cavity which resonates with the jet propagation and leaves behind an oscillatory wake with a distinctive periodicity. Through our numerical analysis we also discover type-I spicule turbulence leading to a convection-based motion in the low corona.
Neutrino oscillations: another physics?
S. N. Vergeles
2014-07-21T23:59:59.000Z
It is shown that the neutrino oscillations phenomenon may be attributed to the Wilson fermion doubling phenomenon. The Wilson fermion doubling exists only on the lattices, both periodic and non-periodic (simplicial complexes). Just the last case plays a key role here. Thereby, the neutrino oscillations may show for the existence of a space-time granularity.
Wessendorf, Kurt O. (Albuquerque, NM)
2001-01-01T23:59:59.000Z
An active bridge oscillator is formed from a differential amplifier where positive feedback is a function of the impedance of one of the gain elements and a relatively low value common emitter resistance. This use of the nonlinear transistor parameter h stabilizes the output and eliminates the need for ALC circuits common to other bridge oscillators.
Neutrino oscillations: another physics?
Vergeles, S N
2014-01-01T23:59:59.000Z
It is shown that the neutrino oscillations phenomenon may be attributed to the Wilson fermion doubling phenomenon. The Wilson fermion doubling exists only on the lattices, both periodic and non-periodic (simplicial complexes). Just the last case plays a key role here. Thereby, the neutrino oscillations may show for the existence of a space-time granularity.
Dwyer, D A
2015-01-01T23:59:59.000Z
A concise summary of the "Oscillation at low energies" parallel session at the 2014 Neutrino Oscillation Workshop is provided. Plans to use man-made neutrinos and antineutrinos to determine the neutrino mass hierarchy, search for sterile neutrinos, and to observe coherent neutrino-nucleus scattering were discussed. Potential measurements of solar neutrinos, supernova neutrinos, and geoneutrinos are also summarized.
Neutrino oscillations beyond two flavours
E. Kh. Akhmedov
2002-07-29T23:59:59.000Z
I review some theoretical aspects of neutrino oscillations in the case when more than two neutrino flavours are involved. These include: approximate analytic solutions for 3-flavour (3f) oscillations in matter; matter effects in nu_mu - nu_tau oscillations; 3f effects in oscillations of solar, atmospheric, reactor and supernova neutrinos and in accelerator long-baseline experiments; CP and T violation in neutrino oscillations in vacuum and in matter; the problem of U_{e3}; 4f oscillations.
The free energy cost of accurate biochemical oscillations
Cao, Yuansheng; Ouyang, Qi; Tu, Yuhai
2015-01-01T23:59:59.000Z
Oscillation is an important cellular process that regulates timing of different vital life cycles. However, in the noisy cellular environment, oscillations can be highly inaccurate due to phase fluctuations. It remains poorly understood how biochemical circuits suppress phase fluctuations and what is the incurred thermodynamic cost. Here, we study four different types of biochemical oscillations representing three basic oscillation motifs shared by all known oscillatory systems. We find that the phase diffusion constant follows the same inverse dependence on the free energy dissipation per period for all systems studied. This relationship between the phase diffusion and energy dissipation is shown analytically in a model of noisy oscillation. Microscopically, we find that the oscillation is driven by multiple irreversible cycles that hydrolyze the fuel molecules such as ATP; the number of phase coherent periods is proportional to the free energy consumed per period. Experimental evidence in support of this un...
Driven harmonic oscillator as a quantum simulator for open systems
Jyrki Piilo; Sabrina Maniscalco
2006-10-03T23:59:59.000Z
We show theoretically how a driven harmonic oscillator can be used as a quantum simulator for non-Markovian damped harmonic oscillator. In the general framework, the results demonstrate the possibility to use a closed system as a simulator for open quantum systems. The quantum simulator is based on sets of controlled drives of the closed harmonic oscillator with appropriately tailored electric field pulses. The non-Markovian dynamics of the damped harmonic oscillator is obtained by using the information about the spectral density of the open system when averaging over the drives of the closed oscillator. We consider single trapped ions as a specific physical implementation of the simulator, and we show how the simulator approach reveals new physical insight into the open system dynamics, e.g. the characteristic quantum mechanical non-Markovian oscillatory behavior of the energy of the damped oscillator, usually obtained by the non-Lindblad-type master equation, can have a simple semiclassical interpretation.
Possible new wave phenomena in the brain
Jerzy Szwed
2009-08-10T23:59:59.000Z
We propose to search for new wave phenomena in the brain by using interference effects in analogy to the well-known double slit (Young) experiment. This method is able to extend the range of oscillation frequencies to much higher values than currently accessible. It is argued that such experiments may test the hypothesis of the wave nature of information coding.
Non-linear numerical simulations of magneto-acoustic wave propagation in small-scale flux tubes
E. Khomenko; M. Collados; T. Felipe
2008-01-25T23:59:59.000Z
We present results of non-linear, 2D, numerical simulations of magneto-acoustic wave propagation in the photosphere and chromosphere of small-scale flux tubes with internal structure. Waves with realistic periods of three to five minutes are studied, after applying horizontal and vertical oscillatory perturbations to the equilibrium model. Spurious reflections of shock waves from the upper boundary are minimized thanks to a special boundary condition. This has allowed us to increase the duration of the simulations and to make it long enough to perform a statistical analysis of oscillations. The simulations show that deep horizontal motions of the flux tube generate a slow (magnetic) mode and a surface mode. These modes are efficiently transformed into a slow (acoustic) mode in the vA propagates vertically along the field lines, forms shocks and remains always within the flux tube. It might deposit effectively the energy of the driver into the chromosphere. When the driver oscillates with a high frequency, above the cut-off, non-linear wave propagation occurs with the same dominant driver period at all heights. At low frequencies, below the cut-off, the dominant period of oscillations changes with height from that of the driver in the photosphere to its first harmonic (half period) in the chromosphere. Depending on the period and on the type of the driver, different shock patterns are observed.
Yan, Jun
2012-07-16T23:59:59.000Z
design methodology of sinusoidal oscillator named digital-harmonic-cancellation (DHC) technique is presented. DHC technique is realized by summing up a set of square-wave signals with different phase shifts and different summing coefficient to cancel...
Microdomain calcium oscillations in Drosophila glia regulate seizure susceptibility and require NCKX
Melom, Jan E. (Jan Elizabeth)
2013-01-01T23:59:59.000Z
Glial cells exhibit spontaneous and activity-dependent fluctuations in intracellular Ca²+, yet it is unclear whether glial Ca²+ oscillations are required during neuronal signaling. Somatic glial Ca²+ waves are primarily ...
High frequency nanotube oscillator
Peng, Haibing (Houston, TX); Zettl, Alexander K. (Kensington, TX)
2012-02-21T23:59:59.000Z
A tunable nanostructure such as a nanotube is used to make an electromechanical oscillator. The mechanically oscillating nanotube can be provided with inertial clamps in the form of metal beads. The metal beads serve to clamp the nanotube so that the fundamental resonance frequency is in the microwave range, i.e., greater than at least 1 GHz, and up to 4 GHz and beyond. An electric current can be run through the nanotube to cause the metal beads to move along the nanotube and changing the length of the intervening nanotube segments. The oscillator can operate at ambient temperature and in air without significant loss of resonance quality. The nanotube is can be fabricated in a semiconductor style process and the device can be provided with source, drain, and gate electrodes, which may be connected to appropriate circuitry for driving and measuring the oscillation. Novel driving and measuring circuits are also disclosed.
Oscillating fluid power generator
Morris, David C
2014-02-25T23:59:59.000Z
A system and method for harvesting the kinetic energy of a fluid flow for power generation with a vertically oriented, aerodynamic wing structure comprising one or more airfoil elements pivotably attached to a mast. When activated by the moving fluid stream, the wing structure oscillates back and forth, generating lift first in one direction then in the opposite direction. This oscillating movement is converted to unidirectional rotational movement in order to provide motive power to an electricity generator. Unlike other oscillating devices, this device is designed to harvest the maximum aerodynamic lift forces available for a given oscillation cycle. Because the system is not subjected to the same intense forces and stresses as turbine systems, it can be constructed less expensively, reducing the cost of electricity generation. The system can be grouped in more compact clusters, be less evident in the landscape, and present reduced risk to avian species.
Neutrino oscillations: theory and phenomenology
E. Kh. Akhmedov
2006-10-05T23:59:59.000Z
A brief overview of selected topics in the theory and phenomenology of neutrino oscillations is given. These include: oscillations in vacuum and in matter; phenomenology of 3-flavour neutrino oscillations and effective 2-flavour approximations; CP and T violation in neutrino oscillations in vacuum and in matter; matter effects on \
Gravitationally Induced Neutrino-Oscillation Phases
D. V. Ahluwalia; C. Burgard
2004-01-22T23:59:59.000Z
In this essay, we introduce a new effect of gravitationally induced quantum mechanical phases in neutrino oscillations. These phases arise from an hitherto unexplored interplay of gravitation and the principle of the linear superposition of quantum mechanics. In the neighborhood of a 1.4 solar-mass neutron star, gravitationally induced quantum mechanical phases are roughly 20% of their kinematical counterparts. When this information is coupled with the mass square differences implied by the existing neutrino-oscillation data we find that the new effect may have profound consequences for type-II supernova evolution.
The impact of bubble diffusivity on confined oscillated bubbly liquid Sergey Shklyaev1
Straube, Arthur V.
their volume. In other words, in a liquid containing bubbles the speed of sound cb can b oscillations4,5 to the frequency of external driving. Here, k= /c0 is the wave number, c0 is the speed of soundThe impact of bubble diffusivity on confined oscillated bubbly liquid Sergey Shklyaev1 and Arthur V
Angular momentum and energy structure of the coherent state of a 2D isotropic harmonic oscillator
LIU Yufeng; HUO Wujun; ZENG Jinyan
1999-12-03T23:59:59.000Z
The angular momentum structure and energy structure of the coherent state of a 2D isotropic harmonic oscillator were investigated. Calculations showed that the average values of angular momentum and energy (except the zero point energy) of this nonspreading 2D wave packet are identical to those of the corresponding classical oscillator moving along a circular or an elliptic orbit.
Weak chimeras in minimal networks of coupled phase oscillators
Peter Ashwin; Oleksandr Burylko
2014-12-10T23:59:59.000Z
We suggest a definition for a type of chimera state that appears in networks of indistinguishable phase oscillators. Defining a "weak chimera" as a type of invariant set showing partial frequency synchronization, we show that this means they cannot appear in phase oscillator networks that are either globally coupled or too small. We exhibit various networks of four, six and ten indistinguishable oscillators where weak chimeras exist with various dynamics and stabilities. We examine the role of Kuramoto-Sakaguchi coupling in giving degenerate (neutrally stable) families of weak chimera states in these example networks.
Neutrino oscillations and supernovae
D. V. Ahluwalia-Khalilova
2004-04-02T23:59:59.000Z
In a 1996 JRO Fellowship Research Proposal (Los Alamos), the author suggested that neutrino oscillations may provide a powerful indirect energy transport mechanism to supernovae explosions. The principal aim of this addendum is to present the relevant unedited text of Section 1 of that proposal. We then briefly remind, (a) of an early suggestion of Mazurek on vacuum neutrino oscillations and their relevance to supernovae explosion, and (b) Wolfenstein's result on suppression of the effect by matter effects. We conclude that whether or not neutrino oscillations play a significant role in supernovae explosions shall depend if there are shells/regions of space in stellar collapse where matter effects play no essential role. Should such regions exist in actual astrophysical situations, the final outcome of neutrino oscillations on supernovae explosions shall depend, in part, on whether or not the LNSD signal is confirmed. Importantly, the reader is reminded that neutrino oscillations form a set of flavor-oscillation clocks and these clock suffer gravitational redshift which can be as large as 20 percent. This effect must be incorporated fully into any calculation of supernova explosion.
A Model of Intra-seasonal Oscillations in the Earth atmosphere
Elena Kartashova; Victor S. L'vov
2007-04-04T23:59:59.000Z
We suggest a way of rationalizing an intra-seasonal oscillations (IOs) of the Earth atmospheric flow as four meteorological relevant triads of interacting planetary waves, isolated from the system of all the rest planetary waves. Our model is independent of the topography (mountains, etc.) and gives a natural explanation of IOs both in the North and South Hemispheres. Spherical planetary waves are an example of a wave mesoscopic system obeying discrete resonances that also appears in other areas of physics.
Driven synchronization in random networks of oscillators
Jason Hindes; Christopher R. Myers
2015-02-28T23:59:59.000Z
Synchronization is a universal phenomenon found in many non-equilibrium systems. Much recent interest in this area has overlapped with the study of complex networks, where a major focus is determining how a system's connectivity patterns affect the types of behavior that it can produce. Thus far, modeling efforts have focused on the tendency of networks of oscillators to mutually synchronize themselves, with less emphasis on the effects of external driving. In this work we discuss the interplay between mutual and driven synchronization in networks of phase oscillators of the Kuramoto type, and resolve how the structure and emergence of such states depends on the underlying network topology for simple random networks with a given degree distribution. We provide a partial bifurcation analysis, centering on the appearance of a Takens-Bogdanov-Cusp singularity, which broadly separates homogeneous and heterogeneous network behavior in a weak coupling limit, and from which the number, stability and appearance of driven and mutually synchronized states can be determined, as a function of a few parameters. We find transitions such as Saddle-Node-Infinite-Periods, Limit-Point-of-Cycles, and Hopf bifurcations (both branches), as well as multiple bistability regions and dynamics that differ for the network types. This description is connected to the underlying dynamics of oscillator clusters for important states and transitions. Our results can provide a basis for studying the problem of frequency controlling disordered oscillator networks.
Kim, Seoktae
2006-04-12T23:59:59.000Z
New millimeter wave interferometric, multifunctional sensors have been studied for industrial sensing applications: displacement measurement, liquid-level gauging and velocimetry. Two types of configuration were investigated to implement the sensor...
-water' balance in a homogeneous fluid. The MASS conservation equation for a constant density fluid implies.1-7.6 (began last week), 10.4 (Kelvin waves) (similar material in Vallis Â§Â§ 2.8, 3.1, 3.6-3.8 Bretherton than a fraction of a wavelength. This is implicit in a scale analysis of the governing equation
Sunspot umbral oscillations in the photosphere and low chromosphere
Lites, B.W.; Thomas, J.H.
1985-07-15T23:59:59.000Z
Velocity oscillations in sunspot umbrae were measured simultaneously in two spectral lines, one formed in the low photosphere and the other formed in the low chromosphere, just above the temperature minimum. The power spectrum of velocity in each spectral line shows the presence of both 5 minute and 3 minute oscillations. The coherence spectrum and phase spectrum between the velocities in the two lines show that the 3 minute umbral oscillation has the character of a coherent, vertically standing wave in the photosphere. Also, the kinetic energy density of the 3 minute oscillation is found to be at least 5 times greater in the low photosphere than in the low chromosphere. These results indicate that the fundamental 3 minute umbral oscillation is caused by a photospheric resonance rather than a chromospheric resonance. Multiple peaks in the power spectrum of chromospheric velocity at periods near 3 minutes may be caused by the additional effect of a chromospheric resonance. The umbral 5 minute oscillations are coherent between the two heights, with a small, positive phase difference between the low photosphere and low chromosphere, much the same as in the quiet Sun. A negative phase difference at frequencies around 2 mHz suggests the presence of gravity waves in the umbra.
TIME-PERIODIC SOUND WAVE PROPAGATION COMPRESSIBLE EULER EQUATIONS
A PARADIGM FOR TIME-PERIODIC SOUND WAVE PROPAGATION IN THE COMPRESSIBLE EULER EQUATIONS BLAKE consistent with time-periodic sound wave propagation in the 3 Ã? 3 nonlinear compressible Euler equations description of shock-free waves that propagate through an oscillating entropy field without breaking or dis
Mandelis, Andreas
, oscillations of diffusing energy or particles. They have complex wave vectors and do not exhibit square), or an oscillating charge carrier density (such as a har- monically-photoexcited carrier plasma wave in a semicon it is absorbed by the medium. For thermal waves, there is usually no delay in the energy conversion process, so F
Aero-Acoustic Analysis of Wells Turbine for Ocean Wave Energy Conversion
Frandsen, Jannette B.
Aero-Acoustic Analysis of Wells Turbine for Ocean Wave Energy Conversion Ralf Starzmann Fluid of harnessing the energy from ocean waves is the oscillating water column (OWC) device. The OWC converts
Experimental studies of the hydrodynamic characteristics of a sloped wave energy device
Lin, Chia-Po
2000-07-19T23:59:59.000Z
Many wave energy convertors are designed to use either vertical (heave) or horizontal (surge) movements of waves. But the frequency response of small heaving buoys and oscillating water column devices shows that they are ...
Wave VelocityWave Velocity Diff t f ti l l itDifferent from particle velocity
Yoo, S. J. Ben
Wave VelocityWave Velocity v=/T =f Diff t f ti l l itDifferent from particle velocity Depends on the medium in which the wave travelsDepends on the medium in which the wave travels stringaonvelocity F v of Waves11-8. Types of Waves Transverse wave Longitudinal wave Liu UCD Phy1B 2014 37 #12;Sound Wave
Kinematic dynamo induced by helical waves
Wei, Xing
2014-01-01T23:59:59.000Z
We investigate numerically the kinematic dynamo induced by the superposition of two helical waves in a periodic box as a simplified model to understand the dynamo action in astronomical bodies. The effects of magnetic Reynolds number, wavenumber and wave frequency on the dynamo action are studied. It is found that this helical-wave dynamo is a slow dynamo. There exists an optimal wavenumber for the dynamo growth rate. A lower wave frequency facilitates the dynamo action and the oscillations of magnetic energy emerge at some particular wave frequencies.
Kayser, Boris
2012-06-01T23:59:59.000Z
To complement the neutrino-physics lectures given at the 2011 International School on Astro Particle Physics devoted to Neutrino Physics and Astrophysics (ISAPP 2011; Varenna, Italy), at the 2011 European School of High Energy Physics (ESHEP 2011; Cheila Gradistei, Romania), and, in modified form, at other summer schools, we present here a written description of the physics of neutrino oscillation. This description is centered on a new way of deriving the oscillation probability. We also provide a brief guide to references relevant to topics other than neutrino oscillation that were covered in the lectures. Neutrinos and photons are by far the most abundant elementary particles in the universe. Thus, if we would like to comprehend the universe, we must understand the neutrinos. Of course, studying the neutrinos is challenging, since the only known forces through which these electrically-neutral leptons interact are the weak force and gravity. Consequently, interactions of neutrinos in a detector are very rare events, so that very large detectors and intense neutrino sources are needed to make experiments feasible. Nevertheless, we have confirmed that the weak interactions of neutrinos are correctly described by the Standard Model (SM) of elementary particle physics. Moreover, in the last 14 years, we have discovered that neutrinos have nonzero masses, and that leptons mix. These discoveries have been based on the observation that neutrinos can change from one 'flavor' to another - the phenomenon known as neutrino oscillation. We shall explain the physics of neutrino oscillation, deriving the probability of oscillation in a new way. We shall also provide a very brief guide to references that can be used to study some major neutrino-physics topics other than neutrino oscillation.
Karney, Charles
is an envelope solitary wave. These solitary waves are not solitons. The occurrence of the constant phase pulses-state propagation of one of the two lower hybrid rays in a homogeneous considering the balance between thermal break up into two types of solitary waves, constant phase pulses or envelope pulses. e examine
Parke, Stephen J.; /Fermilab
2011-07-01T23:59:59.000Z
Starting in the late 1960s, neutrino detectors began to see signs that neutrinos, now known to come in the flavors electron ({nu}{sub e}), muon ({nu}{sub {mu}}), and tau ({nu}{sub {tau}}), could transform from one flavor to another. The findings implied that neutrinos must have mass, since massless particles travel at the speed of light and their clocks, so to speak, don't tick, thus they cannot change. What has since been discovered is that neutrinos oscillate at two distinct scales, 500 km/GeV and 15,000 km/GeV, which are defined by the baseline (L) of the experiment (the distance the neutrino travels) divided by the neutrino energy (E). Neutrinos of one flavor can oscillate into neutrinos of another flavor at both L/E scales, but the amplitude of these oscillations is different for the two scales and depends on the initial and final flavor of the neutrinos. The neutrino states that propogate unchanged in time, the mass eigenstates {nu}1, {nu}2, {nu}3, are quantum mechanical mixtures of the electron, muon, and tau neutrino flavors, and the fraction of each flavor in a given mass eigenstate is controlled by three mixing angles and a complex phase. Two of these mixing angles are known with reasonable precision. An upper bound exists for the third angle, called {theta}{sub 13}, which controls the size of the muon neutrino to electron neutrino oscillation at an L/E of 500 km/GeV. The phase is completely unknown. The existence of this phase has important implications for the asymmetry between matter and antimatter we observe in the universe today. Experiments around the world have steadily assembled this picture of neutrino oscillation, but evidence of muon neutrino to electron neutrino oscillation at 500 km/GeV has remained elusive. Now, a paper from the T2K (Tokai to Kamioka) experiment in Japan, reports the first possible observation of muon neutrinos oscillating into electron neutrinos at 500 km/GeV. They see 6 candidate signal events, above an expected background of 1.5 events. The probability that the 6 events are all background is only about 0.7%. Stated differently, this is a 2.7{sigma} indication that the parameter that controls the oscillation, the neutrino mixing angle {theta}{sub 13}, is nonzero, just shy of the 3{sigma} requirement to claim 'evidence for.' Nevertheless, this experiment provides the strongest indication to date that this oscillation actually occurs in nature.
Cycloidal Wave Energy Converter
Stefan G. Siegel, Ph.D.
2012-11-30T23:59:59.000Z
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 exceed this initial performance estimates. In advancing the Technology Readiness Level (TRL) of this type of wave energy converter from 3 to 4, we find the CycWEC to exceed our initial estimates in terms of hydrodynamic performance. Once fully developed and optimized, it has the potential to not just outperform all other WEC technologies, but to also deliver power at a lower LCOE than competing conventional renewables like wind and solar. Given the large wave power resource both domestically and internationally, this technology has the potential to lead to a large improvement in our ability to produce clean electricity at affordable cost.
SLOW MAGNETOACOUSTIC OSCILLATIONS IN THE MICROWAVE EMISSION OF SOLAR FLARES
Kim, S.; Shibasaki, K. [Nobeyama Solar Radio Observatory/NAOJ, Nagano 384-1305 (Japan); Nakariakov, V. M., E-mail: sjkim@nro.nao.ac.jp [Physics Department, University of Warwick, Coventry, CV4 7AL (United Kingdom)
2012-09-10T23:59:59.000Z
Analysis of the microwave data, obtained in the 17 GHz channel of the Nobeyama Radioheliograph during the M1.6 flare on 2010 November 4, revealed the presence of 12.6 minute oscillations of the emitting plasma density. The oscillations decayed with the characteristic time of about 15 minutes. Similar oscillations with the period of about 13.8 minutes and the decay time of 25 minutes are also detected in the variation of EUV emission intensity measured in the 335 A channel of the Solar Dynamics Observatory/Atmospheric Imaging Assembly. The observed properties of the oscillations are consistent with the oscillations of hot loops observed by the Solar and Heliospheric Observatory/Solar Ultraviolet Measurement of Emitted Radiation (SUMER) in the EUV spectra in the form of periodic Doppler shift. Our analysis presents the first direct observations of the slow magnetoacoustic oscillations in the microwave emission of a solar flare, complementing accepted interpretations of SUMER hot loop oscillations as standing slow magnetoacoustic waves.
Sensitivity of DANSS detector to short range neutrino oscillations
Mikhail Danilov
2014-12-02T23:59:59.000Z
DANSS is a highly segmented $1m^3$ plastic scintillator detector. Its 2500 scintillator strips have a Gd loaded reflective cover. Light is collected with 3 wave length shifting fibers per strip and read out with 50 PMTs and 2500 SiPMs. The DANSS will be installed under the industrial 3GW$_{th}$ reactor of the Kalinin Nuclear Power Plant at distances varying from 9.7m to 12.2m from the reactor core. PMTs and SiPMs collect about 30 photo electrons per MeV distributed approximately equally between two types of the readout. Light collection non-uniformity across and along the strip is about $\\pm13\\%$ from maximum to minimum. The resulting energy resolution is modest, $\\sigma/E=15\\%$ at 5MeV. This leads to a smearing of the oscillation pattern comparable with the smearing due to the large size of the reactor core. Nevertheless because of the large counting rate ($\\sim 10000$ / day), small background ($<1\\%$) and good control of systematic uncertainties due to frequent changes of positions, the DANSS is quite sensitive to reactor antineutrino oscillations to hypothetical sterile neutrinos with a mass in eV ballpark suggested recently to explain a so-called "reactor anomaly". DANSS will have an elaborated calibration system. The high granularity of the detector allows calibration of every strip with about 40 thousand cosmic muons every day. The expected systematic effects do not reduce much the sensitivity region. Tests of the detector prototype DANSSino demonstrated that in spite of a small size ($4\\%$ of DANSS), it is quite sensitive to reactor antineutrinos, detecting about 70 Inverse Beta Decay events per day with the signal-to-background ratio of about unity. The prototype tests have demonstrated feasibility to reach the design performance of the DANSS detector.
Kinetics of Oscillating Neutrinos
P. Strack
2005-05-12T23:59:59.000Z
In the context of core-collapse supernovae, Strack and Burrows (Phys. Rev. D 71, 093004 (2005)) have recently developed an extension of the classical Boltzmann kinetic formalism that retains all the standard neutrino oscillation phenomenology, including resonant flavor conversion (the MSW effect), neutrino self-interactions, and the interplay between neutrino-matter coupling and flavor oscillations. In this thesis, I extend the Strack & Burrows formalism to incorporate general relativity, spin degrees of freedom, and a possible neutrino magnetic-moment/magnetic-field interaction.
Status of Neutrino Oscillations
J. W. F. Valle
2001-04-04T23:59:59.000Z
Solar and atmospheric neutrino data require physics beyond the Standard Model of particle physics. The simplest, most generic, but not yet unique, interpretation of the data is in terms of neutrino oscillations. I summarize the results of the latest three-neutrino oscillation global fit of the data, in particular the bounds on the angle $\\theta_{13}$ probed in reactor experiments. Even though not implied by the data, bi-maximal neutrino mixing emerges as an attractive possibility either in hierarchical or quasi-degenerate neutrino scenarios.
Seismic metamaterials based on isochronous mechanical oscillators
Finocchio, G., E-mail: gfinocchio@unime.it; Garescì, F.; Azzerboni, B. [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, C.da di Dio, I-98166 Messina (Italy); Casablanca, O.; Chiappini, M. [Istituto Nazionale di Geofisica e Vulcanologia (INGV), Via Vigna Murata 605, 00143 Roma (Italy); Ricciardi, G. [Department of Civil, Informatic, Architectural, and Environmental Engineering and Applied Mathematics, C.da di Dio, I-98166 Messina (Italy); Alibrandi, U. [Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576 (Singapore)
2014-05-12T23:59:59.000Z
This Letter introduces a seismic metamaterial (SM) composed by a chain of mass-in-mass system able to filter the S-waves of an earthquake. We included the effect of the SM into the mono dimensional model for the soil response analysis. The SM modifies the soil behavior and in presence of an internal damping the amplitude of the soil amplification function is reduced also in a region near the resonance frequency. This SM can be realized by a continuous structure with inside a 3d-matrix of isochronous oscillators based on a sphere rolling over a cycloidal trajectory.
NOx Emission Reduction by Oscillating combustion
Institute of Gas Technology
2004-01-30T23:59:59.000Z
High-temperature, natural gas-fired furnaces, especially those fired with preheated air, produce large quantities of NO{sub x} per ton of material processed. Regulations on emissions from industrial furnaces are becoming increasingly more stringent. In addition, competition is forcing operators to make their furnaces more productive and/or efficient. Switching from preheated air to industrial oxygen can increase efficiency and reduce NO{sub x}, but oxygen is significantly more costly than air and may not be compatible with the material being heated. What was needed, and what was developed during this project, is a technology that reduces NO{sub x} emissions while increasing furnace efficiency for both air- and oxy-fired furnaces. Oscillating combustion is a retrofit technology that involves the forced oscillation of the fuel flow rate to a furnace. These oscillations create successive, fuel-rich and fuel-lean zones within the furnace. Heat transfer from the flame to the load increases due to the more luminous fuel-rich zones, a longer overall flame length, and the breakup of the thermal boundary layer. The increased heat transfer shortens heat up times, thereby increasing furnace productivity, and reduces the heat going up the stack, thereby increasing efficiency. The fuel-rich and fuel-lean zones also produce substantially less NO{sub x} than firing at a constant excess air level. The longer flames and higher heat transfer rate reduces overall peak flame temperature and thus reduces additional NO{sub x} formation from the eventual mixing of the zones and burnout of combustibles from the rich zones. This project involved the development of hardware to implement oscillating combustion on an industrial scale, the laboratory testing of oscillating combustion on various types of industrial burners, and the field testing of oscillating combustion on several types of industrial furnace. Before laboratory testing began, a market study was conducted, based on the attributes of oscillating combustion and on the results of an earlier project at GTI and Air Liquide, to determine which applications for oscillating combustion would show the greatest probability for technical success and greatest probability for market acceptability. The market study indicated that furnaces in the steel, glass, and metal melting industries would perform well in both categories. These findings guided the selection of burners for laboratory testing and, with the results of the laboratory testing, guided the selection of field test sites.
NOx Emission Reduction by Oscillating Combustion
John C. Wagner
2004-03-31T23:59:59.000Z
High-temperature, natural gas-fired furnaces, especially those fired with preheated air, produce large quantities of NO{sub x} per ton of material processed. Regulations on emissions from industrial furnaces are becoming increasingly more stringent. In addition, competition is forcing operators to make their furnaces more productive and/or efficient. Switching from preheated air to industrial oxygen can increase efficiency and reduce NO{sub x}, but oxygen is significantly more costly than air and may not be compatible with the material being heated. What was needed, and what was developed during this project, is a technology that reduces NO{sub x} emissions while increasing furnace efficiency for both air- and oxy-fired furnaces. Oscillating combustion is a retrofit technology that involves the forced oscillation of the fuel flow rate to a furnace. These oscillations create successive, fuel-rich and fuel-lean zones within the furnace. Heat transfer from the flame to the load increases due to the more luminous fuel-rich zones, a longer overall flame length, and the breakup of the thermal boundary layer. The increased heat transfer shortens heat up times, thereby increasing furnace productivity, and reduces the heat going up the stack, thereby increasing efficiency. The fuel-rich and fuel-lean zones also produce substantially less NO{sub x} than firing at a constant excess air level. The longer flames and higher heat transfer rate reduces overall peak flame temperature and thus reduces additional NO{sub x} formation from the eventual mixing of the zones and burnout of combustibles from the rich zones. This project involved the development of hardware to implement oscillating combustion on an industrial scale, the laboratory testing of oscillating combustion on various types of industrial burners, and the field testing of oscillating combustion on several types of industrial furnace. Before laboratory testing began, a market study was conducted, based on the attributes of oscillating combustion and on the results of an earlier project at GTI and Air Liquide, to determine which applications for oscillating combustion would show the greatest probability for technical success and greatest probability for market acceptability. The market study indicated that furnaces in the steel, glass, and metal melting industries would perform well in both categories. These findings guided the selection of burners for laboratory testing and, with the results of the laboratory testing, guided the selection of field test sites.
Theoretical modelling of two wave-power devices
Lovas, Stéphanie
2010-01-01T23:59:59.000Z
Many wave energy devices are currently studied. In this thesis we focus on two specific devices: the Oscillating Water Column (OWC), and the buoys. In the first part of this thesis we examine the effects of coastline ...
arterial pulse wave: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Cloning and trapping of magnetostatic spin-wave pulses by parametric pumping Kevin R. Smith,1 media,3 phase noise re- duction in crystal oscillators,4 theoretical production of...
aortic pulse wave: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Cloning and trapping of magnetostatic spin-wave pulses by parametric pumping Kevin R. Smith,1 media,3 phase noise re- duction in crystal oscillators,4 theoretical production of...
ankle pulse wave: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Cloning and trapping of magnetostatic spin-wave pulses by parametric pumping Kevin R. Smith,1 media,3 phase noise re- duction in crystal oscillators,4 theoretical production of...
Driven synchronization in random networks of oscillators
Hindes, Jason
2015-01-01T23:59:59.000Z
Synchronization is a universal phenomenon found in many non-equilibrium systems. Much recent interest in this area has overlapped with the study of complex networks, where a major focus is determining how a system's connectivity patterns affect the types of behavior that it can produce. Thus far, modeling efforts have focused on the tendency of networks of oscillators to mutually synchronize themselves, with less emphasis on the effects of external driving. In this work we discuss the interplay between mutual and driven synchronization in networks of phase oscillators of the Kuramoto type, and resolve how the structure and emergence of such states depends on the underlying network topology for simple random networks with a given degree distribution. We provide a partial bifurcation analysis, centering on the appearance of a Takens-Bogdanov-Cusp singularity, which broadly separates homogeneous and heterogeneous network behavior in a weak coupling limit, and from which the number, stability and appearance of dr...
Quasivacuum solar neutrino oscillations
G. L. Fogli; E. Lisi; D. Montanino; A. Palazzo
2000-09-19T23:59:59.000Z
We discuss in detail solar neutrino oscillations with \\delta m^2/E in the range [10^-10,10^-7] eV^2/MeV. In this range, which interpolates smoothly between the so-called ``just-so'' and ``Mikheyev-Smirnov-Wolfenstein'' oscillation regimes, neutrino flavor transitions are increasingly affected by matter effects as \\delta m^2/E increases. As a consequence, the usual vacuum approximation has to be improved through the matter-induced corrections, leading to a ``quasi-vacuum'' oscillation regime. We perform accurate numerical calculations of such corrections, using both the true solar density profile and its exponential approximation. Matter effects are shown to be somewhat overestimated in the latter case. We also discuss the role of Earth crossing and of energy smearing. Prescriptions are given to implement the leading corrections in the quasi-vacuum oscillation range. Finally, the results are applied to a global analysis of solar nu data in a three-flavor framework.
I. Introduction A. Neutrino oscillation results from solar and atmospheric neutrino data.
McDonald, Kirk
V. This scenario is motivated in part by the need for an admixture (20{40%) of hot dark matter|roughly 7 eV worth oscillations in the matter of the Sun, and that the e and the neutrino type into which it oscillates, possibly and IMB imaging water Cherenkov detectors suggest that the observed disappearance of muon type neutrinos
Description of Stellar Acoustic Modes Using the Local Wave Concept
P. A. P. Nghiem
2006-06-26T23:59:59.000Z
An understanding of stellar acoustic oscillations is attempted, using the local wave concept in semi-analytical calculations. The local homogeneity approximation allows to obtain simplified equations that can nevertheless describe the wave behavior down to the central region, as the gravitational potential perturbation is not neglected. Acoustic modes are calculated as classical standing waves in a cavity, by determining the cavity limits and the wave phases at these limits. The internal boundary condition is determined by a fitting with an Airy function. The external boundary condition is defined as the limit where the spatial variation of the background is important compared to the wavelength. This overall procedure is in accordance with the JWKB approximation. When comparing the results with numerical calculations, some drawbacks of the isothermal atmosphere approximation are revealed. When comparing with seismic observations of the Sun, possible improvements at the surface of solar models are suggested. The present semi-analytical method can potentially predict eigenfrequencies at the precision of +-3microHz in the range 800-5600 microHz, for the degrees l=0-10. A numerical calculation using the same type of external boundary conditions could reach a global agreement with observations better than 1 microHz. This approach could contribute to better determine the absolute values of eigenfrequencies for asteroseismology.
Arbo, D.G.; Yoshida, S.; Persson, E.; Dimitriou, K.I.; Burgdoerfer, J. [Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10/136, A-1040 Vienna (Austria)
2006-04-14T23:59:59.000Z
We analyze the two-dimensional momentum distribution of electrons ionized by few-cycle laser pulses in the transition regime from multiphoton absorption to tunneling by solving the time-dependent Schroedinger equation and by a classical-trajectory Monte-Carlo simulation with tunneling (CTMC-T). We find a complex two-dimensional interference pattern that resembles above threshold ionization (ATI) rings at higher energies and displays Ramsauer-Townsend-type diffraction oscillations in the angular distribution near threshold. CTMC-T calculations provide a semiclassical explanation for the dominance of selected partial waves. While the present calculation pertains to hydrogen, we find surprising qualitative agreement with recent experimental data for rare gases [A. Rudenko et al., J. Phys. B 37, L407 (2004)].
Oscillation-supported Information Processing
Diba, Kamran
, intrinsic currents of neurons, dendritic Ca2+ spikes, and other voltage-dependent membrane oscillations7 Oscillation-supported Information Processing and Transfer at the HippocampusÀected by macroscopic oscillations. In each oscillatory cycle, recruitment of principal neurons is temporally protracted
INTEGRATED GHz VOLTAGE CONTROLLED OSCILLATORS
Kinget, Peter
INTEGRATED GHz VOLTAGE CONTROLLED OSCILLATORS Peter Kinget Bell Labs - Lucent Technologies Murray Hill, NJ (USA) Abstract The voltage controlled oscillator (VCO) is a critical sub. We focus on the de- sign of a critical sub-block: the voltage controlled oscillator (VCO). We review
Chen Zhaoquan; Liu Minghai; Tang Liang; Hu Peng; Hu Xiwei [College of Electrical and Electronic Engineering, HuaZhong University of Science and Technology, WuHan, HuBei 430074 (China)
2009-07-01T23:59:59.000Z
The electromagnetic wave through the subwavelength diffraction grating can be largely absorbed by surface-wave plasmas (SWPs). A SWP source is built with two slot-array antennas element. Due to the dissipation of surface waves in overdense plasmas, this source can provide remarkable discharge efficiency of 4.4 cm{sup 2}/W experimentally and 96% of incident power numerically. When the applied power as low as 200 W is supplied to the SWP source, a homogeneous plasma with the uniform area up to 14x36 cm{sup 2} and the plasma density up to 1.04x10{sup 18} m{sup -3} is generated under the quartz slab. By varying the incident power and gas pressure, the parameter of plasmas can be easily controlled without density jumping. Moreover, the characters of bi-Maxwellian electron energy distribution prove that our SWP source yield plasmas by surface heating actually. These excellent performances make the proposed source meet the requirements in large-area plasma processing and also give its advices for plasmas heating in next meter-size SWP sources.
Sensitivity of DANSS detector to short range neutrino oscillations
Danilov, Mikhail
2014-01-01T23:59:59.000Z
DANSS is a highly segmented $1m^3$ plastic scintillator detector. Its 2500 scintillator strips have a Gd loaded reflective cover. Light is collected with 3 wave length shifting fibers per strip and read out with 50 PMTs and 2500 SiPMs. The DANSS will be installed under the industrial 3GW$_{th}$ reactor of the Kalinin Nuclear Power Plant at distances varying from 9.7m to 12.2m from the reactor core. PMTs and SiPMs collect about 30 photo electrons per MeV distributed approximately equally between two types of the readout. Light collection non-uniformity across and along the strip is about $\\pm13\\%$ from maximum to minimum. The resulting energy resolution is modest, $\\sigma/E=15\\%$ at 5MeV. This leads to a smearing of the oscillation pattern comparable with the smearing due to the large size of the reactor core. Nevertheless because of the large counting rate ($\\sim 10000$ / day), small background ($<1\\%$) and good control of systematic uncertainties due to frequent changes of positions, the DANSS is quite se...
Model wave functions and dynamic correlations in light-medium nuclei
E Buendia; F J Galvez; J Praena; A Sarsa
2004-10-13T23:59:59.000Z
The nuclei $^4$He, $^8$Be, $^{12}$C and $^{16}$O have been studied starting from nucleon-nucleon interactions of $v_4$ type. The wave function is built as the product of three terms, a Jastrow correlation factor, a linear correlation factor and a model wave function. The correlation factors account for both the short range repulsive and the spin and isospin dependence of the nuclear potential. The model wave function is antisymmetric and has the values of the angular momentum and parity of the state under description. For the model wave function we have used two different schemes. The first one is based on a Harmonic Oscillator shell model with and without deformation, and the second one is based on the Margenau-Brink model of alpha clustering. Projection operators of parity and total angular momentum are used. The performance of these two models is studied and compared systematically. Wave functions for the ground state and some members of its rotational band and some other bound states of these nuclei have been obtained. Binding energies, root mean square radius and the expectation value of the kinetic energy and the different channels of the nuclear interactions and the one-- and two-- body densities are reported. The two different model wave functions and the effects of the different nucleon-nucleon correlations have been evaluated on those quantities. All the results here presented have been obtained by using the Variational Monte Carlo method.
Robertson, William
Waves The study of waves is clearly an important subject in acoustics because sound energy, wavelength and speed of all types of waves, not only sound. In the case of sound waves in air the wave speed is transmitted by waves traveling though air. Furthermore, it turns out that the properties of waves on strings
Semiclassical wave-packets emerging from interaction with an environment
Recchia, Carla, E-mail: carla.recchia@libero.it [D.I.S.I.M., Università di L’Aquila, Via Vetoio - Loc. Coppito - 67010 L’Aquila (Italy)] [D.I.S.I.M., Università di L’Aquila, Via Vetoio - Loc. Coppito - 67010 L’Aquila (Italy); Teta, Alessandro, E-mail: teta@mat.uniroma1.it [Dipartimento di Matematica, “Sapienza” Università di Roma, P.le A. Moro 5, 00185 Roma (Italy)] [Dipartimento di Matematica, “Sapienza” Università di Roma, P.le A. Moro 5, 00185 Roma (Italy)
2014-01-15T23:59:59.000Z
We study the quantum evolution in dimension three of a system composed by a test particle interacting with an environment made of N harmonic oscillators. At time zero the test particle is described by a spherical wave, i.e., a highly correlated continuous superposition of states with well localized position and momentum, and the oscillators are in the ground state. Furthermore, we assume that the positions of the oscillators are not collinear with the center of the spherical wave. Under suitable assumptions on the physical parameters characterizing the model, we give an asymptotic expression of the solution of the Schrödinger equation of the system with an explicit control of the error. The result shows that the approximate expression of the wave function is the sum of two terms, orthogonal in L{sup 2}(R{sup 3(N+1)}) and describing rather different situations. In the first one, all the oscillators remain in their ground state and the test particle is described by the free evolution of a slightly deformed spherical wave. The second one consists of a sum of N terms where in each term there is only one excited oscillator and the test particle is correspondingly described by the free evolution of a wave packet, well concentrated in position and momentum. Moreover, the wave packet emerges from the excited oscillator with an average momentum parallel to the line joining the oscillator with the center of the initial spherical wave. Such wave packet represents a semiclassical state for the test particle, propagating along the corresponding classical trajectory. The main result of our analysis is to show how such a semiclassical state can be produced, starting from the original spherical wave, as a result of the interaction with the environment.
Entanglement in neutrino oscillations
Massimo Blasone; Fabio Dell'Anno; Silvio De Siena; Fabrizio Illuminati
2009-04-17T23:59:59.000Z
Flavor oscillations in elementary particle physics are related to multi-mode entanglement of single-particle states. We show that mode entanglement can be expressed in terms of flavor transition probabilities, and therefore that single-particle entangled states acquire a precise operational characterization in the context of particle mixing. We treat in detail the physically relevant cases of two- and three-flavor neutrino oscillations, including the effective measure of CP violation. We discuss experimental schemes for the transfer of the quantum information encoded in single-neutrino states to spatially delocalized two-flavor charged lepton states, thus showing, at least in principle, that single-particle entangled states of neutrino mixing are legitimate physical resources for quantum information tasks.
Neutrino oscillations refitted
Forero, D V; Valle, J W F
2014-01-01T23:59:59.000Z
Here we update our previous global fit of neutrino oscillations by including the recent results which have appeared since the Neutrino-2012 conference. These include the measurements of reactor anti-neutrino disappearance reported by Daya Bay and RENO, together with latest T2K and MINOS data including both disappearance and appearance channels. We also include the revised results from the third solar phase of Super-Kamiokande, SK-III, as well as new solar results from the fourth phase of Super-Kamiokande, SK-IV. We find that the preferred global determination of the atmospheric angle $\\theta_{23}$ is consistent with maximal mixing. We also determine the impact of the new data upon all the other neutrino oscillation parameters with emphasis on the increasing sensitivity to the CP phase, thanks to the interplay between accelerator and reactor data.
Four cavity efficiency enhanced magnetically insulated line oscillator
Lemke, R.W.; Clark, M.C.; Calico, S.E.
1998-04-21T23:59:59.000Z
A four cavity, efficient magnetically insulated line oscillator (C4-E MILO) having seven vanes and six cavities formed within a tube-like structure surrounding a cathode is disclosed. The C4-E MILO has a primary slow wave structure which is comprised of four vanes and the four cavities located near a microwave exit end of the tube-like structure. The primary slow wave structure is the four cavity portion of the magnetically insulated line oscillator (MILO). An RF choke is provided which is comprised of three of the vanes and two of the cavities. The RF choke is located near a pulsed power source portion of the tube-like structure surrounding the cathode. The RF choke increases feedback in the primary slow wave structure, prevents microwaves generated in the primary slow wave structure from propagating towards the pulsed power source and modifies downstream electron current so as to enhance microwave power generation. A beam dump/extractor is located at the exit end of the oscillator tube for extracting microwave power from the oscillator, and in conjunction with an RF extractor vane, which comprises the fourth vane of the primary slow wave structure (nearest the exit) having a larger gap radius than the other vanes of the primary SWS, comprises an RF extractor. Uninsulated electron flow is returned downstream towards the exit along an anode/beam dump region located between the beam dump/extractor and the exit where the RF is radiated at said RF extractor vane located near the exit and the uninsulated electron flow is disposed at the beam dump/extractor. 34 figs.
Four cavity efficiency enhanced magnetically insulated line oscillator
Lemke, Raymond W. (Albuquerque, NM); Clark, Miles C. (Albuquerque, NM); Calico, Steve E. (Albuquerque, NM)
1998-04-21T23:59:59.000Z
A four cavity, efficient magnetically insulated line oscillator (C4-E MILO) having seven vanes and six cavities formed within a tube-like structure surrounding a cathode. The C4-E MILO has a primary slow wave structure which is comprised of four vanes and the four cavities located near a microwave exit end of the tube-like structure. The primary slow wave structure is the four cavity (C4) portion of the magnetically insulated line oscillator (MILO). An RF choke is provided which is comprised of three of the vanes and two of the cavities. The RF choke is located near a pulsed power source portion of the tube-like structure surrounding the cathode. The RF choke increases feedback in the primary slow wave structure, prevents microwaves generated in the primary slow wave structure from propagating towards the pulsed power source and modifies downstream electron current so as to enhance microwave power generation. A beam dump/extractor is located at the exit end of the oscillator tube for extracting microwave power from the oscillator, and in conjunction with an RF extractor vane, which comprises the fourth vane of the primary slow wave structure (nearest the exit) having a larger gap radius than the other vanes of the primary SWS, comprises an RF extractor. Uninsulated electron flow is returned downstream towards the exit along an anode/beam dump region located between the beam dump/extractor and the exit where the RF is radiated at said RF extractor vane located near the exit and the uninsulated electron flow is disposed at the beam dump/extractor.
Oscillations of Mossbauer neutrinos
Evgeny Kh. Akhmedov; Joachim Kopp; Manfred Lindner
2008-05-02T23:59:59.000Z
We calculate the probability of recoilless emission and detection of neutrinos (Mossbauer effect with neutrinos) taking into account the boundedness of the parent and daughter nuclei in the neutrino source and detector as well as the leptonic mixing. We show that, in spite of their near monochromaticity, the recoillessly emitted and captured neutrinos oscillate. After a qualitative discussion of this issue, we corroborate and extend our results by computing the combined rate of $\\bar{\
Oscillations in glow discharges
Prickett, Tom
1950-01-01T23:59:59.000Z
1950 CONTENTS Introduction ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1 I. Review of Plasma Oscillations in Gas Discharges ? . . 2 II. Review of Relaxation Processes in Gas Discharges ? . 13 III. Report of Laboratory Investigation... 179540 LIST OF FIGURES Figure Page 1. Sketch of Plasma Space in which Electrons are given Displacements in the X-direction ? ? ? ? ? ? 5 2* Early Circuit Arrangement of Discharge Study ? ? ? ? ? 19 3, Flow Diagram of the Experimental System...
LSND neutrino oscillation results
Louis, W.C.; LSND Collaboration
1996-10-01T23:59:59.000Z
The LSND (Liquid Scintillator Neutrino Detector) experiment at Los Alamos has conducted a search for muon antineutrino {r_arrow} electron antineutrino oscillations using muon neutrinos from antimuon decay at rest. The electron antineutrinos are detected via the reaction electron antineutrino + proton {r_arrow} positron + neutron, correlated with the 2.2-MeV gamma from neutron + proton {r_arrow} deuteron + gamma. The use of tight cuts to identify positron events with correlated gamma rays yields 22 events with positron energy between 36 and 60 MeV and only 4.6 {+-} 0.6 background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1 {times} 10{sup -8}. A chi-squared fit to the entire positron sample results in a total excess of 51.8 {sup +18.7}{sub -16.9} {+-} 8.0 events with positron energy between 20 and 60 MeV. If attributed to muon antineutrino {r_arrow} electron antineutrino oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of (0.31 {+-} 0.12 {+-} 0.05){percent}. 10 refs., 7 figs., 1 tab.
LSND neutrino oscillation results
White, D.H.; LSND Collaboration
1997-11-01T23:59:59.000Z
The LSND experiment at Los Alamos has conducted a search for {anti v}{sub {mu}} {yields} {anti v}{sub e} oscillations using {anti v}{sub {mu}} from {mu}{sup +} decay at rest. The {anti v}{sub e} are detected via the reaction {anti v}{sub e} p {yields} e{sup +}n, correlated with the 2.2 MeV {gamma} from n p {yields} d {gamma}. The use of tight cuts to identify e{sup +} events with correlated {gamma} rays yielded 22 events with e{sup +} energy between 36 and 60 MeV and only 4.6 {+-} 0.6 background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1 {times} 10{sup {minus}8}. A {chi}{sup 2} fit to the entire e{sup +} sample results in a total excess of 51.8{sub {minus}16.9}{sup +18.7} {+-} 8.0 events with e{sup +} energy between 20 and 60 MeV. If attributed to {anti v}{sub {mu}} {yields} {anti v}{sub e} oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of 0.31 {+-} 0.12 {+-} 0.05%.
Gravitational waves from perturbed stars
Valeria Ferrari
2011-05-09T23:59:59.000Z
Non radial oscillations of neutron stars are associated with the emission of gravitational waves. The characteristic frequencies of these oscillations can be computed using the theory of stellar perturbations, and they are shown to carry detailed information on the internal structure of the emitting source. Moreover, they appear to be encoded in various radiative processes, as for instance in the tail of the giant flares of Soft Gamma Repeaters. Thus, their determination is central to the theory of stellar perturbation. A viable approach to the problem consists in formulating this theory as a problem of resonant scattering of gravitational waves incident on the potential barrier generated by the spacetime curvature. This approach discloses some unexpected correspondences between the theory of stellar perturbations and the theory of quantum mechanics, and allows us to predict new relativistic effects.
Are solar neutrino oscillations robust?
O. G. Miranda; M. A. Tortola; J. W. F. Valle
2006-09-07T23:59:59.000Z
The robustness of the large mixing angle (LMA) oscillation (OSC) interpretation of the solar neutrino data is considered in a more general framework where non-standard neutrino interactions (NSI) are present. Such interactions may be regarded as a generic feature of models of neutrino mass. The 766.3 ton-yr data sample of the KamLAND collaboration are included in the analysis, paying attention to the background from the reaction ^13C(\\alpha,n) ^16O. Similarly, the latest solar neutrino fluxes from the SNO collaboration are included. In addition to the solution which holds in the absence of NSI (LMA-I) there is a 'dark-side' solution (LMA-D) with sin^2 theta_Sol = 0.70, essentially degenerate with the former, and another light-side solution (LMA-0) allowed only at 97% CL. More precise KamLAND reactor measurements will not resolve the ambiguity in the determination of the solar neutrino mixing angle theta_Sol, as they are expected to constrain mainly Delta m^2. We comment on the complementary role of atmospheric, laboratory (e.g. CHARM) and future solar neutrino experiments in lifting the degeneracy between the LMA-I and LMA-D solutions. In particular, we show how the LMA-D solution induced by the simplest NSI between neutrinos and down-type-quarks-only is in conflict with the combination of current atmospheric data and data of the CHARM experiment. We also mention that establishing the issue of robustness of the oscillation picture in the most general case will require further experiments, such as those involving low energy solar neutrinos.
Nonlinear extraordinary wave in dense plasma
Krasovitskiy, V. B., E-mail: krasovit@mail.ru [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation); Turikov, V. A. [Russian University of Peoples’ Friendship (Russian Federation)] [Russian University of Peoples’ Friendship (Russian Federation)
2013-10-15T23:59:59.000Z
Conditions for the propagation of a slow extraordinary wave in dense magnetized plasma are found. A solution to the set of relativistic hydrodynamic equations and Maxwell’s equations under the plasma resonance conditions, when the phase velocity of the nonlinear wave is equal to the speed of light, is obtained. The deviation of the wave frequency from the resonance frequency is accompanied by nonlinear longitudinal-transverse oscillations. It is shown that, in this case, the solution to the set of self-consistent equations obtained by averaging the initial equations over the period of high-frequency oscillations has the form of an envelope soliton. The possibility of excitation of a nonlinear wave in plasma by an external electromagnetic pulse is confirmed by numerical simulations.
Evidence for Fine Structure in the Chromospheric Umbral Oscillation
R. Centeno; H. Socas-Navarro; M. Collados; J. Trujillo Bueno
2005-10-26T23:59:59.000Z
Novel spectro-polarimetric observations of the \\ion{He}{1} multiplet are used to explore the dynamics of the chromospheric oscillation above sunspot umbrae. The results presented here provide strong evidence in support of the two-component model proposed by Socas-Navarro and co-authors. According to this model, the waves propagate only inside channels of sub-arcsecond width (the ``active'' component), whereas the rest of the umbra remains nearly at rest (the ``quiet'' component). Although the observations support the fundamental elements of that model, there is one particular aspect that is not compatible with our data. We find that, contrary to the scenario as originally proposed, the active component remains through the entire oscillation cycle and harbors both the upflowing and the downflowing phase of the oscillation.
Collective oscillations in spatially modulated exciton-polariton condensate arrays
A. A. Tikhomirov; O. I. Kanakov; B. L. Altshuler; M. V. Ivanchenko
2014-07-25T23:59:59.000Z
We study collective dynamics of interacting centers of exciton-polariton condensation in presence of spatial inhomogeneity, as modeled by diatomic active oscillator lattices. The mode formalism is developed and employed to derive existence and stability criteria of plane wave solutions. It is demonstrated that $k_0=0$ wave number mode with the binary elementary cell on a diatomic lattice possesses superior existence and stability properties. Decreasing net on-site losses (balance of dissipation and pumping) or conservative nonlinearity favors multistability of modes, while increasing frequency mismatch between adjacent oscillators detriments it. On the other hand, spatial inhomogeneity may recover stability of modes at high nonlinearities. Entering the region where all single-mode solutions are unstable we discover subsequent transitions between localized quasiperiodic, chaotic and global chaotic dynamics in the mode space, as nonlinearity increases. Importantly, the last transition evokes the loss of synchronization. These effects may determine lasing dynamics of interacting exciton-polariton condensation centers.
Dirac bound states of anharmonic oscillator in external fields
Hamzavi, Majid, E-mail: majid.hamzavi@gmail.com [Department of Physics, University of Zanjan, Zanjan (Iran, Islamic Republic of)] [Department of Physics, University of Zanjan, Zanjan (Iran, Islamic Republic of); Ikhdair, Sameer M., E-mail: sikhdair@gmail.com [Department of Physics, Faculty of Science, an-Najah National University, Nablus, West Bank, Palestine (Country Unknown); Department of Electrical and Electronic Engineering, Near East University, 922022 Nicosia, Northern Cyprus, Mersin 10 (Turkey); Falaye, Babatunde J., E-mail: fbjames11@physicist.net [Theoretical Physics Section, Department of Physics, University of Ilorin, P. M. B. 1515, Ilorin (Nigeria)
2014-02-15T23:59:59.000Z
We explore the effect of the external magnetic and Aharonov–Bohm (AB) flux fields on the energy levels of Dirac particle subjects to mixed scalar and vector anharmonic oscillator field in the two-dimensional (2D) space. We calculate the exact energy eigenvalues and the corresponding un-normalized two-spinor-components wave functions in terms of the chemical potential parameter, magnetic field strength, AB flux field and magnetic quantum number by using the Nikiforov–Uvarov (NU) method. -- Highlights: • Effect of the external fields on the energy levels of Dirac particle with the anharmonic oscillator is investigated. • The solutions are discussed in view of spin and pseudospin symmetries limits. • The energy levels and wave function are presented by the Nikiforov–Uvarov method.
Baryogenesis via neutrino oscillations
E. Kh. Akhmedov; V. A. Rubakov; A. Yu. Smirnov
1998-07-29T23:59:59.000Z
We propose a new mechanism of leptogenesis in which the asymmetries in lepton numbers are produced through the CP-violating oscillations of ``sterile'' (electroweak singlet) neutrinos. The asymmetry is communicated from singlet neutrinos to ordinary leptons through their Yukawa couplings. The lepton asymmetry is then reprocessed into baryon asymmetry by electroweak sphalerons. We show that the observed value of baryon asymmetry can be generated in this way, and the masses of ordinary neutrinos induced by the seesaw mechanism are in the astrophysically and cosmologically interesting range. Except for singlet neutrinos, no physics beyond the Standard Model is required.
Calculation of the convex roof for an open entangled harmonic oscillator system
Landau, Mayer A.; Stroud, C. R. Jr. [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States)
2010-05-15T23:59:59.000Z
We explicitly calculate the time dependence of entanglement via the convex roof extension for a system of noninteracting harmonic oscillators. These oscillators interact only indirectly with each other by way of a zero-temperature bath. The initial state of the oscillators is taken to be that of an entangled Schroedinger-cat state. This type of initial condition leads to superexponential decay of the entanglement when the initial state has the same symmetry as the interaction Hamiltonian.
Harmonic oscillator in a background magnetic field in noncommutative quantum phase-space
Joseph Ben Geloun; Sunandan Gangopadhyay; Frederik G Scholtz
2009-01-22T23:59:59.000Z
We solve explicitly the two-dimensional harmonic oscillator and the harmonic oscillator in a background magnetic field in noncommutative phase-space without making use of any type of representation. A key observation that we make is that for a specific choice of the noncommutative parameters, the time reversal symmetry of the systems get restored since the energy spectrum becomes degenerate. This is in contrast to the noncommutative configuration space where the time reversal symmetry of the harmonic oscillator is always broken.
Lorentz Invariance of Neutrino Oscillations
C. Giunti
2003-05-29T23:59:59.000Z
It is shown that, in spite of the appearances, the standard expression for the oscillation probability of ultrarelativistic neutrinos is Lorentz invariant.
Gravitational Correction in Neutrino Oscillations
Yasufumi Kojima
1996-12-17T23:59:59.000Z
We investigate the quantum mechanical oscillations of neutrinos propagating in weak gravitational field. The correction to the result in the flat space-time is derived.
NEUTRINO OSCILLATION RESULTS FROM LSND
Mills, G.B.
2000-10-01T23:59:59.000Z
The Liquid Scintillator Neutrino Detector took data during the years 1993 through 1998. The results of a final analysis of the data are reported here. In summary, the analysis resulted in a cleaner sample of decay-at-rest oscillation candidates and provided a strong constraint on beam related backgrounds. The oscillation probability is fitted to the correlated photon parameter in the inclusive electron sample. The fit yields an excess of 83.3 {+-} 21.2 events attributable to neutrino oscillations. This corresponds to an oscillation probability of (0.25 {+-} 0.06 {+-} 0.04)% for that detector and beam configuration.
Feedback Induced Death in Coupled Oscillators
Ming Luo
2011-11-10T23:59:59.000Z
We investigate oscillation death in systems of coupled nonlinear oscillators with feedback loop. We find that feedback results in oscillation death both in small sets or large ensembles. More importantly, the death zone in parameter space is significantly enlarged and oscillation death could occur even in coupled identical oscillators in the presence of feedback. We find that there are two different ways to oscillation death, namely desynchronization and completely synchronization induced oscillation death. Feedback induced oscillation death may be used to suppress unexpected oscillations, e.g., in chaotic laser arrays.
Wave dynamics in a sunspot umbra
Sych, R
2014-01-01T23:59:59.000Z
The high spatial and time resolution data obtained with SDO/AIA for the sunspot in active region NOAA 11131 on 08 December 2010 were analysed with the time-distance plot technique and the pixelised wavelet filtering method. Oscillations in the 3 min band dominate in the umbra. The integrated spectrum of umbral oscillations contains distinct narrowband peaks at 1.9 min, 2.3 min, and 2.8 min. The power significantly varies in time, forming distinct oscillation trains. The oscillation power distribution over the sunspot in the horizontal plane reveals that the enhancements of the oscillation amplitude, or wave fronts, have a distinct structure consisting of an evolving two-armed spiral and a stationary circular patch at the spiral origin, situated near the umbra centre. This structure is seen from the temperature minimum to the corona. In time, the spiral rotates anti-clockwise. The wave front spirality is most pronounced during the maximum amplitude phases of the oscillations. In the low-amplitude phases the sp...
On the harmonic oscillator realisation of q-oscillators
D. Gangopadhyay; A. P. Isaev
2007-01-05T23:59:59.000Z
The general version of the bosonic harmonic oscillator realisation of bosonic q-oscillators is given. It is shown that the currently known realisation is a special case of our general solution. The investigation has been performed at the Laboratory of theoretical Physics,JINR.
Free Oscillations of a Linear Oscillator Eugene Butikov
Butikov, Eugene
of a Linear Torsion Oscillator The linear oscillator simulated in this computer program is a balanced flywheel whose center of mass lies on the axis of rotation. Such a flywheel may consist, for example, of a rod that passes through its center. A spiral spring with one end fixed and the other attached to the flywheel
Lathrop, Daniel P.
, modulated, and frequency locked wave states lead to a state with fluid spikes. When the excitation of free- quency of 7.4 Hz to excite a (2,2) Fourier mode. A highly viscous liquid is chosen here to dampen high region and the corner areas of the liquid surface oscillate out of phase. Large amplitude waves couple
Particle acceleration in superluminal strong waves
Teraki, Yuto; Nagataki, Shigehiro
2015-01-01T23:59:59.000Z
We calculate the electron acceleration in random superluminal strong waves (SLSWs) and radiation from them by using numerical methods in the context of the termination shock of the pulsar wind nebulae. We pursue the electrons by solving the equation of motion in the analytically expressed electromagnetic turbulences. These consist of primary SLSW and isotropically distributed secondary electromagnetic waves. Under the dominance of the secondary waves, all electrons gain nearly equal energy. On the other hand, when the primary wave is dominant, selective acceleration occurs. The phase of the primary wave felt by the electrons moving nearly along the wavevector changes very slowly compared to the oscillation of the wave, which is called "phase locked", and such electrons are continuously accelerated. This acceleration by SLSWs may play a crucial role in the pre-acceleration for the shock acceleration. In general, the radiation from the phase-locked population is different from the synchro-Compton radiation. How...
Neutrino oscillations refitted
D. V. Forero; M. Tortola; J. W. F. Valle
2014-11-21T23:59:59.000Z
Here we update our previous global fit of neutrino oscillations by including the recent results which have appeared since the Neutrino-2012 conference. These include the measurements of reactor anti-neutrino disappearance reported by Daya Bay and RENO, together with latest T2K and MINOS data including both disappearance and appearance channels. We also include the revised results from the third solar phase of Super-Kamiokande, SK-III, as well as new solar results from the fourth phase of Super-Kamiokande, SK-IV. We find that the preferred global determination of the atmospheric angle $\\theta_{23}$ is consistent with maximal mixing. We also determine the impact of the new data upon all the other neutrino oscillation parameters with emphasis on the increasing sensitivity to the CP phase, thanks to the interplay between accelerator and reactor data. In the appendix we present the updated results obtained after the inclusion of new reactor data presented at the Neutrino 2014 conference. We discuss their impact on the global neutrino analysis.
Nanoscale relaxation oscillator
Zettl, Alexander K. (Kensington, CA); Regan, Brian C. (Los Angeles, CA); Aloni, Shaul (Albany, CA)
2009-04-07T23:59:59.000Z
A nanoscale oscillation device is disclosed, wherein two nanoscale droplets are altered in size by mass transport, then contact each other and merge through surface tension. The device may also comprise a channel having an actuator responsive to mechanical oscillation caused by expansion and contraction of the droplets. It further has a structure for delivering atoms between droplets, wherein the droplets are nanoparticles. Provided are a first particle and a second particle on the channel member, both being made of a chargeable material, the second particle contacting the actuator portion; and electrodes connected to the channel member for delivering a potential gradient across the channel and traversing the first and second particles. The particles are spaced apart a specified distance so that atoms from one particle are delivered to the other particle by mass transport in response to the potential (e.g. voltage potential) and the first and second particles are liquid and touch at a predetermined point of growth, thereby causing merging of the second particle into the first particle by surface tension forces and reverse movement of the actuator. In a preferred embodiment, the channel comprises a carbon nanotube and the droplets comprise metal nanoparticles, e.g. indium, which is readily made liquid.
Characteristics of transverse waves in chromospheric mottles
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.; Erdélyi, 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)
2013-12-10T23:59:59.000Z
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.
Phase conjugation by degenerate forward four-wave mixing
Khyzniak, A.; Kondilenko, V.; Kucherov, Iu.; Lesnik, S.; Odoulov, S.; Soskin, M.
1984-02-01T23:59:59.000Z
Phase conjugation (PC) that is due to degenerate forward four-wave mixing is studied both theoretically and experimentally. Similarity to backward four-wave mixing, the limiting efficiency of this process corresponds to the total energy transfer from each pump wave into the signal and conjugate waves, although in this case the Yariv oscillations do not occur. The numerical solution of the nonstationary problem is presented, revealing the transient oscillations of the PC-beam intensity with maxima many times exceeding the saturation value. PC of Q-switched and free-oscillating solid-state laser radiation is obtained by using the thermal nonlinearity of absorbing solutions. PC of CW laser radiation is obtained in a LiNbO3 crystal, the PC-beam intensity being six times larger than the initial intensity of the signal beam. The self-compensation of nonlinear phase distortions of the recording medium is demonstrated. 33 references.
Modeling solar coronal bright point oscillations with multiple nanoflare heated loops
Chandrashekhar, K
2015-01-01T23:59:59.000Z
Intensity oscillations of coronal bright points (BPs) have been studied for past several years. It has been known for a while that these BPs are closed magnetic loop like structures. However, initiation of such intensity oscillations is still an enigma. There have been many suggestions to explain these oscillations, but modeling of such BPs have not been explored so far. Using a multithreaded nanoflare heated loop model we study the behavior of such BPs in this work. We compute typical loop lengths of BPs using potential field line extrapolation of available data (Chandrashekhar et al. 2013), and set this as the length of our simulated loops. We produce intensity like observables through forward modeling and analyze the intensity time series using wavelet analysis, as was done by previous observers. The result reveals similar intensity oscillation periods reported in past observations. It is suggested these oscillations are actually shock wave propagations along the loop. We also show that if one considers di...
Wave Energy Extraction from buoys
Garnaud, Xavier
2009-01-01T23:59:59.000Z
Different types of Wave Energy Converters currently tested or under development are using the vertical movement of floating bodies to generate electricity. For commercial applications, arrays have to be considered in order ...
Neutrino Oscillations Physics 135c
Golwala, Sunil
Neutrino Oscillations Gary Cheng Physics 135c 6/1/07 #12;Introduction: Theory Neutrinos have mass neutrinos are produced. The difference between the mass eigenstates and the flavor eigenstates of neutrinos is what causes neutrino oscillations. #12;Introduction: Theory 2 The mass eigenstates 1, 2, 3
Neutrino oscillations and dark matter
K. Zuber
1996-12-17T23:59:59.000Z
The significance of light massive neutrinos as hot dark matter is outlined. The power of neutrino oscillation experiments with respect to detect such neutrinos in the eV-region is discussed. Present hints for neutrino oscillations in solar, atmospheric and LSND data are reviewed as well as future experiments and their potential.
Coulomb Oscillations in Antidots in the Integer and Fractional Quantum Hall Regimes
A. Kou; C. M. Marcus; L. N. Pfeiffer; K. W. West
2012-01-08T23:59:59.000Z
We report measurements of resistance oscillations in micron-scale antidots in both the integer and fractional quantum Hall regimes. In the integer regime, we conclude that oscillations are of the Coulomb type from the scaling of magnetic field period with the number of edges bound to the antidot. Based on both gate-voltage and field periods, we find at filling factor {\
Coulomb Oscillations in Antidots in the Integer and Fractional Quantum Hall Regimes
Kou, A; Pfeiffer, L N; West, K W
2012-01-01T23:59:59.000Z
We report measurements of resistance oscillations in micron-scale antidots in both the integer and fractional quantum Hall regimes. In the integer regime, we conclude that oscillations are of the Coulomb type from the scaling of magnetic field period with the number of edges bound to the antidot. Based on both gate-voltage and field periods, we find at filling factor {\
Resolved Sideband Cooling of a Micromechanical Oscillator
A. Schliesser; R. Rivière; G. Anetsberger; O. Arcizet; T. J. Kippenberg
2007-09-26T23:59:59.000Z
Micro- and nanoscale opto-mechanical systems provide radiation pressure coupling of optical and mechanical degree of freedom and are actively pursued for their ability to explore quantum mechanical phenomena of macroscopic objects. Many of these investigations require preparation of the mechanical system in or close to its quantum ground state. Remarkable progress in ground state cooling has been achieved for trapped ions and atoms confined in optical lattices. Imperative to this progress has been the technique of resolved sideband cooling, which allows overcoming the inherent temperature limit of Doppler cooling and necessitates a harmonic trapping frequency which exceeds the atomic species' transition rate. The recent advent of cavity back-action cooling of mechanical oscillators by radiation pressure has followed a similar path with Doppler-type cooling being demonstrated, but lacking inherently the ability to attain ground state cooling as recently predicted. Here we demonstrate for the first time resolved sideband cooling of a mechanical oscillator. By pumping the first lower sideband of an optical microcavity, whose decay rate is more than twenty times smaller than the eigen-frequency of the associated mechanical oscillator, cooling rates above 1.5 MHz are attained. Direct spectroscopy of the motional sidebands reveals 40-fold suppression of motional increasing processes, which could enable reaching phonon occupancies well below unity (cooling as reported here should find widespread use in opto-mechanical cooling experiments. Apart from ground state cooling, this regime allows realization of motion measurement with an accuracy exceeding the standard quantum limit.
Longitudinally propagating arc wave in the pre-onset optical aurora V. M. Uritsky,1
California at Berkeley, University of
Longitudinally propagating arc wave in the pre-onset optical aurora V. M. Uritsky,1 J. Liang,1 E aurora the longitudinally propagating arc wave (LPAW) associated with flapping oscillations, and K. H. Glassmeier (2009), Longitudinally propagating arc wave in the pre-onset optical aurora
Review Article Propagating waves in thalamus, cortex and the thalamocortical system
Destexhe, Alain
Review Article Propagating waves in thalamus, cortex and the thalamocortical system: Experiments-sensitive dye Multi-electrode array Population dynamics Propagating waves Oscillations Sensory cortices Spiking neural networks a b s t r a c t Propagating waves of activity have been recorded in many species
Equal energy phase space trajectories in resonant wave interactions O. Yaakobia
Friedland, Lazar
Equal energy phase space trajectories in resonant wave interactions O. Yaakobia and L. Friedlandb interacting wave systems with nonlinear frequency/ wave vector shifts is discussed. The corresponding these parameters vary in time or space. It is shown that the oscillation periods of two equal energy trajectories
Wave-Particle Duality and the Hamilton-Jacobi Equation
Gregory I. Sivashinsky
2009-12-28T23:59:59.000Z
The Hamilton-Jacobi equation of relativistic quantum mechanics is revisited. The equation is shown to permit solutions in the form of breathers (oscillating/spinning solitons), displaying simultaneous particle-like and wave-like behavior. The de Broglie wave thus acquires a clear deterministic meaning of a wave-like excitation of the classical action function. The problem of quantization in terms of the breathing action function and the double-slit experiment are discussed.
Systematic expansion for infrared oscillator basis extrapolations
R. J. Furnstahl; S. N. More; T. Papenbrock
2014-03-20T23:59:59.000Z
Recent work has demonstrated that the infrared effects of harmonic oscillator basis truncations are well approximated by imposing a partial-wave Dirichlet boundary condition at a properly identified radius L. This led to formulas for extrapolating the corresponding energy E_L and other observables to infinite L and thus infinite basis size. Here we reconsider the energy for a two-body system with a Dirichlet boundary condition at L to identify and test a consistent and systematic expansion for E_L that depends only on observables. We also generalize the energy extrapolation formula to nonzero angular momentum, and apply it to the deuteron. Formulas given previously for extrapolating the radius are derived in detail.
Neutrino Oscillations and Blazars
Karl Mannheim
1999-01-25T23:59:59.000Z
Three independent predictions follow from postulating the existence of protons co-accelerated with electrons in extragalactic jets (i) multi-TeV gamma ray emission from nearby blazars, (ii) extragalactic cosmic ray protons up to 10^20 eV, and (iii) extragalactic neutrinos up to 5 10^18 eV. Recent gamma ray observations of Mrk 421 and Mrk 501 employing the air-Cerenkov technique are consistent with the predicted gamma ray spectrum, if one corrects for pair attenuation on the infrared background. Prediction (ii) is consistent with cosmic ray data, if one requires that jets are responsible for at least a sizable fraction of the extragalactic gamma ray background. With kubic kilometer neutrino telescopes, it will be possible to test (iii), although the muon event rates are rather low. Neutrino oscillations can increase the event rate by inducing tau-cascades removing the Earth shadowing effect.
Method to improve optical parametric oscillator beam quality
Smith, Arlee V.; Alford, William J.; Bowers, Mark S.
2003-11-11T23:59:59.000Z
A method to improving optical parametric oscillator (OPO) beam quality having an optical pump, which generates a pump beam at a pump frequency greater than a desired signal frequency, a nonlinear optical medium oriented so that a signal wave at the desired signal frequency and a corresponding idler wave are produced when the pump beam (wave) propagates through the nonlinear optical medium, resulting in beam walk off of the signal and idler waves, and an optical cavity which directs the signal wave to repeatedly pass through the nonlinear optical medium, said optical cavity comprising an equivalently even number of non-planar mirrors that produce image rotation on each pass through the nonlinear optical medium. Utilizing beam walk off where the signal wave and said idler wave have nonparallel Poynting vectors in the nonlinear medium and image rotation, a correlation zone of distance equal to approximately .rho.L.sub.crystal is created which, through multiple passes through the nonlinear medium, improves the beam quality of the OPO output.
Forced Oscillations in Fluid Tori and Quasi-Periodic Oscillations
William H. Lee
2005-10-19T23:59:59.000Z
The kilo-Hertz Quasi--Periodic Oscillations in X-ray binaries could originate within the accretion flow, and be a signature of non--linear fluid oscillations and mode coupling in strong gravity. The possibility to decipher these systems will impact our knowledge of fundamental parameters such as the neutron star mass, radius, and spin. Thus they offer the possibility to constrain the nuclear equation of state and the rotation parameter of stellar--mass black holes. We review the general properties of these oscillations from a hydrodynamical point of view, when the accretion flow is subject to external perturbations and summarize recent results.
Clustered Chimera States in Systems of Type-I Excitability
Andrea Vüllings; Johanne Hizanidis; Iryna Omelchenko; Philipp Hövel
2014-07-20T23:59:59.000Z
Chimera is a fascinating phenomenon of coexisting synchronized and desynchronized behaviour that was discovered in networks of nonlocally coupled identical phase oscillators over ten years ago. Since then, chimeras were found in numerous theoretical and experimental studies and more recently in models of neuronal dynamics as well. In this work, we consider a generic model for a saddle-node bifurcation on a limit cycle representative for neural excitability type I. We obtain chimera states with multiple coherent regions (clustered chimeras/multi-chimeras) depending on the distance from the excitability threshold, the range of nonlocal coupling as well as the coupling strength. A detailed stability diagram for these chimera states as well as other interesting coexisting patterns like traveling waves are presented.
Powerful gravitational-wave bursts from supernova neutrino oscillations
Herman J. Mosquera Cuesta; Karen Fiuza
2004-07-26T23:59:59.000Z
During supernova core collapse and bounce resonant active-to-active, as well as active-to-sterile, neutrino ($\
Reference Model 5 (RM5): Oscillating Surge Wave Energy Converter
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection RadiationRecord-SettingHead ofReference-Documents Sign InReference
Method of Focussing Waves by Inhomogeneous Oscillations of the underlying
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighand Retrievals from aRodMIT-HarvardEnergyMethod forEnergyForPlasma
Paul S. Wesson
2012-12-11T23:59:59.000Z
As an example of the unification of gravitation and particle physics, an exact solution of the five-dimensional field equations is studied which describes waves in the classical Einstein vacuum. While the solution is essentially 5D in nature, the waves exist in ordinary 3D space, and may provide a way to test for an extra dimension.
Solar cell as self-oscillating heat engine
Robert Alicki; David Gelbwaser-Klimovsky; Krzysztof Szczygielski
2015-01-04T23:59:59.000Z
Solar cells are engines converting energy supplied by the photon flux into work. Any type of engine is also a self-oscillating system which yields a periodic motion at the expense of a usually non-periodic source of energy. This aspect is absent in the existing descriptions and the main goal of this paper is to show that plasma oscillations provide this necessary ingredient of work extraction process. Our approach is based on Markovian master equations which can be derived in a rigorous way from the underlying Hamiltonian models and are consistent with the laws of thermodynamics.
Transition between Two Oscillation Modes
Ricardo Lopez-Ruiz; Yves Pomeau
2002-05-17T23:59:59.000Z
A model for the symmetric coupling of two self-oscillators is presented. The nonlinearities cause the system to vibrate in two modes of different symmetries. The transition between these two regimes of oscillation can occur by two different scenarios. This might model the release of vortices behind circular cylinders with a possible transition from a symmetric to an antisymmetric Benard-von Karman vortex street.
Geometric gravitational origin of neutrino oscillations and mass-energy
Gustavo R. Gonzalez-Martin
2014-05-21T23:59:59.000Z
A mass-energy scale for neutrinos was calculated from the null cone curvature using geometric concepts. The scale is variable depending on the gravitational potential and the trajectory inclination with respect to the field direction. The proposed neutrino covariant equation provides the adequate curvature. The mass-energy at the Earth surface varies from a horizontal value 0.402 eV to a vertical value 0.569 eV. Earth spinor waves with winding numbers n show squared energy differences within ranges from 2.05 x 10*(-3) to 4.10 x 10*(-3) eV*2 for n=0,1 neutrinos and from 3.89 x 10*(-5) to 7.79 x 10*(-5) eV*2 for n=1,2 neutrinos. These waves interfere and the different phase velocities produce neutrino-like oscillations. The experimental results for atmospheric and solar neutrino oscillation mass parameters respectivelly fall within these theoretical ranges. Neutrinos in outer space, where interactions may be neglected, appear as particles travelling with zero mass on null geodesics. These gravitational curvature energies are consistent with neutrino oscillations, zero neutrino rest masses and Einstein's General Relativity and energy mass equivalence principle. When analyzing or averaging experimental neutrino mass-energy results of different experiments on the Earth it is of interest to consider the possible influence of the trajectory inclination angle.
Intermittent and sustained periodic windows in networked chaotic Rössler oscillators
He, Zhiwei; Sun, Yong [Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China) [Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhan, Meng, E-mail: zhanmeng@wipm.ac.cn [Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China)] [Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China)
2013-12-15T23:59:59.000Z
Route to chaos (or periodicity) in dynamical systems is one of fundamental problems. Here, dynamical behaviors of coupled chaotic Rössler oscillators on complex networks are investigated and two different types of periodic windows with the variation of coupling strength are found. Under a moderate coupling, the periodic window is intermittent, and the attractors within the window extremely sensitively depend on the initial conditions, coupling parameter, and topology of the network. Therefore, after adding or removing one edge of network, the periodic attractor can be destroyed and substituted by a chaotic one, or vice versa. In contrast, under an extremely weak coupling, another type of periodic window appears, which insensitively depends on the initial conditions, coupling parameter, and network. It is sustained and unchanged for different types of network structure. It is also found that the phase differences of the oscillators are almost discrete and randomly distributed except that directly linked oscillators more likely have different phases. These dynamical behaviors have also been generally observed in other networked chaotic oscillators.
Periodic auroral forms and geomagnetic field oscillations in the 1400 MLT region
Potemra, T.A. (Johns Hopkins Univ., Laurel, MD (United States)); Vo, H.; Venkatesan, D.; Cogger, L.L. (Univ. of Calgary, Alberta (Canada)); Erlandson, R.E.; Zanetti, L.J.; Bythrow, P.F.; Anderson, B.J. (Johns Hopkins Univ., Laurel, MD (United States))
1990-05-01T23:59:59.000Z
The UV images obtained with the Viking satellite often show bright features which resemble beads or pearls aligned in the east-west direction between noon and 1800 MLT. Viking acquired a series of 25 UV images during a 28-min period on July 29, 1986, which showed a distinct series of periodic bright features in this region. Magnetic field and hot plasma measurements obtained by Viking confirm that the UV emissions are colocated with the field line projection of an upward-flowing region 1 Birkeland current and precipitating energetic ({approximately}200 eV) electrons. The magnetic field and electric field measurements show transverse oscillations with a nearly constant period of about 3.5 min from 67{degree} invariant latitude equatorward up to the location of the large-scale Birkeland current system near 76{degree} invariant latitude. The electric field oscillations lead the magnetic field oscillations by about a quarter-period. The authors interpret the observed oscillations as standing Alfven waves driven at a frequency near the local resonance frequency by a large-scale wave in the boundary layer. They propose that the energy flux of the precipitating low-energy electrons in this afternoon region is modulated by this boundary wave and produces the periodic UV emission features. The results of this study support the view that large-scale oscillations of magnetospheric boundaries, possibly associated with the Kelvin-Helmholtz instability, can modulate currents, particles, and auroral forms.
THE SOURCE OF 3 MINUTE MAGNETOACOUSTIC OSCILLATIONS IN CORONAL FANS
Jess, D. B.; Mathioudakis, M.; Reardon, K. P.; Keys, P. H.; Keenan, F. P. [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); De Moortel, I. [School of Mathematics and Statistics, University of St Andrews, St Andrews KY16 9SS (United Kingdom); Christian, D. J., E-mail: d.jess@qub.ac.uk [Department of Physics and Astronomy, California State University Northridge, Northridge, CA 91330 (United States)
2012-10-01T23:59:59.000Z
We use images of high spatial, spectral, and temporal resolution, obtained using both ground- and space-based instrumentation, to investigate the coupling between wave phenomena observed at numerous heights in the solar atmosphere. Analysis of 4170 A continuum images reveals small-scale umbral intensity enhancements, with diameters {approx}0.''6, lasting in excess of 30 minutes. Intensity oscillations of Almost-Equal-To 3 minutes are observed to encompass these photospheric structures, with power at least three orders of magnitude higher than the surrounding umbra. Simultaneous chromospheric velocity and intensity time series reveal an 87 Degree-Sign {+-} 8 Degree-Sign out-of-phase behavior, implying the presence of standing modes created as a result of partial wave reflection at the transition region boundary. We find a maximum waveguide inclination angle of Almost-Equal-To 40 Degree-Sign between photospheric and chromospheric heights, combined with a radial expansion factor of <76%. An average blueshifted Doppler velocity of Almost-Equal-To 1.5 km s{sup -1}, in addition to a time lag between photospheric and chromospheric oscillatory phenomena, confirms the presence of upwardly propagating slow-mode waves in the lower solar atmosphere. Propagating oscillations in EUV intensity are detected in simultaneous coronal fan structures, with a periodicity of 172 {+-} 17 s and a propagation velocity of 45 {+-} 7 km s{sup -1}. Numerical simulations reveal that the damping of the magnetoacoustic wave trains is dominated by thermal conduction. The coronal fans are seen to anchor into the photosphere in locations where large-amplitude umbral dot (UD) oscillations manifest. Derived kinetic temperature and emission measure time series display prominent out-of-phase characteristics, and when combined with the previously established sub-sonic wave speeds, we conclude that the observed EUV waves are the coronal counterparts of the upwardly propagating magnetoacoustic slow modes detected in the lower solar atmosphere. Thus, for the first time, we reveal how the propagation of 3 minute magnetoacoustic waves in solar coronal structures is a direct result of amplitude enhancements occurring in photospheric UDs.
Plasma waves reflection from a boundary with specular accommodative boundary conditions
N. V. Gritsienko; A. V. Latyshev; A. A. Yushkanov
2010-01-06T23:59:59.000Z
In the present work the linearized problem of plasma wave reflection from a boundary of a half--space is solved analytically. Specular accommodative conditions of plasma wave reflection from plasma boundary are taken into consideration. Wave reflectance is found as function of the given parameters of the problem, and its dependence on the normal electron momentum accommodation coefficient is shown by the authors. The case of resonance when the frequency of self-consistent electric field oscillations is close to the proper (Langmuir) plasma oscillations frequency, namely, the case of long wave limit is analyzed. Refs. 17. Figs. 6.
POINTWISE GREEN FUNCTION BOUNDS AND STABILITY OF COMBUSTION WAVES
Texier, Benjamin - Institut de Mathématiques de Jussieu, Université Paris 7
POINTWISE GREEN FUNCTION BOUNDS AND STABILITY OF COMBUSTION WAVES GREGORY LYNG, MOHAMMADREZA ROOFI for traveling wave solutions of an abstract viscous combustion model including both Majda's model and the full-wave) approximation. Notably, our results apply to combustion waves of any type: weak or strong, detonations or defla
Chapter 10: Waves Did you read chapter 10
Hart, Gus
Properties: Speed The speed of sound is 340 m/s (about 1/5 mile/sec) The speed of light is 3x108 m/s You unchanged Speed = frequency Ã? wavelength. Sound "Talking" Outboard Propeller whine A compression wave Compression waves can travel through solids and fluids Solid Liquid Gas #12;2 Types of Waves: Transverse waves
Kashinath, Karthik; Waugh, Iain C.; Juniper, Matthew P.
2014-01-01T23:59:59.000Z
Thermoacoustic systems can oscillate self-excitedly, and often non-periodically, due to coupling between unsteady heat release and acoustic waves. We study a slot-stabilized two-dimensional premixed flame in a duct via numerical simulations of a G...
A 27 MHZ TEMPERATURE COMPENSATED MEMS OSCILLATOR WITH SUB-PPM INSTABILITY
Ayazi, Farrokh
A 27 MHZ TEMPERATURE COMPENSATED MEMS OSCILLATOR WITH SUB-PPM INSTABILITY Roozbeh Tabrizian with sub-ppm temperature instability based on a high-Q composite bulk acoustic wave (BAW) resonator transduced silicon resonator to compensate its negative temperature coefficient of frequency (TCF). Using
Design of a terahertz parametric oscillator based on a resonant cavity in a terahertz waveguide
Saito, K., E-mail: k-saito@material.tohoku.ac.jp; Oyama, Y. [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-11-1021, Aoba-ku, 980-8579 Sendai (Japan); Tanabe, T. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aoba-ku, 980-8577 Sendai (Japan)
2014-07-28T23:59:59.000Z
We demonstrate ns-pulsed pumping of terahertz (THz) parametric oscillations in a quasi-triply resonant cavity in a THz waveguide. The THz waves, down converted through parametric interactions between the pump and signal waves at telecom frequencies, are confined to a GaP single mode ridge waveguide. By combining the THz waveguide with a quasi-triply resonant cavity, the nonlinear interactions can be enhanced. A low threshold pump intensity for parametric oscillations can be achieved in the cavity waveguide. The THz output power can be maximized by optimizing the quality factors of the cavity so that an optical to THz photon conversion efficiency, ?{sub p}, of 0.35, which is near the quantum-limit level, can be attained. The proposed THz optical parametric oscillator can be utilized as an efficient and monochromatic THz source.
Ulian, Gianfranco; Valdrè, Giovanni, E-mail: giovanni.valdre@unibo.it [Dipartimento di Scienze Biologiche e Geologico-Ambientali, Centro di Ricerca Interdisciplinare di Biomineralogia, Cristallografia e Biomateriali, Università di Bologna “Alma Mater Studiorum” Piazza di Porta San Donato 1, 40126 Bologna (Italy)] [Dipartimento di Scienze Biologiche e Geologico-Ambientali, Centro di Ricerca Interdisciplinare di Biomineralogia, Cristallografia e Biomateriali, Università di Bologna “Alma Mater Studiorum” Piazza di Porta San Donato 1, 40126 Bologna (Italy); Tosoni, Sergio [Departament de Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, C/ Martí i Franquès 1, E-08028 Barcelona (Spain)] [Departament de Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, C/ Martí i Franquès 1, E-08028 Barcelona (Spain)
2013-11-28T23:59:59.000Z
The quantum chemical characterization of solid state systems is conducted with many different approaches, among which the adoption of periodic boundary conditions to deal with three-dimensional infinite condensed systems. This method, coupled to the Density Functional Theory (DFT), has been proved successful in simulating a huge variety of solids. Only in relatively recent years this ab initio quantum-mechanic approach has been used for the investigation of layer silicate structures and minerals. In the present work, a systematic comparison of different DFT functionals (GGA-PBEsol and hybrid B3LYP) and basis sets (plane waves and all-electron Gaussian-type orbitals) on the geometry, energy, and phonon properties of a model layer silicate, talc [Mg{sub 3}Si{sub 4}O{sub 10}(OH){sub 2}], is presented. Long range dispersion is taken into account by DFT+D method. Results are in agreement with experimental data reported in literature, with minimal deviation given by the GTO/B3LYP-D* method regarding both axial lattice parameters and interaction energy and by PW/PBE-D for the unit-cell volume and angular values. All the considered methods adequately describe the experimental talc infrared spectrum.
The Preliminary Guides to the MegaWave2 Software, Versions 2.x MegaWave2 System Library
The Preliminary Guides to the MegaWave2 Software, Versions 2.x Volume Two MegaWave2 System Library;Contents MegaWave2 System Library Contents 2 Contents 1 Introduction 6 1.1 What you will find in this guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2 The MegaWave2 memory (internal) types . . . . . . . . . . . . . . . . . . . . . . 6 1.3 File
Roberto Chignola; Alessio Del Fabbro; Edoardo Milotti
2009-09-10T23:59:59.000Z
We study the dynamics of intracellular calcium oscillations in the presence of proteins that bind calcium on multiple sites and that are generally believed to act as passive calcium buffers in cells. We find that multisite calcium-binding proteins set a sharp threshold for calcium oscillations. Even with high concentrations of calcium-binding proteins, internal noise, which shows up spontaneously in cells in the process of calcium wave formation, can lead to self-oscillations. This produces oscillatory behaviors strikingly similar to those observed in real cells. In addition, for given intracellular concentrations of both calcium and calcium-binding proteins the regularity of these oscillations changes and reaches a maximum as a function noise variance, and the overall system dynamics displays stochastic coherence. We conclude that calcium-binding proteins may have an important and active role in cellular communication.
Electromagnetic wave propagation in an active medium and the equivalent SchrÃ¶dinger equation to provide an alternative, but equivalent, representation of plane electromagnetic em wave propagation it oscillates and then decreases exponentially. Thus, for large systems, the wave propagation is suppressed
The Preliminary Guides to the MegaWave2 Software, Versions 2.x MegaWave2 System Library
The Preliminary Guides to the MegaWave2 Software, Versions 2.x Volume Two MegaWave2 System Library://www.cmla.ens-cachan.fr/Cmla/Megawave #12; Contents MegaWave2 System Library Contents 2 Contents 1 Introduction 6 1.1 What you will #12;nd) types . . . . . . . . . . . . . . . . . . . . . . 6 1.3 File (external) types or #12;le formats
Wave represents displacement Wave represents pressure Source -Sound Waves
Colorado at Boulder, University of
Wave represents displacement Wave represents pressure Source - Sound Waves Distance between crests is wavelength Number of crests passing a point in 1 second is frequency Wave represents pressure Target - Radio Waves Distance between crests is wavelength Number of crests passing a point in 1 second is frequency
Oscillations of solar atmosphere neutrinos
G. L. Fogli; E. Lisi; A. Mirizzi; D. Montanino; P. D. Serpico
2006-11-10T23:59:59.000Z
The Sun is a source of high energy neutrinos (E > 10 GeV) produced by cosmic ray interactions in the solar atmosphere. We study the impact of three-flavor oscillations (in vacuum and in matter) on solar atmosphere neutrinos, and calculate their observable fluxes at Earth, as well as their event rates in a kilometer-scale detector in water or ice. We find that peculiar three-flavor oscillation effects in matter, which can occur in the energy range probed by solar atmosphere neutrinos, are significantly suppressed by averaging over the production region and over the neutrino and antineutrino components. In particular, we find that the relation between the neutrino fluxes at the Sun and at the Earth can be approximately expressed in terms of phase-averaged ``vacuum'' oscillations, dominated by a single mixing parameter (the angle theta_23).
Symmetries in collective neutrino oscillations
Huaiyu Duan; George M. Fuller; Yong-Zhong Qian
2009-07-31T23:59:59.000Z
We discuss the relationship between a symmetry in the neutrino flavour evolution equations and neutrino flavour oscillations in the collective precession mode. This collective precession mode can give rise to spectral swaps (splits) when conditions can be approximated as homogeneous and isotropic. Multi-angle numerical simulations of supernova neutrino flavour transformation show that when this approximation breaks down, non-collective neutrino oscillation modes decohere kinematically, but the collective precession mode still is expected to stand out. We provide a criterion for significant flavour transformation to occur if neutrinos participate in a collective precession mode. This criterion can be used to understand the suppression of collective neutrino oscillations in anisotropic environments in the presence of a high matter density. This criterion is also useful in understanding the breakdown of the collective precession mode when neutrino densities are small.
Real Oscillations of Virtual Neutrinos
W. Grimus; P. Stockinger
1996-03-28T23:59:59.000Z
We study the conditions for neutrino oscillations in a field theoretical approach by taking into account that only the neutrino production and detection processes, which are localized in space around the coordinates $\\vec{x}_P$ and $\\vec{x}_D$, respectively, can be manipulated. In this sense the neutrinos whose oscillations are investigated appear as virtual lines connecting production with detection in the total Feynman graph and all neutrino fields or states to be found in the discussion are mass eigenfields or eigenstates. We perform a thorough examination of the integral over the spatial components of the inner neutrino momentum and show that in the asymptotic limit $L=|\\vec{x}_D - \\vec{x}_P| \\rightarrow \\infty$ the virtual neutrinos become ``real'' and under certain conditions the usual picture of neutrino oscillations emerges without ambiguities.
Real oscillations of virtual neutrinos
Grimus, Walter
1996-01-01T23:59:59.000Z
We study the conditions for neutrino oscillations in a field theoretical approach by taking into account that only the neutrino production and detection processes, which are localized in space around the coordinates \\vec{x}_P and \\vec{x}_D, respectively, can be manipulated. In this sense the neutrinos whose oscillations are investigated appear as virtual lines connecting production with detection in the total Feynman graph and all neutrino fields or states to be found in the discussion are mass eigenfields or eigenstates. We perform a thorough examination of the integral over the spatial components of the inner neutrino momentum and show that in the asymptotic limit L=|\\vec{x}_D - \\vec{x}_P| \\rightarrow \\infty the virtual neutrinos become ``real'' and under certain conditions the usual picture of neutrino oscillations emerges without ambiguities.
The Preliminary Guides to the MegaWave2 Software, Versions 2.x Volume Two
Two MegaWave2 System Library by Jacques FromentWave2 System Library Contents * * 2 Contents 1 Introduction . . . . . . . . . . . . . . . . . . . * *. . . . . . . . . 6 1.2 The MegaWave2 memory (internal) types . . . . . . . . . . . . . . . . * *. . . . . . 6
On a class of self-similar 2D surface water waves
Sijue Wu
2012-06-11T23:59:59.000Z
We construct a class of self-similar surface water waves and study its properties. This class of surface waves appears to be in very good agreement with a common type of wave crests in the ocean.
Short Baseline Neutrino Oscillation Experiments
Katori, Teppei
2014-01-01T23:59:59.000Z
Series of short baseline neutrino oscillation experiments provided unexpected results, and now they are called short baseline anomalies, and all indicates an existence of sterile neutrinos with a mass scale around 1~eV. The signals of short baseline anomalies are reported from 4 different classes of experiments. However, at this moment, there is no convincing theoretical model to explain such sterile neutrinos, and a single experiment to confirm 1~eV sterile neutrinos may be challenging. In this short note, we describe classes of short baseline neutrino oscillation experiments and their goals.
Ion Acceleration in Plasmas with Alfven Waves
O.Ya. Kolesnychenko; V.V. Lutsenko; R.B. White
2005-06-15T23:59:59.000Z
Effects of elliptically polarized Alfven waves on thermal ions are investigated. Both regular oscillations and stochastic motion of the particles are observed. It is found that during regular oscillations the energy of the thermal ions can reach magnitudes well exceeding the plasma temperature, the effect being largest in low-beta plasmas (beta is the ratio of the plasma pressure to the magnetic field pressure). Conditions of a low stochasticity threshold are obtained. It is shown that stochasticity can arise even for waves propagating along the magnetic field provided that the frequency spectrum is non-monochromatic. The analysis carried out is based on equations derived by using a Lagrangian formalism. A code solving these equations is developed. Steady-state perturbations and perturbations with the amplitude slowly varying in time are considered.
Sea surface wave reconstruction from marine radar images
Qi, Yusheng, S.M. Massachusetts Institute of Technology
2012-01-01T23:59:59.000Z
The X-band marine radar is one type of remote sensing technology which is being increasingly used to measure sea surface waves nowadays. In this thesis, how to reconstruct sea surface wave elevation maps from X-band marine ...
Theoretical and experimental study of nonlinear internal gravity wave beams
Tabaei Befrouei, Ali, 1974-
2005-01-01T23:59:59.000Z
Continuously stratified fluids, like the atmosphere and the oceans, support internal gravity waves due to the effect of buoyancy. This type of wave motion is anisotropic since gravity provides a preferred direction. As a ...
Acoustic waves in random ensembles of magnetic fluxes
Ryutova, M.P.
1995-10-10T23:59:59.000Z
To analyze the observational data and provide the appropriate diagnostic procedure for photospheric manifestation of solar oscillations it is necessary to take into account strong inhomogeneity of solar atmosphere with respect to distribution of magnetic fields. We study the collective phenomena in the propagation of acoustic waves and unsteady wave-packets through quite regions, sunspots and plages, including time-dependent response of these regions to solar oscillations, the energy transfer mechanisms, frequency shift effects and reradiation of the acoustic waves in higher layers of atmosphere. We show that the dynamics of differently magnetized regions, their dispersion properties, and their response to the propagation of acoustic waves are completely different. We describe the effects caused by the specific distribution and randomness of magnetic flux tubes, which can be observed and which can provide the tools for diagnostic goals.
Nonlinear Eigenmodes of a Polariton Harmonic Oscillator
Florian Pinsker; and Tristram J. Alexander
2015-01-28T23:59:59.000Z
We investigate theoretically the quantum oscillator-like states recently observed experimentally in polariton condensates (Nat. Phys. 8, 190 (2012)). We consider a complex Gross-Pitaevskii type model which includes the effects of self-interactions, and creation and decay of exciton-polaritons. We develop a perturbation theory for approximate solutions to this non-equilibrium condensate model and compare the results with numerically calculated solutions for both repulsive and attractive polariton-polariton interactions. While the nonlinearity has a weak effect on the mode selection their density profiles are modified at moderate gain strengths and becomes more dominant when a very large gain of polaritons implies an extended cloud with high condensate densities. Finally, we identify the relation of the observed patterns to the input pump configuration, and suggest this may serve as a generalized NOR gate in the tradition of optical computing.
Sensitivity analysis of oscillating hybrid systems
Saxena, Vibhu Prakash
2010-01-01T23:59:59.000Z
Many models of physical systems oscillate periodically and exhibit both discrete-state and continuous-state dynamics. These systems are called oscillating hybrid systems and find applications in diverse areas of science ...
Single mode pulsed dye laser oscillator
Hackel, R.P.
1992-11-24T23:59:59.000Z
A single mode pulsed dye laser oscillator is disclosed. The dye laser oscillator provides for improved power efficiency by reducing the physical dimensions of the overall laser cavity, which improves frequency selection capability. 6 figs.
Lepton textures and neutrino oscillations
Verma, Rohit
2014-01-01T23:59:59.000Z
Systematic analyses of the textures arising in lepton mass matrices have been carried out using unitary transformations and condition of naturalness for the Dirac and Majorana neutrino possibilities. It is observed that the recent three neutrino oscillation data together with the effective mass in neutrinoless double beta decay provide vital clues in predicting the general structures of these lepton mass matrices.
Pulsar kicks from neutrino oscillations
Alexander Kusenko; Gino Segre
1998-11-10T23:59:59.000Z
Neutrino oscillations can explain the observed motion of pulsars. We show that two different models of neutrino emission from a cooling neutron star are in good quantitative agreement and predict the same order of magnitude for the pulsar kick velocity, consistent with the data.
Lepton textures and neutrino oscillations
Rohit Verma
2014-06-03T23:59:59.000Z
Systematic analyses of the textures arising in lepton mass matrices have been carried out using unitary transformations and condition of naturalness for the Dirac and Majorana neutrino possibilities. It is observed that the recent three neutrino oscillation data together with the effective mass in neutrinoless double beta decay provide vital clues in predicting the general structures of these lepton mass matrices.
Do the Kamiokande results need neutrino oscillations?
Baillon, Paul
1999-01-01T23:59:59.000Z
Neutrino oscillations are a delicate and important subject. One needs to be sure that every aspect of it is well understood. The recent results of the Kamiokande experiment [1], indicate the possibility of -- neutrino oscillations. The period of oscillation observed by Kamiokande is not compatible with what one may deduce from the solar neutrino experiments [2]. In this letter, we examine if another mechanism could fake neutrino oscillations and could be measurement dependent
Neutrino Oscillations and the Early Universe
D. P. Kirilova
2003-12-21T23:59:59.000Z
The observational and theoretical status of neutrino oscillations in connection with solar and atmospheric neutrino anomalies is presented in brief. The effect of neutrino oscillations on the early Universe evolution is discussed in detail. A short review is given of the standard Big Bang Nucleosynthesis and the influence of resonant and nonresonant neutrino oscillations on active neutrinos and on primordial nucleosynthesis of He-4. BBN cosmological constraints on neutrino oscillation parameters are discussed.
Neutrino oscillations: brief history and present status
Bilenky, S M
2014-01-01T23:59:59.000Z
A brief review of the problem of neutrino masses and oscillations is given. In the beginning we present an early history of neutrino masses, mixing and oscillations. Then we discuss all possibilities of neutrino masses and mixing (neutrino mass terms). The phenomenology of neutrino oscillations in vacuum is considered in some details. We present also the neutrino oscillation data and the seesaw mechanism of the neutrino mass generation.
Silicon crystal growing by oscillating crucible technique
Schwuttke, G.H.; Kim, K.M.; Smetana, P.
1983-08-03T23:59:59.000Z
A process for growing silicon crystals from a molten melt comprising oscillating the container during crystal growth is disclosed.
Coronal transverse magnetohydrodynamic waves in a solar prominence
T. J. Okamoto; S. Tsuneta; T. E. Berger; K. Ichimoto; Y. Katsukawa; B. W. Lites; S. Nagata; K. Shibata; T. Shimizu; R. A. Shine; Y. Suematsu; T. D. Tarbell; A. M. Title
2008-01-13T23:59:59.000Z
Solar prominences are cool 10$^4$ Kelvin plasma clouds supported in the surrounding 10$^6$ Kelvin coronal plasma by as-yet undetermined mechanisms. Observations from \\emph{Hinode} show fine-scale threadlike structures oscillating in the plane of the sky with periods of several minutes. We suggest these transverse magnetohydrodynamic waves may represent Alfv\\'en waves propagating on coronal magnetic field lines and these may play a role in heating the corona.
Krysl, Svatopluk
C -algebras Oscillator or Segal-Shale-Weil representation Geometry: Associating the oscillator or Segal-Shale-Weil representation Geometry: Associating the oscillator to symplectic manifolds Global and (x) = 0 implies x = 0 2 S. KrÃ½sl #12;C -algebras Oscillator or Segal-Shale-Weil representation
Radiation reaction and quantum damped harmonic oscillator
F. Kheirandish; M. Amooshahi
2005-07-19T23:59:59.000Z
By taking a Klein-Gordon field as the environment of an harmonic oscillator and using a new method for dealing with quantum dissipative systems (minimal coupling method), the quantum dynamics and radiation reaction for a quantum damped harmonic oscillator investigated. Applying perturbation method, some transition probabilities indicating the way energy flows between oscillator, reservoir and quantum vacuum, obtained
Neutrino oscillations: Current status and prospects
Thomas Schwetz
2005-10-25T23:59:59.000Z
I summarize the status of neutrino oscillations from world neutrino oscillation data with date of October 2005. The results of a global analysis within the three-flavour framework are presented. Furthermore, a prospect on where we could stand in neutrino oscillations in ten years from now is given, based on a simulation of upcoming long-baseline accelerator and reactor experiments.
Neutrino oscillations: present status and outlook
Thomas Schwetz
2007-10-26T23:59:59.000Z
I summarize the status of three-flavour neutrino oscillations with date of Oct. 2007, and provide an outlook for the developments to be expected in the near future. Furthermore, I discuss the status of sterile neutrino oscillation interpretations of the LSND anomaly in the light of recent MiniBooNE results, and comment on implications for the future neutrino oscillation program.
The Quantum Harmonic Oscillator C. David Sherrill
Sherrill, David
The Quantum Harmonic Oscillator C. David Sherrill School of Chemistry and Biochemistry Georgia Institute of Technology February 2002 1 Introduction The harmonic oscillator is extremely useful by coupled harmonic oscillators. The atoms are viewed as point masses which are connected by bonds which act
Velocity Induced Neutrino Oscillation and its Possible Implications for Long Baseline Neutrinos
Banik, Amit Dutta
2014-01-01T23:59:59.000Z
If the three types of active neutrinos possess different maximum attainable velocities and the neutrino eigenstates in the velocity basis are different from those in the flavour (and mass) basis then this will induce a flavour oscillation in addition to the normal mass flavour oscillation. Here we study such an oscillation scenario in three neutrino framework including also the matter effect and apply our results to demonstrate its consequences for long baseline neutrinos. We also predict the possible signatures in terms of yields in a possible long baseline neutrino experiment.
Ion beam oscillation due to fluctuation of a hot filament driven magnetized plasma
Imakita, S.; Kasuya, T.; Kimura, Y.; Wada, M. [Graduate School of Engineering, Doshisha University, Kyoto 610-0321 (Japan); Miyamoto, N. [Nissin Ion Equipment Co. Ltd., Kyoto 601-8205 (Japan)
2010-02-15T23:59:59.000Z
Ion beam current extracted from a modified Bernas type ion source occasionally exhibits an oscillation at a frequency of several 100 kHz. Increase in the strength of a linear magnetic field induced to the ion source has either decreased or increased the frequency of this oscillation. The frequency showed an increase in proportion to the ion extraction voltage when the frequency decreased with increasing magnetic field. The change of extraction voltage did not affect the frequency when the frequency increased with the increasing magnetic field. Mechanisms causing these oscillations of an ion beam had been investigated.
Shock Wave Impact on Weak Concrete , K.D. Gardner1
Texas at Arlington, University of
. The major effect of a terrorist-type bomb is from the blast, particularly from blast wave reflection when. This paper reports on the use of a shock wave to simulate the effect of a blast wave on weak concrete. A high/19, Moscow, Russia Abstract. A blast wave front possesses characteristics similar to a shock wave created
Bragg scattering and wave-power extraction by an array of small buoys
Boyer, Edmond
Bragg scattering and wave-power extraction by an array of small buoys By Xavier Garnaud & Chiang C to power-takeoff devices. The spacing between buoys is assumed to be comparable to the incident wavelength to the potential of power extraction from sea waves by an isolated unit such as a buoy, a raft or an oscillating
Energy oscillations and a possible route to chaos in a modified Riga dynamo
Stefani, Frank; Gerbeth, Gunter
2010-01-01T23:59:59.000Z
Starting from the present version of the Riga dynamo experiment with its rotating magnetic eigenfield dominated by a single frequency we ask for those modifications of this set-up that would allow for a non-trivial magnetic field behaviour in the saturation regime. Assuming an increased ratio of azimuthal to axial flow velocity, we obtain energy oscillations with a frequency below the eigenfrequency of the magnetic field. These new oscillations are identified as magneto-inertial waves that result from a slight imbalance of Lorentz and inertial forces. Increasing the azimuthal velocity further, or increasing the total magnetic Reynolds number, we find transitions to a chaotic behaviour of the dynamo.
Nonlinear Hysteretic Torsional Waves
J. Cabaret; P. Béquin; G. Theocharis; V. Andreev; V. E. Gusev; V. Tournat
2015-01-09T23:59:59.000Z
We theoretically study and experimentally report the propagation of nonlinear hysteretic torsional pulses in a vertical granular chain made of cm-scale, self-hanged magnetic beads. As predicted by contact mechanics, the torsional coupling between two beads is found nonlinear hysteretic. This results in a nonlinear pulse distortion essentially different from the distortion predicted by classical nonlinearities, and in a complex dynamic response depending on the history of the wave particle angular velocity. Both are consistent with the predictions of purely hysteretic nonlinear elasticity and the Preisach-Mayergoyz hysteresis model, providing the opportunity to study the phenomenon of nonlinear dynamic hysteresis in the absence of other type of material nonlinearities. The proposed configuration reveals a plethora of interesting phenomena including giant amplitude-dependent attenuation, short term memory as well as dispersive properties. Thus, it could find interesting applications in nonlinear wave control devices such as strong amplitude-dependent filters.
Nonlinear Hysteretic Torsional Waves
Cabaret, J; Theocharis, G; Andreev, V; Gusev, V E; Tournat, V
2015-01-01T23:59:59.000Z
We theoretically study and experimentally report the propagation of nonlinear hysteretic torsional pulses in a vertical granular chain made of cm-scale, self-hanged magnetic beads. As predicted by contact mechanics, the torsional coupling between two beads is found nonlinear hysteretic. This results in a nonlinear pulse distortion essentially different from the distortion predicted by classical nonlinearities, and in a complex dynamic response depending on the history of the wave particle angular velocity. Both are consistent with the predictions of purely hysteretic nonlinear elasticity and the Preisach-Mayergoyz hysteresis model, providing the opportunity to study the phenomenon of nonlinear dynamic hysteresis in the absence of other type of material nonlinearities. The proposed configuration reveals a plethora of interesting phenomena including giant amplitude-dependent attenuation, short term memory as well as dispersive properties. Thus, it could find interesting applications in nonlinear wave control de...
Combustor oscillating pressure stabilization and method
Gemmen, Randall S. (Morgantown, WV); Richards, George A. (Morgantown, WV); Yip, Mui-Tong Joseph (Morgantown, WV); Robey, Edward H. (Westover, WV); Cully, Scott R. (Morgantown, WV); Addis, Richard E. (Smithfield, PA)
1998-01-01T23:59:59.000Z
High dynamic pressure oscillations in hydrocarbon-fueled combustors typically occur when the transport time of the fuel to the flame front is at some fraction of the acoustic period. These oscillations are reduced to acceptably lower levels by restructuring or repositioning the flame front in the combustor to increase the transport time. A pilot flame front located upstream of the oscillating flame and pulsed at a selected frequency and duration effectively restructures and repositions the oscillating flame in the combustor to alter the oscillation-causing transport time.
Measuring neutrino oscillation parameters using $\
Backhouse, Christopher James; /Oxford U.
2011-02-01T23:59:59.000Z
MINOS is a long-baseline neutrino oscillation experiment. It consists of two large steel-scintillator tracking calorimeters. The near detector is situated at Fermilab, close to the production point of the NuMI muon-neutrino beam. The far detector is 735 km away, 716m underground in the Soudan mine, Northern Minnesota. The primary purpose of the MINOS experiment is to make precise measurements of the 'atmospheric' neutrino oscillation parameters ({Delta}m{sub atm}{sup 2} and sin{sup 2} 2{theta}{sub atm}). The oscillation signal consists of an energy-dependent deficit of {nu}{sub {mu}} interactions in the far detector. The near detector is used to characterize the properties of the beam before oscillations develop. The two-detector design allows many potential sources of systematic error in the far detector to be mitigated by the near detector observations. This thesis describes the details of the {nu}{sub {mu}}-disappearance analysis, and presents a new technique to estimate the hadronic energy of neutrino interactions. This estimator achieves a significant improvement in the energy resolution of the neutrino spectrum, and in the sensitivity of the neutrino oscillation fit. The systematic uncertainty on the hadronic energy scale was re-evaluated and found to be comparable to that of the energy estimator previously in use. The best-fit oscillation parameters of the {nu}{sub {mu}}-disappearance analysis, incorporating this new estimator were: {Delta}m{sup 2} = 2.32{sub -0.08}{sup +0.12} x 10{sup -3} eV{sup 2}, sin {sup 2} 2{theta} > 0.90 (90% C.L.). A similar analysis, using data from a period of running where the NuMI beam was operated in a configuration producing a predominantly {bar {nu}}{sub {mu}} beam, yielded somewhat different best-fit parameters {Delta}{bar m}{sup 2} = (3.36{sub -0.40}{sup +0.46}(stat.) {+-} 0.06(syst.)) x 10{sup -3}eV{sup 2}, sin{sup 2} 2{bar {theta}} = 0.86{sub -0.12}{sup _0.11}(stat.) {+-} 0.01(syst.). The tension between these results is intriguing, and additional antineutrino data is currently being taken in order to further investigate this apparent discrepancy.
Autoresonant Dynamics of Optical Guided Waves Assaf Barak,1
Friedland, Lazar
. Autoresonance offers a different way to maintain phase locking even when the system is excited deeply phase locking and amplification to predetermined amplitudes. This constitutes the first observation resonance, remaining phase locked with driving oscillations (or waves) despite variations in the system
Photon Plasma-Wave Interaction via Compton Scattering
Galina Erochenkova; Cristel Chandre
2012-08-16T23:59:59.000Z
The Kompaneets theory of photon kinetic evolution due to the Compton effect is extended to the case of the Vlasov plasma wave oscillations. Taking into account Zel'dovich-Levich's approximation we study interaction of accumulating photons with plasma in the long wavelength limit.
The Quality of Oscillations in Overdamped Networks
Nathan O. Hodas
2011-08-08T23:59:59.000Z
The second law of thermodynamics implies that no macroscopic system may oscillate indefinitely without consuming energy. The question of the number of possible oscillations and the coherent quality of these oscillations remain unanswered. This paper proves the upper-bounds on the number and quality of such oscillations when the system in question is homogeneously driven and has a discrete network of states. In a closed system, the maximum number of oscillations is bounded by the number of states in the network. In open systems, the size of the network bounds the quality factor of oscillation. This work also explores how the quality factor of macrostate oscillations, such as would be observed in chemical reactions, are bounded by the smallest equivalent loop of the network, not the size of the entire system. The consequences of this limit are explored in the context of chemical clocks and limit cycles.
Berry Phase in Neutrino Oscillations
Xiao-Gang He; Xue-Qian Li; Bruce H. J. McKellar; Yue Zhang
2005-05-18T23:59:59.000Z
We study the Berry phase in neutrino oscillations for both Dirac and Majorana neutrinos. In order to have a Berry phase, the neutrino oscillations must occur in a varying medium, the neutrino-background interactions must depend on at least two independent densities, and also there must be CP violation if the neutrino interactions with matter are mediated only by the standard model W and Z boson exchanges which implies that there must be at least three generations of neutrinos. The CP violating Majorana phases do not play a role in generating a Berry phase. We show that a natural way to satisfy the conditions for the generation of a Berry phase is to have sterile neutrinos with active-sterile neutrino mixing, in which case at least two active and one sterile neutrinos are required. If there are additional new CP violating flavor changing interactions, it is also possible to have a non-zero Berry phase with just two generations.
Carnot cycle for an oscillator
Arnaud, J; Philippe, F
2002-01-01T23:59:59.000Z
Carnot established in 1824 that the efficiency of cyclic engines operating between a hot bath at absolute temperature Th and a cold bath at temperature Tc cannot exceed 1-Tc/Th. This result implies the existence of an entropy function S(U) with the property that d^2S/dU^2 less equal 0, where U denotes the average energy. Linear single-mode systems alternately in contact with hot and cold baths obey these principles. A specific expression of the work done per cycle by an oscillator is derived from a prescription established by Einstein in 1906: heat baths may exchange energy with oscillators at angular frequency omega only by amounts hbar *omega, where 2*pi*hbar denotes the Planck constant. Non-reversible cycles are illustrated. The paper is essentially self-contained.
Ladder operators for isospectral oscillators
S. Seshadri; V. Balakrishnan; S. Lakshmibala
1999-05-31T23:59:59.000Z
We present, for the isospectral family of oscillator Hamiltonians, a systematic procedure for constructing raising and lowering operators satisfying any prescribed `distorted' Heisenberg algebra (including the $q$-generalization). This is done by means of an operator transformation implemented by a shift operator. The latter is obtained by solving an appropriate partial isometry condition in the Hilbert space. Formal representations of the non-local operators concerned are given in terms of pseudo-differential operators. Using the new annihilation operators, new classes of coherent states are constructed for isospectral oscillator Hamiltonians. The corresponding Fock-Bargmann representations are also considered, with specific reference to the order of the entire function family in each case.
Oscillators: Old and new perspectives
Bhattacharjee, Jayanta K. [Harish-Chandra Research Institute, Jhunsi, Allahabad 211019 (India); Roy, Jyotirmoy [UM-DAE Centre for Excellence in Basic Sciences, Santa Cruz(E), Mumbai 400098 (India)
2014-02-11T23:59:59.000Z
We consider some of the well known oscillators in literature which are known to exhibit interesting effects of nonlinearity. We review the Lindstedt-Poincare technique for dealing with with the nonlinear effects and then go on to introduce the relevance of the renormalization group for the oscillator following the pioneering work of Chen et al. It is pointed out that the traditional Lindstedt-Poincare and the renormalization group techniques have operational connections. We use this to find an unexpected mode softening in the double pendulum. This mode softening prompted us to look for chaos in the double pendulum at low energies-energies that are just sufficient to allow the outer pendulum to rotate (the double pendulum is known to be chaotic at high energies-energies that are greater than that needed to make both pendulums to rotate). The emergence of the chaos is strongly dependent on initial conditions.
Neutrino Masses and Flavor Oscillations
Yifang Wang; Zhi-zhong Xing
2015-04-23T23:59:59.000Z
This essay is intended to provide a brief description of the peculiar properties of neutrinos within and beyond the standard theory of weak interactions. The focus is on the flavor oscillations of massive neutrinos, from which one has achieved some striking knowledge about their mass spectrum and flavor mixing pattern. The experimental prospects towards probing the absolute neutrino mass scale, possible Majorana nature and CP-violating effects will also be addressed.
Neutrino Masses and Flavor Oscillations
Wang, Yifang
2015-01-01T23:59:59.000Z
This essay is intended to provide a brief description of the peculiar properties of neutrinos within and beyond the standard theory of weak interactions. The focus is on the flavor oscillations of massive neutrinos, from which one has achieved some striking knowledge about their mass spectrum and flavor mixing pattern. The experimental prospects towards probing the absolute neutrino mass scale, possible Majorana nature and CP-violating effects will also be addressed.
Graphene, neutrino mass and oscillation
Z. Y. Wang
2011-03-28T23:59:59.000Z
A resolution of the Abraham-Minkowski dilemma is presented that other constant velocities can play the role of c in the theory of relativity. For example, in 2005 electrons of graphene were discovered to behave as if the coefficient is a Fermi velocity. Then we propose a conjecture for neutrinos to avoid the contradiction among two-component theory, negative rest mass-square and oscillation.
A Characterization of the Brightness Oscillations During Thermonuclear Bursts From 4U 1636-536
M. Coleman Miller
1999-04-08T23:59:59.000Z
The discovery of nearly coherent brightness oscillations during thermonuclear X-ray bursts from six neutron-star low-mass X-ray binaries has opened up a new way to study the propagation of thermonuclear burning, and may ultimately lead to greater understanding of thermonuclear propagation in other astrophysical contexts, such as in Type Ia supernovae. Here we report detailed analyses of the ~580 Hz brightness oscillations during bursts from 4U 1636-536. We investigate the bursts as a whole and, in more detail, the initial portions of the bursts. We analyze the ~580 Hz oscillations in the initial 0.75 seconds of the five bursts that were used in a previous search for a brightness oscillation at the expected ~290 Hz spin frequency, and find that if the same frequency model describes all five bursts there is insufficient data to require more than a constant frequency or, possibly, a frequency plus a frequency derivative. Therefore, although it is appropriate to use an arbitrarily complicated model of the ~580 Hz oscillations to generate a candidate waveform for the ~290 Hz oscillations, models with more than two parameters are not required by the data. For the bursts as a whole we show that the characteristics of the brightness oscillations vary greatly from burst to burst. We find, however, that in at least one of the bursts, and possibly in three of the four that have strong brightness oscillations throughout the burst, the oscillation frequency reaches a maximum several seconds into the burst and then decreases. This behavior has not been reported previously for burst brightness oscillations, and it poses a challenge to the standard burning layer expansion explanation for the frequency changes.
Micro-machined resonator oscillator
Koehler, Dale R. (Albuquerque, NM); Sniegowski, Jeffry J. (Albuquerque, NM); Bivens, Hugh M. (Albuquerque, NM); Wessendorf, Kurt O. (Albuquerque, NM)
1994-01-01T23:59:59.000Z
A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available.
Micro-machined resonator oscillator
Koehler, D.R.; Sniegowski, J.J.; Bivens, H.M.; Wessendorf, K.O.
1994-08-16T23:59:59.000Z
A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a telemetered sensor beacon'' that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20--100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available. 21 figs.
Guidelines in Wave Energy Conversion System Design
Guiberteau, K. L.; Liu, Y.; Lee, J.; Kozman, T.
2014-01-01T23:59:59.000Z
This paper presents an investigational study on wave energy converters (WECs). The types of WEC available from the market are studied first. The design considerations for implementing a WEC in the Gulf of Mexico (GOM) are then evaluated...
Deepwater Internal Wave Study and Application
Jiang, Lei
2013-12-10T23:59:59.000Z
conforming to the physics of internal waves and to study the effects on offshore drilling semisubmersibles, different types of offshore hull forms and riser systems, including the large diameter cold water pipe of floating Ocean Thermal Energy Conversion...
Coda wave interferometry 1 Coda wave interferometry
Snieder, Roel
Coda wave interferometry 1 Coda wave interferometry An interferometer is an instrument that is sensitive to the interference of two or more waves (optical or acoustic). For example, an optical interferometer uses two interfering light beams to measure small length changes. Coda wave interferometry
Transition from amplitude to oscillation death in a network of oscillators
Mauparna Nandan; C. R. Hens; Pinaki Pal; Syamal K. Dana
2014-09-29T23:59:59.000Z
We report a transition from a homogeneous steady state (HSS) to inhomogeneous steady states (IHSSs) in a network of globally coupled identical oscillators. We perturb a synchronized population in the network with a few local negative mean field links. It is observed that the whole population splits into two clusters for a certain number of negative mean field links and specific range of coupling strength. For further increases of the strength of interaction these clusters collapse to a HSS followed by a transition to IHSSs. We analytically determine the origin of HSS and its transition to IHSS in relation to the number of negative mean-field links and the strength of interaction using a reductionism approach to the model network in a two-cluster state. We verify the results with numerical examples of networks using the paradigmatic Landau-Stuart limit cycle system and the chaotic Rossler oscillator as dynamical nodes. During the transition from HSS to IHSSs, the network follows the Turing type symmetry breaking pitchfork or transcritical bifurcation depending upon the system dynamics.
Peaks and Troughs in Helioseismology: The Power Spectrum of Solar Oscillations
Colin S. Rosenthal
1998-04-15T23:59:59.000Z
I present a matched-wave asymptotic analysis of the driving of solar oscillations by a general localised source. The analysis provides a simple mathematical description of the asymmetric peaks in the power spectrum in terms of the relative locations of eigenmodes and troughs in the spectral response. It is suggested that the difference in measured phase function between the modes and the troughs in the spectrum will provide a key diagnostic of the source of the oscillations. I also suggest a form for the asymmetric line profiles to be used in the fitting of solar power spectra. Finally I present a comparison between the numerical and asymptotic descriptions of the oscillations. The numerical results bear out the qualitative features suggested by the asymptotic analysis but suggest that numerical calculations of the locations of the troughs will be necessary for a quantitative comparison with the observations.
Wave propagation in highly inhomogeneous thin films: exactly solvable models
Boyer, Edmond
Wave propagation in highly inhomogeneous thin films: exactly solvable models Guillaume Petite(1 of wave propagation in some inhomogeneous thin films with highly space- dependent dielectric constant will show that depending on the type of space dependence, an incident wave can either propagate or tunnel
New wave equation for ultrarelativistic particles
Ginés R. Pérez Teruel
2014-12-15T23:59:59.000Z
Starting from first principles and general assumptions based on the energy-momentum relation of the Special Theory of Relativity we present a novel wave equation for ultrarelativistic matter. This wave equation arises when particles satisfy the condition, $p>>m$, i.e, when the energy-momentum relation can be approximated by, $E\\simeq p+\\frac{m^{2}}{2p}$. Interestingly enough, such as the Dirac equation, it is found that this wave equation includes spin in a natural way. Furthermore, the free solutions of this wave equation contain plane waves that are completely equivalent to those of the theory of neutrino oscillations. Therefore, the theory reproduces some standard results of the Dirac theory in the limit $p>>m$, but offers the possibility of an explicit Lorentz Invariance Violation of order, $\\mathcal{O}((mc)^{4}/p^{2})$. As a result, the theory could be useful to test small departures from Dirac equation and Lorentz Invariance at very high energies. On the other hand, the wave equation can also describe particles of spin 1 by a simple substitution of the spin operators, $\\boldsymbol{\\sigma}\\rightarrow\\boldsymbol{\\alpha}$. In addition, it naturally admits a Lagrangian formulation and a Hamiltonian formalism. We also discuss the associated conservation laws that arise through the symmetry transformations of the Lagrangian.
Collective neutrino oscillations and spontaneous symmetry breaking
Duan, Huaiyu
2015-01-01T23:59:59.000Z
Neutrino oscillations in a hot and dense astrophysical environment such as a core-collapse supernova pose a challenging, seven-dimensional flavor transport problem. To make the problem even more difficult (and interesting), neutrinos can experience collective oscillations through nonlinear refraction in the dense neutrino medium in this environment. Significant progress has been made in the last decade towards the understanding of collective neutrino oscillations in various simplified neutrino gas models with imposed symmetries and reduced dimensions. However, a series of recent studies seem to have "reset" this progress by showing that these models may not be compatible with collective neutrino oscillations because the latter can break the symmetries spontaneously if they are not imposed. We review some of the key concepts of collective neutrino oscillations by using a few simple toy models. We also elucidate the breaking of spatial and directional symmetries in these models because of collective oscillation...
Dynamics of two populations of phase oscillators with different frequency distributions
Yu Terada; Toshio Aoyagi
2014-11-19T23:59:59.000Z
A large variety of rhythms have been observed in nature. These rhythms can be often regarded to interact with each other, such as electroencephalogram (EEG) in the brain. To investigate the dynamical properties of such systems, in this paper, we consider two populations of phase oscillators with different frequency distributions, particularly under the condition that the average frequency of fast oscillators is almost equal to the integral multiple of that of slow oscillators. What is the most important point is that we have to use the specific type of the coupling function derived from the phase reduction theory. Under some additional assumption, moreover, we can reduce the system consisting of two populations of coupled phase oscillators to a low-dimensional system in the continuum limit. As a result, we find chimera states in which clustering and incoherent states coexist. We also confirm that the behaviors of the derived low-dimensional model fairly agree with that of the original one.
Dynamics of chiral oscillations - A comparative analysis with spin-flipping
Alex E. Bernardini
2013-01-04T23:59:59.000Z
Chiral oscillation as well as spin flipping effects correspond to quantum phenomena of fundamental importance in the context of particle physics and, in particular, of neutrino physics. From the point of view of first quantized theories, we are specifically interested in appointing the differences between chirality and helicity by obtaining their dynamic equations for a fermionic Dirac-type particle (neutrino). We also identify both effects when the non-minimal coupling with an external (electro)magnetic field in the neutrino interacting Lagrangian is taken into account. We demonstrate that, however, there is no constraint between chiral oscillations, when it takes place in vacuum, and the process of spin flipping related to the helicity quantum number, which does not take place in vacuum. To conclude, we show that the origin of chiral oscillations (in vacuum) can be interpreted as position very rapid oscillation projections onto the longitudinal direction of momentum.
Wave-Packet Revivals for Quantum Systems with Nondegenerate Energies
Robert Bluhm; Alan Kostelecky; Bogdan Tudose
1996-09-26T23:59:59.000Z
The revival structure of wave packets is examined for quantum systems having energies that depend on two nondegenerate quantum numbers. For such systems, the evolution of the wave packet is controlled by two classical periods and three revival times. These wave packets exhibit quantum beats in the initial motion as well as new types of long-term revivals. The issue of whether fractional revivals can form is addressed. We present an analytical proof showing that at certain times equal to rational fractions of the revival times the wave packet can reform as a sum of subsidiary waves and that both conventional and new types of fractional revivals can occur.
N=2 supersymmetric Pais-Uhlenbeck oscillator
Masterov, Ivan
2015-01-01T23:59:59.000Z
We construct an N=2 supersymmetric extension of the Pais-Uhlenbeck oscillator for distinct frequencies of oscillation. A link to a set of decoupled N=2 supersymmetric harmonic oscillators with alternating sign in the Hamiltonian is introduced. Symmetries of the model are discussed in detail. The investigation of a quantum counterpart of the constructed model shows that the corresponding Fock space contains negative norm states and the energy spectrum of the system is unbounded from below.
N=2 supersymmetric Pais-Uhlenbeck oscillator
Ivan Masterov
2015-03-12T23:59:59.000Z
We construct an N=2 supersymmetric extension of the Pais-Uhlenbeck oscillator for distinct frequencies of oscillation. A link to a set of decoupled N=2 supersymmetric harmonic oscillators with alternating sign in the Hamiltonian is introduced. Symmetries of the model are discussed in detail. The investigation of a quantum counterpart of the constructed model shows that the corresponding Fock space contains negative norm states and the energy spectrum of the system is unbounded from below.
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeedingBiomass and Biofuels Biomass and OrganizationalOriginal îƒƒ îƒ‚
On the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation: Might they be related?
Peltier, W. Richard
? Marc d'Orgeville1 and W. Richard Peltier1 Received 3 August 2007; revised 21 September 2007; accepted 1. Peltier (2007), On the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation: Might
Neutrino Oscillation Studies with Reactors
Petr Vogel; Liangjian Wen; Chao Zhang
2015-03-03T23:59:59.000Z
Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.
Neutrino Oscillation Studies with Reactors
Petr Vogel; Liangjian Wen; Chao Zhang
2015-04-27T23:59:59.000Z
Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.
Neutrino Oscillation Studies with Reactors
Vogel, Petr; Zhang, Chao
2015-01-01T23:59:59.000Z
Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.
Carnot cycle for an oscillator
J. Arnaud; L. Chusseau; F. Philippe
2001-11-20T23:59:59.000Z
Carnot established in 1824 that the efficiency of cyclic engines operating between a hot bath at absolute temperature $T_{hot}$ and a bath at a lower temperature $T_{cold}$ cannot exceed $1-T_{cold}/T_{hot}$. We show that linear oscillators alternately in contact with hot and cold baths obey this principle in the quantum as well as in the classical regime. The expression of the work performed is derived from a simple prescription. Reversible and non-reversible cycles are illustrated. The paper begins with historical considerations and is essentially self-contained.
Making space for harmonic oscillators
Michelotti, Leo; /Fermilab
2004-11-01T23:59:59.000Z
If we restrict the number of harmonic oscillator energy eigenstates to some finite value, N, then the discrete spectrum of the corresponding position operator comprise the roots of the Hermite polynomial H{sub N+1}. Its range is just large enough to accommodate classical motion at high energy. A negative energy term must be added to the Hamiltonian which affects only the last eigenstate, |N>, suggesting it is concentrated at the extrema of this finite ''space''. Calculations support a conjecture that, in the limit of large N, the global distribution of points approaches the differential form for classical action.
Neutrino oscillation studies with reactors
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Vogel, P. [California Inst. of Technology (CalTech), Pasadena, CA (United States). Kellog Radiation Lab.; Wen, L.J. [Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics (IHEP); Zhang, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)
2015-04-27T23:59:59.000Z
Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle ?13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.
Neutrino oscillation studies at LAMPF
Louis, W.C.; LSND Collaboration
1994-09-01T23:59:59.000Z
A search for {anti v}{sub {mu}} {yields} {anti v}{sub e} oscillations has been made by the Liquid Scintillator Neutrino Detector experiment at LAMPF after an initial month and a half run. The experiment observes eight events consistent with the reaction {anti v}{sub e}p {yields} e{sup +}n followed by np {yields} d{gamma} (2.2 MeV). The total estimated background is 0.9{plus_minus}0.2 events.
The harmonic oscillator with dissipation within the theory of open quantum systems
A. Isar
2005-08-18T23:59:59.000Z
Time evolution of the expectation values of various dynamical operators of the harmonic oscillator with dissipation is analitically obtained within the framework of the Lindblad theory for open quantum systems. We deduce the density matrix of the damped harmonic oscillator from the solution of the Fokker-Planck equation for the coherent state representation, obtained from the master equation for the density operator. The Fokker-Planck equation for the Wigner distribution function, subject to either the Gaussian type or the $\\delta$-function type of initial conditions, is also solved by using the Wang-Uhlenbeck method. The obtained Wigner functions are two-dimensional Gaussians with different widths.
Impact of Neutrino Oscillation Measurements on Theory
Murayama, Hitoshi
2009-01-01T23:59:59.000Z
was an amazing year in neutrino physics. Before March, thetheorists have a very good track record in neutrino physics.results from neutrino oscillation physics had surprised
High frequency and high wavenumber solar oscillations
H. M. Antia; Sarbani Basu
1999-02-10T23:59:59.000Z
We determine the frequencies of solar oscillations covering a wide range of degree (100< l <4000) and frequency (1.5 <\
Shock propagation and neutrino oscillation in supernova
K. Takahashi; K. Sato; H. E. Dalhed; J. R. Wilson
2003-02-26T23:59:59.000Z
The effect of the shock propagation on neutrino oscillation in supernova is studied paying attention to evolution of average energy of $\
Relaxed constraints on neutrino oscillation parameters
Daniela P. Kirilova; Mariana P. Panayotova
2006-08-04T23:59:59.000Z
We study the cosmological constraints on active-sterile neutrino oscillations nu_e nu_s for the case when nu_s is partially filled initially, i.e. 0 nu_s oscillations, effective after neutrino decoupling, accounting for all known oscillations effects on cosmological nucleosynthesis. Cosmological constraints on oscillation parameters corresponding to higher than 5% He-4 overproduction and different non-zero initial populations of the sterile state delta N_s 0 are relaxed in comparison with the delta N_s = 0 case and the relaxation is proportional to delta N_s.
Markovian evolution of strongly coupled harmonic oscillators
Chaitanya Joshi; Patrik Ohberg; James D. Cresser; Erika Andersson
2014-12-16T23:59:59.000Z
We investigate how to model Markovian evolution of coupled harmonic oscillators, each of them interacting with a local environment. When the coupling between the oscillators is weak, dissipation may be modeled using local Lindblad terms for each of the oscillators in the master equation, as is commonly done. When the coupling between oscillators is strong, this model may become invalid. We derive a master equation for two coupled harmonic oscillators which are subject to individual heat baths modeled by a collection of harmonic oscillators, and show that this master equation in general contains non-local Lindblad terms. We compare the resulting time evolution with that obtained for dissipation through local Lindblad terms for each individual oscillator, and show that the evolution is different in the two cases. In particular, the two descriptions give different predictions for the steady state and for the entanglement between strongly coupled oscillators. This shows that when describing strongly coupled harmonic oscillators, one must take great care in how dissipation is modeled, and that a description using local Lindblad terms may fail. This may be particularly relevant when attempting to generate entangled states of strongly coupled quantum systems.
OTEC cold water pipe design for problems caused by vortex-excited oscillations
Griffin, O. M.
1980-03-14T23:59:59.000Z
Vortex-excited oscillations of marine structures result in reduced fatigue life, large hydrodynamic forces and induced stresses, and sometimes lead to structural damage and to diestructive failures. The cold water pipe of an OTEC plant is nominally a bluff, flexible cylinder with a large aspect ratio (L/D = length/diameter), and is likely to be susceptible to resonant vortex-excited oscillations. The objective of this report is to survey recent results pertaining to the vortex-excited oscillations of structures in general and to consider the application of these findings to the design of the OTEC cold water pipe. Practical design calculations are given as examples throughout the various sections of the report. This report is limited in scope to the problems of vortex shedding from bluff, flexible structures in steady currents and the resulting vortex-excited oscillations. The effects of flow non-uniformities, surface roughness of the cylinder, and inclination to the incident flow are considered in addition to the case of a smooth cyliner in a uniform stream. Emphasis is placed upon design procedures, hydrodynamic coefficients applicable in practice, and the specification of structural response parameters relevant to the OTEC cold water pipe. There are important problems associated with in shedding of vortices from cylinders in waves and from the combined action of waves and currents, but these complex fluid/structure interactions are not considered in this report.
Wave turbulence revisited: Where does the energy flow?
L. V. Abdurakhimov; I. A. Remizov; A. A. Levchenko; G. V. Kolmakov; Y. V. Lvov
2014-04-03T23:59:59.000Z
Turbulence in a system of nonlinearly interacting waves is referred to as wave turbulence. It has been known since seminal work by Kolmogorov, that turbulent dynamics is controlled by a directional energy flux through the wavelength scales. We demonstrate that an energy cascade in wave turbulence can be bi-directional, that is, can simultaneously flow towards large and small wavelength scales from the pumping scales at which it is injected. This observation is in sharp contrast to existing experiments and wave turbulence theory where the energy flux only flows in one direction. We demonstrate that the bi-directional energy cascade changes the energy budget in the system and leads to formation of large-scale, large-amplitude waves similar to oceanic rogue waves. To study surface wave turbulence, we took advantage of capillary waves on a free, weakly charged surface of superfluid helium He-II at temperature 1.7K. Although He-II demonstrates non-classical thermomechanical effects and quantized vorticity, waves on its surface are identical to those on a classical Newtonian fluid with extremely low viscosity. The possibility of directly driving a charged surface by an oscillating electric field and the low viscosity of He-II have allowed us to isolate the surface dynamics and study nonlinear surface waves in a range of frequencies much wider than in experiments with classical fluids.
Surface electromagnetic wave equations in a warm magnetized quantum plasma
Li, Chunhua; Yang, Weihong [Department of Modern Physics, University of Science and Technology of China, 230026 Hefei (China); Wu, Zhengwei, E-mail: wuzw@ustc.edu.cn [Department of Modern Physics, University of Science and Technology of China, 230026 Hefei (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Center of Low Temperature Plasma Application, Yunnan Aerospace Industry Company, Kunming, 650229 Yunnan (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)
2014-07-15T23:59:59.000Z
Based on the single-fluid plasma model, a theoretical investigation of surface electromagnetic waves in a warm quantum magnetized inhomogeneous plasma is presented. The surface electromagnetic waves are assumed to propagate on the plane between a vacuum and a warm quantum magnetized plasma. The quantum magnetohydrodynamic model includes quantum diffraction effect (Bohm potential), and quantum statistical pressure is used to derive the new dispersion relation of surface electromagnetic waves. And the general dispersion relation is analyzed in some special cases of interest. It is shown that surface plasma oscillations can be propagated due to quantum effects, and the propagation velocity is enhanced. Furthermore, the external magnetic field has a significant effect on surface wave's dispersion equation. Our work should be of a useful tool for investigating the physical characteristic of surface waves and physical properties of the bounded quantum plasmas.
Wave propagation and shock formation in different magnetic structures
Rebecca Centeno; Manuel Collados; Javier Trujillo Bueno
2008-10-20T23:59:59.000Z
Velocity oscillations "measured" simultaneously at the photosphere and the chromosphere -from time series of spectropolarimetric data in the 10830 A region- of different solar magnetic features allow us to study the properties of wave propagation as a function of the magnetic flux of the structure (i.e. two different-sized sunspots, a tiny pore and a facular region). While photospheric oscillations have similar characteristics everywhere, oscillations measured at chromospheric heights show different amplitudes, frequencies and stages of shock development depending on the observed magnetic feature. The analysis of the power and the phase spectra, together with simple theoretical modeling, lead to a series of results concerning wave propagation within the range of heights of this study. We find that, while the atmospheric cut-off frequency and the propagation properties of the different oscillating modes depend on the magnetic feature, in all the cases the power that reaches the high chromosphere above the atmospheric cut-off comes directly from the photosphere by means of linear vertical wave propagation rather than from non-linear interaction of modes.
The oscillations of a magnetic flux tube and its application to sunspots
Evans, D.J.; Roberts, B. (Saint Andrews Univ. (Scotland))
1990-01-01T23:59:59.000Z
The modes of oscillation of an isolated magnetic flux tube in the absence of gravity is examined, with parameters chosen to mimic a sunspot. Gravitational stratification of the umbral atmosphere leads to consider two cases, distinguished primarily by the ordering of the Alfven speed and the external sound speed. The transition between these two regimes occurs at about the level where the optical depth, tau(c), is equal to 1 in the umbra. The modes given by the model, taken together with the observations, suggest that 3 minute oscillations are slow-body modes (driven by overstable convection) and that a sunspot consists of a bundle of pore-sized flux tubes rather than a single monolithic one. Fast-body modes are identified in the tube with the observed 5 minute oscillations of the umbral photosphere and below. The excitation of these modes propagating up or down the tube may explain the recent observation that sunspots act as sinks for p-modes propagating in their environment. Running penumbral waves are associated with fast- and slow-surface modes. The fast-surface wave could arise from fast-body modes driven below the level where tau(c) = 1; the slow-surface waves may arise from granular buffeting or overstable convection. 55 refs.
Constraining the gravitational wave energy density of the Universe using Earth's ring
Coughlin, Michael
2014-01-01T23:59:59.000Z
The search for gravitational waves is one of today's major scientific endeavors. A gravitational wave can interact with matter by exciting vibrations of elastic bodies. Earth itself is a large elastic body whose so-called normal-mode oscillations ring up when a gravitational wave passes. Therefore, precise measurement of vibration amplitudes can be used to search for the elusive gravitational-wave signals. Earth's free oscillations that can be observed after high-magnitude earthquakes have been studied extensively with gravimeters and low-frequency seismometers over many decades leading to invaluable insight into Earth's structure. Making use of our detailed understanding of Earth's normal modes, numerical models are employed for the first time to accurately calculate Earth's gravitational-wave response, and thereby turn a network of sensors that so far has served to improve our understanding of Earth, into an astrophysical observatory exploring our Universe. In this article, we constrain the energy density o...
Constraining the gravitational wave energy density of the Universe using Earth's ring
Michael Coughlin; Jan Harms
2014-06-04T23:59:59.000Z
The search for gravitational waves is one of today's major scientific endeavors. A gravitational wave can interact with matter by exciting vibrations of elastic bodies. Earth itself is a large elastic body whose so-called normal-mode oscillations ring up when a gravitational wave passes. Therefore, precise measurement of vibration amplitudes can be used to search for the elusive gravitational-wave signals. Earth's free oscillations that can be observed after high-magnitude earthquakes have been studied extensively with gravimeters and low-frequency seismometers over many decades leading to invaluable insight into Earth's structure. Making use of our detailed understanding of Earth's normal modes, numerical models are employed for the first time to accurately calculate Earth's gravitational-wave response, and thereby turn a network of sensors that so far has served to improve our understanding of Earth, into an astrophysical observatory exploring our Universe. In this article, we constrain the energy density of gravitational waves to values in the range 0.035 - 0.15 normalized by the critical energy density of the Universe at frequencies between 0.3mHz and 5mHz, using 10 years of data from the gravimeter network of the Global Geodynamics Project that continuously monitors Earth's oscillations. This work is the first step towards a systematic investigation of the sensitivity of gravimeter networks to gravitational waves. Further advance in gravimeter technology could improve sensitivity of these networks and possibly lead to gravitational-wave detection.
Self-oscillation in spin torque oscillator stabilized by field-like torque
Taniguchi, Tomohiro; Tsunegi, Sumito; Kubota, Hitoshi; Imamura, Hiroshi [National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba 305-8568 (Japan)
2014-04-14T23:59:59.000Z
The effect of the field-like torque on the self-oscillation of the magnetization in spin torque oscillator with a perpendicularly magnetized free layer was studied theoretically. A stable self-oscillation at zero field is excited for negative ? while the magnetization dynamics stops for ??=?0 or ??>?0, where ? is the ratio between the spin torque and the field-like torque. The reason why only the negative ? induces the self-oscillation was explained from the view point of the energy balance between the spin torque and the damping. The oscillation power and frequency for various ? were also studied by numerical simulation.
Multipole expansion method for supernova neutrino oscillations
Duan, Huaiyu
2014-01-01T23:59:59.000Z
We demonstrate a multipole expansion method to calculate collective neutrino oscillations in supernovae using the neutrino bulb model. We show that it is much more efficient to solve multi-angle neutrino oscillations in multipole basis than in angle basis. The multipole expansion method also provides interesting insights into multi-angle calculations that were accomplished previously in angle basis.
Multipole expansion method for supernova neutrino oscillations
Huaiyu Duan; Shashank Shalgar
2014-12-24T23:59:59.000Z
We demonstrate a multipole expansion method to calculate collective neutrino oscillations in supernovae using the neutrino bulb model. We show that it is much more efficient to solve multi-angle neutrino oscillations in multipole basis than in angle basis. The multipole expansion method also provides interesting insights into multi-angle calculations that were accomplished previously in angle basis.
Behavioral/Systems/Cognitive Synchronous, Focally Modulated -Band Oscillations
Graybiel, Ann M.
, primarily synchronous -band voltage oscillations occur in the sensorimotor and frontal cortex of humansBehavioral/Systems/Cognitive Synchronous, Focally Modulated -Band Oscillations Characterize Local oscillations in the -frequency band ( 1530Hz
Influence of the backward propagating waves on the threshold in planar nematic liquid crystal films
Dmitry O. Krimer; Andrey E. Miroshnichenko; Etienne Brasselet
2010-10-19T23:59:59.000Z
We analyze theoretically the influence of backward propagating waves on the primary threshold when a linearly polarized light impinges at normal incidence on a planarly aligned nematic liquid crystal films. We show, that the primary threshold, as a function of the phase delay induced by the nematic layer, exhibits oscillations. The amplitude of oscillations depends strongly on the drop of the refractivity indices of the nematic and outer media at the boundaries.
Massless neutrino oscillations via quantum tunneling
Zhao, Hai-Long
2015-01-01T23:59:59.000Z
In order for different kinds of neutrino to transform into each other, the eigenvalues of energy of neutrino must be different. In the present theory of neutrino oscillations, this is guaranteed by the mass differences between the different eigenstates of neutrino. Thus neutrino cannot oscillate if it is massless. We suggest an explanation for neutrino oscillations by analogy with the oscillation of quantum two-state system, where the flipping of one state into the other may be regarded as a process of quantum tunneling and the required energy difference between the two eigenstates comes from the barrier potential energy. So neutrino with vanishing mass can also oscillate. One of the advantages of the explanation is that neutrino can still be described with Weyl equation within the framework of standard model.
Massless neutrino oscillations via quantum tunneling
Hai-Long Zhao
2015-02-03T23:59:59.000Z
In order for different kinds of neutrino to transform into each other, the eigenvalues of energy of neutrino must be different. In the present theory of neutrino oscillations, this is guaranteed by the mass differences between the different eigenstates of neutrino. Thus neutrino cannot oscillate if it is massless. We suggest an explanation for neutrino oscillations by analogy with the oscillation of quantum two-state system, where the flipping of one state into the other may be regarded as a process of quantum tunneling and the required energy difference between the two eigenstates comes from the barrier potential energy. So neutrino with vanishing mass can also oscillate. One of the advantages of the explanation is that neutrino can still be described with Weyl equation within the framework of standard model.
Collective behavior of coupled nonuniform stochastic oscillators
Vladimir R. V. Assis; Mauro Copelli
2012-01-27T23:59:59.000Z
Theoretical studies of synchronization are usually based on models of coupled phase oscillators which, when isolated, have constant angular frequency. Stochastic discrete versions of these uniform oscillators have also appeared in the literature, with equal transition rates among the states. Here we start from the model recently introduced by Wood et al. [Phys. Rev. Lett. 96}, 145701 (2006)], which has a collectively synchronized phase, and parametrically modify the phase-coupled oscillators to render them (stochastically) nonuniform. We show that, depending on the nonuniformity parameter $0\\leq \\alpha \\leq 1$, a mean field analysis predicts the occurrence of several phase transitions. In particular, the phase with collective oscillations is stable for the complete graph only for $\\alpha \\leq \\alpha^\\prime collective oscillations were found in the model.
Chemical sensor with oscillating cantilevered probe
Adams, Jesse D
2013-02-05T23:59:59.000Z
The invention provides a method of detecting a chemical species with an oscillating cantilevered probe. A cantilevered beam is driven into oscillation with a drive mechanism coupled to the cantilevered beam. A free end of the oscillating cantilevered beam is tapped against a mechanical stop coupled to a base end of the cantilevered beam. An amplitude of the oscillating cantilevered beam is measured with a sense mechanism coupled to the cantilevered beam. A treated portion of the cantilevered beam is exposed to the chemical species, wherein the cantilevered beam bends when exposed to the chemical species. A second amplitude of the oscillating cantilevered beam is measured, and the chemical species is determined based on the measured amplitudes.
Geometrical vs wave optics under gravitational waves
Raymond Angélil; Prasenjit Saha
2015-05-20T23:59:59.000Z
We present some new derivations of the effect of a plane gravitational wave on a light ray. A simple interpretation of the results is that a gravitational wave causes a phase modulation of electromagnetic waves. We arrive at this picture from two contrasting directions, namely null geodesics and Maxwell's equations, or, geometric and wave optics. Under geometric optics, we express the geodesic equations in Hamiltonian form and solve perturbatively for the effect of gravitational waves. We find that the well-known time-delay formula for light generalizes trivially to massive particles. We also recover, by way of a Hamilton-Jacobi equation, the phase modulation obtained under wave optics. Turning then to wave optics - rather than solving Maxwell's equations directly for the fields, as in most previous approaches - we derive a perturbed wave equation (perturbed by the gravitational wave) for the electromagnetic four-potential. From this wave equation it follows that the four-potential and the electric and magnetic fields all experience the same phase modulation. Applying such a phase modulation to a superposition of plane waves corresponding to a Gaussian wave packet leads to time delays.
Flavor Oscillation from the Two-Point Function
Mario Martone; Dean J. Robinson
2011-10-25T23:59:59.000Z
We present a formalism for the flavor oscillation of unstable particles that relies only upon the structure of the time Fourier-transformed two-point Green's function. We derive exact oscillation probability and integrated oscillation probability formulae, and verify that our results reproduce the known results for both neutrino and neutral meson oscillation in the expected regimes of parameter space. The generality of our approach permits us to investigate flavor oscillation in exotic parameter regimes, and present the corresponding oscillation formulae.
Pulse combustor with controllable oscillations
Richards, George A. (Morgantown, WV); Welter, Michael J. (Columbiana, OH); Morris, Gary J. (Morgantown, WV)
1992-01-01T23:59:59.000Z
A pulse combustor having thermally induced pulse combustion in a continuously flowing system is described. The pulse combustor is fitted with at lease one elongated ceramic body which significantly increases the heat transfer area in the combustion chamber of the combustor. The ceramic body or bodies possess sufficient mass and heat capacity to ignite the fuel-air charge once the ceramic body or bodies are heated by conventional spark plug initiated combustion so as to provide repetitive ignition and combustion of sequentially introduced fuel-air charges without the assistance of the spark plug and the rapid quenching of the flame after each ignition in a controlled manner so as to provide a selective control over the oscillation frequency and amplitude. Additional control over the heat transfer in the combustion chamber is provided by employing heat exchange mechanisms for selectively heating or cooling the elongated ceramic body or bodies and/or the walls of the combustion chamber.
Oscillation of Capacitance inside Nanopores
Jiang, Deen [ORNL; Wu, Jianzhong [University of California, Riverside; Jin, Zhehui [University of California, Riverside
2011-01-01T23:59:59.000Z
materials for supercapacitors. Although great attention has been given to the anomalous increase of the capacitance as the pore size approaches the ionic dimensions, there remains a lack of full comprehension of the size dependence of the capacitance in nanopores. Here we predict from a classical density functional theory that the capacitance of an ionic-liquid electrolyte inside a nanopore oscillates with a decaying envelope as the pore size increases. The oscillatory behavior can be attributed to the interference of the overlapping electric double layers (EDLs); namely, the maxima in capacitance appear when superposition of the two EDLs is most constructive. The theoretical prediction agreeswell with the experiment when the pore size is less than twice the ionic diameter.Confirmation of the entire oscillatory spectruminvites future experiments with a precise control of the pore size from micro- to mesoscales.
accuracy neutrino oscillation: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
effects are reviewed. The results from oscillations are confronted with neutrinoless double beta decay. G. Rajasekaran 2000-04-17 22 Neutrino Mass and Oscillation HEP -...
A flowing plasma model to describe drift waves in a cylindrical helicon discharge
Chang, L.; Hole, M. J.; Corr, C. S. [Plasma Research Laboratory, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)
2011-04-15T23:59:59.000Z
A two-fluid model developed originally to describe wave oscillations in the vacuum arc centrifuge, a cylindrical, rapidly rotating, low temperature, and confined plasma column, is applied to interpret plasma oscillations in a RF generated linear magnetized plasma [WOMBAT (waves on magnetized beams and turbulence)], with similar density and field strength. Compared to typical centrifuge plasmas, WOMBAT plasmas have slower normalized rotation frequency, lower temperature, and lower axial velocity. Despite these differences, the two-fluid model provides a consistent description of the WOMBAT plasma configuration and yields qualitative agreement between measured and predicted wave oscillation frequencies with axial field strength. In addition, the radial profile of the density perturbation predicted by this model is consistent with the data. Parameter scans show that the dispersion curve is sensitive to the axial field strength and the electron temperature, and the dependence of oscillation frequency with electron temperature matches the experiment. These results consolidate earlier claims that the density and floating potential oscillations are a resistive drift mode, driven by the density gradient. To our knowledge, this is the first detailed physics model of flowing plasmas in the diffusion region away from the RF source. Possible extensions to the model, including temperature nonuniformity and magnetic field oscillations, are also discussed.
Relativistic Bernstein waves in a degenerate plasma
Ali, Muddasir; Hussain, Azhar [Department of Physics, G.C. University, Lahore 54000 (Pakistan); Salam Chair in Physics, G.C. University, Lahore 54000 (Pakistan); Murtaza, G. [Salam Chair in Physics, G.C. University, Lahore 54000 (Pakistan)
2011-09-15T23:59:59.000Z
Bernstein mode for a relativistic degenerate electron plasma is investigated. Using relativistic Vlasov-Maxwell equations, a general expression for the conductivity tensor is derived and then employing Fermi-Dirac distribution function a generalized dispersion relation for the Bernstein mode is obtained. Two limiting cases, i.e., non-relativistic and ultra-relativistic are discussed. The dispersion relations obtained are also graphically presented for some specific values of the parameters depicting how the propagation characteristics of Bernstein waves as well as the Upper Hybrid oscillations are modified with the increase in plasma number density.
Sunandan Gangopadhyay; Anirban Saha; Swarup Saha
2014-09-11T23:59:59.000Z
The response of a test particle, both for the free case and under the harmonic oscillator potential, to circularly polarized gravitational waves is investigated in a noncommutative quantum mechanical setting. The system is quantized following the prescription in \\cite{ncgw1}. Standard algebraic techniques are then employed to solve the Hamiltonian of the system. The solutions, in both cases, show signatures of the coordinate noncommutativity. In the harmonic oscillator case, this signature plays a key role in altering the resonance point and the oscillation frequency of the system.
Wave Propagation in Lipid Monolayers
J. Griesbauer; A. Wixforth; M. F. Schneider
2010-05-26T23:59:59.000Z
Sound waves are excited on lipid monolayers using a set of planar electrodes aligned in parallel with the excitable medium. By measuring the frequency dependent change in the lateral pressure we are able to extract the sound velocity for the entire monolayer phase diagram. We demonstrate that this velocity can also be directly derived from the lipid monolayer compressibility and consequently displays a minimum in the phase transition regime. This minimum decreases from v0=170m/s for one component lipid monolayers down to vm=50m/s for lipid mixtures. No significant attenuation can be detected confirming an adiabatic phenomenon. Finally our data propose a relative lateral density oscillation of \\Delta\\rho/\\rho ~ 2% implying a change in all area dependent physical properties. Order of magnitude estimates from static couplings therefore predict propagating changes in surface potential of 1-50mV, 1 unit in pH (electrochemical potential) and 0.01{\\deg}K in temperature and fall within the same order of magnitude as physical changes measured during nerve pulse propagation. These results therefore strongly support the idea of propagating adiabatic sound waves along nerves as first thoroughly described by Kaufmann in 1989 and recently by Heimburg and Jackson, but claimed by Wilke already in 1912.
Chaplin, W. J.; Broomhall, A.-M.; Hekker, S.; Elsworth, Y.; Stevens, I. R. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Bedding, T. R.; Huber, D. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Bonanno, A. [INAF Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123, Catania (Italy); GarcIa, R. A. [Laboratoire AIM, CEA/DSM, CNRS, Universite Paris Diderot, IRFU/SAp, 91191 Gif-sur-Yvette Cedex (France); Verner, G. A. [Astronomy Unit, Queen Mary, University of London, Mile End Road, London, E1 4NS (United Kingdom); Basu, S. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Houdek, G. [Institute of Astronomy, University of Vienna, A-1180 Vienna (Austria); Mathur, S.; Metcalfe, T. S. [High Altitude Observatory and, Scientific Computing Division, National Center for Atmospheric Research, Boulder, Colorado 80307 (United States); Mosser, B. [LESIA, CNRS, Universite Pierre et Marie Curie, Universite Denis Diderot, Observatoire de Paris, 92195 Meudon Cedex (France); New, R. [Materials Engineering Research Institute, Faculty of Arts, Computing, Engineering and Sciences, Sheffield Hallam University, Sheffield, S1 1WB (United Kingdom); Appourchaux, T. [Institut d'Astrophysique Spatiale, Universite Paris XI, CNRS (UMR8617), Batiment 121, 91405 Orsay Cedex (France); Karoff, C. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Molenda-Zakowicz, J. [Astronomical Institute, University of Wroclaw, ul. Kopernika, 11, 51-622 Wroclaw (Poland); Monteiro, M. J. P. F. G. [Centro de Astrofisica and Faculdade de Ciencias, Universidade do Porto, Rua das Estrelas, 4150-762 (Portugal)
2011-05-01T23:59:59.000Z
We use photometric observations of solar-type stars, made by the NASA Kepler Mission, to conduct a statistical study of the impact of stellar surface activity on the detectability of solar-like oscillations. We find that the number of stars with detected oscillations falls significantly with increasing levels of activity. The results present strong evidence for the impact of magnetic activity on the properties of near-surface convection in the stars, which appears to inhibit the amplitudes of the stochastically excited, intrinsically damped solar-like oscillations.
Gamma Oscillation by Synaptic Inhibition in a Hippocampal Interneuronal Network Model
Wang, Xiao-Jing
both EPSPs and IPSPs phase-locked to the field oscillation frequencies (Jagadeesh et al., 1992; Chen and Sompolinsky, 1996). Traditionally, recurrent excitation between principal (pyramidal) neurons is viewed excitation of the AMPA type usually desynchronizes rather than synchronizes re- petitive spike firings
The Intraseasonal Oscillation and the Energetics of Summertime Tropical Western North Pacific
Maloney, Eric
The Intraseasonal Oscillation and the Energetics of Summertime Tropical Western North Pacific University of New York Albany, New York Journal of the Atmospheric Sciences Submitted October 14, 2002 the energetics of tropical depression (TD)-type disturbances. An energetics analysis is conducted with NCEP
Feedback Control Of An Azimuthal Oscillation In The ExB Discharge of Hall Thrusters
Griswold, Martin E.; Ellison, C. L.; Raitses, Y.; Fisch, N. J.
2012-04-06T23:59:59.000Z
Feedback control of a low-frequency azimuthal wave known as a "rotating spoke" in the ExB discharge of a cylindrical Hall thruster was demonstrated. The rotating spoke is an m=1 azimuthal variation in density, electron temperature, and potential that rotates at about 10% of the local E x B electron rotation speed. It causes increased electron transport across the magnetic field and is suspected to be an ionization wave. Feedback control of this wave required special consideration because, although it causes a rotating azimuthal variation in the current density to the anode, it does not show up as a signal in the total thruster discharge current. Therefore, an extra source of information was needed to track the oscillation, which was addressed by using a special anode that was split azimuthally into four segments. The current to each segment oscillates as the rotating spoke passes over it, and feedback is accomplished by resistors connected in series with each anode segment which cause the voltage on a segment to decrease in proportion to the current through that segment. The feedback resulted in the disappearance of a coherent azimuthal wave and a decrease in the time-averaged total discharge current by up to 13.2%.
MHD Wave Propagation in the Neighbourhood of Two Null Points
J. A. McLaughlin; A. W. Hood
2007-12-11T23:59:59.000Z
The nature of fast magnetoacoustic and Alfv\\'en waves is investigated in a zero $\\beta$ plasma in the neighbourhood of a pair of two-dimensional null points. This gives an indication of wave propagation in the low $\\beta$ solar corona, for a more complicated magnetic configuration than that looked at by McLaughlin & Hood (2004). It is found that the fast wave is attracted to the null points and that the front of the wave slows down as it approaches the null point pair, with the wave splitting and part of the wave accumulating at one null and the rest at the other. Current density will then accumulate at these points and ohmic dissipation will then extract the energy in the wave at these points. This suggests locations where wave heating will occur in the corona. The Alfv\\'en wave behaves in a different manner in that the wave accumulates along the separatrices. Hence, the current density will accumulate at this part of the topology and this is where wave heating will occur. However, the phenomenon of wave accumulation at a specific place is a feature of both wave types, and illustrates the importance of studying the topology of the corona when considering MHD wave propagation.
Oscillation modes of dc microdischarges with parallel-plate geometry
Stefanovi?, Ilija; Škoro, Nikola; Mari?, Dragana; Petrovi?, Zoran Lj; Winter, Jörg
2011-01-01T23:59:59.000Z
Two different oscillation modes in microdischarge with parallel-plate geometry has been observed: relaxation oscillations with frequency range between 1.23 and 2.1 kHz and free-running oscillations with 7 kHz frequency. The oscillation modes are induced by increasing power supply voltage or discharge current. For a given power supply voltage, there is a spontaneous transition from one to other oscillation mode and vice versa. Before the transition from relaxation to free-running oscillations, the spontaneous increase of oscillation frequency of relaxation oscillations form 1.3 kHz to 2.1 kHz is measured. Fourier Transform Spectra of relaxation oscillations reveal chaotic behaviour of microdischarge. Volt-Ampere characteristics associated with relaxation oscillations describes periodical transition between low current, diffuse discharge and normal glow. However, free-running oscillations appear in subnormal glow only.
,2) provide a kinematic description of water waves, which to this point means that the conditionsWater Waves Roger Grimshaw May 7, 2003 Abstract A short review of the theory of weakly nonlinear water waves, prepared for the forthcoming Encyclopedia of Nonlinear Science 1 Introduction Water waves
Neutrino Physics: Fundamentals of Neutrino Oscillations
C. W. Kim
1996-07-22T23:59:59.000Z
In this lecture we review some of the basic properties of neutrinos, in particular their mass and the oscillation behavior. First we discuss how to describe the neutrino mass. Then, under the assumption that neutrinos are massive and mixed, the fundamentals of the neutrino oscillations are discussed with emphasis on subtle aspects which have been overlooked in the past. We then review the terrestrial neutrino oscillation experiments in the framework of three generations of neutrinos with the standard mass hierarchy. Finally, a brief summary of the current status of the solar and atmospheric neutrino problems will be given.
Measuring Atmospheric Neutrino Oscillations with Neutrino Telescopes
Ivone F. M. Albuquerque; George F. Smoot
2001-03-28T23:59:59.000Z
Neutrino telescopes with large detection volumes can demonstrate that the current indications of neutrino oscillation are correct or if a better description can be achieved with non-standard alternatives. Observations of contained muons produced by atmospheric neutrinos can better constrain the allowed region for oscillations or determine the relevant parameters of non-standard models. We analyze the possibility of neutrino telescopes measuring atmospheric neutrino oscillations. We suggest adjustments to improve this potential. An addition of four densely-instrumented strings to the AMANDA II detector makes observations feasible. Such a configuration is competitive with current and proposed experiments.
Self-seeding ring optical parametric oscillator
Smith, Arlee V. (Albuquerque, NM); Armstrong, Darrell J. (Albuquerque, NM)
2005-12-27T23:59:59.000Z
An optical parametric oscillator apparatus utilizing self-seeding with an external nanosecond-duration pump source to generate a seed pulse resulting in increased conversion efficiency. An optical parametric oscillator with a ring configuration are combined with a pump that injection seeds the optical parametric oscillator with a nanosecond duration, mJ pulse in the reverse direction as the main pulse. A retroreflecting means outside the cavity injects the seed pulse back into the cavity in the direction of the main pulse to seed the main pulse, resulting in higher conversion efficiency.
Axion Induced Oscillating Electric Dipole Moments
Hill, Christopher T
2015-01-01T23:59:59.000Z
The axion electromagnetic anomaly induces an oscillating electric dipole for any static magnetic dipole. Static electric dipoles do not produce oscillating magnetic moments. This is a low energy theorem which is a consequence of the space-time dependent cosmic background field of the axion. The electron will acquire an oscillating electric dipole of frequency $m_a$ and strength $\\sim 10^{-32}$ e-cm, two orders of magnitude above the nucleon, and within four orders of magnitude of the present standard model DC limit. This may suggest sensitive new experimental venues for the axion dark matter search.
Emission Origin for the Wave of Quanta
Sanjay M Wagh
2009-07-07T23:59:59.000Z
We argue that certain assumptions about the process of the emission of the quanta by their (oscillating) emitter provide for their changing (oscillatory) flux at any location. This mechanism underlying (such) wave phenomena is not based, both, on the newtonian notion of force and the field concept (of Faraday, Maxwell, Lorentz and Einstein). When applied to the case of thermal radiation, this emission origin for the wave of quanta is shown here to be consistent with the laws of the black body radiation. We conclude therefore also that a conceptual framework, which is not rooted in the notion of force and in the field concept, may provide a deterministic basis underlying the probabilistic methods of the quantum theory.
Flows and Waves in Braided Solar Coronal Magnetic Structures
Pant, V; Banerjee, Dipankar
2015-01-01T23:59:59.000Z
We study the high frequency dynamics in the braided magnetic structure of an active region (AR 11520) moss as observed by High-Resolution Coronal Imager (Hi-C). We detect quasi periodic flows and waves in these structures. We search for high frequency dynamics while looking at power maps of the observed region. We find that shorter periodicites (30 - 60 s) are associated with small spatial scales which can be resolved by Hi-C only. We detect quasi periodic flows with wide range of velocities from 13 - 185 km/s associated with braided regions. This can be interpreted as plasma outflows from reconnection sites. We also find presence of short period and large amplitude transverse oscillations associated with braided magnetic region. Such oscillations could be triggered by reconnection or such oscillation may trigger reconnection.
Khan, S. A., E-mail: sakhan@ncp.edu.pk; Hassan, Sunia [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan)
2014-05-28T23:59:59.000Z
Using macroscopic quantum hydrodynamic formulation, we study the dispersion properties of electrostatic electron plasma oscillations in single-walled carbon nanotubes. The electrons and ions are considered uniformly distributed over the cylindrical surface of a nanotube thus forming a two-component (electron-ion) quantum plasma system. Electron degeneracy via Fermi-Dirac statistics as well as electron exchange and correlation effects is taken into account. It is found that the quantum (Bohm) potential arising due to fermionic nature of electrons and exchange-correlations effects has significant impact on the wave. The frequency of wave is influenced by variation in azimuthal index and radius of the nanotube. The results are analyzed numerically for typical systems for relatively longer wavelength waves and possible consequences are discussed. The results can be important in general understanding of the role of exchange-correlation potential in quantum hydrodynamic treatment of charge-carriers in nanotubes.
Khan, S. A. [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Ayub, M. K. [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Pohang University of Science and Technology (POSTECH), Pohang, Gyunbuk 790-784 (Korea, Republic of); Ahmad, Ali [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)
2012-10-15T23:59:59.000Z
Quantum plasma oscillations are studied in a strongly magnetized, ultra-dense plasma with degenerate electrons and positrons. The dispersive role of electron and positron quantum effects on low frequency (in comparison to electron cyclotron frequency) shear electromagnetic wave is investigated by employing hydrodynamic formulation. In the presence of ions, the density balance changes, and the electromagnetic wave (with frequency lower than the ion cyclotron frequency) is shown to couple with electrostatic ion mode under certain conditions. For such low frequency waves, it is also seen that the contribution of electron and positron degeneracy pressure is dominant as compared to their diffraction effects. The results are analyzed numerically for illustrative purpose pointing out their relevance to the dense laboratory (e.g., super-intense laser-dense matter interactions) and astrophysical plasmas.
Okamoto, Takenori J; De Pontieu, Bart; Uitenbroek, Han; Van Doorsselaere, Tom; Yokoyama, Takaaki
2015-01-01T23:59:59.000Z
Transverse magnetohydrodynamic (MHD) waves have been shown to be ubiquitous in the solar atmosphere and can in principle carry sufficient energy to generate and maintain the Sun's million-degree outer atmosphere or corona. However, direct evidence of the dissipation process of these waves and subsequent heating has not yet been directly observed. Here we report on high spatial, temporal, and spectral resolution observations of a solar prominence that show a compelling signature of so-called resonant absorption, a long hypothesized mechanism to efficiently convert and dissipate transverse wave energy into heat. Aside from coherence in the transverse direction, our observations show telltale phase differences around 180 degrees between transverse motions in the plane-of-sky and line-of-sight velocities of the oscillating fine structures or threads, and also suggest significant heating from chromospheric to higher temperatures. Comparison with advanced numerical simulations support a scenario in which transverse...
Lemke, R.W.; DeMuth, G.E.; Biggs, A.W. (Sandia National Labs., Albuquerque, NM (USA); Air Force Weapons Lab., Kirtland AFB, NM (USA); Alabama Univ., Huntsville, AL (USA). Dept. of Electrical and Computer Engineering)
1989-01-01T23:59:59.000Z
The utility of the magnetically insulated transmission line oscillator (MILO) as a high power microwave source depends on how efficiently power can be extracted from it. We have designed a slow-wave stepped transformer for the purpose of axially extracting microwave power from a 3.6 GHz coaxial MILO. The slow-wave transformer design was optimized using particle-in-cell simulation, and tested in experiments performed on the HPM Simulation Division's GEMINI and GYPSY water Blumlein pulse power sources. In this paper we summarize the slow-wave stepped transformer design, and describe MILO axial power extraction experiments which yielded up to 300 MW of radiated power. 10 refs., 4 figs., 2 tabs.
the wave model A traveling wave is an organized disturbance
Winokur, Michael
1 waves the wave model A traveling wave is an organized disturbance propagating at a well-defined wave speed v. · In transverse waves the particles of the medium move perpendicular to the direction of wave propagation. · In longitudinal waves the particles of the medium move parallel to the direction
Supernova Seismology: Gravitational Wave Signatures of Rapidly Rotating Core Collapse
Fuller, Jim; Abdikamalov, Ernazar; Ott, Christian
2015-01-01T23:59:59.000Z
Gravitational waves (GW) generated during a core-collapse supernova open a window into the heart of the explosion. At core bounce, progenitors with rapid core rotation rates exhibit a characteristic GW signal which can be used to constrain the properties of the core of the progenitor star. We investigate the dynamics of rapidly rotating core collapse, focusing on hydrodynamic waves generated by the core bounce and the GW spectrum they produce. The centrifugal distortion of the rapidly rotating proto-neutron star (PNS) leads to the generation of axisymmetric quadrupolar oscillations within the PNS and surrounding envelope. Using linear perturbation theory, we estimate the frequencies, amplitudes, damping times, and GW spectra of the oscillations. Our analysis provides a qualitative explanation for several features of the GW spectrum and shows reasonable agreement with nonlinear hydrodynamic simulations, although a few discrepancies due to non-linear/rotational effects are evident. The dominant early postbounce...
Sawtooth oscillations in shaped plasmas
Lazarus, E. A. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Luce, T. C.; Burrell, K. H.; Chu, M. S.; Ferron, J. R.; Hyatt, A. W.; Lao, L. L.; Lohr, J.; Osborne, T. H.; Petty, C. C.; Politzer, P. A.; Prater, R.; Scoville, J. T.; Strait, E. J.; Turnbull, A. D. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Austin, M. E.; Waelbroeck, F. L. [University of Texas, Austin, Texas 78712 (United States); Brennan, D. P. [University of Tulsa, Tulsa, Oklahoma 74104 (United States); Jayakumar, R. J.; Makowski, M. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] (and others)
2007-05-15T23:59:59.000Z
The role of interchange and internal kink modes in the sawtooth oscillations is explored by comparing bean- and oval-shaped plasmas. The n=1 instability that results in the collapse of the sawtooth has been identified as a quasi-interchange in the oval cases and the internal kink in the bean shape. The ion and electron temperature profiles are followed in detail through the sawtooth ramp. It is found that electron energy transport rates are very high in the oval and quite low in the bean shape. Ion energy confinement in the oval is excellent and the sawtooth amplitude ({delta}T/T) in the ion temperature is much larger than that of the electrons. The sawtooth amplitudes for ions and electrons are comparable in the bean shape. The measured q profiles in the bean and oval shapes are found to be consistent with neoclassical current diffusion of the toroidal current, and the observed differences in q largely result from the severe differences in electron energy transport. For both shapes the collapse flattens the q profile and after the collapse return to q{sub 0} > or approx. 1. Recent results on intermediate shapes are reported. These shapes show that the electron energy transport improves gradually as the plasma triangularity is increased.
Torsional oscillations of strange stars
Massimo Mannarelli
2014-09-12T23:59:59.000Z
Strange stars are one of the hypothetical compact stellar objects that can be formed after a supernova explosion. The existence of these objects relies on the absolute stability of strange {\\it collapsed} quark matter with respect to standard nuclear matter. We discuss simple models of strange stars with a bare quark matter surface, thus standard nuclear matter is completely absent. In these models an electric dipole layer a few hundreds Fermi thick should exist close to the star surface. Studying the torsional oscillations of the electrically charged layer we estimate the emitted power, finding that it is of the order of $10^{45}$ erg/s, meaning that these objects would be among the brightest compact sources in the heavens. The associated relaxation times are very uncertain, with values ranging between microseconds and minutes, depending on the crust thickness. Although part of the radiated power should be absorbed by the electrosphere surrounding the strange star, a sizable fraction of photons should escape and be detectable.
The characterization of Lamb and Rayleigh waves in plates with ramp-like changes in thickness
Uzzell, Christopher Tinsley
1994-01-01T23:59:59.000Z
The research described in this thesis uses broadband laser generation and detection techniques to investigate acoustic wave propagation in wedge type structures. The interrogating waves were generated by a Q-switched ND:YAG laser. Fizeau based...
Direct simulation and deterministic prediction of large-scale nonlinear ocean wave-field
Wu, Guangyu, 1972-
2004-01-01T23:59:59.000Z
Despite its coarse approximation of physics, the phase-averaged wave spectrum model has been the only type of tool available for ocean wave prediction in the past 60 years. With the rapid advances in sensing technology, ...
Four-Neutrino Oscillations at SNO
M. C. Gonzalez-Garcia; C. Peña-Garay
2001-03-20T23:59:59.000Z
We discuss the potential of SNO to constraint the four-neutrino mixing schemes favoured by the results of all neutrino oscillations experiments. These schemes allow simultaneous transitions of solar $\
Solar mass-varying neutrino oscillations
Marfatia, Danny; Huber, P.; Barger, V.
2005-11-18T23:59:59.000Z
We propose that the solar neutrino deficit may be due to oscillations of mass-varying neutrinos (MaVaNs). This scenario elucidates solar neutrino data beautifully while remaining comfortably compatible with atmospheric ...
Oscillation damping means for magnetically levitated systems
Post, Richard F. (Walnut Creek, CA)
2009-01-20T23:59:59.000Z
The present invention presents a novel system and method of damping rolling, pitching, or yawing motions, or longitudinal oscillations superposed on their normal forward or backward velocity of a moving levitated system.
The Case for Strategic Oscillation Fred Glover
Hao, Jin-Kao
for Strategic Oscillation Fred Glover OptTek Systems, Inc., 1919 Seventh Street, Boulder, CO 80302 USA glover implications for future research. Manuscript Click here to download Manuscript: ANOR Glover and Jin
Chimera States in Mechanical Oscillator Networks
Martens, Erik Andreas; Fourrière, Antoine; Hallatschek, Oskar
2013-01-01T23:59:59.000Z
The synchronization of coupled oscillators is a fascinating manifestation of self-organization that nature employs to orchestrate essential processes of life, such as the beating of the heart. While it was long thought that synchrony or disorder were mutually exclusive steady states for a network of identical oscillators, numerous theoretical studies in recent years revealed the intriguing possibility of 'chimera states', in which the symmetry of the oscillator population is broken into a synchronous and an asynchronous part. However, a striking lack of empirical evidence raises the question of whether chimeras are indeed characteristic to natural systems. This calls for a palpable realization of chimera states without any fine-tuning, from which physical mechanisms underlying their emergence can be uncovered. Here, we devise a simple experiment with mechanical oscillators coupled in a hierarchical network to show that chimeras emerge naturally from a competition between two antagonistic synchronization patte...
Chimeras in networks of planar oscillators
Carlo R. Laing
2010-06-23T23:59:59.000Z
Chimera states occur in networks of coupled oscillators, and are characterized by having some fraction of the oscillators perfectly synchronized, while the remainder are desynchronized. Most chimera states have been observed in networks of phase oscillators with coupling via a sinusoidal function of phase differences, and it is only for such networks that any analysis has been performed. Here we present the first analysis of chimera states in a network of planar oscillators, each of which is described by both an amplitude and a phase. We find that as the attractivity of the underlying periodic orbit is reduced chimeras are destroyed in saddle-node bifurcations, and supercritical Hopf and homoclinic bifurcations of chimeras also occur.
A Torsional Oscillator Study Solid Helium
Sheldon, Nathan D.
A Torsional Oscillator Study of Solid Helium George Edgar Marcus Nichols Royal Holloway College and Andy Nichols and Alexandra Zuckermann for theirs out of it. #12;Contents 1 Motivation 10 1.1 Helium
Spatial xenon oscillation control with expert systems
Alten, S. (Turkish Atomic Energy Authority, Ankara (Turkey)); Danofsky, R.A. (Iowa State Univ., Ames, IA (United States))
1993-01-01T23:59:59.000Z
Spatial power oscillations were attributed to the xenon transients in a reactor core in 1958 by Randall and St. John. These transients are usually initiated by a local reactivity insertion and lead to divergent axial flux oscillations in the core at constant power. Several heuristic manual control strategies and automatic control methods were developed to damp the xenon oscillations at constant power operations. However, after the load-follow operation of the reactors became a necessity of life, a need for better control strategies arose. Even though various advanced control strategies were applied to solve the xenon oscillation control problem for the load-follow operation, the complexity of the system created difficulties in modeling. The strong nonlinearity of the problem requires highly sophisticated analytical approaches that are quite inept for numerical solutions. On the other hand, the complexity of a system and heuristic nature of the solutions are the basic reasons for using artificial intelligence techniques such as expert systems.
CFD analysis of laminar oscillating flows
Booten, C. W. Charles W.); Konecni, S. (Snezana); Smith, B. L. (Barton L.); Martin, R. A. (Richard A.)
2001-01-01T23:59:59.000Z
This paper describes a numerical simulations of oscillating flow in a constricted duct and compares the results with experimental and theoretical data. The numerical simulations were performed using the computational fluid dynamics (CFD) code CFX4.2. The numerical model simulates an experimental oscillating flow facility that was designed to test the properties and characteristics of oscillating flow in tapered ducts, also known as jet pumps. Jet pumps are useful devices in thermoacoustic machinery because they produce a secondary pressure that can counteract an unwanted effect called streaming, and significantly enhance engine efficiency. The simulations revealed that CFX could accurately model velocity, shear stress and pressure variations in laminar oscillating flow. The numerical results were compared to experimental data and theoretical predictions with varying success. The least accurate numerical results were obtained when laminar flow approached transition to turbulent flow.
Experimental investigation of a coaxial gyrotron oscillator
Advani, Rahul N
1999-01-01T23:59:59.000Z
This thesis presents experimental results of a megawatt power level, 140 GHz coaxial gyrotron oscillator. The coaxial gyrotron has the potential to transport very high power electron beams and thus achieve higher microwave ...
Evidence for Neutrino Oscillations I: Solar and Reactor Neutrinos
A. B. McDonald
2004-12-06T23:59:59.000Z
This paper discusses evidence for neutrino oscillations obtained from measurements with solar neutrinos and reactor neutrinos.
Newtonian gravity, red shift, confinement, asymptotic freedom and quarks oscillations
G. Quznetsov
2008-10-18T23:59:59.000Z
Quarks oscillations give the Newtonian gravity law, the red shift, the confinement and the asymptotic freedom.
Generalized oscillator strength of endohedral molecules
M. Ya. Amusia; L. V. Chernysheva; E. Z. Liverts
2012-03-03T23:59:59.000Z
We investigate here the fast electron scattering upon endohedral atoms that present a fullerene CN staffed by an atom A, A@CN. We calculate the inelastic scattering cross-section expressing it via generalized oscillator strengths (GOS) density. We take into account two major effects of CN upon ionization of the atom A. Namely, the scattering of the electron by the static potential of the fullerenes shell and modification of the interaction between the fast incoming and atomic electrons due to polarization of the fullerenes shell by the incoming electron beam. To obtain the main features of the effect, we substitute the complex fullerenes shell CN by a static zero thickness potential, express its deformation under incoming electron action via CN polarizabilities. We perform all consideration in the frame of the so-called random phase approximation with exchange (RPAE) that gave reliable results for GOSes of isolated atoms, and expressions for absolute and differential in angle cross-sections. We limit ourselves with dipole and biggest non-dipole contributions to the differential in angle cross-section. We compare fast electron scattering with photoionization as a source of information on the target electronic structure and emphasize some advantages of fast electron scattering. As concrete objects of calculations, we choose noble gas endohedrals Ar@C60 and Xe@C60. The results are presented for two transferred momentum q values: q=0.1 and 1.0. Even for small q=0.1, in the so-called optical limit, the deviation from photoionization case is prominent and instructive. As an interesting and very specific object, we study onion-type endohedrals A@CN1@CN2, in which the all construction A@CN1 is stuffed inside CN2 with N2 >> N1.
Sergeev, Igor N [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)] [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)
2013-01-31T23:59:59.000Z
Lyapunov-type oscillation and wandering indicators are defined for solutions of systems of differential equations; these are the average frequency of zeros for the projection of a solution onto some line and the average angular velocity of rotation of a solution about the origin in some basis, respectively. An integral equality relating these indicators is obtained. The indicators introduced are shown to coincide if, prior to averaging, the oscillation indicators are minimized over all possible lines, and the wandering indicators over all possible bases. Bibliography: 17 titles.
Grimus, Walter; Stockinger, P
1999-01-01T23:59:59.000Z
We discuss conceptual aspects of neutrino oscillations with the main emphasis on the field-theoretical approach. This approach includes the neutrino source and detector processes and allows to obtain the neutrino transition or survival probabilities as cross sections derived from the Feynman diagram of the combined source - detection process. In this context, the neutrinos which are supposed to oscillate appear as propagators of the neutrino mass eigenfields, connecting the source and detection processes. We consider also the question why the canonical neutrino oscillation formula is so robust against corrections and discuss the nature of the oscillating neutrino state emerging in the field-theoretical approach.
W. Grimus; S. Mohanty; P. Stockinger
1999-09-13T23:59:59.000Z
We discuss conceptual aspects of neutrino oscillations with the main emphasis on the field-theoretical approach. This approach includes the neutrino source and detector processes and allows to obtain the neutrino transition or survival probabilities as cross sections derived from the Feynman diagram of the combined source - detection process. In this context, the neutrinos which are supposed to oscillate appear as propagators of the neutrino mass eigenfields, connecting the source and detection processes. We consider also the question why the canonical neutrino oscillation formula is so robust against corrections and discuss the nature of the oscillating neutrino state emerging in the field-theoretical approach.
Chaos control of parametric driven Duffing oscillators
Jin, Leisheng; Mei, Jie; Li, Lijie, E-mail: L.Li@swansea.ac.uk [College of Engineering, Swansea University, Swansea SA2 8PP (United Kingdom)
2014-03-31T23:59:59.000Z
Duffing resonators are typical dynamic systems, which can exhibit chaotic oscillations, subject to certain driving conditions. Chaotic oscillations of resonating systems with negative and positive spring constants are identified to investigate in this paper. Parametric driver imposed on these two systems affects nonlinear behaviours, which has been theoretically analyzed with regard to variation of driving parameters (frequency, amplitude). Systematic calculations have been performed for these two systems driven by parametric pumps to unveil the controllability of chaos.
Field-theoretical treatment of neutrino oscillations
Grimus, Walter; Stockinger, P
2000-01-01T23:59:59.000Z
We discuss the field-theoretical approach to neutrino oscillations. This approach includes the neutrino source and detector processes and allows to obtain the neutrino transition or survival probabilities as cross sections derived from the Feynman diagram of the combined source -- detection process. In this context, the neutrinos which are supposed to oscillate appear as propagators of the neutrino mass eigenfields, connecting the source and detection processes.
Field-theoretical treatment of neutrino oscillations
W. Grimus; S. Mohanty; P. Stockinger
1999-04-15T23:59:59.000Z
We discuss the field-theoretical approach to neutrino oscillations. This approach includes the neutrino source and detector processes and allows to obtain the neutrino transition or survival probabilities as cross sections derived from the Feynman diagram of the combined source -- detection process. In this context, the neutrinos which are supposed to oscillate appear as propagators of the neutrino mass eigenfields, connecting the source and detection processes.
Oscillation dynamics of multi-well condensates
S. Mossmann; C. Jung
2006-12-05T23:59:59.000Z
We propose a new approach to the macroscopic dynamics of three-well Bose-Einstein condensates, giving particular emphasis to self-trapping and Josephson oscillations. Although these effects have been studied quite thoroughly in the mean-field approximation, a full quantum description is desirable, since it avoids pathologies due to the nonlinear character of the mean-field equations. Using superpositions of quantum eigenstates, we construct various oscillation and trapping scenarios.
ARE PULSING SOLITARY WAVES RUNNING INSIDE THE SUN?
Wolff, Charles L., E-mail: charles.l.wolff@nasa.gov [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
2012-09-10T23:59:59.000Z
A precise sequence of frequencies-detected four independent ways-is interpreted as a system of solitary waves below the Sun's convective envelope. Six future observational or theoretical tests of this idea are suggested. Wave properties (rotation rates, radial energy distribution, nuclear excitation strength) follow from conventional dynamics of global oscillation modes after assuming a localized nuclear term strong enough to perturb and hold mode longitudes into alignments that form 'families'. To facilitate future tests, more details are derived for a system of two dozen solitary waves 2 {<=} l {<=} 25. Wave excitation by {sup 3}He and {sup 14}C burning is complex. It spikes by factors M{sub 1} {<=} 10{sup 3} when many waves overlap in longitude but its long-time average is M{sub 2} {<=} 10. Including mixing can raise overall excitation to {approx}50 times that in a standard solar model. These spikes cause tiny phase shifts that tend to pull wave rotation rates toward their ideal values {proportional_to}[l(l + 1)]{sup -1}. A system like this would generate some extra nuclear energy in two spots at low latitude on opposite sides of the Sun. Each covers about 20 Degree-Sign of longitude. Above a certain wave amplitude, the system starts giving distinctly more nuclear excitation to some waves (e.g., l = 9, 14, and 20) than to neighboring l values. The prominence of l = 20 has already been reported. This transition begins at temperature amplitudes {Delta}T/T = 0.03 in the solar core for a typical family of modes, which corresponds to {delta}T/T {approx} 0.001 for one of its many component oscillation modes.
Observations of Running Waves in a Sunspot Chromosphere
D. Shaun Bloomfield; Andreas Lagg; Sami K. Solanki
2007-03-26T23:59:59.000Z
Spectropolarimetric time series data of the primary spot of active region NOAA 9448 were obtained in the Si I 10827 \\AA line and the He I 10830 \\AA multiplet with the Tenerife Infrared Polarimeter. Throughout the time series the spectrograph slit was fixed over a region covering umbra, a light bridge, penumbra, and quiet sun. We present speeds of running penumbral waves in the chromosphere, their relation to both photospheric and chromospheric umbral oscillations, and their dependence on the magnetic field topology.
Nikolay Kuznetsov
2015-03-07T23:59:59.000Z
The coupled motion is investigated for a mechanical system consisting of water and a body freely floating in it. Water occupies either a half-space or a layer of constant depth into which an infinitely long surface-piercing cylinder is immersed, thus allowing us to study two-dimensional modes. Under the assumption that the motion is of small amplitude near equilibrium, a linear setting is applicable and for the time-harmonic oscillations it reduces to a spectral problem with the frequency of oscillations as the spectral parameter. It is essential that one of the problem's relations is linear with respect to the parameter, whereas two others are quadratic with respect to it. Within this framework, it is shown that the total energy of the water motion is finite and the equipartition of energy holds for the whole system. On this basis, it is proved that no wave modes can be trapped provided their frequencies exceed a bound depending on cylinder's properties, whereas its geometry is subject to some restrictions and, in some cases, certain restrictions are imposed on the type of mode.
Oscillations During Thermonuclear X-ray Bursts
Tod E. Strohmayer
2001-01-12T23:59:59.000Z
High amplitude, nearly coherent X-ray brightness oscillations during thermonuclear X-ray bursts were discovered with the Rossi X-ray Timing Explorer (RXTE) in early 1996. Spectral and timing evidence strongly supports the conclusion that these oscillations are caused by rotational modulation of the burst emission and that they reveal the spin frequency of neutron stars in low mass X-ray binaries, a long sought goal of X-ray astronomy. Studies carried out over the past year have led to the discovery of burst oscillations in four new sources, bringing to ten the number with confirmed burst oscillations. I review the status of our knowledge of these oscillations and indicate how they can be used to probe the physics of neutron stars. For a few burst oscillation sources it has been proposed that the strongest and most ubiquitous frequency is actually the first overtone of the spin frequency and hence that two nearly antipodal hot spots are present on the neutron star. This inference has important implications for both the physics of thermonuclear burning as well as the mass - radius relation for neutron stars, so its confirmation is crucial. I discuss recent attempts to confirm this hypothesis for 4U 1636-53, the source for which a signal at the putative fundamental (290 Hz) has been claimed.
Magnetohydrodynamics wave propagation in the neighbourhood of two dipoles
J. A. McLaughlin; A. W. Hood
2007-12-11T23:59:59.000Z
This paper is the third in a series of investigations by the authors. The nature of fast magnetoacoustic and Alfv\\'en waves is investigated in a 2D $\\beta=0$ plasma in the neighbourhood of two dipoles. We use both numerical simulations (two-step Lax-Wendroff scheme) and analytical techniques (WKB approximation). It is found that the propagation of the linear fast wave is dictated by the Alfv\\'en speed profile and that close to the null, the wave is attracted to the neutral point. However, it is also found that in this magnetic configuration some of the wave can escape the refraction effect; this had not been seen in previous investigations by the authors. The wave split occurs near the regions of very high Alfv\\'en speed (found near the loci of the two dipoles). Also, for the set-up investigated it was found that 40% of the wave energy accumulates at the null. Ohmic dissipation will then extract the wave energy at this point. The Alfv\\'en wave behaves in a different manner in that part of the wave accumulates along the separatrices and part escapes. Hence, the current density will accumulate at this part of the topology and this is where wave heating will occur. The phenomenon of wave accumulation at a specific place is a feature of both wave types, as is the result that a fraction of the wave can now escape the numerical box when propagating in this magnetic configuration.
Alla Weinstein, Dominique Roddier, Kevin Banister
2012-03-30T23:59:59.000Z
Principle Power Inc. and National Renewable Energy Lab (NREL) have completed a contract to assess the technical and economic feasibility of integrating wave energy converters into the WindFloat, resulting in a new concept called the WindWaveFloat (WWF). The concentration of several devices on one platform could offer a potential for both economic and operational advantages. Wind and wave energy converters can share the electrical cable and power transfer equipment to transport the electricity to shore. Access to multiple generation devices could be simplified, resulting in cost saving at the operational level. Overall capital costs may also be reduced, provided that the design of the foundation can be adapted to multiple devices with minimum modifications. Finally, the WindWaveFloat confers the ability to increase energy production from individual floating support structures, potentially leading to a reduction in levelized energy costs, an increase in the overall capacity factor, and greater stability of the electrical power delivered to the grid. The research conducted under this grant investigated the integration of several wave energy device types into the WindFloat platform. Several of the resulting system designs demonstrated technical feasibility, but the size and design constraints of the wave energy converters (technical and economic) make the WindWaveFloat concept economically unfeasible at this time. Not enough additional generation could be produced to make the additional expense associated with wave energy conversion integration into the WindFloat worthwhile.
Peralta, J.; López-Valverde, M. A. [Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía, 18008 Granada (Spain); Imamura, T. [Institute of Space and Astronautical Science-Japan Aerospace Exploration Agency 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Read, P. L. [Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford (United Kingdom); Luz, D. [Centro de Astronomia e Astrofísica da Universidade de Lisboa (CAAUL), Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisboa (Portugal); Piccialli, A., E-mail: peralta@iaa.es [LATMOS, UVSQ, 11 bd dAlembert, 78280 Guyancourt (France)
2014-07-01T23:59:59.000Z
This paper is the first of a two-part study devoted to developing tools for a systematic classification of the wide variety of atmospheric waves expected on slowly rotating planets with atmospheric superrotation. Starting with the primitive equations for a cyclostrophic regime, we have deduced the analytical solution for the possible waves, simultaneously including the effect of the metric terms for the centrifugal force and the meridional shear of the background wind. In those cases when the conditions for the method of the multiple scales in height are met, these wave solutions are also valid when vertical shear of the background wind is present. A total of six types of waves have been found and their properties were characterized in terms of the corresponding dispersion relations and wave structures. In this first part, only waves that are direct solutions of the generic dispersion relation are studied—acoustic and inertia-gravity waves. Concerning inertia-gravity waves, we found that in the cases of short horizontal wavelengths, null background wind, or propagation in the equatorial region, only pure gravity waves are possible, while for the limit of large horizontal wavelengths and/or null static stability, the waves are inertial. The correspondence between classical atmospheric approximations and wave filtering has been examined too, and we carried out a classification of the mesoscale waves found in the clouds of Venus at different vertical levels of its atmosphere. Finally, the classification of waves in exoplanets is discussed and we provide a list of possible candidates with cyclostrophic regimes.
Kinematic Density Waves in Accretion Disks
Svetlin Tassev; Edmund Bertschinger
2008-10-14T23:59:59.000Z
When thin accretion disks around black holes are perturbed, the main restoring force is gravity. If gas pressure, magnetic stresses, and radiation pressure are neglected, the disk remains thin as long as orbits do not intersect. Intersections would result in pressure forces which limit the growth of perturbations. We find that a discrete set of perturbations is possible for which orbits remain non-intersecting for arbitrarily long times. These modes define a discrete set of frequencies. We classify all long-lived perturbations for arbitrary potentials and show how their mode frequencies are related to pattern speeds computed from the azimuthal and epicyclic frequencies. We show that modes are concentrated near radii where the pattern speed has vanishing radial derivative. We explore these modes around Kerr black holes as a possible explanation for the high-frequency quasi-periodic oscillations of black hole binaries such as GRO J1655-40. The long-lived modes are shown to coincide with diskoseismic waves in the limit of small sound speed. While the waves have long lifetime, they have the wrong frequencies to explain the pairs of high-frequency quasi-periodic oscillations observed in black hole binaries.
Lighthouses with two lights: burst oscillations from the accretion-powered millisecond pulsars
Anna L. Watts
2008-08-19T23:59:59.000Z
The key contribution of the discovery of nuclear-powered pulsations from the accretion-powered millisecond pulsars (AMPs) has been the establishment of burst oscillation frequency as a reliable proxy for stellar spin rate. This has doubled the sample of rapidly-rotating accreting neutron stars and revealed the unexpected absence of any stars rotating near the break-up limit. The resulting `braking problem' is now a major concern for theorists, particularly given the possible role of gravitational wave emission in limiting spin. This, however, is not the only area where burst oscillations from the AMPs are having an impact. Burst oscillation timing is developing into a promising technique for verifying the level of spin variability in the AMPs (a topic of considerable debate). These sources also provide unique input to our efforts to understand the still-elusive burst oscillation mechanism. This is because they are the only stars where we can reliably gauge the role of uneven fuel deposition and, of course, the magnetic field.
Iwo Bialynicki-Birula
2005-08-26T23:59:59.000Z
Photon wave function is a controversial concept. Controversies stem from the fact that photon wave functions can not have all the properties of the Schroedinger wave functions of nonrelativistic wave mechanics. Insistence on those properties that, owing to peculiarities of photon dynamics, cannot be rendered, led some physicists to the extreme opinion that the photon wave function does not exist. I reject such a fundamentalist point of view in favor of a more pragmatic approach. In my view, the photon wave function exists as long as it can be precisely defined and made useful.
Synthetic observations of wave propagation in a sunspot umbra
Felipe, T; Khomenko, E
2014-01-01T23:59:59.000Z
Spectropolarimetric temporal series from Fe I $\\lambda$ 6301.5 \\AA\\ and Ca II infrared triplet lines are obtained by applying the Stokes synthesis code NICOLE to a numerical simulation of wave propagation in a sunspot umbra from MANCHA code. The analysis of the phase difference between Doppler velocity and intensity core oscillations of the Fe I $\\lambda$ 6301.5 \\AA\\ line reveals that variations in the intensity are produced by opacity fluctuations rather than intrinsic temperature oscillations, except for frequencies between 5 and 6.5 mHz. On the other hand, the photospheric magnetic field retrieved from the weak field approximation provides the intrinsic magnetic field oscillations associated to wave propagation. Our results suggest that this is due to the low magnetic field gradient of our sunspot model. The Stokes parameters of the chromospheric Ca II infrared triplet lines show striking variations as shock waves travel through the formation height of the lines, including emission self-reversals in the li...
Organized Oscillations of Initially-Turbulent Flow Past a Cavity
J.C. Lin; D. Rockwell
2002-09-17T23:59:59.000Z
Flow past an open cavity is known to give rise to self-sustained oscillations in a wide variety of configurations, including slotted-wall, wind and water tunnels, slotted flumes, bellows-type pipe geometries, high-head gates and gate slots, aircraft components and internal piping systems. These cavity-type oscillations are the origin of coherent and broadband sources of noise and, if the structure is sufficiently flexible, flow-induced vibration as well. Moreover, depending upon the state of the cavity oscillation, substantial alterations of the mean drag may be induced. In the following, the state of knowledge of flow past cavities, based primarily on laminar inflow conditions, is described within a framework based on the flow physics. Then, the major unresolved issues for this class of flows will be delineated. Self-excited cavity oscillations have generic features, which are assessed in detail in the reviews of Rockwell and Naudascher, Rockwell, Howe and Rockwell. These features, which are illustrated in the schematic of Figure 1, are: (i) interaction of a vorticity concentration(s) with the downstream corner, (ii) upstream influence from this corner interaction to the sensitive region of the shear layer formed from the upstream corner of the cavity; (iii) conversion of the upstream influence arriving at this location to a fluctuation in the separating shear layer; and (iv) amplification of this fluctuation in the shear layer as it develops in the streamwise direction. In view of the fact that inflow shear-layer in the present investigation is fully turbulent, item (iv) is of particular interest. It is generally recognized, at least for laminar conditions at separation from the leading-corner of the cavity, that the disturbance growth in the shear layer can be described using concepts of linearized, inviscid stability theory, as shown by Rockwell, Sarohia, and Knisely and Rockwell. As demonstrated by Knisely and Rockwell, on the basis of experiments interpreted with the aid of linearized theory, not only the fundamental component of the shear layer instability may be present, but a number of additional, primarily lower frequency components can exist as well. In fact, the magnitude of these components can be of the same order as the fundamental component. These issues have not been addressed for the case of a fully-turbulent in-flow and its separation from the leading corner of the cavity.
Rogue Wave Modes for the Long Wave-Short Wave Resonance Kwok Wing CHOW*(1)
1 Rogue Wave Modes for the Long Wave-Short Wave Resonance Model Kwok Wing CHOW*(1) , Hiu Ning CHAN.45.Yv; 47.35.Fg ABSTRACT The long wave-short wave resonance model arises physically when the phase velocity of a long wave matches the group velocity of a short wave. It is a system of nonlinear evolution
Intensity oscillations in the carbon 1s ionization cross sections of 2-butyne
Carroll, Thomas X. [Division of Natural Sciences, Keuka College, Keuka Park, New York 14478 (United States); Zahl, Maria G.; Borve, Knut J.; Saethre, Leif J. [Department of Chemistry, University of Bergen, Allegaten 41, NO-5007 Bergen (Norway); Decleva, Piero; Ponzi, Aurora [Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, 34127 Trieste (Italy); Kas, Joshua J.; Vila, Fernando D.; Rehr, John J. [Department of Physics, University of Washington, Box 351560, Seattle, Washington 98195-1560 (United States); Thomas, T. Darrah [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)
2013-06-21T23:59:59.000Z
Carbon 1s photoelectron spectra for 2-butyne (CH{sub 3}C{identical_to}CCH{sub 3}) measured in the photon energy range from threshold to 150 eV above threshold show oscillations in the intensity ratio C2,3/C1,4. Similar oscillations have been seen in chloroethanes, where the effect has been attributed to EXAFS-type scattering from the substituent chlorine atoms. In 2-butyne, however, there is no high-Z atom to provide a scattering center and, hence, oscillations of the magnitude observed are surprising. The results have been analyzed in terms of two different theoretical models: a density-functional model with B-spline atom-centered functions to represent the continuum electrons and a multiple-scattering model using muffin-tin potentials to represent the scattering centers. Both methods give a reasonable description of the energy dependence of the intensity ratios.
Chimera states in systems of nonlocal nonidentical phase-coupled oscillators
Jianbo Xie; Hsien-Ching Kao; Edgar Knobloch
2015-01-02T23:59:59.000Z
Chimera states consisting of domains of coherently and incoherently oscillating nonlocally-coupled phase oscillators in systems with spatial inhomogeneity are studied. The inhomogeneity is introduced through the dependence of the oscillator frequency on its location. Two types of spatial inhomogeneity, localized and spatially periodic, are considered and their effects on the existence and properties of multi-cluster and traveling chimera states are explored. The inhomogeneity is found to break up splay states, to pin the chimera states to specific locations and to trap traveling chimeras. Many of these states can be studied by constructing an evolution equation for a complex order parameter. Solutions of this equation are in good agreement with the results of numerical simulations.
Tests of Lorentz and CPT violation with MiniBooNE neutrino oscillation excesses
Teppei Katori
2014-04-28T23:59:59.000Z
Violation of Lorentz invariance and CPT symmetry is a predicted phenomenon of Planck-scale physics. Various types of data are analyzed to search for Lorentz violation under the Standard-Model Extension (SME) framework, including neutrino oscillation data. MiniBooNE is a short-baseline neutrino oscillation experiment at Fermilab. The measured excesses from MiniBooNE cannot be reconciled within the neutrino Standard Model; thus it might be a signal of new physics, such as Lorentz violation. We have analyzed the sidereal time dependence of MiniBooNE data for signals of the possible breakdown of Lorentz invariance in neutrinos. In this brief review, we introduce Lorentz violation, the neutrino sector of the SME, and the analysis of short-baseline neutrino oscillation experiments. We then present the results of the search for Lorentz violation in MiniBooNE data. This review is based on the published result (ArXiv:1109.3480).
Oscillations During Thermonuclear X-ray Bursts: A New Probe of Neutron Stars
Tod E. Strohmayer
1999-11-19T23:59:59.000Z
Observations of thermonuclear (Type I) X-ray bursts from neutron stars in low mass X-ray binaries (LMXB) with the Rossi X-ray Timing Explorer (RXTE) have revealed large amplitude, high coherence X-ray brightness oscillations with frequencies in the 300 - 600 Hz range. Substantial spectral and timing evidence point to rotational modulation of the X-ray burst flux as the cause of these oscillations, and it is likely that they reveal the spin frequencies of neutron stars in LMXB from which they are detected. Here I review the status of our knowledge of these oscillations and describe how they can be used to constrain the masses and radii of neutron stars as well as the physics of thermonuclear burning on accreting neutron stars.
M Alvaro; L L Bonilla
2010-12-14T23:59:59.000Z
Semiconductor superlattices (SL) may be described by a Boltzmann-Poisson kinetic equation with a Bhatnagar-Gross-Krook (BGK) collision term which preserves charge, but not momentum or energy. Under appropriate boundary and voltage bias conditions, these equations exhibit time-periodic oscillations of the current caused by repeated nucleation and motion of charge dipole waves. Despite this clear nonequilibrium behavior, if we `close' the system by attaching insulated contacts to the superlattice and keeping its voltage bias to zero volts, we can prove the H theorem, namely that a free energy $\\Phi(t)$ of the kinetic equations is a Lyapunov functional ($\\Phi\\geq 0$, $d\\Phi/dt\\leq 0$). Numerical simulations confirm that the free energy decays to its equilibrium value for a closed SL, whereas for an `open' SL under appropriate dc voltage bias and contact conductivity $\\Phi(t)$ oscillates in time with the same frequency as the current self-sustained oscillations.
Generation of high power sub-terahertz radiation from a gyrotron with second harmonic oscillation
Saito, Teruo; Yamada, Naoki; Ikeuti, Shinji; Tatematsu, Yoshinori; Ikeda, Ryosuke; Ogawa, Isamu; Idehara, Toshitaka [Research Center for Development of Far-Infrared Region, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507 (Japan); Ogasawara, Shinya [Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8463 (Japan); Manuilov, Vladimir N. [Nizhny Novgorod State University, Nizhny Novgorod 603600 (Russian Federation); Shimozuma, Takashi; Kubo, Shin; Nishiura, Masaki; Tanaka, Kenji; Kawahata, Kazuo [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)
2012-06-15T23:59:59.000Z
New power records of second harmonic gyrotron oscillation have been demonstrated in the sub-THz band. The first step gyrotron of demountable type had succeeded in oscillation with power more than 50 kW at 350 GHz and nearly 40 kW at 390 GHz [T. Notake et al., Phys. Rev. Lett. 103, 225002 (2009)]. Then, the second step gyrotron of sealed-off type was manufactured. A cavity mode was carefully selected to avoid mode competition with a neighboring fundamental harmonic mode. Matching of the selected mode with the electron gun was also circumspectly considered. The second step gyrotron has attained higher power radiation than the first gyrotron. The maximum single mode power was 62 kW at 388 GHz. Then, the electron gun was modified for use of a different cavity mode with a higher coupling coefficient than that for the 62 kW mode. The new mode proved single mode oscillation power of 83 kW at about 389 GHz. These results are new second-harmonic-oscillation power records for sub-THz gyrotrons. The present study constitutes foundations of development of high power second harmonic sub-THz gyrotron for application to collective Thomson scattering measurement on fusion plasmas, especially on high-density plasmas such as those produced in LHD [N. Ohyabu et al., Phys. Rev. Lett. 97, 055002 (2006)]. This paper reports the design consideration to realize high power single mode gyrotron oscillation at second harmonic and the examination of oscillation characteristics of the gyrotron.
Mathur, Manikandan S.
Internal waves are a ubiquitous and significant means of momentum and energy transport in the oceans, atmosphere, and astrophysical bodies. Here, we show that internal wave propagation in nonuniform density stratifications, ...
Mercier, Matthieu J.
We present the results of a combined experimental and numerical study of the generation of internal waves using the novel internal wave generator design of Gostiaux et al. (Exp. Fluids, vol. 42, 2007, pp. 123–130). This ...
Phase-mixing of Langmuir oscillations in cold electron-positron-ion plasmas
Maity, Chandan [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)
2014-07-15T23:59:59.000Z
Space-time evolution of Langmuir oscillations in a cold homogeneous electron-positron-ion plasma has been analyzed by employing a straightforward perturbation expansion method, showing phase-mixing and, thus, wave-breaking of excited oscillations at arbitrary amplitudes. Within an assumption of infinitely massive ions, an approximate phase-mixing time is found to scale as ?{sub pe}t{sub mix}?[(6/?{sup 2})((2??){sup 5/2}/(1??))]{sup 1/3}, where “?” and “?” (= n{sub 0i}/n{sub 0e}) are the amplitude of perturbation and the ratio of equilibrium ion density to equilibrium electron density, respectively, and ?{sub pe}??(4?n{sub 0e}e{sup 2}/m) is the electron plasma frequency. The results presented on phase-mixing of Langmuir modes in multispecies plasmas are expected to be relevant to laboratory and astrophysical environments.
Braenzel, J.; Schnürer, M.; Steinke, S.; Priebe, G.; Sandner, W. [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Str. 2A, 12489 Berlin (Germany)] [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Str. 2A, 12489 Berlin (Germany); Andreev, A. [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Str. 2A, 12489 Berlin (Germany) [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Str. 2A, 12489 Berlin (Germany); Vavilov State Optical Institute, Birzhevaya line 4, 199034 St. Petersburg (Russian Federation); Platonov, K. [Vavilov State Optical Institute, Birzhevaya line 4, 199034 St. Petersburg (Russian Federation)] [Vavilov State Optical Institute, Birzhevaya line 4, 199034 St. Petersburg (Russian Federation)
2013-08-15T23:59:59.000Z
Theoretical and experimental investigations of the dynamics of a relativistically oscillating plasma slab reveal spectral line splitting in laser driven harmonic spectra, leading to double harmonic series. Both series are well characterized with harmonics arising by two fundamental frequencies. While a relativistic oscillation of the critical density drives the harmonic emission, the splitting is a result of an additional acceleration during the laser pulse duration. In comparison with the oscillatory movement, this acceleration is rather weak and can be described by a plasma shock wave driven by the pressure of light. We introduce particle in cell simulations and an analytical model explaining the harmonic line splitting. The derived analytical formula gives direct access between the splitting in the harmonic spectrum and the acceleration of the plasma surface.
Timescales of Kozai-Lidov oscillations at quadrupole and octupole order in the test particle limit
Antognini, Joseph M O
2015-01-01T23:59:59.000Z
Kozai-Lidov (KL) oscillations in hierarchical triple systems have found application to many astrophysical contexts, including planet formation, type Ia supernovae, and supermassive black hole dynamics. The period of these oscillations is known at the order-of-magnitude level, but dependences on the initial mutual inclination or inner eccentricity are not typically included. In this work I calculate the period of KL oscillations ($t_{\\textrm{KL}}$) exactly in the test particle limit at quadrupole order (TPQ). I explore the parameter space of all hierarchical triples at TPQ and show that except for triples on the boundary between libration and rotation, the period of KL oscillations does not vary by more than a factor of a few. The exact period may be approximated to better than 2 per cent for triples with mutual inclinations between 60$^{\\circ}$ and 120$^{\\circ}$ and initial eccentricities less than $\\sim$0.3. In addition, I derive an analytic expression for the period of octupole-order oscillations due to the...
Roberts, Jesse D.; Chang, Grace; Magalen, Jason; Jones, Craig
2014-09-01T23:59:59.000Z
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 .
Degasperis, Antonio; Aceves, Alejandro B
2015-01-01T23:59:59.000Z
We derive the rogue wave solution of the classical massive Thirring model, that describes nonlinear optical pulse propagation in Bragg gratings. Combining electromagnetically induced transparency with Bragg scattering four-wave mixing, may lead to extreme waves at extremely low powers.
Internal wave instability: Wave-wave versus wave-induced mean flow interactions
Sutherland, Bruce
, known as parametric sub- harmonic instability, results generally when a disturbance of one frequency imparts energy to disturbances of half that frequency.13,14 Generally, a plane periodic internal wave, energy from primary waves is transferred, for example, to waves with half frequency. Self
Modulational instability of Rossby and drift waves and generation of zonal jets
Colm Connaughton; Balu Nadiga; Sergey Nazarenko; Brenda Quinn
2009-05-14T23:59:59.000Z
We study the modulational instability of geophysical Rossby and plasma drift waves within the Charney-Hasegawa-Mima (CHM) model both theoretically, using truncated (four-mode and three-mode) models, and numerically, using direct simulations of CHM equation in the Fourier space. The linear theory predicts instability for any amplitude of the primary wave. For strong primary waves the most unstable modes are perpendicular to the primary wave, which correspond to generation of a zonal flow if the primary wave is purely meridional. For weaker waves, the maximum growth occurs for off-zonal inclined modulations. For very weak primary waves the unstable waves are close to being in three-wave resonance with the primary wave. The nonlinear theory predicts that the zonal flows generated by the linear instability experience pinching into narrow zonal jets. Our numerical simulations confirm the theoretical predictions of the linear theory as well as of the nonlinear pinching. We find that, for strong primary waves, these narrow zonal jets further roll up into Karman-like vortex streets. On the other hand, for weak primary waves, the growth of the unstable mode reverses and the system oscillates between a dominant jet and a dominate primary wave. The 2D vortex streets appear to be more stable than purely 1D zonal jets, and their zonal-averaged speed can reach amplitudes much stronger than is allowed by the Rayleigh-Kuo instability criterion for the 1D case. We find that the truncation models work well for both the linear stage and and often even for the medium-term nonlinear behavior. In the long term, the system transitions to turbulence helped by the vortex-pairing instability (for strong waves) and by the resonant wave-wave interactions (for weak waves).
Performance Assessment of the Wave Dragon Wave Energy Converter
Hansen, René Rydhof
Performance Assessment of the Wave Dragon Wave Energy Converter Based on the EquiMar Methodology S of the wave energy sector, device developers are called to provide reliable estimates on power performanceMar, Nissum Bredning, Hanstholm, North Sea, Ekofisk, Wave-to-wire, Wave energy. I. INTRODUCTION The wave
Cyclotron waves in a non-neutral plasma column
Dubin, Daniel H. E. [Department of Physics, University of California at San Diego, La Jolla, California 92093 (United States)
2013-04-15T23:59:59.000Z
A kinetic theory of linear electrostatic plasma waves with frequencies near the cyclotron frequency {Omega}{sub c{sub s}} of a given plasma species s is developed for a multispecies non-neutral plasma column with general radial density and electric field profiles. Terms in the perturbed distribution function up to O(1/{Omega}{sub c{sub s}{sup 2}}) are kept, as are the effects of finite cyclotron radius r{sub c} up to O(r{sub c}{sup 2}). At this order, the equilibrium distribution is not Maxwellian if the plasma temperature or rotation frequency is not uniform. For r{sub c}{yields}0, the theory reproduces cold-fluid theory and predicts surface cyclotron waves propagating azimuthally. For finite r{sub c}, the wave equation predicts that the surface wave couples to radially and azimuthally propagating Bernstein waves, at locations where the wave frequency equals the local upper hybrid frequency. The equation also predicts a second set of Bernstein waves that do not couple to the surface wave, and therefore have no effect on the external potential. The wave equation is solved both numerically and analytically in the WKB approximation, and analytic dispersion relations for the waves are obtained. The theory predicts that both types of Bernstein wave are damped at resonances, which are locations where the Doppler-shifted wave frequency matches the local cyclotron frequency as seen in the rotating frame.
Frischauf, Norbert [QASAR Technologie(s) GmbH, Johann Gottekgasse 39, A-1230, Vienna (Austria); Hettmer, Manfred; Grassauer, Andreas; Bartusch, Tobias [QASAR Technologie(s) GmbH, Johann Gottekgasse 39, A-1230, Vienna (Austria); Koudelka, Otto [Institute of Communication Networks and Satellite Communication, Graz University of Technology, Inffeldgasse 12/I, A-8010 Graz (Austria)
2006-07-01T23:59:59.000Z
More than 60 years after the later Nobel laureate Hannes Alfven had published a letter stating that oscillating magnetic fields can accelerate ionised matter via magneto-hydrodynamic interactions in a wave like fashion, the technical implementation of Alfven waves for propulsive purposes has been proposed, patented and examined for the first time by a group of inventors. The name of the concept, utilising Alfven waves to accelerate ionised matter for propulsive purposes, is MOA - Magnetic field Oscillating Amplified thruster. Alfven waves are generated by making use of two coils, one being permanently powered and serving also as magnetic nozzle, the other one being switched on and off in a cyclic way, deforming the field lines of the overall system. It is this deformation that generates Alfven waves, which are in the next step used to transport and compress the propulsive medium, in theory leading to a propulsion system with a much higher performance than any other electric propulsion system. Based on computer simulations, which were conducted to get a first estimate on the performance of the system, MOA is a highly flexible propulsion system, whose performance parameters might easily be adapted, by changing the mass flow and/or the power level. As such the system is capable to deliver a maximum specific impulse of 13116 s (12.87 mN) at a power level of 11.16 kW, using Xe as propellant, but can also be attuned to provide a thrust of 236.5 mN (2411 s) at 6.15 kW of power. While space propulsion is expected to be the prime application for MOA and is supported by numerous applications such as Solar and/or Nuclear Electric Propulsion or even as an 'afterburner system' for Nuclear Thermal Propulsion, other terrestrial applications can be thought of as well, making the system highly suited for a common space-terrestrial application research and utilisation strategy. (authors)
Phenomena of oscillations in atmospheric pressure direct current glow discharges
Liu, Fu-cheng [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)] [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Yan, Wen; Wang, De-zhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)
2013-12-15T23:59:59.000Z
Self-sustained oscillations in a dc glow discharge with a semiconductor layer at atmospheric pressure were investigated by means of a one-dimensional fluid model. It is found that the dc glow discharge initially becomes unstable in the subnormal glow region and gives rise to oscillations of plasma parameters. A variety of oscillations with one or more frequencies have been observed under different conditions. The discharge oscillates between the glow discharge mode and the Townsend discharge mode in the oscillations with large amplitude while operates in the subnormal glow discharge mode all the while in the oscillations with small amplitude. Fourier Transform spectra of oscillations reveal the transition mechanism between different oscillations. The effects of semiconductor conductivity on the oscillation frequency of the dominant mode, gas voltage, as well as the discharge current have also been analyzed.
SLOW MAGNETOSONIC WAVES AND FAST FLOWS IN ACTIVE REGION LOOPS
Ofman, L.; Wang, T. J. [Department of Physics, Catholic University of America, Washington, DC 20064 (United States); Davila, J. M. [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States)
2012-08-01T23:59:59.000Z
Recent extreme ultraviolet spectroscopic observations indicate that slow magnetosonic waves are present in active region (AR) loops. Some of the spectral data were also interpreted as evidence of fast ({approx}100-300 km s{sup -1}) quasi-periodic flows. We have performed three-dimensional magnetohydrodynamic (3D MHD) modeling of a bipolar AR that contains impulsively generated waves and flows in coronal loops. The model AR is initiated with a dipole magnetic field and gravitationally stratified density, with an upflow-driven steadily or periodically in localized regions at the footpoints of magnetic loops. The resulting flows along the magnetic field lines of the AR produce higher density loops compared to the surrounding plasma by injection of material into the flux tubes and the establishment of siphon flow. We find that the impulsive onset of flows with subsonic speeds result in the excitation of damped slow magnetosonic waves that propagate along the loops and coupled nonlinearly driven fast-mode waves. The phase speed of the slow magnetosonic waves is close to the coronal sound speed. When the amplitude of the driving pulses is increased we find that slow shock-like wave trains are produced. When the upflows are driven periodically, undamped oscillations are produced with periods determined by the periodicity of the upflows. Based on the results of the 3D MHD model we suggest that the observed slow magnetosonic waves and persistent upflows may be produced by the same impulsive events at the bases of ARs.
Attenuation of Beaming Oscillations Near Neutron Stars
M. Coleman Miller
2000-07-17T23:59:59.000Z
Observations with RXTE have revealed kilohertz quasi-periodic brightness oscillations (QPOs) from nearly twenty different neutron-star low-mass X-ray binaries (LMXBs). These frequencies often appear as a pair of kilohertz QPOs in a given power density spectrum. In many models the higher-frequency of these QPOs is a beaming oscillation at the frequency of a nearly circular orbit at some radius near the neutron star. In such models it is expected that there will also be beaming oscillations at the stellar spin frequency and at overtones of the orbital frequency, but no strong QPOs have been detected at these frequencies. We therefore examine the processes that can attenuate beaming oscillations near neutron stars, and in doing so extend the work on this subject that was initiated by the discovery of lower-frequency QPOs from LMXBs. Among our main results are (1)in a spherical scattering cloud, all overtones of rotationally modulated beaming oscillations are attenuated strongly, not just the even harmonics, and (2)it is possible to have a relatively high-amplitude modulation near the star at, e.g., the stellar spin frequency, even if no peak at that frequency is detectable in a power density spectrum taken at infinity. We discuss the application of these results to modeling of kilohertz QPOs.
Antineutrino Oscillations in the Atmospheric Sector
Himmel, Alexander I.; /Caltech
2011-05-01T23:59:59.000Z
This thesis presents measurements of the oscillations of muon antineutrinos in the atmospheric sector, where world knowledge of antineutrino oscillations lags well behind the knowledge of neutrinos, as well as a search for {nu}{sub {mu}} {yields} {bar {nu}}{sub {mu}} transitions. Differences between neutrino and antineutrino oscillations could be a sign of physics beyond the Standard Model, including non-standard matter interactions or the violation of CPT symmetry. These measurements leverage the sign-selecting capabilities of the magnetized steel-scintillator MINOS detectors to analyze antineutrinos from the NuMI beam, both when it is in neutrino-mode and when it is in antineutrino-mode. Antineutrino oscillations are observed at |{Delta}{bar m}{sub atm}{sup 2}| = (3.36{sub -0.40}{sup +0.46}(stat) {+-} 0.06(syst)) x 10{sup -3} eV{sup 2} and sin{sup 2}(2{bar {theta}}{sub 23}) = 0.860{sub -0.12}{sup +0.11}(stat) {+-} 0.01(syst). The oscillation parameters measured for antineutrinos and those measured by MINOS for neutrinos differ by a large enough margin that the chance of obtaining two values as discrepant as those observed is only 2%, assuming the two measurements arise from the same underlying mechanism, with the same parameter values. No evidence is seen for neutrino-to-antineutrino transitions.
Coupled Oscillator Systems Having Partial PT Symmetry
Beygi, Alireza; Bender, Carl M
2015-01-01T23:59:59.000Z
This paper examines chains of $N$ coupled harmonic oscillators. In isolation, the $j$th oscillator ($1\\leq j\\leq N$) has the natural frequency $\\omega_j$ and is described by the Hamiltonian $\\frac{1}{2}p_j^2+\\frac{1}{2}\\omega_j^2x_j^2$. The oscillators are coupled adjacently with coupling constants that are purely imaginary; the coupling of the $j$th oscillator to the $(j+1)$st oscillator has the bilinear form $i\\gamma x_jx_{j+1}$ ($\\gamma$ real). The complex Hamiltonians for these systems exhibit {\\it partial} $\\mathcal{PT}$ symmetry; that is, they are invariant under $i\\to-i$ (time reversal), $x_j\\to-x_j$ ($j$ odd), and $x_j\\to x_j$ ($j$ even). [They are also invariant under $i\\to-i$, $x_j\\to x_j$ ($j$ odd), and $x_j\\to- x_j$ ($j$ even).] For all $N$ the quantum energy levels of these systems are calculated exactly and it is shown that the ground-state energy is real. When $\\omega_j=1$ for all $j$, the full spectrum consists of a real energy spectrum embedded in a complex one; the eigenfunctions correspondi...
Electromechanical Wave Green's Function Estimation from Ambient Electrical Grid Frequency Noise
Backhaus, Scott
2011-01-01T23:59:59.000Z
Many electrical grid transients can be described by the propagation of electromechanical (EM) waves that couple oscillations of power flows over transmission lines and the inertia of synchronous generators. These EM waves can take several forms: large-scale standing waves forming inter-area modes, localized oscillations of single or multi-machine modes, or traveling waves that spread quasi-circularly from major grid disturbances. The propagation speed and damping of these EM waves are potentially a powerful tool for assessing grid stability, e.g. small signal or rotor angle stability, however, EM wave properties have been mostly extracted from post-event analysis of major grid disturbances. Using a small set of data from the FNET sensor network, we show how the spatially resolved Green's function for EM wave propagation can be extracted from ambient frequency noise without the need for a major disturbance. If applied to an entire interconnection, an EM-wave Green's function map will enable a model-independent...
Autoresonant excitation and evolution of nonlinear waves: The variational approach L. Friedland
Friedland, Lazar
evolves by being phase locked with the pump wave in an extended region of space and/or time despite the variation of system's parameters. This automatic phase locking autoresonance yields a possibility of shaping known as a persisting phase lock- ing between resonantly driven nonlinear oscillators and driv- ing
Mammalian Spontaneous Otoacoustic Emissions are Amplitude-Stabilized Cochlear Standing Waves
Allen, Jont
in middle-ear impedance 17 IV Are the Standing Waves Powered by Noise? 19 A Generalization of the Bialek with "certain cells" or parts of cells (e.g., hair-cell stereocilia or somatic motor proteins) within the organ of sound from the ear. Normally, the low-amplitude vibration of the self-tuned critical oscillators would
Wave turbulence and Bose-Einstein condensates Fluctuations turbulentes dans les condensats de Bose-Einstein condensates are considered. A statistical approach is presented following[1] to describe the stationary regime shows rapid oscillation of the condensate. R#19;esum#19;e Le comportement asymptotique des
Section 12: Waves and acoustics 1 Section 12: Waves and acoustics
Kohlenbach, Ulrich
Highly Porous Media Abstract 13:50 Â 14:10: Hoffmann, N.P., Chabchoub, A. (TU Hamburg-Harburg): Experiments on Peregrine soliton type deep water gravity waves Abstract 14:10 Â 14:30: Thomas MÃ¼llner (TU Wien): Acoustical performance of concreted wood fiber materials Abstract S12.4: Elastic Waves Wed, 16:00Â18:00 Chair
Wave-particle Interactions In Rotating Mirrors
Abraham J. Fetterman and Nathaniel J. Fisch
2011-01-11T23:59:59.000Z
Wave-particle interactions in E×B rotating plasmas feature an unusual effect: particles are diffused by waves in both potential energy and kinetic energy. This wave-particle interaction generalizes the alpha channeling effect, in which radio frequency waves are used to remove alpha particles collisionlessly at low energy. In rotating plasmas, the alpha particles may be removed at low energy through the loss cone, and the energy lost may be transferred to the radial electric field. This eliminates the need for electrodes in the mirror throat, which have presented serious technical issues in past rotating plasma devices. A particularly simple way to achieve this effect is to use a high azimuthal mode number perturbation on the magnetic field. Rotation can also be sustained by waves in plasmas without a kinetic energy source. This type of wave has been considered for plasma centrifuges used for isotope separation. Energy may also be transferred from the electric field to particles or waves, which may be useful for ion heating and energy generation.
Olmedo, Oscar; Vourlidas, Angelos [Space Science Division, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Zhang Jie [School of Physics, Astronomy and Computational Sciences, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Cheng Xin, E-mail: oscar.olmedo.ctr@nrl.navy.mil [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)
2012-09-10T23:59:59.000Z
For the first time, the kinematic evolution of a coronal wave over the entire solar surface is studied. Full Sun maps can be made by combining images from the Solar Terrestrial Relations Observatory satellites, Ahead and Behind, and the Solar Dynamics Observatory, thanks to the wide angular separation between them. We study the propagation of a coronal wave, also known as the 'Extreme Ultraviolet Imaging Telescope' wave, and its interaction with a coronal hole (CH) resulting in secondary waves and/or reflection and transmission. We explore the possibility of the wave obeying the law of reflection. In a detailed example, we find that a loop arcade at the CH boundary cascades and oscillates as a result of the extreme ultraviolet (EUV) wave passage and triggers a wave directed eastward that appears to have reflected. We find that the speed of this wave decelerates to an asymptotic value, which is less than half of the primary EUV wave speed. Thanks to the full Sun coverage we are able to determine that part of the primary wave is transmitted through the CH. This is the first observation of its kind. The kinematic measurements of the reflected and transmitted wave tracks are consistent with a fast-mode magnetohydrodynamic wave interpretation. Eventually, all wave tracks decelerate and disappear at a distance. A possible scenario of the whole process is that the wave is initially driven by the expanding coronal mass ejection and subsequently decouples from the driver and then propagates at the local fast-mode speed.
Three-flavour neutrino oscillation update
Thomas Schwetz; Mariam Tortola; Jose W. F. Valle
2010-02-11T23:59:59.000Z
We review the present status of three-flavour neutrino oscillations, taking into account the latest available neutrino oscillation data presented at the Neutrino 2008 Conference. This includes the data released this summer by the MINOS collaboration, the data of the neutral current counter phase of the SNO solar neutrino experiment, as well as the latest KamLAND and Borexino data. We give the updated determinations of the leading 'solar' and 'atmospheric' oscillation parameters. We find from global data that the mixing angle $\\theta_{13}$ is consistent with zero within $0.9\\sigma$ and we derive an upper bound of $\\sin^2\\theta_{13} < 0.035 (0.056)$ at 90% CL (3$\\sigma$).
Axion Induced Oscillating Electric Dipole Moments
Christopher T. Hill
2015-04-10T23:59:59.000Z
The axion electromagnetic anomaly induces an oscillating electric dipole for {\\em any} static magnetic dipole. Static electric dipoles do not produce oscillating magnetic moments. This is a low energy theorem which is a consequence of the space-time dependent cosmic background field of the axion in the limit that it is only locally time dependent $(\\overrightarrow{\\beta}=0)$. The electron will acquire an oscillating electric dipole of frequency $m_a$ and strength $\\sim 10^{-32}$ e-cm, three orders of magnitude above the nucleon, and within four orders of magnitude of the present standard model DC limit. This may suggest sensitive new experimental venues for the axion dark matter search.
Frequency stabilization in nonlinear MEMS and NEMS oscillators
Lopez, Omar Daniel; Antonio, Dario
2014-09-16T23:59:59.000Z
An illustrative system includes an amplifier operably connected to a phase shifter. The amplifier is configured to amplify a voltage from an oscillator. The phase shifter is operably connected to a driving amplitude control, wherein the phase shifter is configured to phase shift the amplified voltage and is configured to set an amplitude of the phase shifted voltage. The oscillator is operably connected to the driving amplitude control. The phase shifted voltage drives the oscillator. The oscillator is at an internal resonance condition, based at least on the amplitude of the phase shifted voltage, that stabilizes frequency oscillations in the oscillator.
Coastal Wave Generation and Wave Breaking over Terrain: Two Problems in Mesoscale Wave Dynamics
Qian, Tingting
2010-07-14T23:59:59.000Z
Two problems in mesoscale wave dynamics are addressed: (i) wave-turbulence interaction in a breaking mountain wave and (ii) gravity wave generation associated with coastal heating gradients. The mean and turbulent structures in a breaking mountain...
Coastal Wave Generation and Wave Breaking over Terrain: Two Problems in Mesoscale Wave Dynamics
Qian, Tingting
2010-07-14T23:59:59.000Z
Two problems in mesoscale wave dynamics are addressed: (i) wave-turbulence interaction in a breaking mountain wave and (ii) gravity wave generation associated with coastal heating gradients. The mean and turbulent structures in a breaking mountain...
Millimeter Wave Sensor For On-Line Inspection Of Thin Sheet Dielectrics
Bakhtiari, Sasan (Westmont, IL); Gopalsami, Nachappa (Naperville, IL); Raptis, Apostolos C. (Downers Grove, IL)
1999-03-23T23:59:59.000Z
A millimeter wave sensor is provided for non-destructive inspection of thin sheet dielectric materials. The millimeter wave sensor includes a Gunn diode oscillator (GDO) source generating a mill meter wave electromagnetic energy signal having a single frequency. A heater is coupled to the GDO source for stabilizing the single frequency. A small size antenna is coupled to the GDO source for transmitting the millimeter wave electromagnetic energy signal to a sample material and for receiving a reflected millimeter wave electromagnetic energy signal from the sample material. Ferrite circulator isolators coupled between the GDO source and the antenna separate the millimeter wave electromagnetic energy signal into transmitted and received electromagnetic energy signal components and a detector detects change in both amplitude and phase of the transmitted and received electromagnetic energy signal components. A millimeter wave sensor is provided for non-destructive inspection of thin sheet dielectric materials. The millimeter wave sensor includes a Gunn diode oscillator (GDO) source generating a mill meter wave electromagnetic energy signal having a single frequency. A heater is coupled to the GDO source for stabilizing the single frequency. A small size antenna is coupled to the GDO source for transmitting the millimeter wave electromagnetic energy signal to a sample material and for receiving a reflected millimeter wave electromagnetic energy signal from the sample material. Ferrite circulator isolators coupled between the GDO source and the antenna separate the millimeter wave electromagnetic energy signal into transmitted and received electromagnetic energy signal components and a detector detects change in both amplitude and phase of the transmitted and received electromagnetic energy signal components.
MATHEMATICAL ANALYSIS OF A WAVE ENERGY CONVERTER ARNAUD ROUGIREL
Paris-Sud XI, Université de
for buoy-type ocean wave energy converter. The simplest model for this scheme is a non autonomous piecewise): see [OOS10]. Basically, a WEC is a floating body with a power takeoff system. It uses the vertical
Marcin Wilczewski; Marek Czachor
2009-05-28T23:59:59.000Z
The paper continues the analysis of vacuum Rabi oscillations we started in Part I [Phys. Rev. A {\\bf 79}, 033836 (2009)]. Here we concentrate on experimental consequences for cavity QED of two different classes of representations of harmonic oscillator Lie algebras. The zero-temperature master equation, derived in Part I for irreducible representations of the algebra, is reformulated in a reducible representation that models electromagnetic fields by a gas of harmonic oscillator wave packets. The representation is known to introduce automatic regularizations that in irreducible representations would have to be justified by ad hoc arguments. Predictions based on this representation are characterized in thermodynamic limit by a single parameter $\\varsigma$, responsible for collapses and revivals of Rabi oscillations in exact vacuum. Collapses and revivals disappear in the limit $\\varsigma\\to\\infty$. Observation of a finite $\\varsigma$ would mean that cavity quantum fields are described by a non-Wightmanian theory, where vacuum states are zero-temperature Bose-Einstein condensates of a finite-particle bosonic oscillator gas and, thus, are non-unique. The data collected in the experiment of Brune {\\it et al.} [Phys. Rev. Lett. {\\bf{76}}, 1800 (1996)] are consistent with any $\\varsigma>400$.
Neutrino oscillations in the early Universe
D. Kirilova; M. Chizhov
2001-02-09T23:59:59.000Z
We discuss the oscillations effects on neutrinos in the early Universe and update the cosmological constraints on the oscillation parameters. It is shown that sterile LOW solution to the solar neutrino problem is almost completely excluded from cosmological nucleosynthesis considerations. Two possibilities for the relaxation of this constraint are discussed: high primordial helium-4 yield and a relic lepton asymmetry present at nucleosynthesis epoch. The numerical analysis proved that Y_p=0.25 only relaxes the constraint on LOW solution, while L > 10^{-5} is capable to remove it.
New parametrization of cosmic neutrino oscillations
Palladino, Andrea
2015-01-01T23:59:59.000Z
A new parameterization of neutrinos oscillations in vacuum, assuming the conventional three flavor scheme, is proposed and discussed. Applications of this parameterization are considered, that concern the study of the flavor ratios, of their uncertainties, the expectations for the signal due to Glashow resonance. It is shown that a Gaussian treatment describes to a good level of approximation the effects of the uncertainties on the mixing angles and on the CP violating phase. The recently obtained agreement of observations with the hypothesis of cosmic neutrino oscillations is confirmed.
Large neutrino asymmetries from neutrino oscillations
R. Foot; M. J. Thomson; R. R. Volkas
1995-09-19T23:59:59.000Z
We re-examine neutrino oscillations in the early universe. Contrary to previous studies, we show that large neutrino asymmetries can arise due to oscillations between ordinary neutrinos and sterile neutrinos. This means that the Big Bang Nucleosynthesis (BBN) bounds on the mass and mixing of ordinary neutrinos with sterile neutrinos can be evaded. Also, it is possible that the neutrino asymmetries can be large (i.e. $\\stackrel{>}{\\sim} 10\\%$), and hence have a significant effect on BBN through nuclear reaction rates.
Variations on Four-Neutrino Oscillations
V. Barger; S. Pakvasa; T. J. Weiler; K. Whisnant
1998-06-09T23:59:59.000Z
We make a model-independent analysis of all available data that indicate neutrino oscillations. Using probability diagrams, we confirm that a mass spectrum with two nearly degenerate pairs of neutrinos separated by a mass gap of $\\simeq1$ eV is preferred over a spectrum with one mass eigenstate separated from the others. We derive some new relations among the four-neutrino mixing matrix elements. We design four-neutrino mass matrices with three active neutrinos and one sterile neutrino that naturally incorporate maximal oscillations of atmospheric $\
Probing supernova physics with neutrino oscillations
H. Minakata; H. Nunokawa; R. Tomas; J. W. F. Valle
2002-07-26T23:59:59.000Z
We point out that solar neutrino oscillations with large mixing angle as evidenced in current solar neutrino data have a strong impact on strategies for diagnosing collapse-driven supernova (SN) through neutrino observations. Such oscillations induce a significant deformation of the energy spectra of neutrinos, thereby allowing us to obtain otherwise inaccessible features of SN neutrino spectra. We demonstrate that one can determine temperatures and luminosities of non-electron flavor neutrinos by observing bar{nu}_{e} from galactic SN in massive water Cherenkov detectors by the charged current reactions on protons.
Dirac oscillator interacting with a topological defect
Carvalho, J.; Furtado, C.; Moraes, F. [Unidade Academica de Tecnologia de Alimentos, CCTA, Universidade Federal de Campina Grande, Pereiros, 58840-000, Pombal, Paraiba (Brazil); Departamento de Fisica, CCEN, Universidade Federal da Paraiba, Cidade Universitaria, 58051-970 Joao Pessoa, Paraiba (Brazil)
2011-09-15T23:59:59.000Z
In this work we study the interaction problem of a Dirac oscillator with gravitational fields produced by topological defects. The energy levels of the relativistic oscillator in the cosmic string and in the cosmic dislocation space-times are sensible to curvature and torsion associated to these defects and are important evidence of the influence of the topology on this system. In the presence of a localized magnetic field the energy levels acquire a term associated with the Aharonov-Bohm effect. We obtain the eigenfunctions and eigenvalues and see that in the nonrelativistic limit some results known in standard quantum mechanics are reached.
Faceting oscillations in nano-ferroelectrics
Scott, J. F., E-mail: jfs32@cam.ac.uk, E-mail: ashok553@nplindia.org [Cavendish Laboratory, Cambridge University, Cambridge (United Kingdom); Kumar, Ashok, E-mail: jfs32@cam.ac.uk, E-mail: ashok553@nplindia.org [CSIR-National Physical Laboratory, Delhi (India)
2014-08-04T23:59:59.000Z
We observe periodic faceting of 8-nm diameter ferroelectric disks on a 10?s time-scale when thin Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} film is exposed to constant high-resolution transmission electron microscopy beams. The oscillation is between circular disk geometry and sharply faceted hexagons. The behavior is analogous to that of spin structure and magnetic domain wall velocity oscillations in permalloy [Bisig et al., Nat. Commun. 4, 2328 (2013)], involving overshoot and de-pinning from defects [Amann et al., J. Rheol. 57, 149–175 (2013)].
Single-ion nonlinear mechanical oscillator
Akerman, N.; Kotler, S.; Glickman, Y.; Dallal, Y.; Keselman, A.; Ozeri, R. [Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100 (Israel)
2010-12-15T23:59:59.000Z
We study the steady-state motion of a single trapped ion oscillator driven to the nonlinear regime. Damping is achieved via Doppler laser cooling. The ion motion is found to be well described by the Duffing oscillator model with an additional nonlinear damping term. We demonstrate here the unique ability of tuning both the linear as well as the nonlinear damping coefficients by controlling the laser-cooling parameters. Our observations pave the way for the investigation of nonlinear dynamics on the quantum-to-classical interface as well as mechanical noise squeezing in laser-cooling dynamics.
Harmonic-Oscillator-Based Effective Theory
W. C. Haxton
2006-08-06T23:59:59.000Z
I describe harmonic-oscillator-based effective theory (HOBET) and explore the extent to which the effects of excluded higher-energy oscillator shells can be represented by a contact-gradient expansion in next-to-next-to-leading order (NNLO). I find the expansion can be very successful provided the energy dependence of the effective interaction, connected with missing long-wavelength physics associated with low-energy breakup channels, is taken into account. I discuss a modification that removes operator mixing from HOBET, simplifying the task of determining the parameters of an NNLO interaction.
Storage of orbital angular momenta of light via coherent population oscillation
de Almeida, A J F; Martins, W S; Felinto, R A de Oliveira D; Pruvost, L; Tabosa, J W R
2015-01-01T23:59:59.000Z
We report on the storage of Orbital Angular Momentum (OAM) of light via the phenomenon of Coherent Population Oscillation (CPO) in cold cesium atoms. The experiment is performed using a delayed four wave mixing configuration where the transverse optical information of a probe field carrying OAM associated with its azimuthal phase dependence is stored in the CPO of Zeeman sublevels of the hyperfine transition $F=3\\rightarrow F^{\\prime}=2$ of cesium $D_{2}$ line. We also demonstrate experimentally the simultaneous storage and retrieval of different OAM states propagating along different directions in space, leading to algebric operations with OAM and therefore opening the possibility of multiplexing OAM states.
Gill, Robert Wayne
1971-01-01T23:59:59.000Z
of mismatch. The selection of a detector was the next problem which had to be solved. The first unit tried was a Hewlett Packard 310A harmonic wave analyzer. Figure 7 shows the block diagram for using 18 12 10 1 2 3 4 5 6 7 8 TIME (HOURS) Figure 6.../division. Circuit configuration used for direct counting of r-f oscillation. 14 Circuit configuration and voltage waveforms used for eliminating system transients. 16 Frequency drift of the Hewlett Packard 608F signal generator with a stabilization period of 48...
H. Abele; T. Jenke; H. Leeb; J. Schmiedmayer
2009-07-30T23:59:59.000Z
We propose to apply Ramsey's method of separated oscillating fields to the spectroscopy of the quantum states in the gravity potential above a vertical mirror. This method allows a precise measurement of quantum mechanical phaseshifts of a Schr\\"odinger wave packet bouncing off a hard surface in the gravitational field of the earth. Measurements with ultra-cold neutrons will offer a sensitivity to Newton's law or hypothetical short-ranged interactions, which is about 21 orders of magnitude below the energy scale of electromagnetism.
Pacôme Delva; Marie-Christine Angonin; Philippe Tourrenc
2006-09-20T23:59:59.000Z
We calculate and compare the response of light wave interferometers and matter wave interferometers to gravitational waves. We find that metric matter wave interferometers will not challenge kilometric light wave interferometers such as Virgo or LIGO, but could be a good candidate for the detection of very low frequency gravitational waves.
Asteroseismology of solar-type stars with K2
Chaplin, W J; Handberg, R; Basu, S; Buchhave, L A; Campante, T L; Davies, G R; Huber, D; Latham, D W; Latham, C A; Serenelli, A; Antia, H M; Appourchaux, T; Ball, W H; Benomar, O; Casagrande, L; Christensen-Dalsgaard, J; Coelho, H R; Creevey, O L; Elsworth, Y; Garc, R A; Gaulme, P; Hekker, S; Kallinger, T; Karoff, C; Kawaler, S D; Kjeldsen, H; Lundkvist, M S; Marcadon, F; Mathur, S; Miglio, A; Mosser, B; R, C; Roxburgh, I W; Aguirre, V Silva; Stello, D; Verma, K; White, T R; Bedding, T R; Barclay, T; Buzasi, D L; Deheuvels, S; Gizon, L; Houdek, G; Howell, S B; Salabert, D; Soderblom, D R
2015-01-01T23:59:59.000Z
We present the first detections by the NASA K2 Mission of oscillations in solar-type stars, using short-cadence data collected during K2 Campaign\\,1 (C1). We understand the asteroseismic detection thresholds for C1-like levels of photometric performance, and we can detect oscillations in subgiants having dominant oscillation frequencies around $1000\\,\\rm \\mu Hz$. Changes to the operation of the fine-guidance sensors are expected to give significant improvements in the high-frequency performance from C3 onwards. A reduction in the excess high-frequency noise by a factor of two-and-a-half in amplitude would bring main-sequence stars with dominant oscillation frequencies as high as ${\\simeq 2500}\\,\\rm \\mu Hz$ into play as potential asteroseismic targets for K2.
The oscillating two-cluster chimera state in non-locally coupled phase oscillators
Yun Zhu; Yuting Li; Mei Zhang; Junzhong Yang
2011-09-20T23:59:59.000Z
We investigate an array of identical phase oscillators non-locally coupled without time delay, and find that chimera state with two coherent clusters exists which is only reported in delay-coupled systems previously. Moreover, we find that the chimera state is not stationary for any finite number of oscillators. The existence of the two-cluster chimera state and its time-dependent behaviors for finite number of oscillators are confirmed by the theoretical analysis based on the self-consistency treatment and the Ott-Antonsen ansatz.
Self-generation and management of spin-electromagnetic wave solitons and chaos
Ustinov, Alexey B.; Kondrashov, Alexandr V.; Nikitin, Andrey A.; Kalinikos, Boris A. [Department of Physical Electronics and Technology, St. Petersburg Electrotechnical University, St. Petersburg 197376 (Russian Federation)
2014-06-09T23:59:59.000Z
Self-generation of microwave spin-electromagnetic wave envelope solitons and chaos has been observed and studied. For the investigation, we used a feedback active ring oscillator based on artificial multiferroic, which served as a nonlinear waveguide. We show that by increasing the wave amplification in the feedback ring circuit, a transition from monochromatic auto-generation to soliton train waveform and then to dynamical chaos occurs in accordance with the Ruelle-Takens scenario. Management of spin-electromagnetic-wave solitons and chaos parameters by both dielectric permittivity and magnetic permeability of the multiferroic waveguiding structure is demonstrated.
A Modified Fermi Model for Wave-Particle Interactions in Plasmas
De Marco, Rossana; Carbone, Vincenzo; Veltri, Pierluigi [Dipartimento di Fisica and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Universita della Calabria, Ponte P. Bucci Cubo 31C, 87036 Rende (Serbia and Montenegro) (Italy)
2006-03-31T23:59:59.000Z
Wave-particle interactions in plasmas are investigated through a nonlinear map that describes elastic collisions between an ensemble of particles and two barriers. The amplitude of the barriers, proportional to the energy of the wave, can increase or decrease due to the sequence of stochastic collisions. After an initial exponential decrease, the nonlinear strong trapping regime is characterized by low-frequency oscillations of the amplitude of the barriers around a certain saturation value. This is a transitory phenomenon stemming from the dynamical approach towards equilibrium in the wave-particle conservative system.
Critical Waves and the Length Problem of Biology
Laughlin, R B
2015-01-01T23:59:59.000Z
It is pointed out that the mystery of how biological systems measure their lengths vanishes away if one premises that they have discovered a way to generate linear waves analogous to compressional sound. These can be used to detect length at either large or small scales using echo timing and fringe counting. It is shown that suitable linear chemical potential waves can, in fact, be manufactured by tuning to criticality conventional reaction-diffusion with a small number substances. Min oscillations in E. coli are cited as precedent resonant length measurement using chemical potential waves analogous to laser detection. Mitotic structures in eucaryotes are identified as candidates for such an effect at higher frequency. The engineering principle is shown to be very general and functionally the same as that used by hearing organs. PNAS Significance Statement: This paper invokes physical principles to address the question of how living things might use reaction-diffusion to measure out and regulate the many thou...
Bursting in a Subcritical Hopf Oscillator with a Nonlinear Feedback
Gautam C Sethia; Abhijit Sen
2006-03-24T23:59:59.000Z
Bursting is a periodic transition between a quiescent state and a state of repetitive spiking. The phenomenon is ubiquitous in a variety of neurophysical systems. We numerically study the dynamical properties of a normal form of subcritical Hopf oscillator (at the bifurcation point) subjected to a nonlinear feedback. This dynamical system shows an infinite-period or a saddle-node on a limit cycle (SNLC) bifurcation for certain strengths of the nonlinear feedback. When the feedback is time delayed, the bifurcation scenario changes and the limit cycle terminates through a homoclinic or a saddle separatrix loop (SSL) bifurcation. This system when close to the bifurcation point exhibits various types of bursting phenomenon when subjected to a slow periodic external stimulus of an appropriate strength. The time delay in the feedback enhances the spiking rate i.e. reduces the interspike interval in a burst and also increases the width or the duration of a burst.
Are the small neutrino oscillation parameters all related?
Pramanick, Soumita
2014-01-01T23:59:59.000Z
Neutrino oscillations reveal several small parameters, namely, \\theta_{13}, the solar mass splitting vis-a-vis the atmospheric one, and the deviation of \\theta_{23} from maximal mixing. Can these small quantities all be traced to a single source and, if so, how could that be tested? Here a see-saw model for neutrino masses is presented wherein a dominant term generates the atmospheric mass splitting with maximal mixing in this sector, keeping \\theta_{13} = 0 and zero solar splitting. A Type-I see-saw perturbative contribution results in non-zero values of \\theta_{13}, \\Delta m^2_{solar}, \\theta_{12}, as well as allows \\theta_{23} to deviate from \\pi/4 in consistency with the data while interrelating them all. CP-violation is a natural consequence and is large for inverted mass ordering. The model will be tested as precision on the neutrino parameters is sharpened.
Dipole gravity waves from unbound quadrupoles
Felber, Franklin
2010-01-01T23:59:59.000Z
Dipole gravitational disturbances from gravitationally unbound mass quadrupoles propagate to the radiation zone with signal strength at least of quadrupole order if the quadrupoles are nonrelativistic, and of dipole order if relativistic. Angular distributions of parallel-polarized and transverse-polarized dipole power in the radiation zone are calculated for simple unbound quadrupoles, like a linear-oscillator/stress-wave pair and a particle storage ring. Laboratory tests of general relativity through measurements of dipole gravity waves in the source region are proposed. A NASA G2 flywheel module with a modified rotor can produce a post-Newtonian dc bias signal at a gradiometer up to 1 mE. At peak luminosity, the repulsive dipole impulses of proton bunches at the LHC can produce an rms velocity of a high-Q detector surface up to 4 micron/s. Far outside the source region, Newtonian lunar dipole gravity waves can produce a 1-cm displacement signal at LISA. Dipole signal strengths of astrophysical events invol...
Dipole gravity waves from unbound quadrupoles
Franklin Felber
2010-06-10T23:59:59.000Z
Dipole gravitational disturbances from gravitationally unbound mass quadrupoles propagate to the radiation zone with signal strength at least of quadrupole order if the quadrupoles are nonrelativistic, and of dipole order if relativistic. Angular distributions of parallel-polarized and transverse-polarized dipole power in the radiation zone are calculated for simple unbound quadrupoles, like a linear-oscillator/stress-wave pair and a particle storage ring. Laboratory tests of general relativity through measurements of dipole gravity waves in the source region are proposed. A NASA G2 flywheel module with a modified rotor can produce a post-Newtonian dc bias signal at a gradiometer up to 1 mE. At peak luminosity, the repulsive dipole impulses of proton bunches at the LHC can produce an rms velocity of a high-Q detector surface up to 4 micron/s. Far outside the source region, Newtonian lunar dipole gravity waves can produce a 1-cm displacement signal at LISA. Dipole signal strengths of astrophysical events involving unbound quadrupoles, like near collisions and neutron star kicks in core-collapse supernovae, are estimated.
Neutrino Oscillations and the Supernova 1987A Signal
B. Jegerlehner; F. Neubig; G. Raffelt
1996-03-29T23:59:59.000Z
We study the impact of neutrino oscillations on the interpretation of the supernova (SN) 1987A neutrino signal by means of a maximum-likelihood analysis. We focus on oscillations between $\\overline\
Geometric Solutions for the Neutrino Oscillation Length Resonance
Jason Pruet; George M. Fuller
1999-04-02T23:59:59.000Z
We give a geometric interpretation of the neutrino 'oscillation length resonance' recently discovered by Petcov. We use this picture to identify two new solutions for oscillation length resonances in a 3-layer earth model.
Striatal origin of the pathologic beta oscillations in Parkinson's disease
Boyden, Edward Stuart
Enhanced oscillations at beta frequencies (8–30 Hz) are a signature neural dynamic pathology in the basal ganglia and cortex of Parkinson's disease patients. The mechanisms underlying these pathological beta oscillations ...
Start-Up of FEL Oscillator from Shot Noise
Kumar, V.; Krishnagopal, S.; Fawley, W.M.
2007-01-01T23:59:59.000Z
of start-up of the CUTE-FEL oscillator from shot noiseof passes required for the FEL to saturate is equivalent toSTART-UP OF FEL OSCILLATOR FROM SHOT NOISE V. Kumar ? , S.
Maximum entropy method and oscillations in the diffraction cone
O. Dumbrajs; J. Kontros; A. Lengyel
2000-07-15T23:59:59.000Z
The maximum entropy method has been applied to investigate the oscillating structure in the pbarp- and pp-elastic scattering differential cross-section at high energy and small momentum transfer. Oscillations satisfying quite realistic reliability criteria have been found.
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Mapping the nano-Hertz gravitational wave sky
Neil J. Cornish; Rutger van Haasteren
2014-06-19T23:59:59.000Z
We describe a new method for extracting gravitational wave signals from pulsar timing data. We show that any gravitational wave signal can be decomposed into an orthogonal set of sky maps, with the number of maps equal to the number of pulsars in the timing array. These maps may be used as a basis to construct gravitational wave templates for any type of source, including collections of point sources. A variant of the standard Hellings-Downs correlation analysis is recovered for statistically isotropic signals. The template based approach allows us to probe potential anisotropies in the signal and produce maps of the gravitational wave sky.
Improved Theory of Neutrino Oscillations in Matter
Leonard S. Kisslinger
2014-11-19T23:59:59.000Z
This is revision of the S-Matrix theory of neutrino oscillations used for many years. We evaluate the transition probability of a $\\mu$ to $e$ neutrino without an approximation used for many theoretical studies, and find important differences which could improve the extraction of neutrino parameters from experimental data in the future.
Neutrino Oscillations and the Solar Neutrino Problem
W. C. Haxton
2000-04-28T23:59:59.000Z
I describe the current status of the solar neutrino problem, summarizing the arguments that its resolution will require new particle physics. The phenomenon of matter-enhanced neutrino oscillations is reviewed. I consider the implications of current experiments -- including the SuperKamiokande atmospheric and LSND measurements -- and the need for additional constraints from SNO and other new detectors.
Neutrino Mixing and Oscillations in Astrophysical Environments
A. B. Balantekin
2014-01-22T23:59:59.000Z
A brief review of the current status of neutrino mixing and oscillations in astrophysical environments, with particular emphasis on the Sun and core-collapse supernovae, is given. Implications of the existence of sterile states which mix with the active neutrinos are discussed.
SOME ASPECTS OF NEUTRINO MIXING AND OSCILLATIONS
Shyamasundar, R.K.
SOME ASPECTS OF NEUTRINO MIXING AND OSCILLATIONS THESIS SUBMITTED TO THE UNIVERSITY OF CALCUTTA into the fascinating world of neutrinos and for being an excellent teacher and a perfect guide. I convey my regards everything I know about neutrino phenomenology, I owe to him. I consider myself very fortunate to have him
Improved Theory of Neutrino Oscillations in Matter
Kisslinger, Leonard S
2014-01-01T23:59:59.000Z
This is revision of the S-Matrix theory of neutrino oscillations used for many years. We evaluate the transition probability of a $\\mu$ to $e$ neutrino without an approximation used for many theoretical studies, and find important differences which could improve the extraction of neutrino parameters from experimental data in the future.
Vacuum Oscillations and Future Solar Neutrino Experiments
Naoya Hata
1994-02-17T23:59:59.000Z
Vacuum oscillations are considered for the combined solar neutrino observations, including the Kamiokande II spectrum data and incorporating theoretical uncertainties and their correlations. Despite the conceptual difficulty of the fine tuning between the neutrino parameters and the Sun-Earth distance, 2-flavor vacuum oscillations provide phenomenologically acceptable solutions. There are allowed regions at 99\\% C.L. for $\\Delta m^2 = (0.45 - 1.2) \\times 10^{-10} \\; \\mbox{eV}\\,^2$ and $\\sin^22\\theta = 0.6 - 1$; the best fit solution is $\\chi^2 / \\mbox{d.f.} = 19.2 / 16$, which is acceptable at 16\\% C.L. Oscillations for sterile neutrinos are, however, excluded by the averaged data at 99.4\\% C.L. The vacuum oscillation solutions predict characteristic energy spectrum distortions and seasonal variations in Sudbury Neutrino Observatory, Super-Kamiokande, and BOREXINO. Those predictions are given in detail, emphasizing that the vacuum solutions are distinguishable from the MSW solutions.