National Library of Energy BETA

Sample records for national spherical torus

  1. National Spherical Torus Experiment (NSTX) Torus Design, Fabrication and Assembly

    SciTech Connect (OSTI)

    C. Neumeyer; G. Barnes; J.H. Chrzanowski; P. Heitzenroeder; et al

    1999-11-01

    The National Spherical Torus Experiment (NSTX) is a low aspect ratio spherical torus (ST) located at Princeton Plasma Physics Laboratory (PPPL). Fabrication, assembly, and initial power tests were completed in February of 1999. The majority of the design and construction efforts were constructed on the Torus system components. The Torus system includes the centerstack assembly, external Poloidal and Toroidal coil systems, vacuum vessel, torus support structure and plasma facing components (PFC's). NSTX's low aspect ratio required that the centerstack be made with the smallest radius possible. This, and the need to bake NSTXs carbon-carbon composite plasma facing components at 350 degrees C, was major drivers in the design of NSTX. The Centerstack Assembly consists of the inner legs of the Toroidal Field (TF) windings, the Ohmic Heating (OH) solenoid and its associated tension cylinder, three inner Poloidal Field (PF) coils, thermal insulation, diagnostics and an Inconel casing which forms the inner wall of the vacuum vessel boundary. It took approximately nine months to complete the assembly of the Centerstack. The tight radial clearances and the extreme length of the major components added complexity to the assembly of the Centerstack components. The vacuum vessel was constructed of 304-stainless steel and required approximately seven months to complete and deliver to the Test Cell. Several of the issues associated with the construction of the vacuum vessel were control of dimensional stability following welding and controlling the permeability of the welds. A great deal of time and effort was devoted to defining the correct weld process and material selection to meet our design requirements. The PFCs will be baked out at 350 degrees C while the vessel is maintained at 150 degrees C. This required care in designing the supports so they can accommodate the high electromagnetic loads resulting from plasma disruptions and the resulting relative thermal expansions

  2. Implementation of BN Control in the National Spherical Torus...

    Office of Scientific and Technical Information (OSTI)

    the normalized B in the National Spherical Torus Experiment M. Ono, et al., Nuclear Fusion 40, 557 (2000). A PID operator is applied to the difference between the present value...

  3. National Spherical Torus Experiment Upgrade (NSTX-U) | Princeton Plasma

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

    Physics Lab National Spherical Torus Experiment Upgrade (NSTX-U) NSTX-U The National Spherical Torus Experiment Upgrade (NSTX-U) is an innovative magnetic fusion device that was constructed by the Princeton Plasma Physics Laboratory (PPPL) in collaboration with the Oak Ridge National Laboratory, Columbia University, and the University of Washington at Seattle. History First plasma was obtained on NSTX on Friday, February 12, 1999 at 6:06 p.m. NSTX-U is being used to study the physics

  4. Developing the digital safeguard that protects the National Spherical Torus

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

    Experiment-Upgrade at PPPL | Princeton Plasma Physics Lab Developing the digital safeguard that protects the National Spherical Torus Experiment-Upgrade at PPPL By John Greenwald February 22, 2016 Tweet Widget Google Plus One Share on Facebook Members of the team that developed the DCPS, from left: Gretchen Zimmer, Kevin Lamb, Greg Tchillingarian, Paul Sichta, John Lawson, Tim Stevenson, Stefan Gerhardt and Roman Rozenblat. Not shown: Vince Mastrocola, John Dong, Gary Gibilisco. (Photo by

  5. Developing the digital safeguard that protects the National Spherical Torus

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

    Experiment-Upgrade at PPPL | Princeton Plasma Physics Lab Developing the digital safeguard that protects the National Spherical Torus Experiment-Upgrade at PPPL By John Greenwald February 22, 2016 Tweet Widget Google Plus One Share on Facebook Members of the team that developed the DCPS, from left: Gretchen Zimmer, Kevin Lamb, Greg Tchillingarian, Paul Sichta, John Lawson, Tim Stevenson, Stefan Gerhardt and Roman Rozenblat. Not shown: Vince Mastrocola, John Dong, Gary Gibilisco. (Photo by

  6. National Spherical Torus Experiment (NSTX) | U.S. DOE Office...

    Office of Science (SC) Website

    It is one of the world's two largest embodiments of the spherical torus confinement concept. NSTX has a unique, nearly spherical plasma shape that provides a test of the theory of ...

  7. Divertor Heat Flux Mitigation in the National Spherical Torus...

    Office of Scientific and Technical Information (OSTI)

    for both ITER and spherical torus-based devices with compact high power density divertors. ... Fusion 40, 557 2000 using high magnetic flux expansion at the divertor strike point and ...

  8. Simulation of microtearing turbulence in national spherical torus experiment

    SciTech Connect (OSTI)

    Guttenfelder, W.; Kaye, S. M.; Bell, R. E.; Hammett, G. W.; LeBlanc, B. P.; Mikkelsen, D. R.; Ren, Y.; Candy, J.; Nevins, W. M.; Wang, E.; Zhang, J.; Crocker, N. A.; Yuh, H.

    2012-05-15

    Thermal energy confinement times in National Spherical Torus Experiment (NSTX) dimensionless parameter scans increase with decreasing collisionality. While ion thermal transport is neoclassical, the source of anomalous electron thermal transport in these discharges remains unclear, leading to considerable uncertainty when extrapolating to future spherical tokamak (ST) devices at much lower collisionality. Linear gyrokinetic simulations find microtearing modes to be unstable in high collisionality discharges. First non-linear gyrokinetic simulations of microtearing turbulence in NSTX show they can yield experimental levels of transport. Magnetic flutter is responsible for almost all the transport ({approx}98%), perturbed field line trajectories are globally stochastic, and a test particle stochastic transport model agrees to within 25% of the simulated transport. Most significantly, microtearing transport is predicted to increase with electron collisionality, consistent with the observed NSTX confinement scaling. While this suggests microtearing modes may be the source of electron thermal transport, the predictions are also very sensitive to electron temperature gradient, indicating the scaling of the instability threshold is important. In addition, microtearing turbulence is susceptible to suppression via sheared E Multiplication-Sign B flows as experimental values of E Multiplication-Sign B shear (comparable to the linear growth rates) dramatically reduce the transport below experimental values. Refinements in numerical resolution and physics model assumptions are expected to minimize the apparent discrepancy. In cases where the predicted transport is strong, calculations suggest that a proposed polarimetry diagnostic may be sensitive to the magnetic perturbations associated with the unique structure of microtearing turbulence.

  9. New Capabilities and Results for the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    M.G. Bell, R.E. Bell, D.A. Gates, S.M. Kaye, H. Kugel, B.P. LeBlanc, F.M. Levinton, R. Maingi, J.E. Menard, R. Raman, S.A. Sabbagh, D. Stutman and the NSTX Research Team

    2008-02-29

    The National Spherical Torus Experiment (NSTX) produces plasmas with toroidal aspect ratio as low as 1.25, which can be heated by up to 6 MW High-Harmonic Fast Waves and up to 7 MW of deuterium Neutral Beam Injection. Using new poloidal fields coils, plasmas with cross-section elongation up to 2.7, triangularity 0.8, plasma currents Ip up to 1.5 MA and normalized currents Ip/a?BT up to 7.5 MA/m?T have been achieved. A significant extension of the plasma pulse length, to 1.5 s at a plasma current of 0.7 MA, has been achieved by exploiting the bootstrap and NBI-driven currents to reduce the dissipation of poloidal flux. Inductive plasma startup has been supplemented by Coaxial Helicity Injection (CHI) and the production of persistent current on closed flux surfaces by CHI has now been demonstrated in NSTX. The plasma response to magnetic field perturbations with toroidal mode numbers n = 1 or 3 and the effects on the plasma rotation have been investigated using three pairs of coils outside the vacuum vessel. Recent studies of both MHD stability and of transport benefitted from improved diagnostics, including measurements of the internal poloidal field using the motional Stark effect (MSE). In plasmas with a region of reversed magnetic shear in the core, now confirmed by the MSE data, improved electron confinement has been observed.

  10. Electron Bernstein Wave Research on the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    G. Taylor; A. Bers; T.S. Bigelow; M.D. Carter; J.B. Caughman; J. Decker; S. Diem; P.C. Efthimion; N.M. Ershov; E. Fredd; R.W. Harvey; J. Hosea; F. Jaeger; J. Preinhaelter; A.K. Ram; D.A. Rasmussen; A.P. Smirnov; J.B. Wilgen; J.R. Wilson

    2005-04-21

    Off-axis electron Bernstein wave current drive (EBWCD) may be critical for sustaining noninductive high-beta National Spherical Torus Experiment (NSTX) plasmas. Numerical modeling results predict that the {approx}100 kA of off-axis current needed to stabilize a solenoid-free high-beta NSTX plasma could be generated via Ohkawa current drive with 3 MW of 28 GHz EBW power. In addition, synergy between EBWCD and bootstrap current may result in a 10% enhancement in current-drive efficiency with 4 MW of EBW power. Recent dual-polarization EBW radiometry measurements on NSTX confirm that efficient coupling to EBWs can be readily accomplished by launching elliptically polarized electromagnetic waves oblique to the confining magnetic field, in agreement with numerical modeling. Plans are being developed for implementing a 1 MW, 28 GHz proof-of-principle EBWCD system on NSTX to test the EBW coupling, heating and current-drive physics at high radio-frequency power densities.

  11. Overview of Results from the National Spherical Torus Experiment (NSTX)

    SciTech Connect (OSTI)

    Gates, D; Ahn, J; Allain, J; Andre, R; Bastasz, R; Bell, M; Bell, R; Belova, E; Berkery, J; Betti, R; Bialek, J; Biewer, T; Bigelow, T; Bitter, M; Boedo, J; Bonoli, P; Bozzer, A; Brennan, D; Breslau, J; Brower, D; Bush, C; Canik, J; Caravelli, G; Carter, M; Caughman, J; Chang, C; Choe, W; Crocker, N; Darrow, D; Delgado-Aparicio, L; Diem, S; D'Ippolito, D; Domier, C; Dorland, W; Efthimion, P; Ejiri, A; Ershov, N; Evans, T; Feibush, E; Fenstermacher, M; Ferron, J; Finkenthal, M; Foley, J; Frazin, R; Fredrickson, E; Fu, G; Funaba, H; Gerhardt, S; Glasser, A; Gorelenkov, N; Grisham, L; Hahm, T; Harvey, R; Hassanein, A; Heidbrink, W; Hill, K; Hillesheim, J; Hillis, D; Hirooka, Y; Hosea, J; Hu, B; Humphreys, D; Idehara, T; Indireshkumar, K; Ishida, A; Jaeger, F; Jarboe, T; Jardin, S; Jaworski, M; Ji, H; Jung, H; Kaita, R; Kallman, J; Katsuro-Hopkins, O; Kawahata, K; Kawamori, E; Kaye, S; Kessel, C; Kim, J; Kimura, H; Kolemen, E; Krasheninnikov, S; Krstic, P; Ku, S; Kubota, S; Kugel, H; La Haye, R; Lao, L; LeBlanc, B; Lee, W; Lee, K; Leuer, J; Levinton, F; Liang, Y; Liu, D; Luhmann, N; Maingi, R; Majeski, R; Manickam, J; Mansfield, D; Maqueda, R; Mazzucato, E; McCune, D; McGeehan, B; McKee, G; Medley, S; Menard, J; Menon, M; Meyer, H; Mikkelsen, D; Miloshevsky, G; Mitarai, O; Mueller, D; Mueller, S; Munsat, T; Myra, J; Nagayama, Y; Nelson, B; Nguyen, X; Nishino, N; Nishiura, M; Nygren, R; Ono, M; Osborne, T; Pacella, D; Park, H; Park, J; Paul, S; Peebles, W; Penaflor, B; Peng, M; Phillips, C; Pigarov, A; Podesta, M; Preinhaelter, J; Ram, A; Raman, R; Rasmussen, D; Redd, A; Reimerdes, H; Rewoldt, G; Ross, P; Rowley, C; Ruskov, E; Russell, D; Ruzic, D; Ryan, P; Sabbagh, S; Schaffer, M; Schuster, E; Scott, S; Shaing, K; Sharpe, P; Shevchenko, V; Shinohara, K; Sizyuk, V; Skinner, C; Smirnov, A; Smith, D; Smith, S; Snyder, P; Soloman, W; Sontag, A; Soukhanovskii, V; Stoltzfus-Dueck, T; Stotler, D; Strait, T; Stratton, B; Stutman, D; Takahashi, R; Takase, Y; Tamura, N; Tang, X; Taylor, G; Taylor, C; Ticos, C; Tritz, K; Tsarouhas, D; Turrnbull, A; Tynan, G; Ulrickson, M; Umansky, M; Urban, J; Utergberg, E; Walker, M; Wampler, W; Wang, J; Wang, W; Weland, A

    2009-01-05

    The mission of NSTX is the demonstration of the physics basis required to extrapolate to the next steps for the spherical torus (ST), such as a plasma facing component test facility (NHTX) or an ST based component test facility (ST-CTF), and to support ITER. Key issues for the ST are transport, and steady state high {beta} operation. To better understand electron transport, a new high-k scattering diagnostic was used extensively to investigate electron gyro-scale fluctuations with varying electron temperature gradient scale-length. Results from n = 3 braking studies confirm the flow shear dependence of ion transport. New results from electron Bernstein wave emission measurements from plasmas with lithium wall coating applied indicate transmission efficiencies near 70% in H-mode as a result of reduced collisionality. Improved coupling of High Harmonic Fast-Waves has been achieved by reducing the edge density relative to the critical density for surface wave coupling. In order to achieve high bootstrap fraction, future ST designs envision running at very high elongation. Plasmas have been maintained on NSTX at very low internal inductance l{sub i} {approx} 0.4 with strong shaping ({kappa} {approx} 2.7, {delta} {approx} 0.8) with {beta}{sub N} approaching the with-wall beta limit for several energy confinement times. By operating at lower collisionality in this regime, NSTX has achieved record non-inductive current drive fraction f{sub NI} {approx} 71%. Instabilities driven by super-Alfvenic ions are an important issue for all burning plasmas, including ITER. Fast ions from NBI on NSTX are super-Alfvenic. Linear TAE thresholds and appreciable fast-ion loss during multi-mode bursts are measured and these results are compared to theory. RWM/RFA feedback combined with n = 3 error field control was used on NSTX to maintain plasma rotation with {beta} above the no-wall limit. The impact of n > 1 error fields on stability is a important result for ITER. Other highlights are

  12. Overview of Results from the National Spherical Torus Experiment (NSTX)

    SciTech Connect (OSTI)

    Gates, D. A.; Ahn, J.; Allain, J.; Andre, R.; Bastasz, R.; Bell, M.; Bell, R.; Belova, E.; Berkery, J.; Betti, R.; Bialek, J.; Biewer, T.; Bigelow, T.; Bitter, M.; Choe, W.; Crocker, N.; Darrow, D.; Delgado-Aparicio, L.; Diem, S.; DIppolito, D.; Domier, C.; Dorland, W.; Efthimion, P.; Ejiri, A.; Ershov, N.; Evans, T.; Feibush, E.; Fenstermacher, M.; Ferron, J.; Finkenthal, M.; Foley, J.; Frazin, R.; Fredrickson, E.; Fu, G.; Funaba, H.; Gerhardt, S.; Glasser, A.; Gorelenkov, N.; Grisham, L.; Hahm, T.; Harvey, R.; Hassanein, A.; Heidbrink, W.; Hill, K.; Hillesheim, J.; Hillis, D.; Hirooka, Y.; Hu, B.; Humphreys, D.; Idehara, T.; Indireshkumar, K.; Ishida, A.; Jaeger, F.; Jarboe, T.; Jardin, S.; Jaworski, M.; Ji, H.; Jung, H.; Kaita, R.; Kallman, J.; Katsuro-Hopkins, O.; Kawahata, K.; Kawamori, E.; Kaye, S.; Kessel, C.; Kim, J.; Kimura, H.; Kolemen, E.; Krasheninnikov, S.; Krstic, P.; Ku, S.; Kubota, S.; Kugel, H.; La Haye, R.; Lao, L.; LeBlanc, B.; Lee, W.; Lee, K.; Leuer, J.; Levinton, F.; Liang, Y.; Liu, D.; Luhmann, Jr., N.; Maingi, R.; Majeski, R.; Manickam, J.; Mansfield, D.; Maqueda, R.; Mazzucato, E.; McCune, D.; McGeehan, B.; McKee, G.; Medley, S.; Menard, J.; Menon, M.; Meyer, H.; Mikkelsen, D.; Miloshevsky, G.; Mitarai, O.; Mueller, D.; Mueller, S.; Munsat, T.; Myra, J.; Nagayama, Y.; Nelson, B.; Nguyen, X.; Nishino, N.; Nishiura, M.; Nygren, R.; Ono, M.; Osborne, T.; Pacella, D.; Park, H.; Park, J.; Paul, S.; Peebles, W.; Penaflor, B.; Peng, M.; Phillips, C.; Pigarov, A.; Podesta, M.; Preinhaelter, J.; Ram, A.; Raman, R.; Rasmussen, D.; Redd, A.; Reimerdes, H.; Rewo, G.; Ross, P.; Rowley, C.; Ruskov, E.; Russell, D.; Ruzic, D.; Ryan, P.; Sabbagh, S.; Schaffer, M.; Schuster, E.; Scott, S.; Shaing, K.; Sharpe, P.; Shevchenko, V.; Shinohara, K.; Sizyuk, V.; Skinner, C.; Smirnov, A.; Smith, D.; Smith, S.; Snyder, P.; Solomon, W.; Sontag, A.; Soukhanovskii, V.; Stoltzfus-Dueck, T.; Stotler, D.; Strait, T.; Stratton, B.; Stutman, D.; Takahashi, R.; Takase, Y.; Tamura, N.; Tang, X.; Taylor, G.; Taylor, C.; Ticos, C.; Tritz, K.; Tsarouhas, D.; Turrnbull, A.; Tynan, G.; Ulrickson, M.; Umansky, M.; Urban, J.; Utergberg, E.; Walker, M.; Wampler, W.; Wang, J.; Wang, W.; Welander, A.; Whaley, J.; White, R.; Wilgen, J.; Wilson, R.; Wong, K.; Wright, J.; Xia, Z.; Xu, X.; Youchison, D.; Yu, G.; Yuh, H.; Zakharov, L.; Zemlyanov, D.; Zweben, S.

    2009-03-24

    The mission of NSTX is the demonstration of the physics basis required to extrapolate to the next steps for the spherical torus (ST), such as a plasma facing component test facility (NHTX) or an ST based component test facility (ST-CTF), and to support ITER. Key issues for the ST are transport, and steady state high ? operation. To better understand electron transport, a new high-k scattering diagnostic was used extensively to investigate electron gyro-scale fluctuations with varying electron temperature gradient scale-length. Results from n = 3 braking studies are consistent with the flow shear dependence of ion transport. New results from electron Bernstein wave emission measurements from plasmas with lithium wall coating applied indicate transmission efficiencies near 70% in H-mode as a result of reduced collisionality. Improved coupling of High Harmonic Fast-Waves has been achieved by reducing the edge density relative to the critical density for surface wave coupling. In order to achieve high bootstrap current fraction, future ST designs envision running at very high elongation. Plasmas have been maintained on NSTX at very low internal inductance li ~0.4 with strong shaping (? ~ 2.7, ? ~ 0.8) with ?N approaching the with-wall beta limit for several energy confinement times. By operating at lower collisionality in this regime, NSTX has achieved record non-inductive current drive fraction fNI ~71%. Instabilities driven by super-Alfvenic ions will be an important issue for all burning plasmas, including ITER. Fast ions from NBI on NSTX are super-Alfvenic. Linear TAE thresholds and appreciable fast-ion loss during multi-mode bursts are measured and these results are compared to theory. The impact of n > 1 error fields on stability is a important result for ITER. RWM/RFA feedback combined with n=3 error field control was used on NSTX to maintain plasma rotation with ? above the no-wall limit. Other highlights are: results of

  13. Spherical torus fusion reactor

    DOE Patents [OSTI]

    Peng, Yueng-Kay M.

    1989-04-04

    A fusion reactor is provided having a near spherical-shaped plasma with a modest central opening through which straight segments of toroidal field coils extend that carry electrical current for generating a toroidal magnet plasma confinement fields. By retaining only the indispensable components inboard of the plasma torus, principally the cooled toroidal field conductors and in some cases a vacuum containment vessel wall, the fusion reactor features an exceptionally small aspect ratio (typically about 1.5), a naturally elongated plasma cross section without extensive field shaping, requires low strength magnetic containment fields, small size and high beta. These features combine to produce a spherical torus plasma in a unique physics regime which permits compact fusion at low field and modest cost.

  14. Spherical torus fusion reactor

    DOE Patents [OSTI]

    Peng, Yueng-Kay M.

    1989-01-01

    A fusion reactor is provided having a near spherical-shaped plasma with a modest central opening through which straight segments of toroidal field coils extend that carry electrical current for generating a toroidal magnet plasma confinement fields. By retaining only the indispensable components inboard of the plasma torus, principally the cooled toroidal field conductors and in some cases a vacuum containment vessel wall, the fusion reactor features an exceptionally small aspect ratio (typically about 1.5), a naturally elongated plasma cross section without extensive field shaping, requires low strength magnetic containment fields, small size and high beta. These features combine to produce a spherical torus plasma in a unique physics regime which permits compact fusion at low field and modest cost.

  15. Imaging x-ray crystal spectrometers for the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Bitter, M.; Hill, K.W.; Roquemore, A.L.; Beiersdorfer, P.; Kahn, S.M.; Elliott, S.R.; Fraenkel, B.

    1999-01-01

    A new type of high-resolution x-ray imaging crystal spectrometers is described for implementation on the National Spherical Torus Experiment (NSTX) to provide spatially and temporally resolved data on the ion temperature, toroidal and poloidal plasma rotation, electron temperature, impurity ion-charge state distributions, and impurity transport. These data are derived from observations of the satellite spectra of heliumlike argon, ArthinspXVII, which is the dominant charge state for electron temperatures in the range from 0.4 to 3.0 keV and which is accessible to NSTX. Experiments at the Torus Experiment for Technology Oriented Research (TEXTOR) demonstrate that a throughput of 2{times}10{sup 5}thinspphotons/s (corresponding to the count-rate limit of the present detectors) can easily be obtained with small, nonperturbing argon gas puffs of less than 1{times}10{sup {minus}3}thinspTorrthinspscr(l)/s, so that it is possible to record spectra with a small statistical error and a good time resolution (typically 50 and 1 ms in some cases). Employing a novel design, which is based on the imaging properties of spherically bent crystals, the spectrometers will provide spectrally and spatially resolved images of the plasma for all experimental conditions, which include ohmically heated discharges as well as plasmas with rf and neutral-beam heating. The conceptual design, experimental results on the focusing properties, and relevant spectral data from TEXTOR are presented. {copyright} {ital 1999 American Institute of Physics.}

  16. Modification Of The Electron Energy Distribution Function During Lithium Experiments On The National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Jaworski, M A; Gray, T K; Kaita, R; Kallman, J; Kugel, H; LeBlanc, B; McLean, A; Sabbagh, S A; Soukanovskii, V; Stotler, D P

    2011-06-03

    The National Spherical Torus Experiment (NSTX) has recently studied the use of a liquid lithium divertor (LLD). Divertor Langmuir probes have also been installed for making measurements of the local plasma conditions. A non-local probe interpretation method is used to supplement the classical probe interpretation and obtain measurements of the electron energy distribution function (EEDF) which show the occurrence of a hot-electron component. Analysis is made of two discharges within a sequence that exhibited changes in plasma fueling efficiency. It is found that the local electron temperature increases and that this increase is most strongly correlated with the energy contained within the hot-electron population. Preliminary interpretative modeling indicates that kinetic effects are likely in the NSTX.

  17. Direct X-B mode conversion for high-? national spherical torus experiment in nonlinear regime

    SciTech Connect (OSTI)

    Ali Asgarian, M. E-mail: maa@msu.edu; Parvazian, A.; Abbasi, M.; Verboncoeur, J. P.

    2014-09-15

    Electron Bernstein wave (EBW) can be effective for heating and driving currents in spherical tokamak plasmas. Power can be coupled to EBW via mode conversion of the extraordinary (X) mode wave. The most common and successful approach to study the conditions for optimized mode conversion to EBW was evaluated analytically and numerically using a cold plasma model and an approximate kinetic model. The major drawback in using radio frequency waves was the lack of continuous wave sources at very high frequencies (above the electron plasma frequency), which has been addressed. A future milestone is to approach high power regime, where the nonlinear effects become significant, exceeding the limits of validity for present linear theory. Therefore, one appropriate tool would be particle in cell (PIC) simulation. The PIC method retains most of the nonlinear physics without approximations. In this work, we study the direct X-B mode conversion process stages using PIC method for incident wave frequency f{sub 0}?=?15?GHz, and maximum amplitude E{sub 0}?=?10{sup 5?}V/m in the national spherical torus experiment (NSTX). The modelling shows a considerable reduction in X-B mode conversion efficiency, C{sub modelling}?=?0.43, due to the presence of nonlinearities. Comparison of system properties to the linear state reveals predominant nonlinear effects; EBW wavelength and group velocity in comparison with linear regime exhibit an increment around ?36% and 17%, respectively.

  18. Spherical torus fusion reactor

    DOE Patents [OSTI]

    Martin Peng, Y.K.M.

    1985-10-03

    The object of this invention is to provide a compact torus fusion reactor with dramatic simplification of plasma confinement design. Another object of this invention is to provide a compact torus fusion reactor with low magnetic field and small aspect ratio stable plasma confinement. In accordance with the principles of this invention there is provided a compact toroidal-type plasma confinement fusion reactor in which only the indispensable components inboard of a tokamak type of plasma confinement region, mainly a current conducting medium which carries electrical current for producing a toroidal magnet confinement field about the toroidal plasma region, are retained.

  19. Techniques for the measurement of disruption halo currents in the National Spherical Torus Experiment

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

    Gerhardt, S. P.; Fredrickson, E.; Guttadora, L.; Kaita, R.; Kugel, H.; Menard, J.; Takahashi, H.

    2011-10-06

    This paper describes techniques for measuring halo currents, and their associated toroidal peaking, in the National Spherical Torus Experiments. The measurements are based on three techniques: (i) measurement of the toroidal field created by the poloidal halo current, either with segmented Rogowski coils or discrete toroidal field sensors, (ii) the direct measurement of halo currents into specially instrument tiles, and (iii) small Rogowski coils placed on the mechanical supports of in-vessel components. For the segmented Rogowski coils and discrete toroidal field detectors, it is shown that the toroidal peaking factor inferred from the data is significantly less than the peakingmore » factor of the underlying halo current distribution, and a simple model is developed to relate the two. For the array of discrete toroidal field detectors and small Rogowski sensors, the compensation steps that are used to isolate the halo current signal are described. The electrical and mechanical design of compact under-tile resistive shunts and mini-Rogowski coils is described. Example data from the various systems is shown.« less

  20. Fast response of electron-scale turbulence to auxiliary heating cessation in National Spherical Torus Experiment

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

    Ren, Y.; Wang, W. X.; LeBlanc, B. P.; Guttenfelder, W.; Kaye, S. M.; Ethier, S.; Mazzucato, E.; Lee, K. C.; Domier, C. W.; Bell, R.; et al

    2015-11-03

    In this letter, we report the first observation of the fast response of electron-scale turbulence to auxiliary heating cessation in National Spherical Torus eXperiment [Ono et al., Nucl. Fusion 40, 557 (2000)]. The observation was made in a set of RF-heated L-mode plasmas with toroidal magnetic field of 0.55 T and plasma current of 300 kA. It is observed that electron-scale turbulence spectral power (measured with a high-k collective microwave scattering system) decreases significantly following fast cessation of RF heating that occurs in less than 200 μs. The large drop in the turbulence spectral power has a short time delaymore » of about 1–2 ms relative to the RF cessation and happens on a time scale of 0.5–1 ms, much smaller than the energy confinement time of about 10 ms. Power balance analysis shows a factor of about 2 decrease in electron thermal diffusivity after the sudden drop of turbulence spectral power. Measured small changes in equilibrium profiles across the RF cessation are unlikely able to explain this sudden reduction in the measured turbulence and decrease in electron thermal transport, supported by local linear stability analysis and both local and global nonlinear gyrokinetic simulations. Furthermore, the observations imply that nonlocal flux-driven mechanism may be important for the observed turbulence and electron thermal transport.« less

  1. Characterization of the plasma current quench during disruptions in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Gerhardt, S.P., Menard, J.E., and the NSTX Research Team

    2008-12-17

    A detailed analysis of the plasma current quench in the National Spherical Torus Experiment [M.Ono, et al Nuclear Fusion 40, 557 (2000)] is presented. The fastest current quenches are fit better by a linear waveform than an exponential one. Area-normalized current quench times down to .4 msec/m2 have been observed, compared to the minimum of 1.7 msec/m2 recommendation based on conventional aspect ratio tokamaks; as noted in previous ITPA studies, the difference can be explained by the reduced self-inductance at low aspect ratio and high-elongation. The maximum instantaneous dIp/dt is often many times larger than the mean quench rate, and the plasma current before the disruption is often substantially less than the flat-top value. The poloidal field time-derivative during the disruption, which is directly responsible for driving eddy currents, has been recorded at various locations around the vessel. The Ip quench rate, plasma motion, and magnetic geometry all play important roles in determining the rate of poloidal field change.

  2. Status and Plans for the National Spherical Torus Experimental Research Facility

    SciTech Connect (OSTI)

    M. Ono; M.G. Bell; R.E. Bell; J.M. Bialek; T. Bigelow; M. Bitter; plus 148 additional authors

    2005-07-27

    An overview of the research capabilities and the future plans on the MA-class National Spherical Torus Experiment (NSTX) at Princeton is presented. NSTX research is exploring the scientific benefits of modifying the field line structure from that in more conventional aspect ratio devices, such as the tokamak. The relevant scientific issues pursued on NSTX include energy confinement, MHD stability at high beta, non-inductive sustainment, solenoid-free start-up, and power and particle handling. In support of the NSTX research goal, research tools are being developed by the NSTX team. In the context of the fusion energy development path being formulated in the US, an ST-based Component Test Facility (CTF) and, ultimately a high beta Demo device based on the ST, are being considered. For these, it is essential to develop high performance (high beta and high confinement), steady-state (non-inductively driven) ST operational scenarios and an efficient solenoid-free start-up concept. We will also briefly describe the Next-Step-ST (NSST) device being designed to address these issues in fusion-relevant plasma conditions.

  3. Physics of forced magnetic reconnection in coaxial helicity injection experiments in National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Ebrahimi, F.; Bhattacharjee, A.; Raman, R.; Hooper, E. B.; Sovinec, C. R.

    2014-05-15

    We numerically examine the physics of fast flux closure in transient coaxial helicity injection (CHI) experiments in National Spherical Torus Experiment (NSTX). By performing resistive Magnetohydrodynamics (MHD) simulations with poloidal injector coil currents held constant in time, we find that closed flux surfaces are formed through forced magnetic reconnection. Through a local Sweet-Parker type reconnection with an elongated current sheet in the injector region, closed flux surfaces expand in the NSTX global domain. Simulations demonstrate outflows approaching poloidally Alfvénic flows and reconnection times consistent with the Sweet-Parker model. Critical requirements for magnetic reconnection and flux closure are studied in detail. These primary effects, which are magnetic diffusivity, injector flux, injector flux footprint width, and rate of injector voltage reduction, are simulated for transient CHI experiments. The relevant time scales for effective reconnection are τ{sub V}<τ{sub rec}≈τ{sub A}√(S)(1+Pm){sup 1/4}<τ{sub R}, where τ{sub V} is the time for the injector voltage reduction, τ{sub A} is the poloidal Alfvén transit time, τ{sub R} is the global resistive diffusion time, and Pm and S are Prandtl and Lundquist numbers.

  4. Quasi-linear gyrokinetic predictions of the Coriolis momentum pinch in National Spherical Torus Experiment

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

    Guttenfelder, W.; Kaye, S. M.; Ren, Y.; Solomon, W.; Bell, R. E.; Candy, J.; Gerhardt, S. P.; LeBlanc, B. P.; Yuh, H.

    2016-05-11

    This paper presents quasi-linear gyrokinetic predictions of the Coriolis momentum pinch for low aspect-ratio National Spherical Torus Experiment (NSTX) H-modes where previous experimental measurements were focused. Local, linear calculations predict that in the region of interest (just outside the mid-radius) of these relatively high-beta plasmas, profiles are most unstable to microtearing modes that are only effective in transporting electron energy. However, sub-dominant electromagnetic and electrostaticballooning modes are also unstable, which are effective at transporting energy, particles, and momentum. The quasi-linear prediction of transport from these weaker ballooning modes, assuming they contribute transport in addition to that from microtearing modes inmore » a nonlinear turbulent state, leads to a very small or outward convection of momentum, inconsistent with the experimentally measured inward pinch, and opposite to predictions in conventional aspect ratio tokamaks. Additional predictions of a low beta L-mode plasma, unstable to more traditional electrostatic ion temperature gradient-trapped electron mode instability, show that the Coriolis pinch is inward but remains relatively weak and insensitive to many parameter variations. The weak or outward pinch predicted in NSTX plasmas appears to be at least partially correlated to changes in the parallel mode structure that occur at a finite beta and low aspect ratio, as discussed in previous theories. The only conditions identified where a stronger inward pinch is predicted occur either in the purely electrostatic limit or if the aspect ratio is increased. Lastly, as the Coriolis pinch cannot explain the measured momentum pinch, additional theoretical momentum transport mechanisms are discussed that may be potentially important.« less

  5. Recent Progress on Spherical Torus Research

    SciTech Connect (OSTI)

    Ono, Masayuki; Kaita, Robert

    2014-01-01

    The spherical torus or spherical tokamak (ST) is a member of the tokamak family with its aspect ratio (A = R0/a) reduced to A ~ 1.5, well below the normal tokamak operating range of A ≥ 2.5. As the aspect ratio is reduced, the ideal tokamak beta β (radio of plasma to magnetic pressure) stability limit increases rapidly, approximately as β ~ 1/A. The plasma current it can sustain for a given edge safety factor q-95 also increases rapidly. Because of the above, as well as the natural elongation κ, which makes its plasma shape appear spherical, the ST configuration can yield exceptionally high tokamak performance in a compact geometry. Due to its compactness and high performance, the ST configuration has various near term applications, including a compact fusion neutron source with low tritium consumption, in addition to its longer term goal of attractive fusion energy power source. Since the start of the two megaampere class ST facilities in 2000, National Spherical Torus Experiment (NSTX) in the US and Mega Ampere Spherical Tokamak (MAST) in UK, active ST research has been conducted worldwide. More than sixteen ST research facilities operating during this period have achieved remarkable advances in all of fusion science areas, involving fundamental fusion energy science as well as innovation. These results suggest exciting future prospects for ST research both near term and longer term. The present paper reviews the scientific progress made by the worldwide ST research community during this new mega-ampere-ST era.

  6. Enhanced Conversion of Thermal Electron Bernstein Waves to the Extraordinary Electromagnetic Mode on the National Spherical Torus Experiment (NSTX)

    SciTech Connect (OSTI)

    G. Taylor; P.C. Efthimion; B. Jones; B.P. LeBlanc; J.R. Wilson; J.B. Wilgen; G.L. Bell; T.S. Bigelow; R. Maingi; D.A. Rasmussen; R.W. Harvey; A.P. Smirnov; F. Paoletti; S.A. Sabbagh

    2002-10-15

    A four-fold increase in the conversion of thermal electron-Bernstein waves (EBW) to the extraordinary mode (X-mode) was measured when the density scale length (L subscript ''n'') was progressively shortened by a local Boron nitride limiter in the scrape-off of an ohmically heated National Spherical Torus Experiment (NSTX) plasma [M. Ono, S. Kaye, M. Peng, et al., Proceedings 17th IAEA Fusion Energy Conference (IAEA, Vienna, Austria, 1999), Vol. 3, p. 1135]. The maximum conversion efficiency approached 50% when L subscript ''n'' was reduced to 0.7 cm, in agreement with theoretical predictions that used locally measured L subscript ''n''. Calculations indicate that it is possible to establish L subscript ''n'' < 0.3 cm with a local limiter, a value predicted to attain approximately 100% EBW conversion to the X-mode in support of proposed EBW heating and current drive scenarios.

  7. A dual wavelength imaging system for plasma-surface interaction studies on the National Spherical Torus Experiment Upgrade

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

    Scotti, F.; Soukhanovskii, V. A.

    2015-12-09

    A two-channel spectral imaging system based on a charge injection device radiation-hardened intensified camera was built for studies of plasma-surface interactions on divertor plasma facing components in the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak. By means of commercially available mechanically referenced optical components, the two-wavelength setup images the light from the plasma, relayed by a fiber optic bundle, at two different wavelengths side-by-side on the same detector. Remotely controlled filter wheels are used for narrow band pass and neutral density filters on each optical path allowing for simultaneous imaging of emission at wavelengths differing in brightness up to 3more » orders of magnitude. Applications on NSTX-U will include the measurement of impurity influxes in the lower divertor strike point region and the imaging of plasma-material interaction on the head of the surface analysis probe MAPP (Material Analysis and Particle Probe). Furthermore, the diagnostic setup and initial results from its application on the lithium tokamak experiment are presented.« less

  8. Chosen Solutions to the Engineering Challenges of the National Spherical Torus Experiment (NSTX) Magnets

    SciTech Connect (OSTI)

    C. Neumeyer; H.M. Fan; J. Chrzanowski; P. Heitzenroeder; and the NSTX Team

    1999-10-01

    NSTX is one of the largest of a new class of magnetic plasma research devices known as spherical toroids (STs). The plasma in a ST is characterized by its almost spherical shape with a slender cylindrical region through its vertical axis. The so-called ''center stack'' is located in this region. It contains magnetic windings for confining the plasma, induce the plasma current, and shape the plasma. This paper will describe the engineering challenges of designing the center stack magnets to meet their operational requirements within this constrained space.

  9. Electron Bernstein wave-bootstrap current synergy in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Harvey, R.W.; Taylor, G.

    2005-05-15

    Current driven by electron Bernstein waves (EBW) and by the electron bootstrap effect are calculated separately and concurrently with a kinetic code to determine the degree of synergy between them. A target {beta}=40% NSTX [M. Ono, S. Kaye, M. Peng et al., Proceedings of the 17th IAEA Fusion Energy Conference, edited by M. Spak (IAEA, Vienna, Austria, 1999), Vol. 3, p. 1135] plasma is examined. A simple bootstrap model in the collisional-quasilinear CQL3D Fokker-Planck code (National Technical Information Service document No. DE93002962) is used in these studies: the transiting electron distributions are connected in velocity space at the trapped-passing boundary to trapped-electron distributions that are displaced radially by a half-banana-width outwards/inwards for the co-passing/counter-passing regions. This model agrees well with standard bootstrap current calculations over the outer 60% of the plasma radius. Relatively small synergy net bootstrap current is obtained for EBW power up to 4 MW. Locally, bootstrap current density increases in proportion to increased plasma pressure, and this effect can significantly affect the radial profile of driven current.

  10. MHD-induced Energetic Ion Loss during H-mode Discharges in the National Spherical Torus Experiment (NSTX)

    SciTech Connect (OSTI)

    S.S. Medley; N.N. Gorelenkov; R. Andre; R.E. Bell; D.S. Darrow; E.D. Fredrickson; S.M. Kaye; B.P. LeBlanc; A.L. Roquemore; and the NSTX Team

    2004-03-15

    MHD-induced energetic ion loss in neutral-beam-heated H-mode [high-confinement mode] discharges in NSTX [National Spherical Torus Experiment] is discussed. A rich variety of energetic ion behavior resulting from magnetohydrodynamic (MHD) activity is observed in the NSTX using a horizontally scanning Neutral Particle Analyzer (NPA) whose sightline views across the three co-injected neutral beams. For example, onset of an n = 2 mode leads to relatively slow decay of the energetic ion population (E {approx} 10-100 keV) and consequently the neutron yield. The effect of reconnection events, sawteeth, and bounce fishbones differs from that observed for low-n, low-frequency, tearing-type MHD modes. In this case, prompt loss of the energetic ion population occurs on a time scale of less than or equal to 1 ms and a precipitous drop in the neutron yield occurs. This paper focuses on MHD-induced ion loss during H-mode operation in NSTX. After H-mode onset, the NPA charge-exchange spectrum usually exhibits a significant loss of energetic ions only for E > E(sub)b/2 where E(sub)b is the beam injection energy. The magnitude of the energetic ion loss was observed to decrease with increasing tangency radius, R(sub)tan, of the NPA sightline, increasing toroidal field, B(sub)T, and increasing neutral-beam injection energy, E(sub)b. TRANSP modeling suggests that MHD-induced ion loss is enhanced during H-mode operation due to an evolution of the q and beam deposition profiles that feeds both passing and trapped ions into the region of low-n MHD activity. ORBIT code analysis of particle interaction with a model magnetic perturbation supported the energy selectivity of the MHD-induced loss observed in the NPA measurements. Transport analysis with the TRANSP code using a fast-ion diffusion tool to emulate the observed MHD-induced energetic ion loss showed significant modifications of the neutral- beam heating as well as the power balance, thermal diffusivities, energy confinement times

  11. Intermittency in the Scrape-off Layer of the National Spherical Torus Experiment During H-mode Confinement

    SciTech Connect (OSTI)

    R.J. Maqueda, D.P. Stotler, S.J. Zweben, and the NSTX Team

    2010-11-22

    A gas puff imaging diagnostic is used in the National Spherical Tokamak Experiment [M. Ono, et al., Nucl. Fusion 40, 557 (2000)] to study the edge turbulence and intermittency present during H-mode discharges. In the case of low power Ohmic H-modes the suppression of turbulence/blobs is maintained through the duration of the (short lived) H-modes. Similar quiescent edges are seen during the early stages of H-modes created with the use of neutral beam injection. Nevertheless, as time progresses following the L-H transition, turbulence and blobs reappear although at a lower level than that typically seen during L-mode confinement. It is also seen that the time-averaged SOL emission profile broadens, as the power loss across the separatrix increases. These broad profiles are characterized by a large level of fluctuations and intermittent events.

  12. Simulations towards the achievement of non-inductive current ramp-up and sustainment in the National Spherical Torus Experiment Upgrade

    SciTech Connect (OSTI)

    Poli, F. M.; Andre, R. G.; Bertelli, N.; Gerhardt, S. P.; Mueller, D.; Taylor, G.

    2015-10-30

    One of the goals of the National Spherical Torus Experiment Upgrade (NSTX-U) (Menard et al 2012 Nucl. Fusion 52 083015) is the demonstration of fully non-inductive start-up, current ramp-up and sustainment. This work discusses predictive simulations where the available heating and current drive systems are combined to maximize the non-inductive current and minimize the solenoidal contribution. Radio-frequency waves at harmonics higher than the ion cyclotron resonance (high-harmonic fast waves (HHFW)) and neutral beam injection are used to ramp the plasma current non-inductively starting from an initial Ohmic plasma. An interesting synergy is observed in the simulations between the HHFW and electron cyclotron (EC) wave heating. Furthermore, time-dependent simulations indicate that, depending on the phasing of the HHFW antenna, EC wave heating can significantly increase the effectiveness of the radio-frequency power, by heating the electrons and increasing the current drive efficiency, thus relaxing the requirements on the level of HHFW power that needs to be absorbed in the core plasma to drive the same amount of fast-wave current.

  13. Simulations towards the achievement of non-inductive current ramp-up and sustainment in the National Spherical Torus Experiment Upgrade

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

    Poli, F. M.; Andre, R. G.; Bertelli, N.; Gerhardt, S. P.; Mueller, D.; Taylor, G.

    2015-10-30

    One of the goals of the National Spherical Torus Experiment Upgrade (NSTX-U) (Menard et al 2012 Nucl. Fusion 52 083015) is the demonstration of fully non-inductive start-up, current ramp-up and sustainment. This work discusses predictive simulations where the available heating and current drive systems are combined to maximize the non-inductive current and minimize the solenoidal contribution. Radio-frequency waves at harmonics higher than the ion cyclotron resonance (high-harmonic fast waves (HHFW)) and neutral beam injection are used to ramp the plasma current non-inductively starting from an initial Ohmic plasma. An interesting synergy is observed in the simulations between the HHFW andmore » electron cyclotron (EC) wave heating. Furthermore, time-dependent simulations indicate that, depending on the phasing of the HHFW antenna, EC wave heating can significantly increase the effectiveness of the radio-frequency power, by heating the electrons and increasing the current drive efficiency, thus relaxing the requirements on the level of HHFW power that needs to be absorbed in the core plasma to drive the same amount of fast-wave current.« less

  14. Simulation of non-resonant internal kink mode with toroidal rotation in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Wang, Feng; Liu, J. Y. [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); Fu, G. Y.; Breslau, J. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Tritz, Kevin [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States)] [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2013-07-15

    Plasmas in spherical and conventional tokamaks, with weakly reversed shear q profile and minimum q above but close to unity, are susceptible to an non-resonant (m,n) = (1,1) internal kink mode. This mode can saturate and persist and can induce a (2,1) seed island for Neoclassical Tearing Mode. [Breslau et al. Nucl. Fusion 51, 063027 (2011)]. The mode can also lead to large energetic particle transport and significant broadening of beam-driven current. Motivated by these important effects, we have carried out extensive nonlinear simulations of the mode with finite toroidal rotation using parameters and profiles of an NTSX plasma with a weakly reversed shear profile. The numerical results show that, at the experimental level, plasma rotation has little effect on either equilibrium or linear stability. However, rotation can significantly influence the nonlinear dynamics of the (1,1) mode and the induced (2,1) magnetic island. The simulation results show that a rotating helical equilibrium is formed and maintained in the nonlinear phase at finite plasma rotation. In contrast, for non-rotating cases, the nonlinear evolution exhibits dynamic oscillations between a quasi-2D state and a helical state. Furthermore, the effects of rotation are found to greatly suppress the (2,1) magnetic island even at a low level.

  15. Flow and shear behavior in the edge and scrape-off layer of L-mode plasmas in National Spherical Torus Experiment

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

    Sechrest, Y.; Munsat, T.; D’Ippolito, D. A.; Maqueda, R. J.; Myra, J. R.; Russell, D.; Zweben, S. J.

    2011-01-01

    Fluctuations in the edge and scrape-off layer (SOL) of L-mode plasmas in the National Spherical Torus Experiment (NSTX) as observed by the gas puff imaging (GPI) diagnostic are studied. Calculation of local, time resolved velocity maps using the Hybrid Optical Flow and Pattern Matching Velocimetry (HOP-V) code enables analysis of turbulent flow and shear behavior. Periodic reversals in the direction of the poloidal flow near the separatrix are observed. Also, poloidal velocities and their radial shearing rate are found to be well correlated with the fraction of Dα light contained in the SOL, which acts as a measure of turbulentmore » bursts. The spectra of GPI intensity and poloidal velocity both have a strong feature near 3 kHz, which appears to correspond with turbulent bursts. This mode exhibits a poloidal structure with poloidal wavenumber of 7.7 m-1 for GPI intensity and 3.4 m-1 for poloidal velocity, and the poloidal velocity fluctuations near 3 kHz remain coherent over length scales in excess of the turbulent scales. Furthermore, recent SOL Turbulence (SOLT) simulations find a parameter regime that exhibits periodic bursty transport and shares many qualitative similarities with the experimental data. Strong correlations between the shearing rate and the turbulent bursts are observed for time periods of ~ 2 ms, but the relationship is complicated by several factors. Finally, measurements of the radial profiles of the Reynolds shear stresses are reported. These radial profiles exhibit many similarities for several shots, and a region with positive radial gradient is seen to be coincident with local flow shear.« less

  16. Scientific Opportunities and Challenges in the Upgraded National Spherical

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

    Torus Experiment | Princeton Plasma Physics Lab March 14, 2015, 9:30am to 11:00am Science On Saturday MBG Auditorium Scientific Opportunities and Challenges in the Upgraded National Spherical Torus Experiment Dr. Jonathan Menard, Principal Research Physicist PPPL Abstract: PDF icon Menard.pdf Science On Saturday, March 14, 2015, "Scientific Opportunities & Challenges in the Upgraded National Spherical Torus Experiment", Dr. Jonathan Menard, PPPL Contact Information Website:

  17. Progress Towards High Performance, Steady-state Spherical Torus

    SciTech Connect (OSTI)

    M. Ono; M.G. Bell; R.E. Bell; T. Bigelow; M. Bitter; W. Blanchard; J. Boedo; C. Bourdelle; C. Bush; W. Choe; J. Chrzanowski; D.S. Darrow; S.J. Diem; R. Doerner; P.C. Efthimion; J.R. Ferron; R.J. Fonck; E.D. Fredrickson; G.D. Garstka; D.A. Gates; T. Gray; L.R. Grisham; W. Heidbrink; K.W. Hill; D. Hoffman; T.R. Jarboe; D.W. Johnson; R. Kaita; S.M. Kaye; C. Kessel; J.H. Kim; M.W. Kissick; S. Kubota; H.W. Kugel; B.P. LeBlanc; K. Lee; S.G. Lee; B.T. Lewicki; S. Luckhardt; R. Maingi; R. Majeski; J. Manickam; R. Maqueda; T.K. Mau; E. Mazzucato; S.S. Medley; J. Menard; D. Mueller; B.A. Nelson; C. Neumeyer; N. Nishino; C.N. Ostrander; D. Pacella; F. Paoletti; H.K. Park; W. Park; S.F. Paul; Y.-K. M. Peng; C.K. Phillips; R. Pinsker; P.H. Probert; S. Ramakrishnan; R. Raman; M. Redi; A.L. Roquemore; A. Rosenberg; P.M. Ryan; S.A. Sabbagh; M. Schaffer; R.J. Schooff; R. Seraydarian; C.H. Skinner; A.C. Sontag; V. Soukhanovskii; J. Spaleta; T. Stevenson; D. Stutman; D.W. Swain; E. Synakowski; Y. Takase; X. Tang; G. Taylor; J. Timberlake; K.L. Tritz; E.A. Unterberg; A. Von Halle; J. Wilgen; M. Williams; J.R. Wilson; X. Xu; S.J. Zweben; R. Akers; R.E. Barry; P. Beiersdorfer; J.M. Bialek; B. Blagojevic; P.T. Bonoli; M.D. Carter; W. Davis; B. Deng; L. Dudek; J. Egedal; R. Ellis; M. Finkenthal; J. Foley; E. Fredd; A. Glasser; T. Gibney; M. Gilmore; R.J. Goldston; R.E. Hatcher; R.J. Hawryluk; W. Houlberg; R. Harvey; S.C. Jardin; J.C. Hosea; H. Ji; M. Kalish; J. Lowrance; L.L. Lao; F.M. Levinton; N.C. Luhmann; R. Marsala; D. Mastravito; M.M. Menon; O. Mitarai; M. Nagata; G. Oliaro; R. Parsells; T. Peebles; B. Peneflor; D. Piglowski; G.D. Porter; A.K. Ram; M. Rensink; G. Rewoldt; P. Roney; K. Shaing; S. Shiraiwa; P. Sichta; D. Stotler; B.C. Stratton; R. Vero; W.R. Wampler; G.A. Wurden

    2003-10-02

    Research on the Spherical Torus (or Spherical Tokamak) is being pursued to explore the scientific benefits of modifying the field line structure from that in more moderate aspect-ratio devices, such as the conventional tokamak. The Spherical Tours (ST) experiments are being conducted in various U.S. research facilities including the MA-class National Spherical Torus Experiment (NSTX) at Princeton, and three medium-size ST research facilities: Pegasus at University of Wisconsin, HIT-II at University of Washington, and CDX-U at Princeton. In the context of the fusion energy development path being formulated in the U.S., an ST-based Component Test Facility (CTF) and, ultimately a Demo device, are being discussed. For these, it is essential to develop high-performance, steady-state operational scenarios. The relevant scientific issues are energy confinement, MHD stability at high beta (B), noninductive sustainment, ohmic-solenoid-free start-up, and power and particle handling. In the confinement area, the NSTX experiments have shown that the confinement can be up to 50% better than the ITER-98-pby2 H-mode scaling, consistent with the requirements for an ST-based CTF and Demo. In NSTX, CTF-relevant average toroidal beta values bT of up to 35% with the near unity central betaT have been obtained. NSTX will be exploring advanced regimes where bT up to 40% can be sustained through active stabilization of resistive wall modes. To date, the most successful technique for noninductive sustainment in NSTX is the high beta-poloidal regime, where discharges with a high noninductive fraction ({approx}60% bootstrap current + neutral-beam-injected current drive) were sustained over the resistive skin time. Research on radio-frequency-based heating and current drive utilizing HHFW (High Harmonic Fast Wave) and EBW (Electron Bernstein Wave) is also pursued on NSTX, Pegasus, and CDX-U. For noninductive start-up, the Coaxial Helicity Injection (CHI), developed in HIT/HIT-II, has been

  18. The contribution of radio-frequency rectification to field-aligned losses of high-harmonic fast wave power to the divertor in the National Spherical Torus eXperiment

    SciTech Connect (OSTI)

    Perkins, R. J. Hosea, J. C.; Jaworski, M. A.; Diallo, A.; Bell, R. E.; Bertelli, N.; Gerhardt, S.; Kramer, G. J.; LeBlanc, B. P.; Phillips, C. K.; Podestà, M.; Roquemore, L.; Taylor, G.; Wilson, J. R.; Ahn, J.-W.; Gray, T. K.; McLean, A.; Sabbagh, S.

    2015-04-15

    The National Spherical Torus eXperiment (NSTX) can exhibit a major loss of high-harmonic fast wave (HHFW) power along scrape-off layer (SOL) field lines passing in front of the antenna, resulting in bright and hot spirals on both the upper and lower divertor regions. One possible mechanism for this loss is RF sheaths forming at the divertors. Here, we demonstrate that swept-voltage Langmuir probe characteristics for probes under the spiral are shifted relative to those not under the spiral in a manner consistent with RF rectification. We estimate both the magnitude of the RF voltage across the sheath and the sheath heat flux transmission coefficient in the presence of the RF field. Although precise comparison between the computed heat flux and infrared (IR) thermography cannot yet be made, the computed heat deposition compares favorably with the projections from IR camera measurements. The RF sheath losses are significant and contribute substantially to the total SOL losses of HHFW power to the divertor for the cases studied. This work will guide future experimentation on NSTX-U, where a wide-angle IR camera and a dedicated set of coaxial Langmuir probes for measuring the RF sheath voltage directly will quantify the contribution of RF sheath rectification to the heat deposition from the SOL to the divertor.

  19. CONSTRUCTING THE NATIONAL Spherical Torus Experiment Upgrade...

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

    ... 5 a.m. to check emails each day. He oversaw the progress of construction twice every morning and twice in the afternoon, seven days a week, then rechecked emails at 10 p.m. when ...

  20. Disruptions, Disruptivity, and Safer Operating Windows in the High-? Spherical Torus NSTX

    SciTech Connect (OSTI)

    Gerhardt, S P; Diallo, A; Gates, D; LeBlanc, B P; Menard, J E; Mueller, D; Sabbagh, S A; Soukhanovskii, V; Tritz, K

    2012-09-27

    This paper discusses disruption rates, disruption causes, and disruptivity statistics in the high- ?N National Spherical Torus Experiment (NSTX) [M. Ono, et al. Nuclear Fusion 40, 557 (2000)]. While the overall disruption rate is rather high, configurations with high ?N , moderate q*, strong boundary shaping, sufficient rotation, and broad pressure and current profiles are found to have the lowest disruptivity; active n=1 control further reduces the disruptivity. The disruptivity increases rapidly for q*<2.7, which is substantially above the ideal MHD current limit. In quiescent conditions, qmin >1.25 is generally acceptable for avoiding the onset of core rotating n=1 kink/tearing modes; when EPM and ELM disturbances are present, the required qmin for avoiding those modes is raised to ~1.5. The current ramp and early flat-top phase of the discharges are prone to n=1 core rotating modes locking to the wall, leading to a disruption. Small changes to the discharge fueling during this phase can often mitigate the rotation damping associated with these modes and eliminate the disruption. The largest stored energy disruptions are those that occur at high current when a plasma current rampdown is initiated incorrectly.

  1. Measured improvement of global magnetohydrodynamic mode stability at high-beta, and in reduced collisionality spherical torus plasmas

    SciTech Connect (OSTI)

    Berkery, J. W.; Sabbagh, S. A.; Balbaky, A.; Bell, R. E.; Diallo, A.; Gerhardt, S. P.; LeBlanc, B. P.; Manickam, J.; Menard, J. E.; Podest, M.; Betti, R.

    2014-05-15

    Global mode stability is studied in high-? National Spherical Torus Experiment (NSTX) plasmas to avoid disruptions. Dedicated experiments in NSTX using low frequency active magnetohydrodynamic spectroscopy of applied rotating n?=?1 magnetic fields revealed key dependencies of stability on plasma parameters. Observations from previous NSTX resistive wall mode (RWM) active control experiments and the wider NSTX disruption database indicated that the highest ?{sub N} plasmas were not the least stable. Significantly, here, stability was measured to increase at ?{sub N}?l{sub i} higher than the point where disruptions were found. This favorable behavior is shown to correlate with kinetic stability rotational resonances, and an experimentally determined range of measured E??B frequency with improved stability is identified. Stable plasmas appear to benefit further from reduced collisionality, in agreement with expectation from kinetic RWM stabilization theory, but low collisionality plasmas are also susceptible to sudden instability when kinetic profiles change.

  2. Design of solid state neutral particle analyzer array for National...

    Office of Scientific and Technical Information (OSTI)

    Torus Experiment-Upgrade Citation Details In-Document Search Title: Design of solid state neutral particle analyzer array for National Spherical Torus Experiment-Upgrade A ...

  3. Divertor Heat Flux Mitigation in the National Spherical Torus...

    Office of Scientific and Technical Information (OSTI)

    The modeling showed that the observed peak heat flux reduction and detachment are possible with high radiated power and momentum loss fractions, achievable with divertor gas ...

  4. Development of a radio frequency ion source with multi-helicon plasma injectors for neutral beam injection system of Versatile Experiment Spherical Torus

    SciTech Connect (OSTI)

    Choe, Kyumin; Jung, Bongki; Chung, Kyoung-Jae; Hwang, Y. S.; Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744

    2014-02-15

    Despite of high plasma density, helicon plasma has not yet been applied to a large area ion source such as a driver for neutral beam injection (NBI) system due to intrinsically poor plasma uniformity in the discharge region. In this study, a radio-frequency (RF) ion source with multi-helicon plasma injectors for high plasma density with good uniformity has been designed and constructed for the NBI system of Versatile Experiment Spherical Torus at Seoul National University. The ion source consists of a rectangular plasma expansion chamber (120 120 120 mm{sup 3}), four helicon plasma injectors with annular permanent magnets and RF power system. Main feature of the source is downstream plasma confinement in the cusp magnetic field configuration which is generated by arranging polarities of permanent magnets in the helicon plasma injectors. In this paper, detailed design of the multi-helicon plasma injector and plasma characteristics of the ion source are presented.

  5. Observations of Improved Stability and Confinement in a High-{beta} Self-Organized Spherical-Torus-Like Field-Reversed Configuration

    SciTech Connect (OSTI)

    Guo, H.Y.; Hoffman, A.L.; Steinhauer, L.C.; Miller, K.E.

    2005-10-21

    An extremely high-{beta} (over 85%) self-organized field-reversed configuration (FRC) with a spherical-torus- (ST-)like core is produced in the translation, confinement, and sustainment experiment by highly super-Alfvenic translation of a spheromaklike plasmoid. Substantial flux conversion from toroidal into poloidal occurs during the capture process, resulting in the ST-like core. This plasma state exhibits a remarkable stabilizing property for the ubiquitous n=2 centrifugally driven interchange modes present in {theta}-pinch formed FRCs. This is explained, for the first time, by a simple model taking into account magnetic shear and centrifugal effects. The FRC-ST configuration has up to 4 times improvement in flux confinement times over the scaling of conventional {theta}-pinch formed FRCs and, thus, a significant improvement in the resistivity and transport.

  6. Status of the Control System on the National Spherical Torus Experiment (NSTX)

    SciTech Connect (OSTI)

    D.A. Gates; J.R. Ferron; M. Bell; T. Gibney; R. Johnson; R.J. Marsala; D. Mastrovito; J.E. Menard; D. Mueller; B. Penaflor; T. Stevenson

    2005-08-05

    In 2003, the NSTX plasma control system was used for plasma shape control using real-time equilibrium reconstruction (using the rtEFIT code - J. Ferron, et al., Nucl. Fusion 38 1055 (1998)). rtEFIT is now in routine use for plasma boundary control [D. A. Gates, et al., submitted to Nuclear Fusion (2005)]. More recently, the system has been upgraded to support feedback control of the resistive wall mode (RWM). This paper describes the hardware and software improvements that were made in support of these physics requirements. The real-time data acquisition system now acquires 352 channels of data at 5kHz for each NSTX plasma discharge. The latency for the data acquisition, which uses the FPDP (Front Panel Data Port) protocol, is measured to be {approx}8 microseconds. A Stand-Alone digitizer (SAD), designed at PPPL, along with an FPDP Input multiplexing module (FIMM) allows for simple modular upgrades. An interface module was built to interface between the FPDP output of the NSTX control system and the legacy Power Conversion link (PCLINK) used for communicating with the PPPL power supplies (first used for TFTR). Additionally a module has been built for communicating with the switching power amplifiers (SPA) recently installed on NSTX. In addition to the hardware developments, the control software [D. Mastrovito, Fusion Eng. And Design 71 65 (2004)] on the NSTX control system has been upgraded. The control computer is an eight processor (8x333MHz G4) built by Sky Computers (Helmsford, MA). The device driver software for the hardware described above will be discussed, as well as the new control algorithms that have been developed to control the switching power supplies for RWM control. An important initial task in RWM feedback is to develop a reliable mode detection algorithm.

  7. Major Milestone: PPPL completes first quadrant of the heart of the National

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

    Spherical Torus Experiment Upgrade | Princeton Plasma Physics Lab Major Milestone: PPPL completes first quadrant of the heart of the National Spherical Torus Experiment Upgrade By John Greenwald March 18, 2013 Tweet Widget Google Plus One Share on Facebook Mission accomplished: The completed first section of the NSTX-U center stack capped months of demanding preparations and close teamwork. (Photo by Elle Starkman, PPPL Office of Communications) Mission accomplished: The completed first

  8. Liquid Lithium Divertor and Scrape-Off-Layer Interactions on the National Spherical Torus Experiment: 2010 ? 2013 Progress Report

    SciTech Connect (OSTI)

    2013-08-27

    The implementation of the liquid Lithium Divertor (LLD) in NSTX presented a unique opportunity in plasma-material interactions studies. A high density Langmuir Probe (HDLP) array utilizing a dense pack of triple Langmuir probes was built at PPPL and the electronics designed and built by UIUC. It was shown that the HDLP array could be used to characterize the modification of the EEDF during lithium experiments on NSTX as well as characterize the transient particle loads during lithium experiments as a means to study ELMs. With NSTX being upgraded and a new divertor being installed, the HDLP array will not be used in NSTX-U. However UIUC is currently helping to develop two new systems for depositing lithium into NSTX-U, a Liquid Lithium Pellet Dripper (LLPD) for use with the granular injector for ELM mitigation and control studies as well as an Upward-Facing Lithium Evaporator (U-LITER) based on a flash evaporation system using an electron beam. Currently UIUC has Daniel Andruczyk Stationed at PPPL and is developing these systems as well as being involved in preparing the Materials Analysis Particle Probe (MAPP) for use in LTX and NSTX-U. To date the MAPP preparations have been completed. New sample holders were designed by UIUC?s Research Engineer at PPPL and manufactured at PPPL and installed. MAPP is currently being used on LTX to do calibration and initial studies. The LLPD has demonstrated that it can produce pellets. There is still some adjustments needed to control the frequency and particle size. Equipment for the U-LITER has arrived and initial test are being made of the electron beam and design of the U-LITER in progress. It is expected to have these ready for the first run campaign of NSTX-U.

  9. Edge transport studies in the edge and scrape-off layer of the National Spherical Torus Experiment with Langmuir probes

    SciTech Connect (OSTI)

    Boedo, J. A. Rudakov, D. L.; Myra, J. R.; D'Ippolito, D. A.; Zweben, S.; Maingi, R.; Maqueda, R. J.; Bell, R.; Kugel, H.; Leblanc, B.; Roquemore, L. A.; Soukhanovskii, V. A.; Ahn, J. W.; Canik, J.; Crocker, N.

    2014-04-15

    Transport and turbulence profiles were directly evaluated using probes for the first time in the edge and scrape-off layer (SOL) of NSTX [Ono et al., Nucl. Fusion 40, 557 (2000)] in low (L) and high (H) confinement, low power (P{sub in}? 1.3?MW), beam-heated, lower single-null discharges. Radial turbulent particle fluxes peak near the last closed flux surface (LCFS) at ?410{sup 21}?s{sup ?1} in L-mode and are suppressed to ?0.210{sup 21}?s{sup ?1} in H mode (80%90% lower) mostly due to a reduction in density fluctuation amplitude and of the phase between density and radial velocity fluctuations. The radial particle fluxes are consistent with particle inventory based on SOLPS fluid modeling. A strong intermittent component is identified. Hot, dense plasma filaments 410?cm in diameter, appear first ?2?cm inside the LCFS at a rate of ?110{sup 21}?s{sup ?1} and leave that region with radial speeds of ?35?km/s, decaying as they travel through the SOL, while voids travel inward toward the core. Profiles of normalized fluctuations feature levels of 10% inside LCFS to ?150% at the LCFS and SOL. Once properly normalized, the intermittency in NSTX falls in similar electrostatic instability regimes as seen in other devices. The L-H transition causes a drop in the intermittent filaments velocity, amplitude and number in the SOL, resulting in reduced outward transport away from the edge and a less dense SOL.

  10. Evaluation of thermal helium beam and line-ratio fast diagnostic on the National Spherical Torus Experiment-Upgrade

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

    Munoz Burgos, Jorge M.; Agostini, Matteo; Scarin, Paolo; Stotler, Daren P.; Unterberg, Ezekial A.; Loch, Stuart D.; Schmitz, Oliver; Tritz, Kevin; Stutman, Dan

    2015-05-06

    A 1-D kinetic collisional radiative model (CRM) with state-of-the-art atomic data is developed and employed to simulate line emission to evaluate the Thermal Helium Beam (THB) diagnostic on NSTX-U. This diagnostic is currently in operation on RFX-mod, and it is proposed to be installed on NSTX-U. The THB system uses the intensity ratios of neutral helium lines 667.8, 706.5, and 728.1 nm to derive electron temperature (eV ) and density (cm–3) profiles. The purpose of the present analysis is to evaluate the applications of this diagnostic for determining fast (~4 μs) electron temperature and density radial profiles on the scrape-offmore » layer (SOL) and edge regions of NSTX-U that are needed in turbulence studies. The diagnostic is limited by the level of detection of the 728.1 nm line, which is the weakest of the three. In conclusion, this study will also aid in future design of a similar 2-D diagnostic systems on the divertor.« less

  11. Radiative shocks produced from spherical cryogenic implosions at the National Ignition Facility

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

    Pak, A.; Divol, L.; Gregori, G.; Weber, S.; Atherton, J.; Bennedetti, R.; Bradley, D. K.; Callahan, D.; Dewald, E.; Doppner, T.; et al

    2013-05-20

    Spherically expanding radiative shock waves have been observed from inertially confined implosion experiments at the National Ignition Facility. In these experiments, a spherical fusion target, initially 2 mm in diameter, is compressed via the pressure induced from the ablation of the outer target surface. At the peak compression of the capsule, x-ray and nuclear diagnostics indicate the formation of a central core, with a radius and ion temperature of ~20 μm and ~ 2 keV, respectively. This central core is surrounded by a cooler compressed shell of deuterium-tritium fuel that has an outer radius of ~40 μm and a densitymore » of >500 g/cm3. Using inputs from multiple diagnostics, the peak pressure of the compressed core has been inferred to be of order 100 Gbar for the implosions discussed here. Furthermore, the shock front, initially located at the interface between the high pressure compressed fuel shell and surrounding in-falling low pressure ablator plasma, begins to propagate outwards after peak compression has been reached.« less

  12. Mechanisms of Stochastic Diffusion of Energetic Ions in Spherical Tori

    SciTech Connect (OSTI)

    Ya.I. Kolesnichenko; R.B. White; Yu.V. Yakovenko

    2001-01-18

    Stochastic diffusion of the energetic ions in spherical tori is considered. The following issues are addressed: (I) Goldston-White-Boozer diffusion in a rippled field; (ii) cyclotron-resonance-induced diffusion caused by the ripple; (iii) effects of non-conservation of the magnetic moment in an axisymmetric field. It is found that the stochastic diffusion in spherical tori with a weak magnetic field has a number of peculiarities in comparison with conventional tokamaks; in particular, it is characterized by an increased role of mechanisms associated with non-conservation of the particle magnetic moment. It is concluded that in current experiments on National Spherical Torus eXperiment (NSTX) the stochastic diffusion does not have a considerable influence on the confinement of energetic ions.

  13. MPI Multicore Torus Communication Benchmark

    Energy Science and Technology Software Center (OSTI)

    2008-02-05

    The MPI Multicore Torus Communications Benchmark (TorusTest) measues the aggegate bandwidth across all six links from/to any multicore node in a logical torus. It can run in wo modi: using a static or a random mapping of tasks to torus locations. The former can be used to achieve optimal mappings and aggregate bandwidths that can be achieved with varying node mappings.

  14. Science and Technology of the 10-MA Spherical Tori

    SciTech Connect (OSTI)

    Peng, Y-K.M.

    1999-11-14

    The Spherical Torus (ST) configuration has recently emerged as an example of confinement concept innovation that enables attractive steps in the development of fusion energy. The scientific potential for the ST has been indicated by recent encouraging results from START,2 CDX-U, and HIT. The scientific principles for the D-fueled ST will soon be tested by NSTX (National Spherical Torus Experiment3) in the U.S. and MAST (Mega-Amp Spherical Tokamak4) in the U.K. at the level of l-2 MA in plasma current. More recently, interest has grown in the U.S. in the possibility of near-term ST fusion burn devices at the level of 10 MA in plasma current. The missions for these devices would be to test burning plasma performance in a small, pulsed D-T-fueled ST (i.e., DTST) and to develop fusion energy technologies in a small steady state ST-based Volume Neutron Source (VNS). This paper reports the results of analysis of the key science and technology issues for these devices.

  15. Characteristics of Energy Transport of Li-conditioned and non-Li-conditioned Plasmas in the National Spherical Torus Experiment (NSTX)

    SciTech Connect (OSTI)

    Ding, S.; Kaye, S. M.; Bell, R. E.; Kaita, R.; Kugel, H.; LeBlanc, B. P.; Paul, S.; Wan, B.

    2009-10-21

    The transport properties of NSTX plasmas obtained during the 2008 experimental cam- paign have been studied and are reported here. Transport trends and dependences have been isolated, and it is found that both electron and ion energy transport coefficients have strong dependences on local values of n?T, which in turn is strongly dependent on local current density profile. Without identifying this dependence, it is difficult to identify others, such as the dependence of transport coefficients on Bp (or q), Ip and Pheat. In addition, a comparison between discharges with and without Lithium wall conditioning has been made. While the trends in the two sets of data are similar, the thermal transport loss, especially in the electron channel, is found to strongly depend on the amount of Lithium deposited, decreasing by up to 50% of its no-Lithium value.

  16. Energy Secretary Moniz Launches the Nation's Newest Fusion Experiment at

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

    PPPL | Princeton Plasma Physics Lab Energy Secretary Moniz Launches the Nation's Newest Fusion Experiment at PPPL National Spherical Torus Experiment - Upgrade will help determine the course of fusion energy for years to come By Larry Bernard May 20, 2016 Tweet Widget Google Plus One Share on Facebook U.S. Energy Secretary Ernest Moniz, center, in the NSTX-U test cell. From left: PPPL physicist Stefan Gerhardt; Princeton University President Christopher L. Eisgruber; Princeton University

  17. DIII-D National Fusion Facility (DIII-D) | U.S. DOE Office of Science (SC)

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

    DIII-D National Fusion Facility (DIII-D) Fusion Energy Sciences (FES) FES Home About Research Facilities User Facilities DIII-D National Fusion Facility (DIII-D) National Spherical Torus Experiment (NSTX) Alcator C-Mod ITER External link Science Highlights Benefits of FES Funding Opportunities Fusion Energy Sciences Advisory Committee (FESAC) Community Resources Contact Information Fusion Energy Sciences U.S. Department of Energy SC-24/Germantown Building 1000 Independence Ave., SW Washington,

  18. 3D TORUS V1.0

    Energy Science and Technology Software Center (OSTI)

    002440MLTPL00 3D Torus Routing Engine Module for OFA OpenSM v. 1.0 http://www.openfabrics.org/git?p=sashak/management.git;a=sum

  19. Ion heating during magnetic relaxation in the helicity injected torus-II experiment

    SciTech Connect (OSTI)

    O'Neill, R.G.; Redd, A.J.; Hamp, W.T.; Smith, R.J.; Jarboe, T.R.

    2005-12-15

    Ion doppler spectroscopy (IDS) is applied to the helicity injected torus (HIT-II) spherical torus to measure impurity ion temperature and flows. [A. J. Redd et al., Phys. Plasmas 9, 2006 (2002)] The IDS instrument employs a 16-channel photomultiplier and can track temperature and velocity continuously through a discharge. Data for the coaxial helicity injection (CHI), transformer, and combined current drive configurations are presented. Ion temperatures for transformer-driven discharges are typically equal to or somewhat lower than electron temperatures measured by Thomson scattering. Internal reconnection events in transformer-driven discharges cause rapid ion heating. The CHI discharges exhibit anomalously high ion temperatures >250 eV, which are an order of magnitude higher than Thomson measurements, indicating ion heating through magnetic relaxation. The CHI discharges that exhibit current and poloidal flux buildup after bubble burst show sustained ion heating during current drive.

  20. Distinct turbulence sources and confinement features in the spherical tokamak plasma regime

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

    Wang, W. X.; Ethier, S.; Ren, Y.; Kaye, S.; Chen, J.; Startsev, E.; Lu, Z.

    2015-10-30

    New turbulence contributions to plasma transport and confinement in the spherical tokamak (ST) regime are identified through nonlinear gyrokinetic simulations. The drift wave Kelvin-Helmholtz (KH) mode characterized by intrinsic mode asymmetry is shown to drive significant ion thermal transport in strongly rotating national spherical torus experiment (NSTX) L-modes. The long wavelength, quasi-coherent dissipative trapped electron mode (TEM) is destabilized in NSTX H-modes despite the presence of strong E x B shear, providing a robust turbulence source dominant over collisionless TEM. Dissipative trapped electron mode (DTEM)-driven transport in the NSTX parametric regime is shown to increase with electron collision frequency, offeringmore » one possible source for the confinement scaling observed in experiments. There exists a turbulence-free regime in the collision-induced collisionless trapped electron mode to DTEM transition for ST plasmas. In conclusion, this predicts a natural access to a minimum transport state in the low collisionality regime that future advanced STs may cover.« less

  1. Spherical neutron generator

    DOE Patents [OSTI]

    Leung, Ka-Ngo

    2006-11-21

    A spherical neutron generator is formed with a small spherical target and a spherical shell RF-driven plasma ion source surrounding the target. A deuterium (or deuterium and tritium) ion plasma is produced by RF excitation in the plasma ion source using an RF antenna. The plasma generation region is a spherical shell between an outer chamber and an inner extraction electrode. A spherical neutron generating target is at the center of the chamber and is biased negatively with respect to the extraction electrode which contains many holes. Ions passing through the holes in the extraction electrode are focused onto the target which produces neutrons by D-D or D-T reactions.

  2. Arithmetic functions in torus and tree networks

    DOE Patents [OSTI]

    Bhanot, Gyan; Blumrich, Matthias A.; Chen, Dong; Gara, Alan G.; Giampapa, Mark E.; Heidelberger, Philip; Steinmacher-Burow, Burkhard D.; Vranas, Pavlos M.

    2007-12-25

    Methods and systems for performing arithmetic functions. In accordance with a first aspect of the invention, methods and apparatus are provided, working in conjunction of software algorithms and hardware implementation of class network routing, to achieve a very significant reduction in the time required for global arithmetic operation on the torus. Therefore, it leads to greater scalability of applications running on large parallel machines. The invention involves three steps in improving the efficiency and accuracy of global operations: (1) Ensuring, when necessary, that all the nodes do the global operation on the data in the same order and so obtain a unique answer, independent of roundoff error; (2) Using the topology of the torus to minimize the number of hops and the bidirectional capabilities of the network to reduce the number of time steps in the data transfer operation to an absolute minimum; and (3) Using class function routing to reduce latency in the data transfer. With the method of this invention, every single element is injected into the network only once and it will be stored and forwarded without any further software overhead. In accordance with a second aspect of the invention, methods and systems are provided to efficiently implement global arithmetic operations on a network that supports the global combining operations. The latency of doing such global operations are greatly reduced by using these methods.

  3. UCID-20974 Spherical Explosions

    Office of Scientific and Technical Information (OSTI)

    UCID-20974 Spherical Explosions and the Equation of State of Water D. J. Steinberg ... Explosions and the Equation of State of Water D. J. Steinberg February 1987 r This is an ...

  4. Large displacement spherical joint

    DOE Patents [OSTI]

    Bieg, Lothar F.; Benavides, Gilbert L.

    2002-01-01

    A new class of spherical joints has a very large accessible full cone angle, a property which is beneficial for a wide range of applications. Despite the large cone angles, these joints move freely without singularities.

  5. Recent progress toward an advanced spherical torus operating point in NSTX

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

    S. P. Gerhardt; Gates, D. A.; Kaye, S.; Maingi, R.; Menard, J. E.; Sabbagh, S. A.; Soukhanovskii, V.; Bell, M. G.; Bell, R. E.; Canik, J. M.; et al

    2011-05-13

    Progress in the development of integrated advanced ST plasma scenarios in NSTX (Ono et al., 2000 Nucl. Fusion 40 557) is reported. Recent high-performance plasmas in NSTX following lithium coating of the plasma facing surfaces have achieved higher elongation and lower internal inductance than previously. Analysis of the thermal confinement in these lithiumized discharges shows a stronger plasma current and weaker toroidal field dependence than in previous ST confinement scaling studies; the ITER-98(y, 2) scaling expression describes these scenarios reasonably well. Analysis during periods free of MHD activity has shown that the reconstructed current profile can be understood as themore » sum of pressure driven, inductive and neutral beam driven currents, without requiring any anomalous fast-ion transport. Non-inductive fractions of 65–70%, and βP > 2, have been achieved at lower plasma current. Some of these low-inductance discharges have a significantly reduced no-wall βN limit, and often have βN at or near the with-wall limit. Coupled m/n = 1/1 + 2/1 kink/tearing modes can limit the sustained β values when rapidly growing ideal modes are avoided. A βN controller has been commissioned and utilized in sustaining high-performance plasmas. 'Snowflake' divertors compatible with high-performance plasmas have been developed. Scenarios with significantly larger aspect ratios have also been developed, in support of next-step ST devices. Furthermore, these NSTX plasmas have many characteristics required for next-step ST devices.« less

  6. Progress in Understanding Error-field Physics in NSTX Spherical Torus Plasmas

    SciTech Connect (OSTI)

    E. Menard, R.E. Bell, D.A. Gates, S.P. Gerhardt, J.-K. Park, S.A. Sabbagh, J.W. Berkery, A. Egan, J. Kallman, S.M. Kaye, B. LeBlanc, Y.Q. Liu, A. Sontag, D. Swanson, H. Yuh, W. Zhu and the NSTX Research Team

    2010-05-19

    The low aspect ratio, low magnetic field, and wide range of plasma beta of NSTX plasmas provide new insight into the origins and effects of magnetic field errors. An extensive array of magnetic sensors has been used to analyze error fields, to measure error field amplification, and to detect resistive wall modes in real time. The measured normalized error-field threshold for the onset of locked modes shows a linear scaling with plasma density, a weak to inverse dependence on toroidal field, and a positive scaling with magnetic shear. These results extrapolate to a favorable error field threshold for ITER. For these low-beta locked-mode plasmas, perturbed equilibrium calculations find that the plasma response must be included to explain the empirically determined optimal correction of NSTX error fields. In high-beta NSTX plasmas exceeding the n=1 no-wall stability limit where the RWM is stabilized by plasma rotation, active suppression of n=1 amplified error fields and the correction of recently discovered intrinsic n=3 error fields have led to sustained high rotation and record durations free of low-frequency core MHD activity. For sustained rotational stabilization of the n=1 RWM, both the rotation threshold and magnitude of the amplification are important. At fixed normalized dissipation, kinetic damping models predict rotation thresholds for RWM stabilization to scale nearly linearly with particle orbit frequency. Studies for NSTX find that orbit frequencies computed in general geometry can deviate significantly from those computed in the high aspect ratio and circular plasma cross-section limit, and these differences can strongly influence the predicted RWM stability. The measured and predicted RWM stability is found to be very sensitive to the E B rotation profile near the plasma edge, and the measured critical rotation for the RWM is approximately a factor of two higher than predicted by the MARS-F code using the semi-kinetic damping model.

  7. Detection of Disruptions in the High-β Spherical Torus NSTX...

    Office of Scientific and Technical Information (OSTI)

    Publisher: Nuclear Fusion (January 2013) Research Org: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States) Sponsoring Org: USDOE Office of Science (SC) ...

  8. Detection of Disruptions in the High-β Spherical Torus NSTX

    Office of Scientific and Technical Information (OSTI)

    ... This actual point total is based on that associated with a 1.5% false positive rate; see discussion below for motivation on the connections between point totals and false positive ...

  9. Identification of new turbulence contributions to plasma transport and confinement in spherical tokamak regime

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

    Wang, W. X.; Ethier, S.; Ren, Y.; Kaye, S.; Chen, J.; Startsev, E.; Lu, Z.; Li, Z. Q.

    2015-10-15

    Highly distinct features of spherical tokamaks (ST), such as National Spherical Torus eXperiment (NSTX) and NSTX-U, result in a different fusion plasma regime with unique physics properties compared to conventional tokamaks. Nonlinear global gyrokinetic simulations critical for addressing turbulence and transport physics in the ST regime have led to new insights. The drift wave Kelvin-Helmholtz (KH) instability characterized by intrinsic mode asymmetry is identified in strongly rotating NSTX L-mode plasmas. While the strong E x B shear associated with the rotation leads to a reduction in KH/ion temperature gradient turbulence, the remaining fluctuations can produce a significant ion thermal transportmore » that is comparable to the experimental level in the outer core region (with no "transport shortfall"). The other new, important turbulence source identified in NSTX is the dissipative trapped electron mode (DTEM), which is believed to play little role in conventional tokamak regime. Due to the high fraction of trapped electrons, long wavelength DTEMs peaking around kθρs ~ 0.1 are destabilized in NSTX collisionality regime by electron density and temperature gradients achieved there. Surprisingly, the E x B shear stabilization effect on DTEM is remarkably weak, which makes it a major turbulence source in the ST regime dominant over collisionless TEM (CTEM). The latter, on the other hand, is subject to strong collisional and E x B shear suppression in NSTX. DTEM is shown to produce significant particle, energy and toroidal momentum transport, in agreement with experimental levels in NSTX H-modes. Furthermore, DTEM-driven transport in NSTX parametric regime is found to increase with electron collision frequency, providing one possible source for the scaling of confinement time observed in NSTX H-modes. Most interestingly, the existence of a turbulence-free regime in the collision-induced CTEM to DTEM transition, corresponding to a minimum plasma transport in

  10. Microsoft Word - 9-Menard.doc

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

    March 2015 Scientific Opportunities and Challenges in the Upgraded National Spherical Torus Experiment* Dr. Jonathan Menard Program Director for the National Spherical Torus eXperiment - Upgrade (NSTX-U) Princeton Plasma Physics Laboratory Princeton, NJ ABSTRACT: Upon completion, the National Spherical Torus Experiment - Upgrade (NSTX-U) will be the most capable spherical torus (ST) facility in the world fusion program. A major mission of NSTX-U is to develop the physics and technology basis for

  11. Torus through Integrated Data Analysis Mark Nornberg Matthew...

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

    Z eff in the Madison Symmetric Torus through Integrated Data Analysis Mark Nornberg Matthew Galante (Nova Photonics) L.M. Reusch, D.J. Den Hartog, J.R. Johnson, M.B. McGarry H. D. ...

  12. Hollow spherical shell manufacture

    DOE Patents [OSTI]

    O'Holleran, T.P.

    1991-11-26

    A process is disclosed for making a hollow spherical shell of silicate glass composition in which an aqueous suspension of silicate glass particles and an immiscible liquid blowing agent is placed within the hollow spherical cavity of a porous mold. The mold is spun to reduce effective gravity to zero and to center the blowing agent, while being heated so as to vaporize the immiscible liquid and urge the water carrier of the aqueous suspension to migrate into the body of the mold, leaving a green shell compact deposited around the mold cavity. The green shell compact is then removed from the cavity, and is sintered for a time and a temperature sufficient to form a silicate glass shell of substantially homogeneous composition and uniform geometry. 3 figures.

  13. Hollow spherical shell manufacture

    DOE Patents [OSTI]

    O'Holleran, Thomas P.

    1991-01-01

    A process for making a hollow spherical shell of silicate glass composition in which an aqueous suspension of silicate glass particles and an immiscible liquid blowing agent is placed within the hollow spherical cavity of a porous mold. The mold is spun to reduce effective gravity to zero and to center the blowing agent, while being heated so as to vaporize the immiscible liquid and urge the water carrier of the aqueous suspension to migrate into the body of the mold, leaving a green shell compact deposited around the mold cavity. The green shell compact is then removed from the cavity, and is sintered for a time and a temperature sufficient to form a silicate glass shell of substantially homogeneous composition and uniform geometry.

  14. Spherical nitroguanidine process

    DOE Patents [OSTI]

    Sanchez, John A.; Roemer, Edward L.; Stretz, Lawrence A.

    1990-01-01

    A process of preparing spherical high bulk density nitroguanidine by dissing low bulk density nitroguanidine in N-methyl pyrrolidone at elevated temperatures and then cooling the solution to lower temperatures as a liquid characterized as a nonsolvent for the nitroguanidine is provided. The process is enhanced by inclusion in the solution of from about 1 ppm up to about 250 ppm of a metal salt such as nickel nitrate, zinc nitrate or chromium nitrate, preferably from about 20 to about 50 ppm.

  15. The CLAS12 Torus Detector Magnet at Jefferson Laboratory

    SciTech Connect (OSTI)

    Luongo, Cesar; Ballard, Joshua; Biallas, George; Elouadrhiri, Latifa; Fair, Ruben; Ghoshal, Probir; Kashy, Dave; Legg, Robert; Pastor, Orlando; Rajput-Ghoshal, Renuka; Rode, Claus; Wiseman, Mark; Young, Glenn; Elementi, Luciano; Krave, Steven; Makarov, Alexander; Nobrega, Fred; Velev, George

    2015-12-17

    The CLAS12 Torus is a toroidal superconducting magnet, which is part of the detector for the 12-GeV accelerator upgrade at Jefferson Laboratory (JLab). The coils were wound/fabricated by Fermilab, with JLab responsible for all other parts of the project scope, including design, integration, cryostating the individual coils, installation, cryogenics, I&C, etc. This paper provides an overview of the CLAS12 Torus magnet features and serves as a status report of its installation in the experimental hall. Completion and commissioning of the magnet is expected in 2016.

  16. Maass Cusp Forms on Singly Punctured Two-Torus

    SciTech Connect (OSTI)

    Siddig, Abubaker Ahmed Mohamed [Laboratory of Computational Sciences and Informatics, Institute for Mathematical Research Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Shah, Nurisya Mohd [Theoretical Physics Group, Department of Physics, Faculty of Science Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Zainuddin, Hishamuddin [Laboratory of Computational Sciences and Informatics, Institute for Mathematical Research Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Theoretical Physics Group, Department of Physics, Faculty of Science Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

    2009-07-07

    Quantum mechanical systems on punctured surfaces modeled by hyperbolic spaces can play an interesting role in exploring quantum chaos and in studying behaviour of future quantum nano-devices. The case of singly-punctured two-torus, for example, has been well-studied in the literature particularly for its scattering states. However, the bound states on the punctured torus given by Maass cusp forms are lesser known. In this note, we report on the algorithm of numerically computing these functions and we present ten lower-lying eigenvalues for each odd and even Maass cusp forms.

  17. The CLAS12 torus detector magnet at Jefferson Laboratory

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

    Luongo, Cesar; Wiseman, Mark A.; Kashy, David H.; Pastor, Orlando; Ghoshal, Probir K.; Fair, Ruben J.; Ballard, Joshua T.; Legg, Robert A.; Rajput-Ghoshal, Renuka; Biallas, George H.; et al

    2015-12-17

    The CLAS12 Torus is a toroidal superconducting magnet, part of the detector for the 12GeV accelerator upgrade at Jefferson Lab. The coils were wound/fabricated by Fermi Lab, with Jlab responsible for all other parts of the project scope, including design, integration, cryostating the individual coils, installation, cryogenics, I&C, etc. The study provides an overview of the CLAS12 Torus magnet features, and serves as a status report of its installation in the experimental hall. Completion and commissioning of the magnet is expected in 2016.

  18. Spherically symmetric quantum horizons

    SciTech Connect (OSTI)

    Bojowald, Martin; Swiderski, Rafal

    2005-04-15

    Isolated horizon conditions specialized to spherical symmetry can be imposed directly at the quantum level. This answers several questions concerning horizon degrees of freedom, which are seen to be related to orientation, and its fluctuations at the kinematical as well as dynamical level. In particular, in the absence of scalar or fermionic matter the horizon area is an approximate quantum observable. Including different kinds of matter fields allows to probe several aspects of the Hamiltonian constraint of quantum geometry that are important in inhomogeneous situations.

  19. Double slotted socket spherical joint

    SciTech Connect (OSTI)

    Bieg, Lothar F.; Benavides, Gilbert L.

    2001-05-22

    A new class of spherical joints is disclosed. These spherical joints are capable of extremely large angular displacements (full cone angles in excess of 270.degree.), while exhibiting no singularities or dead spots in their range of motion. These joints can improve or simplify a wide range of mechanical devices.

  20. Torus Network on a BG/Q System | Argonne Leadership Computing...

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

    Blue GeneQ Versus Blue GeneP BGQ Drivers Status Machine Overview Machine Partitions Torus Network Data Storage & File Systems Compiling & Linking Queueing & Running Jobs Data...

  1. The Physics of Tokamak Start-up (Technical Report) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    In some cases inductive startup is assisted with auxiliary power from electron cyclotron radio frequency heating. ITER, the National Spherical Torus eXperiment Upgrade and JT60, ...

  2. Full toroidal imaging of non-axisymmetric plasma material interaction...

    Office of Scientific and Technical Information (OSTI)

    plasma material interaction in the National Spherical Torus eXperiment divertor Citation Details In-Document Search Title: Full toroidal imaging of non-axisymmetric plasma ...

  3. Kelsey Tresemer | Princeton Plasma Physics Lab

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

    Tresemer has been the primary design engineer and cost account manager for plasma-facing components for the National Spherical Torus Experiment (NSTX), and currently serves as...

  4. A Snowflake-Shaped Magnetic Field Holds Promise for Taming Harsh...

    Office of Science (SC) Website

    Recent experiments have confirmed the great potential of a novel plasma-material interface ... The National Spherical Torus Experiment Device at Princeton Plasma Physics Laboratory ...

  5. Bernard named communications director of the Princeton Plasma...

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

    "Larry arrives at an exciting time for the Laboratory," said PPPL Director Stewart Prager. "We have completed construction of the National Spherical Torus...

  6. Numerical simulation of torus breakdown to chaos in an atmospheric-pressure dielectric barrier discharge

    SciTech Connect (OSTI)

    Zhang, J.; Wang, Y. H.; Wang, D. Z. [Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2013-08-15

    Understanding the routes to chaos occurring in atmospheric-pressure dielectric barrier discharge systems by changing controlling parameters is very important to predict and control the dynamical behaviors. In this paper, a route of a quasiperiodic torus to chaos via the strange nonchaotic attractor is observed in an atmospheric-pressure dielectric barrier discharge driven by triangle-wave voltage. By increasing the driving frequency, the discharge system first bifurcates to a quasiperiodic torus from a stable single periodic state, and then torus and phase-locking periodic state appear and disappear alternately. In the meantime, the torus becomes increasingly wrinkling and stretching, and gradually approaches a fractal structure with the nonpositive largest Lyapunov exponent, i.e., a strange nonchaotic attractor. After that, the discharge system enters into chaotic state. If the driving frequency is further increased, another well known route of period-doubling bifurcation to chaos is also observed.

  7. Design and Manufacture of the Conduction Cooled Torus Coils for the Jefferson Lab 12GeV Upgrade

    SciTech Connect (OSTI)

    Wiseman, M; Elouadhiri, L; Ghoshal, P K; Kashy, D; Elementi, L; Gabrielli, G; Gardner, T J; Kiemschies, O; Krave, S; Makarov, A; Robotham, B; Szal, J; Velev, G

    2015-06-01

    The design of the 12-GeV torus required the construction of six superconducting coils with a unique geometry required for the experimental needs of Jefferson Laboratory Hall B. Each of these coils consists of 234 turns of copper-stabilized superconducting cable conduction cooled by 4.6 K helium gas. The finished coils are each roughly 2 × 4 × 0.05 m and supported in an aluminum coil case. Because of its geometry, new tooling and manufacturing methods had to be developed for each stage of construction. The tooling was designed and developed while producing a practice coil at Fermi National Laboratory. This paper describes the tooling and manufacturing techniques required to produce the six production coils and two spare coils required by the project. Project status and future plans are also presented.

  8. Design and Manufacture of the Conduction Cooled Torus Coils for The Jefferson Laboratory 12-GeV Upgrade

    SciTech Connect (OSTI)

    Wiseman, M.; Elementi, L.; Elouadhiri, L.; Gabrielli, G.; Gardner, T. J.; Ghoshal, P. K.; Kashy, D.; Kiemschies, O.; Krave, S.; Makarov, A.; Robotham, B.; Szal, J.; Velev, G.

    2015-01-01

    The design of the 12-GeV torus required the construction of six superconducting coils with a unique geometry required for the experimental needs of Jefferson Laboratory Hall B. Each of these coils consists of 234 turns of copper-stabilized superconducting cable conduction cooled by 4.6 K helium gas. The finished coils are each roughly 2 × 4 × 0.05 m and supported in an aluminum coil case. Because of its geometry, new tooling and manufacturing methods had to be developed for each stage of construction. The tooling was designed and developed while producing a practice coil at Fermi National Laboratory. This paper describes the tooling and manufacturing techniques required to produce the six production coils and two spare coils required by the project. Project status and future plans are also presented.

  9. Overview of torus magnet coil production at Fermilab for the Jefferson Lab 12-GeV Hall B upgrade

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

    Krave, S.; Velev, G.; Makarov, A.; Nobrega, F.; Kiemschies, O.; Robotham, B.; Elementi, L.; Elouadrhiri, Latifa; Luongo, Cesar; Kashy, David H.; et al

    2016-02-29

    Fermi National Accelerator Laboratory (Fermilab) fabricated the torus magnet coils for the 12 GeV Hall B upgrade at Jefferson Laboratory (JLab). The production consisted of 6 large superconducting coils for the magnet and 2 spare coils. The toroidal field coils are approximately 2 m x 4 m x 5 cm thick. Each of these coils consists of two layers, each of which has 117 turns of copper-stabilized superconducting cable which will be conduction cooled by helium gas. Due to the size of the coils and their unique geometry, Fermilab designed and fabricated specialized tooling and, together with JLab, developed uniquemore » manufacturing techniques for each stage of the coil construction. In conclusion, this paper describes the tooling and manufacturing techniques required to produce the six production coils and two spare coils needed by the project.« less

  10. Numerical Simulations of Small Non-spherical Particles in Turbulence |

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

    Argonne Leadership Computing Facility Numerical Simulations of Small Non-spherical Particles in Turbulence Event Sponsor: Mathematics and Computer Science Division LANS Seminar Start Date: Aug 31 2016 - 3:00pm Building/Room: Building 240/Room 1404-1405 Location: Argonne National Laboratory Speaker(s): Nimish Pujara Speaker(s) Title: UC Berkeley Motivated by the ubiquity of natural particles in turbulent flows in the natural environment as well as in many industrial processes, we investigate

  11. Low energy ion distribution measurements in Madison Symmetric Torus plasmas

    SciTech Connect (OSTI)

    Titus, J. B. Mezonlin, E. D.; Johnson, J. A.

    2014-06-15

    Charge-exchange neutrals contain information about the contents of a plasma and can be detected as they escape confinement. The Florida A and M University compact neutral particle analyzer (CNPA), used to measure the contents of neutral particle flux, has been reconfigured, calibrated, and installed on the Madison Symmetric Torus (MST) for high temperature deuterium plasmas. The energy range of the CNPA has been extended to cover 0.34–5.2 keV through an upgrade of the 25 detection channels. The CNPA has been used on all types of MST plasmas at a rate of 20 kHz throughout the entire discharge (∼70 ms). Plasma parameter scans show that the ion distribution is most dependent on the plasma current. Magnetic reconnection events throughout these scans produce stronger poloidal electric fields, stronger global magnetic modes, and larger changes in magnetic energy all of which heavily influence the non-Maxwellian part of the ion distribution (the fast ion tail)

  12. Nonlinear coupling of tearing fluctuations in the Madison Symmetric Torus

    SciTech Connect (OSTI)

    Sarff, J.S.; Almagri, A.F.; Cekic, M.; Den Hartog, D.J.; Fiksel, G.; Hokin, S.A.; Ji, H.; Prager, S.C.; Shen, W.; Stoneking, M.R.; Assadi, S.; Sidikman, K.L.

    1992-11-01

    Three-wave, nonlinear, tearing mode coupling has been measured in the Madison Symmetric Torus (MST) reversed-field pinch (RFP) [Fusion Technol. 19, 131 (1991)] using bispectral analysis of edge magnetic fluctuations resolved in ``k-space. The strength of nonlinear three-wave interactions satisfying the sum rules m{sub 1} + m{sub 2} = m{sub 3} and n{sub 1} + n{sub 2} = n{sub 3} is measured by the bicoherency. In the RFP, m=l, n{approximately}2R/a (6 for MST) internally resonant modes are linearly unstable and grow to large amplitude. Large values of bicoherency occur for two m=l modes coupled to an m=2 mode and the coupling of intermediate toroidal modes, e.g., n=6 and 7 coupled to n=13. These experimental bispectral features agree with predicted bispectral features derived from MHD computation. However, in the experiment, enhanced coupling occurs in the ``crash`` phase of a sawtooth oscillation concomitant with a broadened mode spectrum suggesting the onset of a nonlinear cascade.

  13. Nonlinear coupling of tearing fluctuations in the Madison Symmetric Torus

    SciTech Connect (OSTI)

    Sarff, J.S.; Almagri, A.F.; Cekic, M.; Den Hartog, D.J.; Fiksel, G.; Hokin, S.A.; Ji, H.; Prager, S.C.; Shen, W.; Stoneking, M.R. ); Assadi, S. ); Sidikman, K.L. )

    1992-11-01

    Three-wave, nonlinear, tearing mode coupling has been measured in the Madison Symmetric Torus (MST) reversed-field pinch (RFP) [Fusion Technol. 19, 131 (1991)] using bispectral analysis of edge magnetic fluctuations resolved in k-space. The strength of nonlinear three-wave interactions satisfying the sum rules m[sub 1] + m[sub 2] = m[sub 3] and n[sub 1] + n[sub 2] = n[sub 3] is measured by the bicoherency. In the RFP, m=l, n[approximately]2R/a (6 for MST) internally resonant modes are linearly unstable and grow to large amplitude. Large values of bicoherency occur for two m=l modes coupled to an m=2 mode and the coupling of intermediate toroidal modes, e.g., n=6 and 7 coupled to n=13. These experimental bispectral features agree with predicted bispectral features derived from MHD computation. However, in the experiment, enhanced coupling occurs in the crash'' phase of a sawtooth oscillation concomitant with a broadened mode spectrum suggesting the onset of a nonlinear cascade.

  14. Ideal magnetohydrodynamic equilibrium in a non-symmetric topological torus

    SciTech Connect (OSTI)

    Weitzner, Harold

    2014-02-15

    An alternative representation of an ideal magnetohydrodynamic equilibrium is developed. The representation is a variation of one given by A. Salat, Phys. Plasmas 2, 1652 (1995). The system of equations is used to study the possibility of non-symmetric equilibria in a topological torus, here an approximate rectangular parallelopiped, with periodicity in two of the three rectangular coordinates. An expansion is carried out in the deviation of pressure surfaces from planes. Resonances are manifest in the process. Nonetheless, provided the magnetic shear is small, it is shown that it is possible to select the magnetic fields and flux surfaces in such a manner that no singularities appear on resonant surfaces. One boundary surface of the parallelopiped is not arbitrary but is dependent on the equilibrium in question. A comparison of the solution sets of axisymmetric and non-axisymmetric equilibria suggests that the latter have a wider class of possible boundary shapes but more restrictive rotational transform profiles. No proof of convergence of the series is given.

  15. Reversed-field pinch studies in the Madison Symmetric Torus

    SciTech Connect (OSTI)

    Hokin, S.; Almagri, A.; Cekic, M.; Chapman, B.; Crocker, N.; Den Hartog, D.J.; Fiksel, G.; Henry, J.; Ji, H.; Prager, S.; Sarff, J.; Scime, E.; Shen, W.; Stoneking, M.; Watts, C.

    1993-04-03

    Studies of large-size (R = 1.5 m, a = 0.5 m), moderate current (I < 750 kA) reversed-field pinch (RFP) plasmas are carried out in the Madison Symmetric Torus in order to evaluate and improve RFP confinement, study general toroidal plasma MHD issues, determine the mechanism of the RFP dynamo, and measure fluctuation-induced transport and anomalous ion heating. MST confinement has been improved by reduction of magnetic field errors with correction coils in the primary circuit and reduction of impurities using boronization; high densities have been achieved with hydrogen pellet injection. MHD tearing modes with poloidal mode number m = 1 and toroidal mode numbers n = 5--7 are prevalent and nonlinearly couple to produce sudden relaxations akin to tokamak sawteeth. Edge fluctuation-induced transport has been measured with a variety of insertable probes. Ions exhibit anomalous heating, with increases of ion temperature occuring during strong MHD relaxation. The RFP dynamo has been studied with attention to various possible mechanisms, including motion-EMF drive, the Hall effect, and superthermal electrons. Initial profile control experiments have begun using insertable biased probes and plasma guns. The toroidal field capacity of MST will be upgraded during Summer, 1993 to allow low-current tokamak operation as well as improved RFP operation.

  16. Three-point spherical mirror mount

    DOE Patents [OSTI]

    Cutburth, R.W.

    1984-01-23

    A three-point spherical mirror mount for use with lasers is disclosed. The improved mirror mount is adapted to provide a pivot ring having an outer surface with at least three spaced apart mating points to engage an inner spherical surface of a support housing.

  17. Turbulent transport in the Madison Symmetric Torus reversed-field pinch

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

    transport in the Madison Symmetric Torus reversed-field pinch* T. D. Rempel,+ A. F. Almagri, S. Assadi, D. J. Den Hartog, S. A. Hokin, S. C. Prager, J. S. Sarff, W. Shen, K. L. Sidikman, C. W. Spragins, J. C. Sprott, M. R. Stoneking, and E. J. Zita University of Wisconsin, Madison, Wisconsin 53 706 (Received 22 November 1991; accepted 20 February 1992) Measurements of edge turbulence and the associated transport are ongoing in the Madison Symmetric Torus (MST) reversed-field pinch [Fusion

  18. FMEA on the superconducting torus for the Jefferson Lab 12 GeV accelerator upgrade

    SciTech Connect (OSTI)

    Ghoshal, Probir K.; Biallas, George H.; Fair, Ruben J.; Rajput-Ghoshal, Renuka; Schneider, William J.; Legg, Robert A.; Kashy, David H.; Hogan, John P.; Wiseman, Mark A.; Luongo, Cesar; Ballard, Joshua T.; Young, Glenn R.; Elouadrhiri, Latifa; Rode, Claus H.

    2015-01-16

    As part of the Jefferson Lab 12GeV accelerator upgrade project, Hall B requires two conduction cooled superconducting magnets. One is a magnet system consisting of six superconducting trapezoidal racetrack-type coils assembled in a toroidal configuration and the second is an actively shielded solenoidal magnet system consisting of 5 coils. Both magnets are to be wound with Superconducting Super Collider-36 NbTi strand Rutherford cable soldered into a copper channel. This paper describes the various failure modes in torus magnet along with the failure modes that could be experienced by the torus and its interaction with the solenoid which is located in close proximity.

  19. Polarimetric Scattering Database for Non-spherical Ice Particles...

    Office of Scientific and Technical Information (OSTI)

    Polarimetric Scattering Database for Non-spherical Ice Particles at Microwave Wavelengths Title: Polarimetric Scattering Database for Non-spherical Ice Particles at Microwave ...

  20. Method for making spherical binderless pellets

    DOE Patents [OSTI]

    Grubbs, Donald K.; Kochanowski, Andrew T.

    1983-01-01

    A method for making spherical binderless pellets using a rotating drum mixer whereby at least a portion of the particles comprising the pellets is comprised of coking coal particles.

  1. Sphericity determination using resonant ultrasound spectroscopy

    DOE Patents [OSTI]

    Dixon, Raymond D.; Migliori, Albert; Visscher, William M.

    1994-01-01

    A method is provided for grading production quantities of spherical objects, such as roller balls for bearings. A resonant ultrasound spectrum (RUS) is generated for each spherical object and a set of degenerate sphere-resonance frequencies is identified. From the degenerate sphere-resonance frequencies and known relationships between degenerate sphere-resonance frequencies and Poisson's ratio, a Poisson's ratio can be determined, along with a "best" spherical diameter, to form spherical parameters for the sphere. From the RUS, fine-structure resonant frequency spectra are identified for each degenerate sphere-resonance frequency previously selected. From each fine-structure spectrum and associated sphere parameter values an asphericity value is determined. The asphericity value can then be compared with predetermined values to provide a measure for accepting or rejecting the sphere.

  2. Sphericity determination using resonant ultrasound spectroscopy

    DOE Patents [OSTI]

    Dixon, R.D.; Migliori, A.; Visscher, W.M.

    1994-10-18

    A method is provided for grading production quantities of spherical objects, such as roller balls for bearings. A resonant ultrasound spectrum (RUS) is generated for each spherical object and a set of degenerate sphere-resonance frequencies is identified. From the degenerate sphere-resonance frequencies and known relationships between degenerate sphere-resonance frequencies and Poisson's ratio, a Poisson's ratio can be determined, along with a 'best' spherical diameter, to form spherical parameters for the sphere. From the RUS, fine-structure resonant frequency spectra are identified for each degenerate sphere-resonance frequency previously selected. From each fine-structure spectrum and associated sphere parameter values an asphericity value is determined. The asphericity value can then be compared with predetermined values to provide a measure for accepting or rejecting the sphere. 14 figs.

  3. PREPARATION OF SPHERICAL URANIUM DIOXIDE PARTICLES

    DOE Patents [OSTI]

    Levey, R.P. Jr.; Smith, A.E.

    1963-04-30

    This patent relates to the preparation of high-density, spherical UO/sub 2/ particles 80 to 150 microns in diameter. Sinterable UO/sub 2/ powder is wetted with 3 to 5 weight per cent water and tumbled for at least 48 hours. The resulting spherical particles are then sintered. The sintered particles are useful in dispersion-type fuel elements for nuclear reactors. (AEC)

  4. Developing the digital safeguard that protects the National Spherical...

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

    designed the real-time computer and software system for the DCPS. (Photo by Elle StarkmanPPPL Office of Communications) Keith Erickson designed the real-time computer and ...

  5. Preliminary Physics Motivation and Engineering Design Assessment of the National High Power Torus

    SciTech Connect (OSTI)

    Robert D. Woolley

    2009-06-11

    In April 2006, Dr. Ray Orbach, Director of the DOE Office of Science, challenged the fusion community to "propose a new facility... which will put the U.S. at the lead in world fusion science." Analysis of the gaps between expected ITER performance and the requirements of a demonstration power plant (Demo) pointed to the critical and urgent need to develop fusion-relvant plasma-material interface (PMI) solutions consistent with sustained high plasma performance. A survey of world fusion program indicated that present and planned experimental devices do not advance the PMI issue beyond ITER, and a major dedicated experimental facility is warranted. Such a facility should provide the flexibility and access needed to solve plasma boundary challenges related to divertor heat flux and particle exhaust while also developing methods to minimize hydrogenic isotope retention and remaining compatible with high plasma performance.

  6. 3D Torus Routing Engine Module for OFA OpenSM v. 1.0

    Energy Science and Technology Software Center (OSTI)

    2009-11-12

    This OpenFabrics Alliance (OFA) OpenSM routing engine module provides credit-loop-free routing while supporting two quality of service (QoS) levels for an InfiniBand fabric with a 3D torus topology. In addition it is able to route around multiple failed fabric links or a single failed fabric switch without introducing credit loops, and without changing path Service Level (SL) values granted before the failure.This OFA OpenSM routing engine module improves the operational characteristics of a parallel computermore » built using an InfiniBand fabric with a 3D torus topology. By providing two QoS levels, it allows system administrators to prevent application interprocess communication and file system communication from impacting each other. By providing the capability to route traffic around failed fabric components, it enables repair of failed components without impacting jobs running on the computer system.« less

  7. Numerical study of the Columbia high-beta device: Torus-II

    SciTech Connect (OSTI)

    Izzo, R.

    1981-01-01

    The ionization, heating and subsequent long-time-scale behavior of the helium plasma in the Columbia fusion device, Torus-II, is studied. The purpose of this work is to perform numerical simulations while maintaining a high level of interaction with experimentalists. The device is operated as a toroidal z-pinch to prepare the gas for heating. This ionization of helium is studied using a zero-dimensional, two-fluid code. It is essentially an energy balance calculation that follows the development of the various charge states of the helium and any impurities (primarily silicon and oxygen) that are present. The code is an atomic physics model of Torus-II. In addition to ionization, we include three-body and radiative recombination processes.

  8. FMEA on the superconducting torus for the Jefferson Lab 12 GeV accelerator upgrade

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

    Ghoshal, Probir K.; Biallas, George H.; Fair, Ruben J.; Rajput-Ghoshal, Renuka; Schneider, William J.; Legg, Robert A.; Kashy, David H.; Hogan, John P.; Wiseman, Mark A.; Luongo, Cesar; et al

    2015-01-16

    As part of the Jefferson Lab 12GeV accelerator upgrade project, Hall B requires two conduction cooled superconducting magnets. One is a magnet system consisting of six superconducting trapezoidal racetrack-type coils assembled in a toroidal configuration and the second is an actively shielded solenoidal magnet system consisting of 5 coils. Both magnets are to be wound with Superconducting Super Collider-36 NbTi strand Rutherford cable soldered into a copper channel. This paper describes the various failure modes in torus magnet along with the failure modes that could be experienced by the torus and its interaction with the solenoid which is located inmore » close proximity.« less

  9. Summary of TFTR (Tokamak Fusion Test Reactor) diagnostics, including JET (Joint European Torus) and JT-60

    SciTech Connect (OSTI)

    Hill, K.W.; Young, K.M.; Johnson, L.C.

    1990-05-01

    The diagnostic instrumentation on TFTR (Tokamak Fusion Test Reactor) and the specific properties of each diagnostic, i.e., number of channels, time resolution, wavelength range, etc., are summarized in tables, grouped according to the plasma parameter measured. For comparison, the equivalent diagnostic capabilities of JET (Joint European Torus) and the Japanese large tokamak, JT-60, as of late 1987 are also listed in the tables. Extensive references are given to publications on each instrument.

  10. Spherical strong-shock generation for shock-ignition inertial...

    Office of Scientific and Technical Information (OSTI)

    Spherical strong-shock generation for shock-ignition inertial fusion Citation Details In-Document Search Title: Spherical strong-shock generation for shock-ignition inertial fusion ...

  11. TORUS AND ACTIVE GALACTIC NUCLEUS PROPERTIES OF NEARBY SEYFERT GALAXIES: RESULTS FROM FITTING INFRARED SPECTRAL ENERGY DISTRIBUTIONS AND SPECTROSCOPY

    SciTech Connect (OSTI)

    Alonso-Herrero, Almudena; Ramos Almeida, Cristina; Mason, Rachel; Asensio Ramos, Andres; Rodriguez Espinosa, Jose Miguel; Perez-Garcia, Ana M.; Roche, Patrick F.; Levenson, Nancy A.; Elitzur, Moshe; Packham, Christopher; Young, Stuart; Diaz-Santos, Tanio

    2011-08-01

    We used the CLUMPY torus models and a Bayesian approach to fit the infrared spectral energy distributions and ground-based high angular resolution mid-infrared spectroscopy of 13 nearby Seyfert galaxies. This allowed us to put tight constraints on torus model parameters such as the viewing angle i, the radial thickness of the torus Y, the angular size of the cloud distribution {sigma}{sub torus}, and the average number of clouds along radial equatorial rays N{sub 0}. We found that the viewing angle i is not the only parameter controlling the classification of a galaxy into type 1 or type 2. In principle, type 2s could be viewed at any viewing angle i as long as there is one cloud along the line of sight. A more relevant quantity for clumpy media is the probability for an active galactic nucleus (AGN) photon to escape unabsorbed. In our sample, type 1s have relatively high escape probabilities, P{sub esc} {approx} 12%-44%, while type 2s, as expected, tend to have very low escape probabilities. Our fits also confirmed that the tori of Seyfert galaxies are compact with torus model radii in the range 1-6 pc. The scaling of the models to the data also provided the AGN bolometric luminosities L{sub bol}(AGN), which were found to be in good agreement with estimates from the literature. When we combined our sample of Seyfert galaxies with a sample of PG quasars from the literature to span a range of L{sub bol}(AGN) {approx} 10{sup 43}-10{sup 47} erg s{sup -1}, we found plausible evidence of the receding torus. That is, there is a tendency for the torus geometrical covering factor to be lower (f{sub 2} {approx} 0.1-0.3) at high AGN luminosities than at low AGN luminosities (f{sub 2} {approx} 0.9-1 at {approx}10{sup 43}-10{sup 44} erg s{sup -1}). This is because at low AGN luminosities the tori appear to have wider angular sizes (larger {sigma}{sub torus}) and more clouds along radial equatorial rays. We cannot, however, rule out the possibility that this is due to

  12. Afterburning in spherical premixed turbulent explosions

    SciTech Connect (OSTI)

    Bradley, D.; Lawes, M.; Scott, M.J. . Dept. of Mechanical Engineering); Mushi, E.M.J. )

    1994-12-01

    During the early stages of spherical turbulent flame propagation, more than half of the gas behind the visible flame front may be unburned. Previous models of the afterburning of the gas behind the apparent flame front have been extended in the present work, to include the effects of flame quenching, consequent upon localized flame stretch. The predictions of the model cover, the spatial and temporal variations of the fraction burned, the flame propagation rate, and the mass burning rate. They are all in dimensionless form and are well supported by associated experimental measurements in a fan-stirred bomb with controlled turbulence. The proportion of the gas that is unburned decreases with time and increases with the product of the Karlovitz stretch factor and the Lewis number. Simultaneous photographs were taken of the spherical schlieren image and of that due to Mie scattering from small seed particles in a thin laser sheet that sectioned the spherical flame. These clearly showed the amount of unburned gas within the sphere and, along with other evidence suggest laminar flamelet burning across a scale of distance which is close to the Taylor confirm the predictions of the fraction of gas unburned and of the rate at which it is burning.

  13. Magnetic reconstruction of nonaxisymmetric quasi-single-helicity configurations in the Madison Symmetric Torus

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

    reconstruction of nonaxisymmetric quasi-single-helicity configurations in the Madison Symmetric Torus This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2011 Plasma Phys. Control. Fusion 53 105006 (http://iopscience.iop.org/0741-3335/53/10/105006) Download details: IP Address: 128.104.166.218 The article was downloaded on 15/04/2013 at 17:18 Please note that terms and conditions apply. View the table of contents for this issue, or go to the journal

  14. Nonlinear coupling of tearing fluctuations in the Madison Symmetric Torus<atother>@f|</atother>

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

    coupling of tearing fluctuations in the Madison Symmetric Torus* J. S. Sarff,? S. Assadi,a) A. F. Almagri, M. Cekic, D. J. Den Hat-tog, G. Fiksel, S. A. Hokin, H. Ji, S. C. Prager, W. Shen, K. L. Sidikman,b) and M. R. Stoneking University of Wisconsin, Madison, Wisconsin 53 706 (Received 9 December 1992; accepted 21 December 1992) Three-wave, nonlinear, tearing mode coupling has been measured in the Madison Symmetric Torus (MST) reversed-field pinch (RFP) [Fusion Technol. 19, 131 ( 1991)] using

  15. TORUS: Theory of Reactions for Unstable iSotopes - Year 1 Continuation and Progress Report

    SciTech Connect (OSTI)

    Arbanas, G; Elster, C; Escher, J; Mukhamedzhanov, A; Nunes, F; Thompson, I J

    2011-02-24

    The TORUS collaboration derives its name from the research it focuses on, namely the Theory of Reactions for Unstable iSotopes. It is a Topical Collaboration in Nuclear Theory, and funded by the Nuclear Theory Division of the Office of Nuclear Physics in the Office of Science of the Department of Energy. The funding started on June 1, 2010, it will have been running for nine months by the date of submission of this Annual Continuation and Progress Report on March 1, 2011. The extent of funding was reduced from the original application, and now supports one postdoctoral researcher for the years 1 through 3. The collaboration brings together as Principal Investigators a large fraction of the nuclear reaction theorists currently active within the USA. The mission of the TORUS Topical Collaboration is to develop new methods that will advance nuclear reaction theory for unstable isotopes by using three-body techniques to improve direct-reaction calculations, and, by using a new partial-fusion theory, to integrate descriptions of direct and compound-nucleus reactions. This multi-institution collaborative effort is directly relevant to three areas of interest: the properties of nuclei far from stability; microscopic studies of nuclear input parameters for astrophysics, and microscopic nuclear reaction theory.

  16. An Engineering Evaluation of Spherical Resorcinol Formaldehyde Resin

    SciTech Connect (OSTI)

    Birdwell Jr, Joseph F; Lee, Denise L; Taylor, Paul Allen; Collins, Robert T; Hunt, Rodney Dale

    2010-09-01

    A small column ion exchange (SCIX) system has been proposed for removal of cesium from caustic, supernatant, and dissolved salt solutions stored or generated from high-level tank wastes at the US Department of Energy (DOE) Hanford Site and Savannah River Sites. In both instances, deployment of SCIX systems, either in-tank or near-tank, is a means of expediting waste pretreatment and dispositioning with minimal or no new infrastructure requirements. Conceptually, the treatment approach can utilize a range of ion exchange media. Previously, both crystalline silicotitanate (CST), an inorganic, nonelutable sorbent, and resorcinol-formaldehyde (RF), an organic, elutable resin, have been considered for cesium removal from tank waste. More recently, Pacific Northwest National Laboratory (PNNL) evaluated use of SuperLig{reg_sign} 644, an elutable ion exchange medium, for the subject application. Results of testing indicate hydraulic limitations of the SuperLig{reg_sign} resin, specifically a high pressure drop through packed ion exchange columns. This limitation is likely the result of swelling and shrinkage of the irregularly shaped (granular) resin during repeated conversions between sodium and hydrogen forms as the resin is first loaded then eluted. It is anticipated that a similar flow limitation would exist in columns packed with conventional, granular RF resin. However, use of spherical RF resin is a likely means of mitigating processing limitations due to excessive pressure drop. Although size changes occur as the spherical resin is cycled through loading and elution operations, the geometry of the resin is expected to effectively mitigate the close packing that leads to high pressure drops across ion exchange columns. Multiple evaluations have been performed to determine the feasibility of using spherical RF resin and to obtain data necessary for design of an SCIX process. The work performed consisted of examination of radiation effects on resin performance

  17. Local Scrape-Off Layer Control Using Biased electrodes in NSTX...

    Office of Scientific and Technical Information (OSTI)

    Title: Local Scrape-Off Layer Control Using Biased electrodes in NSTX An experiment was ... near the outer midplane in the SOL of the National Spherical Torus Experiment (NSTX). ...

  18. Full toroidal imaging of non-axisymmetric plasma material interaction...

    Office of Scientific and Technical Information (OSTI)

    eXperiment divertor Citation Details In-Document Search Title: Full toroidal imaging of non-axisymmetric plasma material interaction in the National Spherical Torus eXperiment ...

  19. Frelinghuysen, Holt visit PPPL to report on bipartisan efforts...

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

    U.S. Rep. Rush Holt (D-NJ-12), Plainsboro Mayor Peter Cantu, and PPPL Director Stewart Prager next to the National Spherical Torus Experiment (NSTX) during a June 13 visit...

  20. DOE Policy for Digital Research Data Management: Resources at...

    Energy Savers [EERE]

    Facility Host Institution Data Management Resources DIII-D General Atomics Link National Spherical Torus Experiment (NSTX) PPPL Link Alcator C-Mod MIT Link High Energy Physics (HEP...

  1. Divertor Heat Flux Mitigation in High-Performance H-mode Plasmas...

    Office of Scientific and Technical Information (OSTI)

    H-mode Plasmas in the National Spherical Torus Experiment. Citation Details In-Document Search Title: Divertor Heat Flux Mitigation in High-Performance H-mode Plasmas ...

  2. Quasi-spherical direct drive fusion.

    SciTech Connect (OSTI)

    VanDevender, J. Pace; Abbott, Lucas M.; Langston, William L.; McDaniel, Dillon Heirman; Nash, Thomas J.; Roderick, Norman Frederick; Silva, M.

    2007-01-01

    The authors present designs of quasi-spherical direction drive z-pinch loads for machines such as ZR at 28 MA load current with a 150 ns implosion time (QSDDI). A double shell system for ZR has produced a 2D simulated yield of 12 MJ, but the drive for this system on ZR has essentially no margin. A double shell system for a 56 MA driver at 150 ns implosion has produced a simulated yield of 130 MJ with considerable margin in attaining the necessary temperature and density-radius product for ignition. They also represent designs for a magnetically insulated current amplifier, (MICA), that modify the attainable ZR load current to 36 MA with a 28 ns rise time. The faster pulse provided by a MICA makes it possible to drive quasi-spherical single shell implosions (QSDD2). They present results from 1D LASNEX and 2D MACH2 simulations of promising low-adiabat cryogenic QSDD2 capsules and 1D LASNEX results of high-adiabat cryogenic QSDD2 capsules.

  3. Understanding pop-ins in spherical nanoindentation

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

    Pathak, Siddhartha; Riesterer, Jessica L.; Kalidindi, Surya R.; Michler, Johann

    2014-10-24

    In this study, pop-ins, or sudden displacement-bursts at constant load in a nanoindentation test, are typically attributed to the difficulty of setting up potent dislocation sources in the very small indentation zones in these experiments. Such displacement (and strain) bursts would intuitively indicate a sharp drop in stress during the pop-in event itself. However, spherical indentation stress-strain curves routinely exhibit a high and stable indentation stress value during the pop-in, and the indentation stresses decrease only after a further finite amount of additional indentation displacement has been applied. In order to understand this discrepancy, we utilize a combination of interruptedmore » spherical indentation tests along with depth profiling of the residual indentation surfaces using in-situ atomic force microscopy (AFM) to study pop-ins. The AFM surface profile maps show that there is an asymmetric profile change over a limited region around the indentation contact area for a single pop-in; the asymmetry disappears upon further loading beyond the pop-in. A plausible sequence of physical processes (related to metal plasticity) occurring underneath the indenter during and immediately after the occurrence of the pop-in is proposed to explain these observations.« less

  4. A Snowflake-Shaped Magnetic Field Holds Promise for Taming Harsh Fusion

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

    Plasmas | Princeton Plasma Physics Lab A Snowflake-Shaped Magnetic Field Holds Promise for Taming Harsh Fusion Plasmas Recent experiments have confirmed the great potential of a novel plasma-material interface concept. By U.S Department of Energy Office of Science October 31, 2012 Tweet Widget Google Plus One Share on Facebook National Spherical Torus Experiment (Photo by Elle Starkman, Office of Communications, PPPL) National Spherical Torus Experiment The Science Heat escaping from the

  5. Praise and suggestions for fusion research from a utility industry think

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

    tank | Princeton Plasma Physics Lab Praise and suggestions for fusion research from a utility industry think tank By John Greenwald November 21, 2012 Tweet Widget Google Plus One Share on Facebook Interior of the National Spherical Torus Experiment at PPPL. (Photo by Elle Starkman, Office of Communications, PPPL) Interior of the National Spherical Torus Experiment at PPPL. Research to develop fusion energy has shown "significant progress" in many areas, according to a new report

  6. Construction completed, PPPL is set to resume world-class fusion research

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

    later this fall | Princeton Plasma Physics Lab Construction completed, PPPL is set to resume world-class fusion research later this fall By John Greenwald October 6, 2015 Tweet Widget Google Plus One Share on Facebook Staffers who worked on the National Spherical Torus Experiment-Upgrade. (Photo by Elle Starkman/Office of Communications) Staffers who worked on the National Spherical Torus Experiment-Upgrade. Gallery: Technicians inspect the new center stack that forms the heart of the

  7. Construction completed, PPPL is set to resume world-class fusion research |

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

    Princeton Plasma Physics Lab Construction completed, PPPL is set to resume world-class fusion research By John Greenwald September 25, 2015 Tweet Widget Google Plus One Share on Facebook Staffers who worked on the National Spherical Torus Experiment-Upgrade. (Photo by Elle Starkman/Office of Communications) Staffers who worked on the National Spherical Torus Experiment-Upgrade. Gallery: Technicians inspect the new center stack that forms the heart of the NSTX-U. (Photo by PPPL) Technicians

  8. Imaging with Spherically Bent Crystals or Reflectors (Technical Report) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Technical Report: Imaging with Spherically Bent Crystals or Reflectors Citation Details In-Document Search Title: Imaging with Spherically Bent Crystals or Reflectors This paper consists of two parts: Part I describes the working principle of a recently developed x-ray imaging crystal spectrometer, where the astigmatism of spherically bent crystals is being used with advantage to record spatially resolved spectra of highly charged ions for Doppler measurements of the

  9. Reverberation measurements of the inner radius of the dust torus in 17 Seyfert galaxies

    SciTech Connect (OSTI)

    Koshida, Shintaro; Minezaki, Takeo; Yoshii, Yuzuru; Sakata, Yu; Sugawara, Shota; Kobayashi, Yukiyasu; Suganuma, Masahiro; Enya, Keigo; Tomita, Hiroyuki; Aoki, Tsutomu; Peterson, Bruce A. E-mail: minezaki@ioa.s.u-tokyo.ac.jp

    2014-06-20

    We present the results of a dust reverberation survey for 17 nearby Seyfert 1 galaxies, which provides the largest homogeneous data collection for the radius of the innermost dust torus. A delayed response of the K-band light curve after the V-band light curve was found for all targets, and 49 measurements of lag times between the flux variation of the dust emission in the K band and that of the optical continuum emission in the V band were obtained by the cross-correlation function analysis and also by an alternative method for estimating the maximum likelihood lag. The lag times strongly correlated with the optical luminosity in the luminosity range of M{sub V} = –16 to –22 mag, and the regression analysis was performed to obtain the correlation log Δt (days) = –2.11 – 0.2 M{sub V} assuming Δt∝L {sup 0.5}, which was theoretically expected. We discuss the possible origins of the intrinsic scatter of the dust lag-luminosity correlation, which was estimated to be approximately 0.13 dex, and we find that the difference of internal extinction and delayed response of changes in lag times to the flux variations could have partly contributed to intrinsic scatter. However, we could not detect any systematic change of the correlation with the subclass of the Seyfert type or the Eddington ratio. Finally, we compare the dust reverberation radius with the near-infrared interferometric radius of the dust torus and the reverberation radius of broad Balmer emission lines. The interferometric radius in the K band was found to be systematically larger than the dust reverberation radius in the same band by the about a factor of two, which could be interpreted by the difference between the flux-weighted radius and response-weighted radius of the innermost dust torus. The reverberation radius of the broad Balmer emission lines was found to be systematically smaller than the dust reverberation radius by about a factor of four to five, which strongly supports the unified

  10. Super- and sub-Einstein intrinsic viscosities of spherical nanoparticl...

    Office of Scientific and Technical Information (OSTI)

    Super- and sub-Einstein intrinsic viscosities of spherical nanoparticles in concentrated low molecular weight polymer solutions Citation Details In-Document Search Title: Super- ...

  11. Measurement of reflectivity of spherically bent crystals using...

    Office of Scientific and Technical Information (OSTI)

    laser-matter interaction Citation Details In-Document Search Title: Measurement of reflectivity of spherically bent crystals using K signal from hot electrons produced by laser-...

  12. Containment of explosions in spherical vessels

    SciTech Connect (OSTI)

    Duffey, T.A.; Greene, J.M. ); Baker, W.E. . Dept. of Mechanical Engineering); Lewis, B.B. )

    1992-01-01

    A correlation of the experimentally recorded dynamic response of a spherical containment vessel with theoretical finite element calculations is presented. Three experiments were performed on the 6-ft-diameter steel vessel using centrally located 12-lb. and 40-lb. high explosive charges. Pressure-time loading on the inner wall of the vessel was recorded for each test using pressure transducers. Resulting dynamic response of the vessel was recorded for each test using strain gages mounted at selected locations on the outer surface of the vessel. Response of the vessel was primarily elastic. A finite element model of the vessel was run using DYNA3D, a dynamic structural analysis code. Pressure loading for the finite element model was based on results from a one-dimensional reactive hydrodynamics code. Correlations between experiments and analysis were generally good for the tests for frequency and strain magnitude at most locations. Comparisons of experimental and calculated pressure-time histories were less satisfactory.

  13. Containment of explosions in spherical vessels

    SciTech Connect (OSTI)

    Duffey, T.A.; Greene, J.M.; Baker, W.E.; Lewis, B.B.

    1992-12-31

    A correlation of the experimentally recorded dynamic response of a spherical containment vessel with theoretical finite element calculations is presented. Three experiments were performed on the 6-ft-diameter steel vessel using centrally located 12-lb. and 40-lb. high explosive charges. Pressure-time loading on the inner wall of the vessel was recorded for each test using pressure transducers. Resulting dynamic response of the vessel was recorded for each test using strain gages mounted at selected locations on the outer surface of the vessel. Response of the vessel was primarily elastic. A finite element model of the vessel was run using DYNA3D, a dynamic structural analysis code. Pressure loading for the finite element model was based on results from a one-dimensional reactive hydrodynamics code. Correlations between experiments and analysis were generally good for the tests for frequency and strain magnitude at most locations. Comparisons of experimental and calculated pressure-time histories were less satisfactory.

  14. Fivefold confinement time increase in the Madison Symmetric Torus using inductive poloidal current drive

    SciTech Connect (OSTI)

    Stoneking, M.R.; Lanier, N.E.; Prager, S.C.; Sarff, J.S.; Sinitsyn, D.

    1996-12-01

    Current profile control is employed in the Madison Symmetric Torus reversed field pinch to reduce the magnetic fluctuations responsible for anomalous transport. An inductive poloidal electric field pulse is applied in the sense to flatten the parallel current profile, reducing the dynamo fluctuation amplitude required to sustain the equilibrium. This technique demonstrates a substantial reduction in fluctuation amplitude (as much as 50%), and improvement in energy confinement (from 1 ms to 5 ms); a record low fluctuation (0.8%) and record high temperature (615 eV) for this device were observed simultaneously during current drive experiments. Plasma beta increases by 50% and the Ohmic input power is three times lower. Particle confinement improves and plasma impurity contamination is reduced. The results of the transient current drive experiments provide motivation for continuing development of steady-state current profile control strategies for the reversed field pinch.

  15. Sextupole system for the correction of spherical aberration

    DOE Patents [OSTI]

    Crewe, A.V.; Kopf, D.A.

    In an electron beam device in which an electron beam is developed and then focused by a lens to a particular spot, there is provided a means for eliminating spherical aberration. A sextupole electromagnetic lens is positioned between two focusing lenses. The interaction of the sextupole with the beam compensates for spherical aberration. (GHT)

  16. Spherical nanoindentation stress–strain curves

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

    Pathak, Siddhartha; Kalidindi, Surya R.

    2015-03-24

    Although indentation experiments have long been used to measure the hardness and Young's modulus, the utility of this technique in analyzing the complete elastic–plastic response of materials under contact loading has only been realized in the past few years – mostly due to recent advances in testing equipment and analysis protocols. This paper provides a timely review of the recent progress made in this respect in extracting meaningful indentation stress–strain curves from the raw datasets measured in instrumented spherical nanoindentation experiments. These indentation stress–strain curves have produced highly reliable estimates of the indentation modulus and the indentation yield strength inmore » the sample, as well as certain aspects of their post-yield behavior, and have been critically validated through numerical simulations using finite element models as well as direct in situ scanning electron microscopy (SEM) measurements on micro-pillars. Much of this recent progress was made possible through the introduction of a new measure of indentation strain and the development of new protocols to locate the effective zero-point of initial contact between the indenter and the sample in the measured datasets. As a result, this has led to an important key advance in this field where it is now possible to reliably identify and analyze the initial loading segment in the indentation experiments.« less

  17. Spherical nanoindentation stress–strain curves

    SciTech Connect (OSTI)

    Pathak, Siddhartha; Kalidindi, Surya R.

    2015-03-24

    Although indentation experiments have long been used to measure the hardness and Young's modulus, the utility of this technique in analyzing the complete elastic–plastic response of materials under contact loading has only been realized in the past few years – mostly due to recent advances in testing equipment and analysis protocols. This paper provides a timely review of the recent progress made in this respect in extracting meaningful indentation stress–strain curves from the raw datasets measured in instrumented spherical nanoindentation experiments. These indentation stress–strain curves have produced highly reliable estimates of the indentation modulus and the indentation yield strength in the sample, as well as certain aspects of their post-yield behavior, and have been critically validated through numerical simulations using finite element models as well as direct in situ scanning electron microscopy (SEM) measurements on micro-pillars. Much of this recent progress was made possible through the introduction of a new measure of indentation strain and the development of new protocols to locate the effective zero-point of initial contact between the indenter and the sample in the measured datasets. As a result, this has led to an important key advance in this field where it is now possible to reliably identify and analyze the initial loading segment in the indentation experiments.

  18. Spherical nanoindentation stressstrain curves

    SciTech Connect (OSTI)

    Pathak, Siddhartha; Kalidindi, Surya R.

    2015-03-24

    Although indentation experiments have long been used to measure the hardness and Young's modulus, the utility of this technique in analyzing the complete elasticplastic response of materials under contact loading has only been realized in the past few years mostly due to recent advances in testing equipment and analysis protocols. This paper provides a timely review of the recent progress made in this respect in extracting meaningful indentation stressstrain curves from the raw datasets measured in instrumented spherical nanoindentation experiments. These indentation stressstrain curves have produced highly reliable estimates of the indentation modulus and the indentation yield strength in the sample, as well as certain aspects of their post-yield behavior, and have been critically validated through numerical simulations using finite element models as well as direct in situ scanning electron microscopy (SEM) measurements on micro-pillars. Much of this recent progress was made possible through the introduction of a new measure of indentation strain and the development of new protocols to locate the effective zero-point of initial contact between the indenter and the sample in the measured datasets. As a result, this has led to an important key advance in this field where it is now possible to reliably identify and analyze the initial loading segment in the indentation experiments.

  19. Observational evidence of torus instability as trigger mechanism for coronal mass ejections: The 2011 August 4 filament eruption

    SciTech Connect (OSTI)

    Zuccarello, F. P.; Poedts, S.; Seaton, D. B.; Mierla, M.; Rachmeler, L. A.; Romano, P.; Zuccarello, F. E-mail: Stefaan.Poedts@wis.kuleuven.be E-mail: marilena@oma.be E-mail: Paolo.Romano@oact.inaf.it

    2014-04-20

    Solar filaments are magnetic structures often observed in the solar atmosphere and consist of plasma that is cooler and denser than their surroundings. They are visible for dayseven weekswhich suggests that they are often in equilibrium with their environment before disappearing or erupting. Several eruption models have been proposed that aim to reveal what mechanism causes (or triggers) these solar eruptions. Validating these models through observations represents a fundamental step in our understanding of solar eruptions. We present an analysis of the observation of a filament eruption that agrees with the torus instability model. This model predicts that a magnetic flux rope embedded in an ambient field undergoes an eruption when the axis of the flux rope reaches a critical height that depends on the topology of the ambient field. We use the two vantage points of the Solar Dynamics Observatory (SDO) and the Solar TErrestrial RElations Observatory to reconstruct the three-dimensional shape of the filament, to follow its morphological evolution, and to determine its height just before eruption. The magnetograms acquired by SDO/Helioseismic and Magnetic Imager are used to infer the topology of the ambient field and to derive the critical height for the onset of the torus instability. Our analysis shows that the torus instability is the trigger of the eruption. We also find that some pre-eruptive processes, such as magnetic reconnection during the observed flares and flux cancellation at the neutral line, facilitated the eruption by bringing the filament to a region where the magnetic field was more vulnerable to the torus instability.

  20. Spherical gravitational collapse in N dimensions

    SciTech Connect (OSTI)

    Goswami, Rituparno; Joshi, Pankaj S.

    2007-10-15

    We investigate here spherically symmetric gravitational collapse in a space-time with an arbitrary number of dimensions and with a general type I matter field, which is a broad class that includes most of the physically reasonable matter forms. We show that given the initial data for matter in terms of the initial density and pressure profiles at an initial surface t=t{sub i} from which the collapse evolves, there exist the rest of the initial data functions and classes of solutions of Einstein equations which we construct here, such that the space-time evolution goes to a final state which is either a black hole or a naked singularity, depending on the nature of initial data and evolutions chosen, and subject to validity of the weak energy condition. The results are discussed and analyzed in the light of the cosmic censorship hypothesis in black hole physics. The formalism here combines the earlier results on gravitational collapse in four dimensions in a unified treatment. Also the earlier work is generalized to higher-dimensional space-times to allow a study of the effect of the number of dimensions on the possible final outcome of the collapse in terms of either a black hole or naked singularity. No restriction is adopted on the number of dimensions, and other limiting assumptions such as self-similarity of space-time are avoided, in order to keep the treatment general. Our methodology allows us to consider to an extent the genericity and stability aspects related to the occurrence of naked singularities in gravitational collapse.

  1. Jonathan E Menard | Princeton Plasma Physics Lab

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

    Jonathan E Menard Principal Research Physicst, Program Director for NSTX Jonathan Menard is program director for the National Spherical Torus Experiment-Upgrade (NSTX-U) and is responsible for guiding the scientific research program of NSTX-U working with an international research team. His research interests include the magnetohydrodynamic (MHD) equilibrium and stability properties of spherical torus (ST) and tokamak plasmas, advanced operating scenarios in the ST, and the development of next-

  2. Spherical rotary valve assembly for an internal combustion engine

    SciTech Connect (OSTI)

    Coates, G.J.

    1991-02-05

    This patent describes an improved rotary intake valve for use in a rotary valved internal combustion engine. It comprises: a drum body of spherical section formed by two parallel planar side walls of a sphere disposed about a center thereof thereby defining a spherically-shaped end wall and formed with a shaft receiving aperture, the drum body formed with a circularly-shaped cavity in a side wall thereof and with a channel extending between the circularly-shaped cavity and an aperture formed in the spherically-shaped end wall.

  3. Gigabar Spherical Shock Generation on the OMEGA Laser (Journal...

    Office of Scientific and Technical Information (OSTI)

    Using the temporal delay between the launching of the strong shock at the outer surface of the spherical target and the time when the shock converges at the center, the ...

  4. Resonant-like behaviour during edge-localised mode cycles in the Joint European Torus

    SciTech Connect (OSTI)

    Webster, A. J.; Morris, J.; Todd, T. N.; Coad, P.; Brezinsek, S.; Likonen, J.; Rubel, M.; Collaboration: JET-EFDA Contributors

    2015-08-15

    A unique sequence of 120 almost identical plasmas in the Joint European Torus (JET) recently provided two orders of magnitude more statistically equivalent data than ever previously available. The purpose was to study movement of eroded plasma-facing material from JET's new Beryllium wall, but it has allowed the statistical detection of otherwise unobservable phenomenon. This includes a sequence of resonant-like waiting times between edge-localised plasma instabilities (ELMs), instabilities that must be mitigated or avoided in large magnetically confined plasmas such as those planned for ITER. Here, we investigate the cause of this phenomenon, using the unprecedented quantity of data to produce a detailed picture of the plasma's behaviour. After combining the data, oscillations are clearly observable in the plasma's vertical position, in edge losses of ions, and in Beryllium II (527 nm) light emissions. The oscillations are unexpected, are not obvious in data from a single pulse alone, and are all clearly correlated with each other. They are likely to be caused by a small vertical oscillation that the plasma control system is not reacting to prevent, but a more complex explanation is possible. The clearly observable but unexpected link between small changes in the plasma's position and changes to edge-plasma transport and stability suggest that these characteristics cannot always be studied in isolation. It also suggests new opportunities for ELM mitigation and control that may exist.

  5. Method to produce large, uniform hollow spherical shells

    DOE Patents [OSTI]

    Hendricks, Charles D. (Livermore, CA)

    1985-01-01

    Large, uniform hollow spherical shells are produced by forming uniform size drops of heat decomposable or vaporizable material, evaporating the drops to form dried particles, coating the dried particles with a layer of shell forming material, and heating the composite particles to melt the outer layer and decompose or vaporize the inner particle to form an expanding inner gas bubble which expands the outer layer. By cycling the temperature and pressure on the hollow shells, spherical shells with uniform walls are produced.

  6. X-ray interferometry with spherically bent crystals (abstract)

    SciTech Connect (OSTI)

    Koch, Jeffrey A.

    2001-01-01

    Recent progress in manufacturing high-quality spherically bent crystals allows highly monochromatic x-ray beams to be produced, and allows efficient x-ray imaging with {mu}m-scale resolution. This article explores some of the constraints for x-ray interferometry utilizing spherically bent crystals and laser-produced plasma sources, and discusses several shearing interferometer concepts that might be experimentally investigated.

  7. Spherical grating based x-ray Talbot interferometry

    SciTech Connect (OSTI)

    Cong, Wenxiang E-mail: xiy2@rpi.edu Xi, Yan E-mail: xiy2@rpi.edu Wang, Ge E-mail: xiy2@rpi.edu

    2015-11-15

    Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and

  8. Magnetohydrodynamic modes analysis and control of Fusion Advanced Studies Torus high-current scenarios

    SciTech Connect (OSTI)

    Villone, F.; Mastrostefano, S.; Calabrò, G.; Vlad, G.; Crisanti, F.; Fusco, V.; Marchiori, G.; Bolzonella, T.; Marrelli, L.; Martin, P.; Liu, Y. Q.

    2014-08-15

    One of the main FAST (Fusion Advanced Studies Torus) goals is to have a flexible experiment capable to test tools and scenarios for safe and reliable tokamak operation, in order to support ITER and help the final DEMO design. In particular, in this paper, we focus on operation close to a possible border of stability related to low-q operation. To this purpose, a new FAST scenario has then been designed at I{sub p} = 10 MA, B{sub T} = 8.5 T, q{sub 95} ≈ 2.3. Transport simulations, carried out by using the code JETTO and the first principle transport model GLF23, indicate that, under these conditions, FAST could achieve an equivalent Q ≈ 3.5. FAST will be equipped with a set of internal active coils for feedback control, which will produce magnetic perturbation with toroidal number n = 1 or n = 2. Magnetohydrodynamic (MHD) mode analysis and feedback control simulations performed with the codes MARS, MARS-F, CarMa (both assuming the presence of a perfect conductive wall and using the exact 3D resistive wall structure) show the possibility of the FAST conductive structures to stabilize n = 1 ideal modes. This leaves therefore room for active mitigation of the resistive mode (down to a characteristic time of 1 ms) for safety purposes, i.e., to avoid dangerous MHD-driven plasma disruption, when working close to the machine limits and magnetic and kinetic energy density not far from reactor values.

  9. Spherical boron nitride particles and method for preparing them

    DOE Patents [OSTI]

    Phillips, Jonathan; Gleiman, Seth S.; Chen, Chun-Ku

    2003-11-25

    Spherical and polyhedral particles of boron nitride and method of preparing them. Spherical and polyhedral particles of boron nitride are produced from precursor particles of hexagonal phase boron nitride suspended in an aerosol gas. The aerosol is directed to a microwave plasma torch. The torch generates plasma at atmospheric pressure that includes nitrogen atoms. The presence of nitrogen atoms is critical in allowing boron nitride to melt at atmospheric pressure while avoiding or at least minimizing decomposition. The plasma includes a plasma hot zone, which is a portion of the plasma that has a temperature sufficiently high to melt hexagonal phase boron nitride. In the hot zone, the precursor particles melt to form molten particles that acquire spherical and polyhedral shapes. These molten particles exit the hot zone, cool, and solidify to form solid particles of boron nitride with spherical and polyhedral shapes. The molten particles can also collide and join to form larger molten particles that lead to larger spherical and polyhedral particles.

  10. OBTAINING POTENTIAL FIELD SOLUTIONS WITH SPHERICAL HARMONICS AND FINITE DIFFERENCES

    SciTech Connect (OSTI)

    Toth, Gabor; Van der Holst, Bart; Huang Zhenguang

    2011-05-10

    Potential magnetic field solutions can be obtained based on the synoptic magnetograms of the Sun. Traditionally, a spherical harmonics decomposition of the magnetogram is used to construct the current- and divergence-free magnetic field solution. This method works reasonably well when the order of spherical harmonics is limited to be small relative to the resolution of the magnetogram, although some artifacts, such as ringing, can arise around sharp features. When the number of spherical harmonics is increased, however, using the raw magnetogram data given on a grid that is uniform in the sine of the latitude coordinate can result in inaccurate and unreliable results, especially in the polar regions close to the Sun. We discuss here two approaches that can mitigate or completely avoid these problems: (1) remeshing the magnetogram onto a grid with uniform resolution in latitude and limiting the highest order of the spherical harmonics to the anti-alias limit; (2) using an iterative finite difference algorithm to solve for the potential field. The naive and the improved numerical solutions are compared for actual magnetograms and the differences are found to be rather dramatic. We made our new Finite Difference Iterative Potential-field Solver (FDIPS) a publicly available code so that other researchers can also use it as an alternative to the spherical harmonics approach.

  11. Elmo Bumpy Torus proof of principle, Phase II: Title 1 report. Volume V. Vacuum-pumping system. Preliminary design report

    SciTech Connect (OSTI)

    Not Available

    1982-02-26

    This report summarizes Title I Preliminary Design of the EBT-P Vacuum Pumping System. The Vacuum Pumping System has been designed by the McDonnell Douglas Astronautics Co. - St. Louis (MDAC). It includes the necessary vacuum pumps and vacuum valves to evacuate the torus, the Mirror Coil Dewars (MC Dewars), and the Gyrotron Magnet Dewars. The pumping ducts, manifolds, and microwave protection system are also included. A summary of the function of each subsystem and a description of its principle components is provided below. The analyses performed during the system design are also identified.

  12. Identification and mitigation of stray laser light in the Thomson scattering system on the Madison Symmetric Torus (MST)

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

    and mitigation of stray laser light in the Thomson scattering system on the Madison Symmetric Torus (MST) C. M. Jacobson, M. T. Borchardt, D. J. Den Hartog, A. F. Falkowski, L. A. Morton, and M. A. Thomas Citation: Review of Scientific Instruments 87, 11E511 (2016); doi: 10.1063/1.4960063 View online: http://dx.doi.org/10.1063/1.4960063 View Table of Contents: http://scitation.aip.org/content/aip/journal/rsi/87/11?ver=pdfcov Published by the AIP Publishing Articles you may be interested in A

  13. Embedding global barrier and collective in torus network with each node combining input from receivers according to class map for output to senders

    DOE Patents [OSTI]

    Chen, Dong; Coteus, Paul W; Eisley, Noel A; Gara, Alan; Heidelberger, Philip; Senger, Robert M; Salapura, Valentina; Steinmacher-Burow, Burkhard; Sugawara, Yutaka; Takken, Todd E

    2013-08-27

    Embodiments of the invention provide a method, system and computer program product for embedding a global barrier and global interrupt network in a parallel computer system organized as a torus network. The computer system includes a multitude of nodes. In one embodiment, the method comprises taking inputs from a set of receivers of the nodes, dividing the inputs from the receivers into a plurality of classes, combining the inputs of each of the classes to obtain a result, and sending said result to a set of senders of the nodes. Embodiments of the invention provide a method, system and computer program product for embedding a collective network in a parallel computer system organized as a torus network. In one embodiment, the method comprises adding to a torus network a central collective logic to route messages among at least a group of nodes in a tree structure.

  14. Method to produce large, uniform hollow spherical shells

    DOE Patents [OSTI]

    Hendricks, C.D.

    1983-09-26

    The invention is a method to produce large uniform hollow spherical shells by (1) forming uniform size drops of heat decomposable or vaporizable material, (2) evaporating the drops to form dried particles, (3) coating the dried particles with a layer of shell forming material and (4) heating the composite particles to melt the outer layer and to decompose or vaporize the inner particle to form an expanding inner gas bubble. The expanding gas bubble forms the molten outer layer into a shell of relatively large diameter. By cycling the temperature and pressure on the molten shell, nonuniformities in wall thickness can be reduced. The method of the invention is utilized to produce large uniform spherical shells, in the millimeter to centimeter diameter size range, from a variety of materials and of high quality, including sphericity, concentricity and surface smoothness, for use as laser fusion or other inertial confinement fusion targets as well as other applications.

  15. Plastic instabilities in statically and dynamically loaded spherical vessels

    SciTech Connect (OSTI)

    Duffey, Thomas A; Rodriguez, Edward A

    2010-01-01

    Significant changes were made in design limits for pressurized vessels in the 2007 version of the ASME Code (Section VIII, Div. 3) and 2008 and 2009 Addenda. There is now a local damage-mechanics based strain-exhaustion limit as well as the well-known global plastic collapse limit. Moreover, Code Case 2564 (Section VIII, Div. 3) has recently been approved to address impulsively loaded vessels. It is the purpose of this paper to investigate the plastic collapse limit as it applies to dynamically loaded spherical vessels. Plastic instabilities that could potentially develop in spherical shells under symmetric loading conditions are examined for a variety of plastic constitutive relations. First, a literature survey of both static and dynamic instabilities associated with spherical shells is presented. Then, a general plastic instability condition for spherical shells subjected to displacement controlled and impulsive loading is given. This instability condition is evaluated for six plastic and visco-plastic constitutive relations. The role of strain-rate sensitivity on the instability point is investigated. Calculations for statically and dynamically loaded spherical shells are presented, illustrating the formation of instabilities as well as the role of imperfections. Conclusions of this work are that there are two fundamental types of instabilities associated with failure of spherical shells. In the case of impulsively loaded vessels, where the pulse duration is short compared to the fundamental period of the structure, one instability type is found not to occur in the absence of static internal pressure. Moreover, it is found that the specific role of strain-rate sensitivity on the instability strain depends on the form of the constitutive relation assumed.

  16. Quantum nonlocal effects on optical properties of spherical nanoparticles

    SciTech Connect (OSTI)

    Moradi, Afshin

    2015-02-15

    To study the scattering of electromagnetic radiation by a spherical metallic nanoparticle with quantum spatial dispersion, we develop the standard nonlocal Mie theory by allowing for the excitation of the quantum longitudinal plasmon modes. To describe the quantum nonlocal effects, we use the quantum longitudinal dielectric function of the system. As in the standard Mie theory, the electromagnetic fields are expanded in terms of spherical vector wavefunctions. Then, the usual Maxwell boundary conditions are imposed plus the appropriate additional boundary conditions. Examples of calculated extinction spectra are presented, and it is found that the frequencies of the subsidiary peaks, due to quantum bulk plasmon excitations exhibit strong dependence on the quantum spatial dispersion.

  17. W

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

    a new era in fusion research at the U.S. Department of Energy's Princeton Plasma Physics Laboratory. Today we unveil the National Spherical Torus Experiment- Upgrade (NSTX-U), the most powerful spherical tokamak in the world and the first major addition to the U.S. fusion program in the 21st century. The NSTX-U represents a $94 million, nearly three-year upgrade of the original National Spherical Torus Experiment that ran from 1999 to 2011 in the Laboratory, which Princeton University manages

  18. Electromagnetic and Mechanical Analysis of the Coil Structure for the CLAS12 Torus for 12 GeV Upgrade

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

    Ghoshal, P. K.; Pastor, O.; Kashy, D.; Schneider, W.; Wiseman, M.; Zarecky, M.; Young, G.; Rode, C.; Elouadrhiri, L.; Burkert, V.

    2014-12-18

    The torus magnet for the CLAS12 spectrometer is a 3.6 T superconducting magnet being designed and built as part of the Jefferson Lab 12 GeV Upgrade. The magnet consists of six coil case assemblies mounted to a cold central hub. The coil case assembly consists of an aluminum case and cover enclosing an epoxy vacuum impregnated coil pack. The coil pack consists of a 117 turn double-pancake winding wrapped with 2 layers of 0.635 mm thick copper cooling sheets. The coil case assembly is cooled by supercritical helium at 4.6 K. This report details the structural analysis of the coilmore » case assembly and the assessment of the coil pack stresses. For the normal operation of the torus magnet, the coil case assembly was analyzed for cool down to 4.6 K and the Lorentz forces at normal operating current. In addition to the normal operating configuration, the coil case assembly was analyzed for Lorentz forces arising from coil misalignment and current imbalances. The allowable stress criteria for the magnet followed the approach of the ASME codes. Primary stresses were limited to the lesser of 2/3 times the yield strength or 1/3 times the ultimate tensile strength. Primary plus secondary stresses were limited to 3 times the primary stress allowable. The analysis was performed using ANSYS Maxwell to calculate the magneto-static loads and ANSYS Mechanical to calculate the stresses.« less

  19. Electromagnetic and Mechanical Analysis of the Coil Structure for the CLAS12 Torus for 12 GeV Upgrade

    SciTech Connect (OSTI)

    Ghoshal, P. K.; Pastor, O.; Kashy, D.; Schneider, W.; Wiseman, M.; Zarecky, M.; Young, G.; Rode, C.; Elouadrhiri, L.; Burkert, V.

    2014-12-18

    The torus magnet for the CLAS12 spectrometer is a 3.6 T superconducting magnet being designed and built as part of the Jefferson Lab 12 GeV Upgrade. The magnet consists of six coil case assemblies mounted to a cold central hub. The coil case assembly consists of an aluminum case and cover enclosing an epoxy vacuum impregnated coil pack. The coil pack consists of a 117 turn double-pancake winding wrapped with 2 layers of 0.635 mm thick copper cooling sheets. The coil case assembly is cooled by supercritical helium at 4.6 K. This report details the structural analysis of the coil case assembly and the assessment of the coil pack stresses. For the normal operation of the torus magnet, the coil case assembly was analyzed for cool down to 4.6 K and the Lorentz forces at normal operating current. In addition to the normal operating configuration, the coil case assembly was analyzed for Lorentz forces arising from coil misalignment and current imbalances. The allowable stress criteria for the magnet followed the approach of the ASME codes. Primary stresses were limited to the lesser of 2/3 times the yield strength or 1/3 times the ultimate tensile strength. Primary plus secondary stresses were limited to 3 times the primary stress allowable. The analysis was performed using ANSYS Maxwell to calculate the magneto-static loads and ANSYS Mechanical to calculate the stresses.

  20. Photoelectric sheath formation around small spherical objects in space

    SciTech Connect (OSTI)

    Misra, Shikha Sodha, M. S.; Mishra, S. K.

    2015-04-15

    The formation of a photoelectron sheath around positively charged small (∼cm) spherical objects roaming in near earth space due to the solar radiation (with continuous spectrum) and the solar wind plasma has been investigated. The sheath structure has been derived, taking into account anisotropic photoelectron flux with the Poisson equation, spherical geometry of the object, and half Fermi Dirac distribution of photoelectron velocities. Two cases, viz., when the object is illuminated by (i) isotropic or (ii) unidirectional (parallel beam) radiation, have been analyzed. The analysis predicts a spherically symmetric sheath in case of isotropic illumination, while a symmetry in sheath about a θ=π/4 is seen in case of parallel beam illumination; θ is the angle of incidence which is the angle made by the normal to a surface element with the direction of incidence of solar radiation. The radial and angular profiles of the electric potential and electron density in the photoelectron sheath have been evaluated and illustrated graphically; the dependence of the sheath structure on the solar wind plasma parameters, material properties of the spherical object, and its size have been discussed.

  1. WAVEMOTH-FAST SPHERICAL HARMONIC TRANSFORMS BY BUTTERFLY MATRIX COMPRESSION

    SciTech Connect (OSTI)

    Seljebotn, D. S.

    2012-03-01

    We present Wavemoth, an experimental open source code for computing scalar spherical harmonic transforms (SHTs). Such transforms are ubiquitous in astronomical data analysis. Our code performs substantially better than existing publicly available codes owing to improvements on two fronts. First, the computational core is made more efficient by using small amounts of pre-computed data, as well as paying attention to CPU instruction pipelining and cache usage. Second, Wavemoth makes use of a fast and numerically stable algorithm based on compressing a set of linear operators in a pre-computation step. The resulting SHT scales as O(L{sup 2}log{sup 2} L) for the resolution range of practical interest, where L denotes the spherical harmonic truncation degree. For low- and medium-range resolutions, Wavemoth tends to be twice as fast as libpsht, which is the current state-of-the-art implementation for the HEALPix grid. At the resolution of the Planck experiment, L {approx} 4000, Wavemoth is between three and six times faster than libpsht, depending on the computer architecture and the required precision. Because of the experimental nature of the project, only spherical harmonic synthesis is currently supported, although adding support for spherical harmonic analysis should be trivial.

  2. Stability and superluminality of spherical DBI Galileon solutions

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

    Goon, Garrett L.; Hinterbichler, Kurt; Trodden, Mark

    2011-04-12

    We showed that, when considered as local modifications to gravity, such as in the solar system, there exists a region of parameter space in which spherically symmetric static solutions to a particular class of modified gravity theories exist and are stable.

  3. Dynamics of multiple double layers in high pressure glow discharge in a simple torus

    SciTech Connect (OSTI)

    Kumar Paul, Manash, E-mail: manashkr@gmail.com [Department of Physics, National Institute of Technology Agartala, Tripura799 046 (India); Sharma, P. K.; Thakur, A.; Kulkarni, S. V.; Bora, D. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat382 428 (India)

    2014-06-15

    Parametric characterization of multiple double layers is done during high pressure glow discharge in a toroidal vessel of small aspect ratio. Although glow discharge (without magnetic field) is known to be independent of device geometry, but the toroidal boundary conditions are conducive to plasma growth and eventually the plasma occupy the toroidal volume partially. At higher anode potential, the visibly glowing spots on the body of spatially extended anode transform into multiple intensely luminous spherical plasma blob structures attached to the tip of the positive electrode. Dynamics of multiple double layers are observed in argon glow discharge plasma in presence of toroidal magnetic field. The radial profiles of plasma parameters measured at various toroidal locations show signatures of double layer formation in our system. Parametric dependence of double layer dynamics in presence of toroidal magnetic field is presented here.

  4. Calibration of Spherically Bent Crystals used in X-Ray Spectroscopy...

    Office of Scientific and Technical Information (OSTI)

    Calibration of Spherically Bent Crystals used in X-Ray Spectroscopy. Citation Details In-Document Search Title: Calibration of Spherically Bent Crystals used in X-Ray Spectroscopy. ...

  5. Compact representation of radiation patterns using spherical mode expansions

    SciTech Connect (OSTI)

    Simpson, T.L.; Chen, Yinchao . Dept. of Electrical and Computer Engineering)

    1990-07-15

    This report presents the results of an investigation of SM (Spherical Mode) expansions as a compact and efficient alternative to the use of current distributions for generating radiation patterns. The study included three areas: (1) SM expansion from the radiation pattern; (2) SM expansion from the antenna current; and (3) Literature search. SM expansions were obtained from radiation patterns during the initial phase of this study. Although straightforward in principal, however, this technique was found to be awkward for the treatment on theoretical radiation patterns. It is included here for completeness and for possible use to summarize experimental results in a more meaningful way than with an exhaustive display of amplitude with azimuth and elevation angles. In essence, the work in this area served as as warm-up problem to develop our skills in computing and manipulating spherical modes as mathematical entities. 6 refs., 21 figs., 6 tabs.

  6. Tidal dissipation in a homogeneous spherical body. I. Methods

    SciTech Connect (OSTI)

    Efroimsky, Michael; Makarov, Valeri V. E-mail: vvm@usno.navy.mil

    2014-11-01

    A formula for the tidal dissipation rate in a spherical body is derived from first principles to correct some mathematical inaccuracies found in the literature. The development is combined with the Darwin-Kaula formalism for tides. Our intermediate results are compared with those by Zschau and Platzman. When restricted to the special case of an incompressible spherical planet spinning synchronously without libration, our final formula can be compared with the commonly used expression from Peale and Cassen. However, the two turn out to differ, as in our expression the contributions from all Fourier modes are positive-definite, which is not the case with the formula from Peale and Cassen. Examples of the application of our expression for the tidal damping rate are provided in the work by Makarov and Efroimsky (Paper II) published back to back with the current paper.

  7. Ion engineering of embedded nanostructures: From spherical to facetted nanoparticles

    SciTech Connect (OSTI)

    Rizza, G.; Dawi, E. A.; Vredenberg, A. M.; Monnet, I.

    2009-07-27

    We show that the high-energy ion irradiation of embedded metallic spherical nanoparticles (NPs) is not limited to their transformation into prolate nanorods or nanowires. Depending on their pristine size, the three following morphologies can be obtained: (i) nanorods, (ii) facettedlike, and (iii) almost spherical nanostructures. Planar silica films containing nearly monodisperse gold NPs (8-100 nm) were irradiated with swift heavy ions (5 GeV Pb) at room temperature for fluences up to 5x10{sup 13} cm{sup -2}. The experimental results are accounted for by considering a liquid-solid transformation of the premelted NP surface driven by the in-plane stress within the ion-deformed host matrix. This work demonstrates the interest of using ion-engineering techniques to shape embedded nanostructures into nonconventional configurations.

  8. Spherical Resorcinol-Formaldehyde Synthesis by Inverse Suspension Polymerization

    SciTech Connect (OSTI)

    Ray, Robert J.; Scrivens, Walter A.; Nash, Charles

    2005-10-21

    Base catalyzed sol-gel polycondensation of resorcinol (1,3-dihydroxybenzene) with formaldehyde by inverse suspension polymerization leads to the formation of uniform, highly cross-linked, translucent, spherical gels, which have increased selectivity and capacity for cesium ion removal from high alkaline solutions. Because of its high selectivity for cesium ion, resorcinol-formaldehyde (R-F) resins are being considered for process scale column radioactive cesium removal by ion-exchange at the Waste Treatment and Immobilization Plant (WTP), which is now under construction at the Hanford site. Other specialty resins such as Superlig{reg_sign} 644 have been ground and sieved and column tested for process scale radioactive cesium removal but show high pressure drops across the resin bed during transition from column regeneration to loading and elution. Furthermore, van Deemter considerations indicate better displacement column chromatography by the use of spherical particle beads rather than irregularly shaped ground or granular particles. In our studies batch contact equilibrium experiments using a high alkaline simulant show a definite increase in cesium loading onto spherical R-F resin. Distribution coefficient (Kd) values ranged from 777 to 429 mL/g in the presence of 0.1M and 0.7M potassium ions, respectively. Though other techniques for making R-F resins have been employed, to our knowledge no one has made spherical R-F resins by inverse suspension polymerization. Moreover, in this study we discuss the data comparisons to known algebraic isotherms used to evaluate ion-exchange resins for WTP plant scale cesium removal operations.

  9. Surface tension of spherical drops from surface of tension

    SciTech Connect (OSTI)

    Homman, A.-A.; Bourasseau, E.; Malfreyt, P.; Strafella, L.; Ghoufi, A.

    2014-01-21

    The determination of surface tension of curved interfaces is a topic that raised many controversies during the last century. Explicit liquid-vapor interface modelling (ELVI) was unable up to now to reproduce interfacial behaviors in drops due to ambiguities in the mechanical definition of the surface tension. In this work, we propose a thermodynamic approach based on the location of surface of tension and its use in the Laplace equation to extract the surface tension of spherical interfaces from ELVI modelling.

  10. Naked singularities in self-similar spherical gravitational collapse

    SciTech Connect (OSTI)

    Ori, A.; Piran, T.

    1987-11-09

    We present general-relativistic solutions of self-similar spherical collapse of an adiabatic perfect fluid. We show that if the equation of state is soft enough (GAMMA-1<<1), a naked singularity forms. The singularity resembles the shell-focusing naked singularities that arise in dust collapse. This solution increases significantly the range of matter fields that should be ruled out in order that the cosmic-censorship hypothesis will hold.

  11. Viscous Rayleigh-Taylor instability in spherical geometry

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

    Mikaelian, Karnig O.

    2016-02-08

    We consider viscous fluids in spherical geometry, a lighter fluid supporting a heavier one. Chandrasekhar [Q. J. Mech. Appl. Math. 8, 1 (1955)] analyzed this unstable configuration providing the equations needed to find, numerically, the exact growth rates for the ensuing Rayleigh-Taylor instability. He also derived an analytic but approximate solution. We point out a weakness in his approximate dispersion relation (DR) and offer one that is to some extent improved.

  12. Method for preparing spherical ferrite beads and use thereof

    DOE Patents [OSTI]

    Lauf, Robert J.; Anderson, Kimberly K.; Montgomery, Frederick C.; Collins, Jack L.

    2002-01-01

    The invention allows the fabrication of small, dense, highly polished spherical beads of hexagonal ferrites with selected compositions for use in nonreciprocal microwave and mm-wave devices as well as in microwave absorbent or reflective coatings, composites, and the like. A porous, generally spherical bead of hydrous iron oxide is made by a sol-gel process to form a substantially rigid bead having a generally fine crystallite size and correspondingly finely distributed internal porosity. The resulting gel bead is washed and hydrothermally reacted with a soluble alkaline earth salt (typically Ba or Sr) under conditions of elevated temperature and pressure to convert the bead into a mixed hydrous iron-alkaline earth oxide while retaining the generally spherical shape. This mixed oxide bead is then washed, dried, and calcined to produce the desired (BaFe.sub.12 O.sub.19 or SrFe.sub.12 O.sub.19) crystal structure. The calcined bead is then sintered to form a dense bead of the BaFe.sub.12 O.sub.19 and SrFe.sub.12 O.sub.19 phase suitable for polishing and incorporation into various microwave devices and components.

  13. Stability of spherically symmetric solutions in modified theories of gravity

    SciTech Connect (OSTI)

    Seifert, Michael D.

    2007-09-15

    In recent years, a number of alternative theories of gravity have been proposed as possible resolutions of certain cosmological problems or as toy models for possible but heretofore unobserved effects. However, the implications of such theories for the stability of structures such as stars have not been fully investigated. We use our 'generalized variational principle', described in a previous work [M. D. Seifert and R. M. Wald, Phys. Rev. D 75, 084029 (2007)], to analyze the stability of static spherically symmetric solutions to spherically symmetric perturbations in three such alternative theories: Carroll et al.'s f(R) gravity, Jacobson and Mattingly's 'Einstein-aether theory', and Bekenstein's TeVeS theory. We find that in the presence of matter, f(R) gravity is highly unstable; that the stability conditions for spherically symmetric curved vacuum Einstein-aether backgrounds are the same as those for linearized stability about flat spacetime, with one exceptional case; and that the 'kinetic terms' of vacuum TeVeS theory are indefinite in a curved background, leading to an instability.

  14. Structural characterization of particle systems using spherical harmonics

    SciTech Connect (OSTI)

    Feinauer, Julian; Spettl, Aaron; Manke, Ingo; Strege, Stefan; Kwade, Arno; Pott, Andres; Schmidt, Volker

    2015-08-15

    Many important properties of particulate materials are heavily influenced by the size and shape of the constituent particles. Thus, in order to control and improve product quality, it is important to develop a good understanding of the shape and size of the particles that make up a given particulate material. In this paper, we show how the spherical harmonics expansion can be used to approximate particles obtained from tomographic 3D images. This yields an analytic representation of the particles which can be used to calculate structural characteristics. We present an estimation method for the optimal length of expansion depending on individual particle shapes, based on statistical hypothesis testing. A suitable choice of this parameter leads to a smooth approximation that preserves the main shape features of the original particle. To show the wide applicability of this procedure, we use it to approximate particles obtained from two different tomographic 3D datasets of particulate materials. The first one describes an anode material from lithium-ion cells that consists of sphere-like particles with different sizes. The second dataset describes a powder of highly non-spherical titanium dioxide particles. - Highlights: • Complex particle shapes are described analytically by spherical harmonics expansion. • The optimal length of the expansion is estimated for each particle individually. • Characteristics like, e.g., particle surface areas can be calculated efficiently. • The method is applied to two tomographic datasets of particulate materials.

  15. News | Princeton Plasma Physics Lab

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

    Major next steps for fusion energy based on the spherical tokamak design Click on an image below to view the high resolution image. Then right click on the image and select "Save Image" or "Save Image As..." Test cell of the National Spherical Torus Experiment-Upgrade with tokamak in the center. Physicist Jonathan Menard. Center stack of the NSTX-U. Mega Ampere Spherical Tokamak. Photo courtesy of Culham Centre for Fusion Energy.

  16. Shearing expansion-free spherical anisotropic fluid evolution

    SciTech Connect (OSTI)

    Herrera, L.; Santos, N. O.; Wang Anzhong

    2008-10-15

    Spherically symmetric expansion-free distributions are systematically studied. The entire set of field equations and junction conditions are presented for a general distribution of dissipative anisotropic fluid (principal stresses unequal), and the expansion-free condition is integrated. In order to understand the physical meaning of expansion-free motion, two different definitions for the radial velocity of a fluid element are discussed. It is shown that the appearance of a cavity is inevitable in the expansion-free evolution. The nondissipative case is considered in detail, and the Skripkin model is recovered.

  17. Spherical Wave Propagation in a Nonlinear Elastic Medium

    SciTech Connect (OSTI)

    Korneev, Valeri A.

    2009-07-01

    Nonlinear propagation of spherical waves generated by a point-pressure source is considered for the cases of monochromatic and impulse primary waveforms. The nonlinear five-constant elastic theory advanced by Murnaghan is used where general equations of motion are put in the form of vector operators, which are independent of the coordinate system choice. The ratio of the nonlinear field component to the primary wave in the far field is proportional to ln(r) where r is a propagation distance. Near-field components of the primary field do not contribute to the far field of nonlinear component.

  18. ECCENTRIC ROLLING OF POWDER AND BONDING AGENT INTO SPHERICAL PELLETS

    DOE Patents [OSTI]

    Patton, G. Jr.; Zirinsky, S.

    1961-06-01

    A machine is described for pelletizing powder and bonding agent into spherical pellets of high density and uniform size. In this device, the material to be compacted is added to a flat circular pan which is moved in a circular orbit in a horizontal plane about an axis displaced from that of the pan's central axis without rotating the pan about its central axis. This movement causes the material contained therein to roll around the outside wall of the container and build up pellets of uniform shape, size, and density.

  19. Hysteresis cycle in a turbulent, spherically bounded MHD dynamo model

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

    Hysteresis cycle in a turbulent, spherically bounded MHD dynamo model This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2009 New J. Phys. 11 013027 (http://iopscience.iop.org/1367-2630/11/1/013027) Download details: IP Address: 128.104.165.161 The article was downloaded on 14/12/2011 at 21:42 Please note that terms and conditions apply. View the table of contents for this issue, or go to the journal homepage for more Home Search Collections

  20. Identifying new sources of turbulence in spherical tokamaks | Princeton

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

    Plasma Physics Lab Identifying new sources of turbulence in spherical tokamaks By John Greenwald November 24, 2015 Tweet Widget Google Plus One Share on Facebook Computer simulation of turbulence in a model of the NSTX-U. Image courtesy of Eliot Feibush. Computer simulation of turbulence in a model of the NSTX-U. Image courtesy of Eliot Feibush. For fusion reactions to take place efficiently, the atomic nuclei that fuse together in plasma must be kept sufficiently hot. But turbulence in the

  1. Identifying new sources of turbulence in spherical tokamaks | Princeton

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

    Plasma Physics Lab Identifying new sources of turbulence in spherical tokamaks By John Greenwald November 25, 2015 Tweet Widget Google Plus One Share on Facebook Computer simulation of turbulence in a model of the NSTX-U. Image courtesy of Eliot Feibush. Computer simulation of turbulence in a model of the NSTX-U. Image courtesy of Eliot Feibush. For fusion reactions to take place efficiently, the atomic nuclei that fuse together in plasma must be kept sufficiently hot. But turbulence in the

  2. A non-conforming 3D spherical harmonic transport solver

    SciTech Connect (OSTI)

    Van Criekingen, S.

    2006-07-01

    A new 3D transport solver for the time-independent Boltzmann transport equation has been developed. This solver is based on the second-order even-parity form of the transport equation. The angular discretization is performed through the expansion of the angular neutron flux in spherical harmonics (PN method). The novelty of this solver is the use of non-conforming finite elements for the spatial discretization. Such elements lead to a discontinuous flux approximation. This interface continuity requirement relaxation property is shared with mixed-dual formulations such as the ones based on Raviart-Thomas finite elements. Encouraging numerical results are presented. (authors)

  3. sandia national labs | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    sandia national labs

  4. Brookhaven National Laboratory | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    Brookhaven National Laboratory

  5. TORUS: Theory of Reactions for Unstable iSotopes.Topical Collaboration for Nuclear Theory Project. Period: June 1, 2010 - May 31, 2015

    SciTech Connect (OSTI)

    Arbanas, Goran; Elster, Charlotte; Escher, Jutta; Nunes, Filomena; Thompson, Ian

    2015-08-28

    The work of this collaboration during its existence is summarized. The mission of the TORUS Topical Collaboration was to develop new methods that advance nuclear reaction theory for unstable isotopes by using three-body techniques to improve direct reaction calculations. This multi-institution collaborative effort was and remains directly relevant to three areas of interest: the properties of nuclei far from stability, microscopic studies of nuclear input parameters for astrophysics, and microscopic nuclear reaction theory. The TORUS project focused on understanding the details of (d,p) reactions for neutron transfer to heavier nuclei. The bulk of the work fell into three areas: coupled channel theory, modeling (d,p) reactions with a Faddeev-AGS approach, and capture reactions.

  6. Horizons versus singularities in spherically symmetric space-times

    SciTech Connect (OSTI)

    Bronnikov, K. A.; Elizalde, E.; Odintsov, S. D.; Zaslavskii, O. B.

    2008-09-15

    We discuss different kinds of Killing horizons possible in static, spherically symmetric configurations and recently classified as 'usual', 'naked', and 'truly naked' ones depending on the near-horizon behavior of transverse tidal forces acting on an extended body. We obtain the necessary conditions for the metric to be extensible beyond a horizon in terms of an arbitrary radial coordinate and show that all truly naked horizons, as well as many of those previously characterized as naked and even usual ones, do not admit an extension and therefore must be considered as singularities. Some examples are given, showing which kinds of matter are able to create specific space-times with different kinds of horizons, including truly naked ones. Among them are fluids with negative pressure and scalar fields with a particular behavior of the potential. We also discuss horizons and singularities in Kantowski-Sachs spherically symmetric cosmologies and present horizon regularity conditions in terms of an arbitrary time coordinate and proper (synchronous) time. It turns out that horizons of orders 2 and higher occur in infinite proper times in the past or future, but one-way communication with regions beyond such horizons is still possible.

  7. METHOD FOR PREPARATION OF SPHERICAL UO$sub 4$

    DOE Patents [OSTI]

    Gregory, J.F. Jr.; Levey, R.P. Jr.

    1962-06-01

    A method is given for continuously precipitating ura nium peroxide in the form of spherical particles. Seed crystals are formed in a first reaction zone by introducing an acidified aqueous uranyl nitrate solution and an aqueous hydrogen peroxide solution at a ratio of 5 to 20 per cent of the stoichiometric amount required for complete precipitation. After a mean residence time of 2 to 5 minutes in the first reaction zone, the resulting mixture is introduced into a second reaction zone, together with a large excess of hydrogen peroxide solution. The resulting UO4 is rapidly separated from the mother liquor after an over-all residence time of 5 to 11 minutes. The first reaction is maintained at a temperature of 85 to 90 deg C and the second zone above 50 deg C. Additional reaction zones may be employed for further crystal growth. The UO/sub 4/ is converted to U/sub 3/O/sub 8/ or UO/sub 2/ by heating in air or hydrogen atmosphere. This method is particularly useful for the preparation of spherical UO/sub 2/ particles 10 to 25 microns in diameter. (AEC)

  8. Phillips-Tikhonov regularization with a priori information for neutron emission tomographic reconstruction on Joint European Torus

    SciTech Connect (OSTI)

    Bielecki, J.; Scholz, M.; Drozdowicz, K.; Giacomelli, L.; Kiptily, V.; Kempenaars, M.; Conroy, S.; Craciunescu, T.; Collaboration: EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB

    2015-09-15

    A method of tomographic reconstruction of the neutron emissivity in the poloidal cross section of the Joint European Torus (JET, Culham, UK) tokamak was developed. Due to very limited data set (two projection angles, 19 lines of sight only) provided by the neutron emission profile monitor (KN3 neutron camera), the reconstruction is an ill-posed inverse problem. The aim of this work consists in making a contribution to the development of reliable plasma tomography reconstruction methods that could be routinely used at JET tokamak. The proposed method is based on Phillips-Tikhonov regularization and incorporates a priori knowledge of the shape of normalized neutron emissivity profile. For the purpose of the optimal selection of the regularization parameters, the shape of normalized neutron emissivity profile is approximated by the shape of normalized electron density profile measured by LIDAR or high resolution Thomson scattering JET diagnostics. In contrast with some previously developed methods of ill-posed plasma tomography reconstruction problem, the developed algorithms do not include any post-processing of the obtained solution and the physical constrains on the solution are imposed during the regularization process. The accuracy of the method is at first evaluated by several tests with synthetic data based on various plasma neutron emissivity models (phantoms). Then, the method is applied to the neutron emissivity reconstruction for JET D plasma discharge #85100. It is demonstrated that this method shows good performance and reliability and it can be routinely used for plasma neutron emissivity reconstruction on JET.

  9. Tomographic analysis of neutron and gamma pulse shape distributions from liquid scintillation detectors at Joint European Torus

    SciTech Connect (OSTI)

    Giacomelli, L.; Department of Physics, Universit degli Studi di Milano-Bicocca, Milano ; Conroy, S.; Department of Physics and Astronomy, Uppsala University, Uppsala ; Gorini, G.; Horton, L.; Murari, A.; Popovichev, S.; Syme, D. B.

    2014-02-15

    The Joint European Torus (JET, Culham, UK) is the largest tokamak in the world devoted to nuclear fusion experiments of magnetic confined Deuterium (D)/Deuterium-Tritium (DT) plasmas. Neutrons produced in these plasmas are measured using various types of neutron detectors and spectrometers. Two of these instruments on JET make use of organic liquid scintillator detectors. The neutron emission profile monitor implements 19 liquid scintillation counters to detect the 2.45 MeV neutron emission from D plasmas. A new compact neutron spectrometer is operational at JET since 2010 to measure the neutron energy spectra from both D and DT plasmas. Liquid scintillation detectors are sensitive to both neutron and gamma radiation but give light responses of different decay time such that pulse shape discrimination techniques can be applied to identify the neutron contribution of interest from the data. The most common technique consists of integrating the radiation pulse shapes within different ranges of their rising and/or trailing edges. In this article, a step forward in this type of analysis is presented. The method applies a tomographic analysis of the 3-dimensional neutron and gamma pulse shape and pulse height distribution data obtained from liquid scintillation detectors such that n/? discrimination can be improved to lower energies and additional information can be gained on neutron contributions to the gamma events and vice versa.

  10. Processes and properties of edge-localised instabilities in 2T 2MA plasmas in the Joint European Torus

    SciTech Connect (OSTI)

    Webster, A. J. Webster, S. J.

    2014-11-15

    During July 2012, 150 almost identical H-mode plasmas were consecutively created in the Joint European Torus, providing a combined total of approximately 8 minutes of steady-state plasma with 15?000 Edge Localised Modes (ELMs). In principle, each of those 15?000 ELMs are statistically equivalent. Here, the changes in edge density and plasma energy associated with those ELMs are explored, using the spikes in Beryllium II (527?nm) radiation as an indicator for the onset of an ELM. Clearly different timescales are observed during the ELM process. Edge temperature falls over a 2?ms timescale, edge density and pressure fall over a 5?ms timescale, and there is an additional 10?ms timescale that is consistent with a resistive relaxation of the plasma's edge. The statistical properties of the energy and density losses due to the ELMs are explored. For these plasmas the ELM energy (?E) is found to be approximately independent of the time between ELMs, despite the average ELM energy (??E?) and average ELM frequency (f) being consistent with the scaling of ??E??1/f. Instead, beyond the first 0.02 s of waiting time between ELMs, the energy losses due to individual ELMs are found to be statistically the same. Surprisingly no correlation is found between the energies of consecutive ELMs either. A weak link is found between the density drop and the ELM waiting time. Consequences of these results for ELM control and modelling are discussed.

  11. Measurement of Adhesion in Alumina/Glass-Epoxy System Using Spherical...

    Office of Scientific and Technical Information (OSTI)

    Setup 116" WC Spherical Indenter Capacitive Gauge Environmental Chamber (LN2 chilled) Indenter attached to load cell bolts to bottom of crosshead. Crosshead rate 0.05 mmmin. ...

  12. A hyper-spherical adaptive sparse-grid method for high-dimensional...

    Office of Scientific and Technical Information (OSTI)

    (SC) Country of Publication: United States Language: English Subject: discontinuity detection; hyper-spherical coordinate system; adaptive sparse grid; rare event; hierarchical ...

  13. A simple procedure to prepare spherical {alpha}-alumina powders

    SciTech Connect (OSTI)

    Liu Hongyu [State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012 (China); Ning Guiling [State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012 (China)], E-mail: ninggl@dlut.edu.cn; Gan Zhihong; Lin Yuan [State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012 (China)

    2009-04-02

    Spherical {alpha}-alumina powders were prepared by the controlled hydrolysis of aluminum isopropoxide in a hydrolysis system consisting of octanol and acetonitrile. Diverse solvents to dissolve reactant formed diverse hydrolysis systems and affected particle shape of {alpha}-alumina powders. The precursors crystallized to {gamma}-alumina at 1000 deg. C and converted to {alpha}-alumina at 1150 deg. C without intermediate phases. The particle morphology of precursor was retained after it crystallized to {alpha}-alumina. The heating rate influenced the particle shape and the state of agglomeration during calcination process. The thermal properties of the precursors were characterized by thermal gravimetric and differential thermal analysis. X-ray diffraction technique was used to confirm the conversion of crystalline phase of alumina powders from amorphous to {alpha}-phase. Transmission electron microscopy was used to investigate the morphologies and size of the precursors and products.

  14. Stress/Strain Response of Irradiated Metallic Materials via Spherical...

    Office of Scientific and Technical Information (OSTI)

    Alamos National Laboratory (LANL) Sponsoring Org: DOELANL Country of Publication: United States Language: English Subject: Materials Science(36); Nanoscience & Nanotechnology(77)

  15. The solid angle (geometry factor) for a spherical surface source and an arbitrary detector aperture

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

    Favorite, Jeffrey A.

    2016-01-13

    It is proven that the solid angle (or geometry factor, also called the geometrical efficiency) for a spherically symmetric outward-directed surface source with an arbitrary radius and polar angle distribution and an arbitrary detector aperture is equal to the solid angle for an isotropic point source located at the center of the spherical surface source and the same detector aperture.

  16. Fire Safety Tests for Cesium-Loaded Spherical Resorcinol Formaldehyde Resin: Data Summary Report

    SciTech Connect (OSTI)

    Kim, Dong-Sang; Schweiger, Michael J.; Peterson, Reid A.

    2012-09-01

    A draft safety evaluation of the scenario for spherical resorcinol formaldehyde (SRF) resin fire inside the ion exchange column was performed by the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Fire Safety organization. The result of this draft evaluation suggested a potential change of the fire safety classification for the Cesium Ion Exchange Process System (CXP) emergency elution vessels, equipment, and piping. To resolve this question, the fire properties of the SRF resin were measured by Southwest Research Institute (SwRI) through a subcontract managed by Pacific Northwest National Laboratory (PNNL). The results of initial fire safety tests on the SRF resin were documented in a previous report (WTP-RPT-218). The present report summarizes the results of additional tests performed by SwRI on the cesium-loaded SRF resin. The efforts by PNNL were limited to summarizing the test results provided by SwRI into one consolidated data report. The as-received SwRI report is attached to this report in the Appendix A. Where applicable, the precision and bias of each test method, as given by each American Society for Testing and Materials (ASTM) standard procedure, are included and compared with the SwRI test results of the cesium-loaded SRF resin.

  17. Fire Safety Tests for Spherical Resorcinol Formaldehyde Resin: Data Summary Report

    SciTech Connect (OSTI)

    Kim, Dong-Sang; Peterson, Reid A.; Schweiger, Michael J.

    2012-07-30

    A draft safety evaluation of the scenario for spherical resorcinol-formaldehyde (SRF) resin fire inside the ion exchange column was performed by the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Fire Safety organization. The result of this draft evaluation suggested a potential change of the fire safety classification for the Cesium Ion Exchange Process System (CXP) emergency elution vessels, equipment, and piping, which may be overly bounding based on the fire performance data from the manufacturer of the ion exchange resin selected for use at the WTP. To resolve this question, the fire properties of the SRF resin were measured by Southwest Research Institute (SwRI), following the American Society for Testing and Materials (ASTM) standard procedures, through a subcontract managed by Pacific Northwest National Laboratory (PNNL). For some tests, the ASTM standard procedures were not entirely appropriate or practical for the SRF resin material, so the procedures were modified and deviations from the ASTM standard procedures were noted. This report summarizes the results of fire safety tests performed and reported by SwRI. The efforts by PNNL were limited to summarizing the test results provided by SwRI into one consolidated data report. All as-received SwRI reports are attached to this report in the Appendix. Where applicable, the precision and bias of each test method, as given by each ASTM standard procedure, are included and compared with the SwRI test results of the SRF resin.

  18. Processes for making dense, spherical active materials for lithium-ion cells

    DOE Patents [OSTI]

    Kang, Sun-Ho; Amine, Khalil

    2011-11-22

    Processes are provided for making dense, spherical mixed-metal carbonate or phosphate precursors that are particularly well suited for the production of active materials for electrochemical devices such as lithium ion secondary batteries. Exemplified methods include precipitating dense, spherical particles of metal carbonates or metal phosphates from a combined aqueous solution using a precipitating agent such as ammonium hydrogen carbonate, sodium hydrogen carbonate, or a mixture that includes sodium hydrogen carbonate. Other exemplified methods include precipitating dense, spherical particles of metal phosphates using a precipitating agent such as ammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, or a mixture of any two or more thereof. Further provided are compositions of and methods of making dense, spherical metal oxides and metal phosphates using the dense, spherical metal precursors. Still further provided are electrodes and batteries using the same.

  19. Spherical strong-shock generation for shock-ignition inertial...

    Office of Scientific and Technical Information (OSTI)

    a shock-ignition target design for the National Ignition Facility. The timing of the x-ray flash from shock convergence in the center of the solid plastic target is used to infer ...

  20. Octahedral spherical hohlraum and its laser arrangement for inertial fusion

    SciTech Connect (OSTI)

    Lan, Ke; He, Xian-Tu; Liu, Jie; Zheng, Wudi; Lai, Dongxian

    2014-05-15

    A recent publication [K. Lan et al., Phys. Plasmas 21, 010704 (2014)] proposed a spherical hohlraum with six laser entrance holes of octahedral symmetry at a specific hohlraum-to-capsule radius ratio of 5.14 for inertial fusion study, which has robust high symmetry during the capsule implosion and superiority on low backscatter without supplementary technology. This paper extends the previous one by studying the laser arrangement and constraints of octahedral hohlraum in detail. As a result, it has serious beam crossing at θ{sub L}≤45°, and θ{sub L}=50° to 60° is proposed as the optimum candidate range for the golden octahedral hohlraum, here θ{sub L} is the opening angle that the laser quad beam makes with the Laser Entrance Hole (LEH) normal direction. In addition, the design of the LEH azimuthal angle should avoid laser spot overlapping on hohlraum wall and laser beam transferring outside hohlraum from a neighbor LEH. The octahedral hohlraums are flexible and can be applicable to diverse inertial fusion drive approaches. This paper also applies the octahedral hohlraum to the recent proposed hybrid indirect-direct drive approach.

  1. All-sky interferometry with spherical harmonic transit telescopes

    SciTech Connect (OSTI)

    Shaw, J. Richard; Pen, Ue-Li; Sigurdson, Kris; Sitwell, Michael; Stebbins, Albert

    2014-02-01

    In this paper, we describe the spherical harmonic transit telescope through the use of a novel formalism for the analysis of transit radio telescopes. This all-sky approach bypasses the curved-sky complications of traditional interferometry and so is particularly well-suited to the analysis of wide-field radio interferometers. It enables compact and computationally efficient representations of the data and its statistics, which allow new ways of approaching important problems like map-making and foreground removal. In particular, we show how it enables the use of the Karhunen-Loève transform as a highly effective foreground filter, suppressing realistic foreground residuals for our fiducial example by at least a factor 20 below the 21 cm signal, even in highly contaminated regions of the sky. This is despite the presence of the mode-mixing inherent in real-world instruments with frequency-dependent beams. We show, using Fisher forecasting, that foreground cleaning has little effect on power spectrum constraints compared to hypothetical foreground-free measurements. Beyond providing a natural real-world data analysis framework for 21 cm telescopes now under construction and future experiments, this formalism allows accurate power spectrum forecasts to be made that include the interplay of design constraints and realistic experimental systematics with 21st century 21 cm science.

  2. Finite Mach number spherical shock wave, application to shock ignition

    SciTech Connect (OSTI)

    Vallet, A.; Ribeyre, X.; Tikhonchuk, V.

    2013-08-15

    A converging and diverging spherical shock wave with a finite initial Mach number M{sub s0} is described by using a perturbative approach over a small parameter M{sub s}{sup ?2}. The zeroth order solution is the Guderley's self-similar solution. The first order correction to this solution accounts for the effects of the shock strength. Whereas it was constant in the Guderley's asymptotic solution, the amplification factor of the finite amplitude shock ?(t)?dU{sub s}/dR{sub s} now varies in time. The coefficients present in its series form are iteratively calculated so that the solution does not undergo any singular behavior apart from the position of the shock. The analytical form of the corrected solution in the vicinity of singular points provides a better physical understanding of the finite shock Mach number effects. The correction affects mainly the flow density and the pressure after the shock rebound. In application to the shock ignition scheme, it is shown that the ignition criterion is modified by more than 20% if the fuel pressure prior to the final shock is taken into account. A good agreement is obtained with hydrodynamic simulations using a Lagrangian code.

  3. National Competitiveness

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

    Competition National Clean Energy Business Plan Competition The National Clean Energy Business Plan Competition inspired nearly 300 university teams across the country to create new businesses to commercialize promising energy technologies developed at U.S. universities and the National Laboratories. After pitching their business plans to panels of judges at the regional semifinals and finals, six teams advanced to the national competition for a chance to compete in the popular vote and a grand

  4. Integrated simulations of saturated neoclassical tearing modes in DIII-D, Joint European Torus, and ITER plasmas

    SciTech Connect (OSTI)

    Halpern, Federico D.; Bateman, Glenn; Kritz, Arnold H.

    2006-06-15

    A revised version of the ISLAND module [C. N. Nguyen et al., Phys. Plasmas 11, 3604 (2004)] is used in the BALDUR code [C. E. Singer et al., Comput. Phys. Commun. 49, 275 (1988)] to carry out integrated modeling simulations of DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)], Joint European Torus (JET) [P. H. Rebut et al., Nucl. Fusion 25, 1011 (1985)], and ITER [R. Aymar et al., Plasma Phys. Control. Fusion 44, 519 (2002)] tokamak discharges in order to investigate the adverse effects of multiple saturated magnetic islands driven by neoclassical tearing modes (NTMs). Simulations are carried out with a predictive model for the temperature and density pedestal at the edge of the high confinement mode (H-mode) plasma and with core transport described using the Multi-Mode model. The ISLAND module, which is used to compute magnetic island widths, includes the effects of an arbitrary aspect ratio and plasma cross sectional shape, the effect of the neoclassical bootstrap current, and the effect of the distortion in the shape of each magnetic island caused by the radial variation of the perturbed magnetic field. Radial transport is enhanced across the width of each magnetic island within the BALDUR integrated modeling simulations in order to produce a self-consistent local flattening of the plasma profiles. It is found that the main consequence of the NTM magnetic islands is a decrease in the central plasma temperature and total energy. For the DIII-D and JET discharges, it is found that inclusion of the NTMs typically results in a decrease in total energy of the order of 15%. In simulations of ITER, it is found that the saturated magnetic island widths normalized by the plasma minor radius, for the lowest order individual tearing modes, are approximately 24% for the 2/1 mode and 12% for the 3/2 mode. As a result, the ratio of ITER fusion power to heating power (fusion Q) is reduced from Q=10.6 in simulations with no NTM islands to Q=2.6 in simulations with fully saturated

  5. Approach of spherical harmonics to the representation of the deformed su(1,1) algebra

    SciTech Connect (OSTI)

    Fakhri, H.; Ghaneh, T.

    2008-11-15

    The m-shifting generators of su(2) algebra together with a pair of l-shifting ladder symmetry operators have been used in the space of all spherical harmonics Y{sub l}{sup m}({theta},{phi}) in order to introduce a new set of operators, expressing the transitions between them. It is shown that the space of spherical harmonics whose l+2m or l-2m is given presents negative and positive irreducible representations of a deformed su(1,1) algebra, respectively. These internal symmetries also suggest new algebraic methods to construct the spherical harmonics in the framework of the spectrum-generating algebras.

  6. Cylindrical and spherical electron acoustic solitary waves with nonextensive hot electrons

    SciTech Connect (OSTI)

    Pakzad, Hamid Reza

    2011-08-15

    Nonlinear propagation of cylindrical and spherical electron-acoustic solitons in an unmagnetized plasma consisting cold electron fluid, hot electrons obeying a nonextensive distribution and stationary ions, are investigated. For this purpose, the standard reductive perturbation method is employed to derive the cylindrical/spherical Korteweg-de-Vries equation, which governs the dynamics of electron-acoustic solitons. The effects of nonplanar geometry and nonextensive hot electrons on the behavior of cylindrical and spherical electron acoustic solitons are also studied by numerical simulations.

  7. Reduced model prediction of electron temperature profiles in...

    Office of Scientific and Technical Information (OSTI)

    FUSION TECHNOLOGY Confinement; H-mode Plasma Confinement; Spherical Torus; Spherical Tokamak; Stability, Microinstability; Tokamaks, NSTX; Transport Phenomena Word Cloud More...

  8. Disruptions, Disruptivity, and Safer Operating Windows in the...

    Office of Scientific and Technical Information (OSTI)

    of Publication: United States Language: English Subject: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY Disruptions, High-beta Plasmas,MHD Instability, Spherical Torus, Spherical...

  9. National RF Test Facility as a multipurpose development tool

    SciTech Connect (OSTI)

    McManamy, T.J.; Becraft, W.R.; Berry, L.A.; Blue, C.W.; Gardner, W.L.; Haselton, H.H.; Hoffman, D.J.; Loring, C.M. Jr.; Moeller, F.A.; Ponte, N.S.

    1983-01-01

    Additions and modifications to the National RF Test Facility design have been made that (1) focus its use for technology development for future large systems in the ion cyclotron range of frequencies (ICRF), (2) expand its applicability to technology development in the electron cyclotron range of frequencies (ECRF) at 60 GHz, (3) provide a facility for ELMO Bumpy Torus (EBT) 60-GHz ring physics studies, and (4) permit engineering studies of steady-state plasma systems, including superconducting magnet performance, vacuum vessel heat flux removal, and microwave protection. The facility will continue to function as a test bed for generic technology developments for ICRF and the lower hybrid range of frequencies (LHRF). The upgraded facility is also suitable for mirror halo physics experiments.

  10. NSTX-U: Builders and Users | Princeton Plasma Physics Lab

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

    NSTX-U: Builders and Users Constructing the National Spherical Torus Experiment Upgrade took years of detailed planning and oversight. The team in charge brought decades of experience to the task, working together to make the $94 million upgrade a reality. Publication File: PDF icon Builders and Users Publication Type: Fact Sheets

  11. Builders and Users | Princeton Plasma Physics Lab

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

    Builders and Users Constructing the National Spherical Torus Experiment Upgrade took years of detailed planning and oversight. The team in charge brought decades of experience to the task, working together to make the $94 million upgrade a reality. Publication File: PDF icon NSTX-U_presskit_print_Builders-Users

  12. Novel Investigation of Iron Cross Sections via Spherical Shell Transmission Measurements and Particle Transport Calculations for Material Embrittlement Studies. Quarterly Status Report 5

    SciTech Connect (OSTI)

    Dr. Derek W. Storm

    2002-04-25

    Previously, measurements were made of the transmission of 14 MeV neutrons through various spherical shell thicknesses of iron in a comprehensive investigation at Lawrence Livermore National Laboratory (LLNL) about 30 years ago. Two of these spheres, composed of hemispherical sections, have appropriate dimensions for the lower energy neutron measurements that we propose to make. Due to their interest in our experimental results, LLNL has agreed to make these hemispheres available for our work. Those hemispheres have been shipped. In addition, a spherical iron shell, composed of two hemispherical sections with an annular thickness of approximately 1 inch, was fabricated at NEST. However, since we will need additional hemispheres for our experiments, we purchased a radius cutter that will allow us to fabricate hemispheres as large as 5 inches in radius at the Ohio University Machine Shop. This will give us maximum flexibility to adapt to the needs of the spherical shell transmission experiments. High purity (99.94% iron) Armco iron has been obtained which can be used to make the smaller hemispheres. Larger hemispheres will be made using ASTM designation steel with high iron content. In all cases compositional analyses will be made of the hemispheres.

  13. A hyper-spherical adaptive sparse-grid method for high-dimensional...

    Office of Scientific and Technical Information (OSTI)

    Title: A hyper-spherical adaptive sparse-grid method for high-dimensional discontinuity ... This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and ...

  14. Application Of A Spherical-Radial Heat Transfer Model To Calculate...

    Open Energy Info (EERE)

    A Spherical-Radial Heat Transfer Model To Calculate Geothermal Gradients From Measurements In Deep Boreholes Jump to: navigation, search OpenEI Reference LibraryAdd to library...

  15. Effect of plasma parameters on growth and field emission properties of spherical carbon nanotube tip

    SciTech Connect (OSTI)

    Sharma, Suresh C.; Tewari, Aarti

    2011-06-15

    The effect of plasma parameters (e.g., electron density and temperature, ion density and temperature, neutral atom density and temperature) on the growth (without a catalyst), structure, and field emission properties of a spherical carbon nanotube (CNT) tip has been theoretically investigated. A theoretical model of charge neutrality, including the kinetics of electrons, positively charged ions, and neutral atoms and the energy balance of the various species in plasma, has been developed. Numerical calculations of the radius of the spherical CNT tip for different CNT number densities and plasma parameters have been carried out for the typical glow discharge plasma parameters. It is found that upon an increase in the CNT number density and plasma parameters, the radius of the spherical CNT tip decreases, and consequently the field emission factor for the spherical CNT tip increases.

  16. ARM - PI Product - Polarimetric Scattering Database for Non-spherical Ice

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

    Particles at Microwave Wavelengths ProductsPolarimetric Scattering Database for Non-spherical Ice Particles at Microwave Wavelengths Citation DOI: 10.5439/1258029 [ What is this? ] ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : Polarimetric Scattering Database for Non-spherical Ice Particles at Microwave Wavelengths [ research data - External funding ] The atmospheric science community has entered

  17. Rayleigh-Taylor instability at spherical interfaces between viscous fluids: Fluid/vacuum interface

    SciTech Connect (OSTI)

    Terrones, Guillermo; Carrara, Mark D.

    2015-05-01

    For a spherical interface of radius R separating two different homogeneous regions of incompressible viscous fluids under the action of a radially directed acceleration, we perform a linear stability analysis in terms of spherical surface harmonics Y n to derive the dispersion relation. The instability behavior is investigated by computing the growth rates and the most-unstable modes as a function of the spherical harmonic degree n. This general methodology is applicable to the entire parameter space spanned by the Atwood number, the viscosity ratio, and the dimensionless number B = (αRΡ²2/μ²²/³ R (where αR, Ρ2 and μ2 are the local radial acceleration at the interface, and the density and viscosity of the denser overlying fluid, respectively). While the mathematical formulation here is general, this paper focuses on instability that arises at a spherical viscous fluid/vacuum interface as there is a great deal to be learned from the effects of one-fluid viscosity and sphericity alone. To quantify and understand the effect that curvature and radial accelerationhave on the Rayleigh-Taylor instability, a comparison of the growth rates, under homologous driving conditions, between the planar and spherical interfaces is performed. The derived dispersion relation for the planar interface accounts for an underlying finite fluid region of thickness L and normal acceleration αR. Under certain conditions, the development of the most-unstable modes at a spherical interface can take place via the superposition of two adjacent spherical harmonics Yn and Yn+1. This bimodality in the evolution of disturbances in the linear regime does not have a counterpart in the planar configuration where the most-unstable modes are associated with a unique wave number.

  18. Rayleigh-Taylor instability at spherical interfaces between viscous fluids: Fluid/vacuum interface

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

    Terrones, Guillermo; Carrara, Mark D.

    2015-05-01

    For a spherical interface of radius R separating two different homogeneous regions of incompressible viscous fluids under the action of a radially directed acceleration, we perform a linear stability analysis in terms of spherical surface harmonics Y n to derive the dispersion relation. The instability behavior is investigated by computing the growth rates and the most-unstable modes as a function of the spherical harmonic degree n. This general methodology is applicable to the entire parameter space spanned by the Atwood number, the viscosity ratio, and the dimensionless number B = (αRΡ²2/μ²²)¹/³ R (where αR, Ρ2 and μ2 are the localmore » radial acceleration at the interface, and the density and viscosity of the denser overlying fluid, respectively). While the mathematical formulation here is general, this paper focuses on instability that arises at a spherical viscous fluid/vacuum interface as there is a great deal to be learned from the effects of one-fluid viscosity and sphericity alone. To quantify and understand the effect that curvature and radial accelerationhave on the Rayleigh-Taylor instability, a comparison of the growth rates, under homologous driving conditions, between the planar and spherical interfaces is performed. The derived dispersion relation for the planar interface accounts for an underlying finite fluid region of thickness L and normal acceleration αR. Under certain conditions, the development of the most-unstable modes at a spherical interface can take place via the superposition of two adjacent spherical harmonics Yn and Yn+1. This bimodality in the evolution of disturbances in the linear regime does not have a counterpart in the planar configuration where the most-unstable modes are associated with a unique wave number.« less

  19. Rayleigh-Taylor instability at spherical interfaces between viscous fluids: Fluid/vacuum interface

    SciTech Connect (OSTI)

    Terrones, Guillermo; Carrara, Mark D.

    2015-05-01

    For a spherical interface of radius R separating two different homogeneous regions of incompressible viscous fluids under the action of a radially directed acceleration, we perform a linear stability analysis in terms of spherical surface harmonics Y n to derive the dispersion relation. The instability behavior is investigated by computing the growth rates and the most-unstable modes as a function of the spherical harmonic degree n. This general methodology is applicable to the entire parameter space spanned by the Atwood number, the viscosity ratio, and the dimensionless number B = (?R?2/?)/ R (where ?R, ?2 and ?2 are the local radial acceleration at the interface, and the density and viscosity of the denser overlying fluid, respectively). While the mathematical formulation here is general, this paper focuses on instability that arises at a spherical viscous fluid/vacuum interface as there is a great deal to be learned from the effects of one-fluid viscosity and sphericity alone. To quantify and understand the effect that curvature and radial accelerationhave on the Rayleigh-Taylor instability, a comparison of the growth rates, under homologous driving conditions, between the planar and spherical interfaces is performed. The derived dispersion relation for the planar interface accounts for an underlying finite fluid region of thickness L and normal acceleration ?R. Under certain conditions, the development of the most-unstable modes at a spherical interface can take place via the superposition of two adjacent spherical harmonics Yn and Yn+1. This bimodality in the evolution of disturbances in the linear regime does not have a counterpart in the planar configuration where the most-unstable modes are associated with a unique wave number.

  20. Building the Most Powerful Spherical Tokamak | Princeton Plasma Physics Lab

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

    Announces New Innovators, Success of First Cohort | Department of Energy Building the American Clean Energy Innovation Ecosystem: Cyclotron Road Announces New Innovators, Success of First Cohort Building the American Clean Energy Innovation Ecosystem: Cyclotron Road Announces New Innovators, Success of First Cohort March 15, 2016 - 2:05pm Addthis Raymond Weitekamp and Corinne Allen utilize the resources and expertise of Lawrence Berkeley National Laboratory’s Molecular Foundry lab to

  1. NSTX-U | Princeton Plasma Physics Lab

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

    NSTX-U Subscribe to RSS - NSTX-U The National Spherical Torus Experiment (NSTX), which is undergoing a $94 million upgrade that will make it the most powerful experimental fusion facility, or tokamak, of its type in the world when work is completed in 2015. Experiments will test the ability of the upgraded spherical facility to maintain a high-performance plasma under conditions of extreme heat and power. Results could strongly influence the design of future fusion reactors. PPPL intern creates

  2. Fact Sheets | Princeton Plasma Physics Lab

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

    Fact Sheets Subscribe to RSS - Fact Sheets Image: DOE Office of Science Fact Sheet DOE Office of Science Fact Sheet Read more about DOE Office of Science Fact Sheet Building the Most Powerful Spherical Tokamak Two major new components power the National Spherical Torus Experiment-Upgrade: A widened center stack that doubles the magnetic field strength and plasma current and quintuples the length of fusion experiments, and a second neutral beam injector that doubles the tokamak's heating power.

  3. Creating a Star on Earth | Department of Energy

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

    a Star on Earth Creating a Star on Earth March 5, 2014 - 11:45am Addthis In the video above, learn how scientists at the Princeton Plasma Physics Lab are creating a star on Earth in the National Spherical Torus Experiment (NSTX), a magnetic fusion device that is used to study the physics principles of spherically shaped plasmas. | Video by Matty Greene, Energy Department. Ben Dotson Ben Dotson Former Project Coordinator for Digital Reform, Office of Public Affairs Matty Greene Matty Greene

  4. Cummins Corporate Energy Management | Department of Energy

    Energy Savers [EERE]

    Creating a Star on Earth Creating a Star on Earth March 5, 2014 - 11:45am Addthis In the video above, learn how scientists at the Princeton Plasma Physics Lab are creating a star on Earth in the National Spherical Torus Experiment (NSTX), a magnetic fusion device that is used to study the physics principles of spherically shaped plasmas. | Video by Matty Greene, Energy Department. Ben Dotson Ben Dotson Former Project Coordinator for Digital Reform, Office of Public Affairs Matty Greene Matty

  5. HEATING AND CURRENT DRIVE IN NSTX WITH ELECTRON BERNSTEIN WAVES AND HIGH HARMONIC FAST WAVES

    SciTech Connect (OSTI)

    Ram, Abhay K

    2010-06-14

    A suitable theoretical and computational framework for studying heating and current drive by electron Bernstein waves in the National Spherical Torus Experiment has been developed. This framework can also be used to study heating and current drive by electron Bernstein waves in spherical tori and other magnetic confinement devices. It is also useful in studying the propagation and damping of electron cyclotron waves in the International Thermonuclear Experimental Reactor

  6. Experimental Fusion Research | Princeton Plasma Physics Lab

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

    Experimental Fusion Research PPPL fusion research centers on the National Spherical Torus Experiment (NSTX), which is undergoing a $94 million upgrade that will make it the most powerful experimental fusion facility, or tokamak, of its type in the world when work is completed in 2014. Experiments will test the ability of the upgraded spherical facility to maintain a high-performance plasma under conditions of extreme heat and power. Results could strongly influence the design of future fusion

  7. Stefan Gerhardt | Princeton Plasma Physics Lab

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

    Stefan Gerhardt Principal Research Physicist Stefan Gerhardt is head of Experimental Research Operations for the National Spherical Torus Experiment- Upgrade (NSTX-U). He operates numerous diagnostics on NSTX-U, along with designing plasma control schemes and running physics experiments. He has previously worked on a wide variety of fusion machines, including spherical tokamaks, stellarators, and field reversed configurations. Interests Fusion energy Plasma diagnostics Plasma physics

  8. Consent Order, Lawrence Livermore National National Security...

    Office of Environmental Management (EM)

    Lawrence Livermore National National Security, LLC - WCO-2010-01 Consent Order, Lawrence Livermore National National Security, LLC - WCO-2010-01 October 29, 2010 Issued to Lawrence ...

  9. Investigation of Gas Solid Fluidized Bed Dynamics with Non-Spherical Particles

    SciTech Connect (OSTI)

    Choudhuri, Ahsan

    2013-06-30

    One of the largest challenges for 21st century is to fulfill global energy demand while also reducing detrimental impacts of energy generation and use on the environment. Gasification is a promising technology to meet the requirement of reduced emissions without compromising performance. Coal gasification is not an incinerating process; rather than burning coal completely a partial combustion takes place in the presence of steam and limited amounts of oxygen. In this controlled environment, a chemical reaction takes place to produce a mixture of clean synthetic gas. Gas-solid fluidized bed is one such type of gasification technology. During gasification, the mixing behavior of solid (coal) and gas and their flow patterns can be very complicated to understand. Many attempts have taken place in laboratory scale to understand bed hydrodynamics with spherical particles though in actual applications with coal, the particles are non-spherical. This issue drove the documented attempt presented here to investigate fluidized bed behavior using different ranges of non-spherical particles, as well as spherical. For this investigation, various parameters are controlled that included particle size, bed height, bed diameter and particle shape. Particles ranged from 355 µm to 1180 µm, bed diameter varied from 2 cm to 7 cm, two fluidized beds with diameters of 3.4 cm and 12.4 cm, for the spherical and non-spherical shaped particles that were taken into consideration. Pressure drop was measured with increasing superficial gas velocity. The velocity required in order to start to fluidize the particle is called the minimum fluidization velocity, which is one of the most important parameters to design and optimize within a gas-solid fluidized bed. This minimum fluidization velocity was monitored during investigation while observing variables factors and their effect on this velocity. From our investigation, it has been found that minimum fluidization velocity is independent of bed

  10. Density- and wavefunction-normalized Cartesian spherical harmonics for l ? 20

    SciTech Connect (OSTI)

    Michael, J. Robert; Volkov, Anatoliy

    2015-03-01

    The widely used pseudoatom formalism in experimental X-ray charge-density studies makes use of real spherical harmonics when describing the angular component of aspherical deformations of the atomic electron density in molecules and crystals. The analytical form of the density-normalized Cartesian spherical harmonic functions for up to l ? 7 and the corresponding normalization coefficients were reported previously by Paturle & Coppens. It was shown that the analytical form for normalization coefficients is available primarily forl ? 4. Only in very special cases it is possible to derive an analytical representation of the normalization coefficients for 4 < l ? 7. In most cases for l > 4 the density normalization coefficients were calculated numerically to within seven significant figures. In this study we review the literature on the density-normalized spherical harmonics, clarify the existing notations, use the PaturleCoppens method in the Wolfram Mathematicasoftware to derive the Cartesian spherical harmonics for l ? 20 and determine the density normalization coefficients to 35 significant figures, and computer-generate a Fortran90 code. The article primarily targets researchers who work in the field of experimental X-ray electron density, but may be of some use to all who are interested in Cartesian spherical harmonics.

  11. Non-astigmatic imaging with matched pairs of spherically bent reflectors

    DOE Patents [OSTI]

    Bitter, Manfred Ludwig; Hill, Kenneth Wayne; Scott, Steven Douglas; Feder, Russell; Ko, Jinseok; Rice, John E.; Ince-Cushman, Alexander Charles; Jones, Frank

    2012-07-10

    Arrangements for the point-to-point imaging of a broad spectrum of electromagnetic radiation and ultrasound at large angles of incidence employ matched pairs of spherically bent reflectors to eliminate astigmatic imaging errors. Matched pairs of spherically bent crystals or spherically bent multi-layers are used for X-rays and EUV radiation; and matched pairs of spherically bent mirrors that are appropriate for the type of radiation are used with microwaves, infrared and visible light, or ultrasound. The arrangements encompass the two cases, where the Bragg angle--the complement to the angle of incidence in optics--is between 45.degree. and 90.degree. on both crystals/mirrors or between 0.degree. and 45.degree. on the first crystal/mirror and between 45.degree. and 90.degree. on the second crystal/mirror, where the angles of convergence and divergence are equal. For x-rays and EUV radiation, also the Bragg condition is satisfied on both spherically bent crystals/multi-layers.

  12. A pseudospectral matrix method for time-dependent tensor fields on a spherical shell

    SciTech Connect (OSTI)

    Brügmann, Bernd

    2013-02-15

    We construct a pseudospectral method for the solution of time-dependent, non-linear partial differential equations on a three-dimensional spherical shell. The problem we address is the treatment of tensor fields on the sphere. As a test case we consider the evolution of a single black hole in numerical general relativity. A natural strategy would be the expansion in tensor spherical harmonics in spherical coordinates. Instead, we consider the simpler and potentially more efficient possibility of a double Fourier expansion on the sphere for tensors in Cartesian coordinates. As usual for the double Fourier method, we employ a filter to address time-step limitations and certain stability issues. We find that a tensor filter based on spin-weighted spherical harmonics is successful, while two simplified, non-spin-weighted filters do not lead to stable evolutions. The derivatives and the filter are implemented by matrix multiplication for efficiency. A key technical point is the construction of a matrix multiplication method for the spin-weighted spherical harmonic filter. As example for the efficient parallelization of the double Fourier, spin-weighted filter method we discuss an implementation on a GPU, which achieves a speed-up of up to a factor of 20 compared to a single core CPU implementation.

  13. Density- and wavefunction-normalized Cartesian spherical harmonics for l ≤ 20

    SciTech Connect (OSTI)

    Michael, J. Robert; Volkov, Anatoliy

    2015-03-01

    The widely used pseudoatom formalism in experimental X-ray charge-density studies makes use of real spherical harmonics when describing the angular component of aspherical deformations of the atomic electron density in molecules and crystals. The analytical form of the density-normalized Cartesian spherical harmonic functions for up to l ≤ 7 and the corresponding normalization coefficients were reported previously by Paturle & Coppens. It was shown that the analytical form for normalization coefficients is available primarily forl ≤ 4. Only in very special cases it is possible to derive an analytical representation of the normalization coefficients for 4 < l ≤ 7. In most cases for l > 4 the density normalization coefficients were calculated numerically to within seven significant figures. In this study we review the literature on the density-normalized spherical harmonics, clarify the existing notations, use the Paturle–Coppens method in the Wolfram Mathematicasoftware to derive the Cartesian spherical harmonics for l ≤ 20 and determine the density normalization coefficients to 35 significant figures, and computer-generate a Fortran90 code. The article primarily targets researchers who work in the field of experimental X-ray electron density, but may be of some use to all who are interested in Cartesian spherical harmonics.

  14. Modeling Ion-Exchange Processing With Spherical Resins For Cesium Removal

    SciTech Connect (OSTI)

    Hang, T.; Nash, C. A.; Aleman, S. E.

    2012-09-19

    The spherical Resorcinol-Formaldehyde and hypothetical spherical SuperLig(r) 644 ion-exchange resins are evaluated for cesium removal from radioactive waste solutions. Modeling results show that spherical SuperLig(r) 644 reduces column cycling by 50% for high-potassium solutions. Spherical Resorcinol Formaldehyde performs equally well for the lowest-potassium wastes. Less cycling reduces nitric acid usage during resin elution and sodium addition during resin regeneration, therefore, significantly decreasing life-cycle operational costs. A model assessment of the mechanism behind ''cesium bleed'' is also conducted. When a resin bed is eluted, a relatively small amount of cesium remains within resin particles. Cesium can bleed into otherwise decontaminated product in the next loading cycle. The bleed mechanism is shown to be fully isotherm-controlled vs. mass transfer controlled. Knowledge of residual post-elution cesium level and resin isotherm can be utilized to predict rate of cesium bleed in a mostly non-loaded column. Overall, this work demonstrates the versatility of the ion-exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. This evaluation justifies further development of a spherical form of the SL644 resin.

  15. Density- and wavefunction-normalized Cartesian spherical harmonics for l ≤ 20

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

    Michael, J. Robert; Volkov, Anatoliy

    2015-03-01

    The widely used pseudoatom formalism in experimental X-ray charge-density studies makes use of real spherical harmonics when describing the angular component of aspherical deformations of the atomic electron density in molecules and crystals. The analytical form of the density-normalized Cartesian spherical harmonic functions for up to l ≤ 7 and the corresponding normalization coefficients were reported previously by Paturle & Coppens. It was shown that the analytical form for normalization coefficients is available primarily forl ≤ 4. Only in very special cases it is possible to derive an analytical representation of the normalization coefficients for 4 < l ≤ 7.more » In most cases for l > 4 the density normalization coefficients were calculated numerically to within seven significant figures. In this study we review the literature on the density-normalized spherical harmonics, clarify the existing notations, use the Paturle–Coppens method in the Wolfram Mathematicasoftware to derive the Cartesian spherical harmonics for l ≤ 20 and determine the density normalization coefficients to 35 significant figures, and computer-generate a Fortran90 code. The article primarily targets researchers who work in the field of experimental X-ray electron density, but may be of some use to all who are interested in Cartesian spherical harmonics.« less

  16. SUZAKU VIEW OF THE SWIFT/BAT ACTIVE GALACTIC NUCLEI. V. TORUS STRUCTURE OF TWO LUMINOUS RADIO-LOUD ACTIVE GALACTIC NUCLEI (3C 206 AND PKS 0707-35)

    SciTech Connect (OSTI)

    Tazaki, Fumie; Ueda, Yoshihiro; Terashima, Yuichi; Mushotzky, Richard F.; Tombesi, Francesco

    2013-07-20

    We present the results from broadband X-ray spectral analysis of 3C 206 and PKS 0707-35 with Suzaku and Swift/BAT, two of the most luminous unobscured and obscured radio-loud active galactic nuclei (AGNs) with hard X-ray luminosities of 10{sup 45.5} erg s{sup -1} and 10{sup 44.9} erg s{sup -1} (14-195 keV), respectively. Based on the radio core luminosity, we estimate that the X-ray spectrum of 3C 206 contains a significant ({approx}60% in the 14-195 keV band) contribution from the jet, while it is negligible in PKS 0707-35. We can successfully model the spectra with the jet component (for 3C 206), the transmitted emission, and two reflection components from the torus and the accretion disk. The reflection strengths from the torus are found to be R{sub torus}({identical_to} {Omega}/2{pi}) = 0.29 {+-} 0.18 and 0.41 {+-} 0.18 for 3C 206 and PKS 0707-35, respectively, which are smaller than those in typical Seyfert galaxies. Utilizing the torus model by Ikeda et al., we quantify the relation between the half-opening angle of a torus ({theta}{sub oa}) and the equivalent width of an iron-K line. The observed equivalent width of 3C 206, < 71 eV, constrains the column density in the equatorial plane to N{sub H}{sup eq} <10{sup 23} cm{sup -2}, or the half-opening angle to {theta}{sub oa} > 80 Degree-Sign if N{sub H}{sup eq} =10{sup 24} cm{sup -2} is assumed. That of PKS 0707-35, 72 {+-} 36 eV, is consistent with N{sub H}{sup eq} {approx}10{sup 23} cm{sup -2}. Our results suggest that the tori in luminous radio-loud AGNs are only poorly developed. The trend is similar to that seen in radio-quiet AGNs, implying that the torus structure is not different between AGNs with jets and without jets.

  17. Representation of correlation statistics functions in heterogeneous materials using layered fast spherical harmonics expansion

    SciTech Connect (OSTI)

    Li, Dongsheng; Khaleel, Mohammad A.; Sun, Xin; Garmestani, Hamid

    2010-03-01

    Statistical correlation function, including two-point function, is one of the popular methods to digitize microstructure quantitatively. This paper investigated how to represent statistical correlations using layered fast spherical harmonics expansion. A set of spherical harmonics coefficients may be used to represent the corresponding microstructures. It is applied to represent carbon nanotube composite microstructures to demonstrate how efficiently and precisely the harmonics coefficients will characterize the microstructure. This microstructure representation methodology will dramatically improve the computational efficiencies for future works in microstructure reconstruction and property prediction.

  18. Short spatial filters with spherical lenses for high-power pulsed lasers

    SciTech Connect (OSTI)

    Burdonov, K F; Soloviev, A A; Shaikin, A A; Potemkin, A K; Egorov, A S

    2013-11-30

    We report possible employment of short spatial filters based on spherical lenses in a pulsed laser source (neodymium glass, 300 J, 1 ns). The influence of the spherical aberration on the quality of output radiation and coefficient of conversion to the second harmonics is studied. The ultra-short aberration spatial filter of length 1.9 m with an aperture of 122 mm is experimentally tested. A considerable shortening of multi-cascade pump lasers for modern petawatt laser systems is demonstrated by the employment of short spatial filters without expensive aspherical optics. (elements of laser systems)

  19. Use of spherically bent crystals to diagnose wire array z pinches

    SciTech Connect (OSTI)

    Shelkovenko, T.A.; Pikuz, S.A.; Hammer, D.A.; Ampleford, D.J.; Bland, S.N.; Bott, S.C.; Chittenden, J.P.; Lebedev, S.V.

    2004-10-01

    Spherically bent mica and quartz crystals have provided time-integrated spectra and monochromatic images in self-radiation of wire array z-pinch implosions on the MAGPIE generator (1 MA, 240 ns) at Imperial College. Diagnostics based on spherically bent crystals offer higher efficiencies than those based on flat or convex dispersion elements, allowing positioning far from the pinch with good debris shielding. A mica crystal spectrometer produced an image of the pinch in each emission line with about 100 {mu}m axial resolution. Combining the results of monochromatic imaging and spectra confirmed the presence of bright spots, probably generated by energetic electrons inside the pinch.

  20. National Laboratory

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

    Supercomputing Challenge draws more than 200 students to Los Alamos National Laboratory April 16, 2015 NOTE TO EDITORS: Media are welcome to attend the awards ceremony from 9 a.m. to noon a.m., April 21 at the Church of Christ, 2323 Diamond Drive, Los Alamos. Student teams from around New Mexico showcase year-long research projects April 20-21 LOS ALAMOS, N.M., April 16, 2015-More than 200 New Mexico students and their teachers are at Los Alamos National Laboratory April 20-21 for the 25th

  1. National Laboratory

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

    Community invited to learn about emerging technologies July 6, 2016 DisrupTech showcases innovation from Los Alamos National Laboratory LOS ALAMOS, N.M., July 6, 2016-New technologies emerging from Los Alamos National Laboratory that address everything from fusion energy to medical testing will be on display for members of the community, investors and business leaders at the DisrupTech showcase, Thursday, July 14, starting at 1:00 p.m. at the Los Alamos Golf Course Event Center. "We call it

  2. National Nuclear Security Administration | National Nuclear Security...

    National Nuclear Security Administration (NNSA)

    National Nuclear Security Administration | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile Preventing...

  3. EA-1108: The National Spherical Tokamah Experiment at the Princeton Plasma Physics Laboratory, Plainsboro Township, New Jersey

    Office of Energy Efficiency and Renewable Energy (EERE)

    This EA evaluates the environmental impacts of the proposal to support fusion physics development and technology, by providing an experimental device to investigate the confinement and performance...

  4. On the extraction of laminar flame speed and Markstein length from outwardly propagating spherical flames

    SciTech Connect (OSTI)

    Chen, Zheng [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China)

    2011-02-15

    Large discrepancies among the laminar flame speeds and Markstein lengths of methane/air mixtures measured by different researchers using the same constant-pressure spherical flame method are observed. As an effort to reduce these discrepancies, one linear model (LM, the stretched flame speed changes linearly with the stretch rate) and two non-linear models (NM I and NM II, the stretched flame speed changes non-linearly with the stretch rate) for extracting the laminar flame speed and Markstein length from propagating spherical flames are investigated. The accuracy and performance of the LM, NM I, and NM II are found to strongly depend on the Lewis number. It is demonstrated that NM I is the most accurate for mixtures with large Lewis number (positive Markstein length) while NM II is the most accurate for mixtures with small Lewis number (negative Markstein length). Therefore, in order to get accurate laminar flame speed and Markstein length from spherical flame experiments, different non-linear models should be used for different mixtures. The validity of the theoretical results is further demonstrated by numerical and experimental studies. The results of this study can be used directly in spherical flame experiments measuring the laminar flame speed and Markstein length. (author)

  5. Summation over histories for a particle in spherical orbit around a black hole

    SciTech Connect (OSTI)

    Bernido, C.C.; Aguarte, G.

    1997-08-01

    An exact path integral treatment of a relativistic scalar particle in a spherical orbit around a Reissner-Nordstr{umlt o}m and Schwarzschild black hole is presented. A closed form for the Green function and the energy spectrum are obtained. {copyright} {ital 1997} {ital The American Physical Society}

  6. Experimental study of layer mixing, relative ionic escape velocity, and electron temperature gradients in spherical multilayered targets by XUV spectroscopy

    SciTech Connect (OSTI)

    Griem, H.R.

    1990-07-01

    This past year we have undertaken experiments at the University of Rochester's Laboratory for Laser Energetics investigating layer mixing and expansion velocities of spherical targets uniformly irradiated by high intensity laser light. We performed high resolution spectroscopic measurements of spherical plasmas, produced using the Omega laser, and have observed enhanced broadening of XUV emission lines due to the expansion velocities.

  7. Synthesis of spherical LiMnPO{sub 4}/C composite microparticles

    SciTech Connect (OSTI)

    Bakenov, Zhumabay; Taniguchi, Izumi

    2011-08-15

    Highlights: {yields} We could prepare LiMnPO{sub 4}/C composites by a novel preparation method. {yields} The LiMnPO{sub 4}/C composites were spherical particles with a mean diameter of 3.65 {mu}m. {yields} The LiMnPO{sub 4}/C composite cathode exhibited 112 mAh g{sup -1} at 0.05 C. {yields} It also showed a good rate capability up to 5 C at room temperature and 55 {sup o}C. -- Abstract: Spherical LiMnPO{sub 4}/C composite microparticles were prepared by a combination of spray pyrolysis and spray drying followed by heat treatment and examined as a cathode material for lithium batteries. The structure, morphology and electrochemical performance of the resulting spherical LiMnPO{sub 4}/C microparticles were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electronic microscopy and standard electrochemical techniques. The final sample was identified as a single phase orthorhombic structure of LiMnPO{sub 4} and spherical powders with a geometric mean diameter of 3.65 {mu}m and a geometric standard deviation of 1.34. The electrochemical cells contained the spherical LiMnPO{sub 4}/C microparticles exhibited first discharge capacities of 112 and 130 mAh g{sup -1} at 0.05 C at room temperature and 55 {sup o}C, respectively. These also showed a good rate capability up to 5 C at room temperature and 55 {sup o}C.

  8. National Laboratory

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

    Ignition Facility Former Army Ranger wins Sandia-sponsored student of the year award Former Army Ranger Damon Alcorn recently received the Sandia National Laboratories-Livermore Chamber of Commerce Student of the Year Award. Presented at the Chamber's State of the City Luncheon last month, the annual award highlights a Las Positas College student with exemplary academic... NNSA makers and hackers engage innovation and partnerships NNSA's labs change the world everyday through cutting-edge

  9. NATIONAL LABORATORY

    Office of Environmental Management (EM)

    N E W U T I L I T Y B U S I N E S S M O D E L S : Utility and Regulatory Models for the Modern Era Ronald Lehr former Public Utilities Commissioner A M E R I C A ' S POWER PLAN A m e r i c a ' s P o w e r P l a n Ralph Cavanagh, Natural Resources Defense Council Peter Fox-Penner, Brattle Group Tom King, National Grid Richard Sedano, Regulatory Assistance Project Alison Silverstein, former Federal Energy Regulatory Lisa Wood, Edison Foundation's Institute for Electric Efficiency We would like to

  10. Masayuki Ono | Princeton Plasma Physics Lab

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

    Masayuki Ono Principal Research Physicist, Head, NSTX Department Masa Ono is project director of the National Spherical Torus Experiment-Upgrade (NSTX-U). Ono has led a number of PPPL research teams including those involved in the Advanced Concept Torus (ACT-1), the Current Drive Experiment (CDX), the Current Drive Experiment Upgrade (CDX-U) and the NSTX. He is a fellow of the American Physical Society and the author of more than 250 scientific papers. Interests Fusion energy NSTX-U Contact

  11. User Facilities | U.S. DOE Office of Science (SC)

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

    Facilities Fusion Energy Sciences (FES) FES Home About Research Facilities User Facilities DIII-D National Fusion Facility (DIII-D) National Spherical Torus Experiment (NSTX) Alcator C-Mod ITER External link Science Highlights Benefits of FES Funding Opportunities Fusion Energy Sciences Advisory Committee (FESAC) Community Resources Contact Information Fusion Energy Sciences U.S. Department of Energy SC-24/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-4941 F:

  12. Alcator C-Mod | U.S. DOE Office of Science (SC)

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

    Alcator C-Mod Fusion Energy Sciences (FES) FES Home About Research Facilities User Facilities DIII-D National Fusion Facility (DIII-D) National Spherical Torus Experiment (NSTX) Alcator C-Mod ITER External link Science Highlights Benefits of FES Funding Opportunities Fusion Energy Sciences Advisory Committee (FESAC) Community Resources Contact Information Fusion Energy Sciences U.S. Department of Energy SC-24/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-4941

  13. A new spherical harmonics scheme for multi-dimensional radiation transport I. Static matter configurations

    SciTech Connect (OSTI)

    Radice, David; Abdikamalov, Ernazar; Rezzolla, Luciano; Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA ; Ott, Christian D.

    2013-06-01

    Recent work by McClarren and Hauck (2010) [31] suggests that the filtered spherical harmonics method represents an efficient, robust, and accurate method for radiation transport, at least in the two-dimensional (2D) case. We extend their work to the three-dimensional (3D) case and find that all of the advantages of the filtering approach identified in 2D are present also in the 3D case. We reformulate the filter operation in a way that is independent of the timestep and of the spatial discretization. We also explore different second- and fourth-order filters and find that the second-order ones yield significantly better results. Overall, our findings suggest that the filtered spherical harmonics approach represents a very promising method for 3D radiation transport calculations.

  14. Spherically symmetric self-dual Yang-Mills instantons on curved backgrounds in all even dimensions

    SciTech Connect (OSTI)

    Radu, Eugen; Tchrakian, D. H.; Yang Yisong

    2008-02-15

    We present several different classes of self-dual Yang-Mills instantons in all even d-dimensional backgrounds with Euclidean signature. In d=4p+2 the only solutions we found are on constant curvature dS (de Sitter) and AdS (anti-de Sitter) backgrounds and are evaluated in closed form. In d=4p an interesting class of instantons are given on black hole backgrounds. One class of solutions are (Euclidean) time-independent and spherically symmetric in d-1 dimensions, and the other class are spherically symmetric in all d dimensions. Some of the solutions in the former class are evaluated numerically, all the rest being given in closed form. Analytic proofs of existence covering all numerically evaluated solutions are given. All instantons studied have finite action and vanishing energy momentum tensor and do not disturb the geometry.

  15. High-resolution monochromatic x-ray imaging system based on spherically bent crystals

    SciTech Connect (OSTI)

    Aglitskiy, Y.; Lehecka, T.; Obenschain, S.; Bodner, S.; Pawley, C.; Gerber, K.; Sethian, J.; Brown, C.M.; Seely, J.; Feldman, U.; Holland, G.

    1998-08-01

    We have developed an improved x-ray imaging system based on spherically curve crystals. It is designed and used for diagnostics of targets ablatively accelerated by the Nike KrF laser. A spherically curved quartz crystal (2d=6.687 {Angstrom}, R=200 mm) has been used to produce monochromatic backlit images with the He-like Si resonance line (1865 eV) as the source of radiation. The spatial resolution of the x-ray optical system is 1.7 {mu}m in selected places and 2{endash}3 {mu}m over a larger area. Time-resolved backlit monochromatic images of polystyrene planar targets driven by the Nike facility have been obtained with a spatial resolution of 2.5 {mu}m in selected places and 5 {mu}m over the focal spot of the Nike laser. {copyright} 1998 Optical Society of America

  16. High resolution monochromatic X-ray imaging system based on spherically bent crystals

    SciTech Connect (OSTI)

    Aglitskiy, Y.; Lehecka, T.; Obenschain, S.; Bodner, S.; Pawley, C.; Gerber, K.; Sethian, J.; Brown, C. M.; Seely, J.; Feldman, U.; Holland, G.

    1997-05-05

    We have developed a new X-ray imaging system based on spherically curved crystals. It is designed and used for diagnostics of targets ablatively accelerated by the Nike KrF laser. The imaging system is used for plasma diagnostics of the main target and for characterization of potential backlighters. A spherically curved quartz crystal (2d=6.687 A, R=200 mm) is used to produce monochromatic backlit images with the He-like Si resonance line (1865 eV) as the source of radiation. The spatial resolution of the X-ray optical system is 3-4 {mu}m. Time resolved backlit monochromatic images of CH planar targets driven by the Nike facility have been obtained with 6-7 {mu}m spatial resolution.

  17. High resolution monochromatic X-ray imaging system based on spherically bent crystals

    SciTech Connect (OSTI)

    Aglitskiy, Y.; Lehecka, T.; Obenschain, S.; Bodner, S.; Pawley, C.; Gerber, K.; Sethian, J.; Brown, C.M.; Seely, J.; Feldman, U.; Holland, G.

    1997-05-01

    We have developed a new X-ray imaging system based on spherically curved crystals. It is designed and used for diagnostics of targets ablatively accelerated by the Nike KrF laser [1,2]. The imaging system is used for plasma diagnostics of the main target and for characterization of potential backlighters. A spherically curved quartz crystal (2d=6.687{Angstrom}, R=200mm) is used to produce monochromatic backlit images with the He-like Si resonance line (1865 eV) as the source of radiation. The spatial resolution of the X-ray optical system is 3{endash}4 {mu}m. Time resolved backlit monochromatic images of CH planar targets driven by the Nike facility have been obtained with 6{endash}7 {mu}m spatial resolution. {copyright} {ital 1997 American Institute of Physics.}

  18. Distribution of ion current density on a rotating spherical cap substrate during ion-assisted deposition

    SciTech Connect (OSTI)

    Marushka, Viktor; Zabeida, Oleg Martinu, Ludvik

    2014-11-01

    The uniformity of ion density is critical for applications relying on the ion assisted deposition technique for the fabrication of the high quality thin films. The authors propose and describe here a method allowing one to calculate the ion density distribution on spherical substrate holders under stationary and rotating conditions for different positions of the ion source. The ion beam shape was approximated by a cos{sup n} function, and the ion current density was represented by a function inversely proportional to the distance from the ion source in accordance with our experimental results. As an example, a calculation of the current density distribution on the spherical cap substrate was performed for a broad beam ion source operated with an anode current of 3?A. The authors propose an approach for process optimization with respect to the ion source position and its inclination, in terms of uniformity and absolute value of the ion current density.

  19. Scalar and tensor spherical harmonics expansion of the velocity correlation in homogeneous anisotropic turbulence

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

    Rubinstein, Robert; Kurien, Susan; Cambon, Claude

    2015-06-22

    The representation theory of the rotation group is applied to construct a series expansion of the correlation tensor in homogeneous anisotropic turbulence. The resolution of angular dependence is the main analytical difficulty posed by anisotropic turbulence; representation theory parametrises this dependence by a tensor analogue of the standard spherical harmonics expansion of a scalar. As a result, the series expansion is formulated in terms of explicitly constructed tensor bases with scalar coefficients determined by angular moments of the correlation tensor.

  20. Evolution of Nuclear Observables in the Spherical-Deformed Phase Transition and the Interacting Boson Model

    SciTech Connect (OSTI)

    Zamfir, N.V.; McCutchan, E.A.; Casten, R.F.

    2004-09-13

    We discuss the empirical evolution of structure in the spherical-deformed phase transition region in the context of the behavior of basic structural signatures in the IBA symmetry triangle. The main signatures of a phase/shape transition are a sharp increase in R{sub 4/2} {identical_to} E(4{sub 1}{sup +})/E(2{sub 1}{sup +}) and minima in E(0{sub 2}{sup +}) and E(2{sub {gamma}}{sup +})

  1. Method of determining elastic and plastic mechanical properties of ceramic materials using spherical indenters

    DOE Patents [OSTI]

    Adler, Thomas A.

    1996-01-01

    The invention pertains a method of determining elastic and plastic mechanical properties of ceramics, intermetallics, metals, plastics and other hard, brittle materials which fracture prior to plastically deforming when loads are applied. Elastic and plastic mechanical properties of ceramic materials are determined using spherical indenters. The method is most useful for measuring and calculating the plastic and elastic deformation of hard, brittle materials with low values of elastic modulus to hardness.

  2. Coupled escape probability for an asymmetric spherical case: Modeling optically thick comets

    SciTech Connect (OSTI)

    Gersch, Alan M.; A'Hearn, Michael F.

    2014-05-20

    We have adapted Coupled Escape Probability, a new exact method of solving radiative transfer problems, for use in asymmetrical spherical situations. Our model is intended specifically for use in modeling optically thick cometary comae, although not limited to such use. This method enables the accurate modeling of comets' spectra even in the potentially optically thick regions nearest the nucleus, such as those seen in Deep Impact observations of 9P/Tempel 1 and EPOXI observations of 103P/Hartley 2.

  3. General variational principle for spherically symmetric perturbations in diffeomorphism covariant theories

    SciTech Connect (OSTI)

    Seifert, Michael D.; Wald, Robert M.

    2007-04-15

    We present a general method for the analysis of the stability of static, spherically symmetric solutions to spherically symmetric perturbations in an arbitrary diffeomorphism covariant Lagrangian field theory. Our method involves fixing the gauge and solving the linearized gravitational field equations to eliminate the metric perturbation variables in terms of the matter variables. In a wide class of cases--which include f(R) gravity, the Einstein-aether theory of Jacobson and Mattingly, and Bekenstein's TeVeS theory--the remaining perturbation equations for the matter fields are second order in time. We show how the symplectic current arising from the original Lagrangian gives rise to a symmetric bilinear form on the variables of the reduced theory. If this bilinear form is positive definite, it provides an inner product that puts the equations of motion of the reduced theory into a self-adjoint form. A variational principle can then be written down immediately, from which stability can be tested readily. We illustrate our method in the case of Einstein's equation with perfect fluid matter, thereby rederiving, in a systematic manner, Chandrasekhar's variational principle for radial oscillations of spherically symmetric stars. In a subsequent paper, we will apply our analysis to f(R) gravity, the Einstein-aether theory, and Bekenstein's TeVeS theory.

  4. Linear analysis on the growth of non-spherical perturbations in supersonic accretion flows

    SciTech Connect (OSTI)

    Takahashi, Kazuya; Yamada, Shoichi

    2014-10-20

    We analyzed the growth of non-spherical perturbations in supersonic accretion flows. We have in mind an application to the post-bounce phase of core-collapse supernovae (CCSNe). Such non-spherical perturbations have been suggested by a series of papers by Arnett, who has numerically investigated violent convections in the outer layers of pre-collapse stars. Moreover, Couch and Ott demonstrated in their numerical simulations that such perturbations may lead to a successful supernova even for a progenitor that fails to explode without fluctuations. This study investigated the linear growth of perturbations during the infall onto a stalled shock wave. The linearized equations are solved as an initial and boundary value problem with the use of a Laplace transform. The background is a Bondi accretion flow whose parameters are chosen to mimic the 15 M {sub ☉} progenitor model by Woosley and Heger, which is supposed to be a typical progenitor of CCSNe. We found that the perturbations that are given at a large radius grow as they flow down to the shock radius; the density perturbations can be amplified by a factor of 30, for example. We analytically show that the growth rate is proportional to l, the index of the spherical harmonics. We also found that the perturbations oscillate in time with frequencies that are similar to those of the standing accretion shock instability. This may have an implication for shock revival in CCSNe, which will be investigated in our forthcoming paper in more detail.

  5. Spherically symmetric analysis on open FLRW solution in non-linear massive gravity

    SciTech Connect (OSTI)

    Chiang, Chien-I; Izumi, Keisuke; Chen, Pisin E-mail: izumi@phys.ntu.edu.tw

    2012-12-01

    We study non-linear massive gravity in the spherically symmetric context. Our main motivation is to investigate the effect of helicity-0 mode which remains elusive after analysis of cosmological perturbation around an open Friedmann-Lemaitre-Robertson-Walker (FLRW) universe. The non-linear form of the effective energy-momentum tensor stemming from the mass term is derived for the spherically symmetric case. Only in the special case where the area of the two sphere is not deviated away from the FLRW universe, the effective energy momentum tensor becomes completely the same as that of cosmological constant. This opens a window for discriminating the non-linear massive gravity from general relativity (GR). Indeed, by further solving these spherically symmetric gravitational equations of motion in vacuum to the linear order, we obtain a solution which has an arbitrary time-dependent parameter. In GR, this parameter is a constant and corresponds to the mass of a star. Our result means that Birkhoff's theorem no longer holds in the non-linear massive gravity and suggests that energy can probably be emitted superluminously (with infinite speed) on the self-accelerating background by the helicity-0 mode, which could be a potential plague of this theory.

  6. National Security Science | Los National Alamos Laboratory

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

    this Issue (pdf) In 2012 NSS received an NNSA Defense Programs AWARD OF EXCELLENCE National Security Science Mail Stop A142 Los Alamos National Laboratory Los Alamos, NM...

  7. Sandia National Laboratories | National Nuclear Security Administratio...

    National Nuclear Security Administration (NNSA)

    nuclear weapons Bay Area national labs team to tackle long-standing automotive hydrogen storage challenge Sandia National Laboratories chemist Mark Allendorf, shown here at...

  8. National System Templates: Building Sustainable National Inventory...

    Open Energy Info (EERE)

    System Templates: Building Sustainable National Inventory Management Systems Jump to: navigation, search Tool Summary LAUNCH TOOL Name: National System Templates: Building...

  9. Lawrence Livermore National Laboratory Lawrence Livermore National...

    National Nuclear Security Administration (NNSA)

    "Green" supercomputer reduces energy footprint by 75% "Green" supercomputer reduces energy footprint by 75% Lawrence Livermore National Laboratory Lawrence Livermore National ...

  10. National Security Science

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

    Science National Security Science Latest Issue:July 2015 past issues All Issues submit National Security Science Showcasing Los Alamos National Laboratory's work on nuclear...

  11. National Security Science Archive

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

    Science NSS Archive National Security Science Latest Issue:July 2015 past issues All Issues submit National Security Science Archive National Security Science magazine...

  12. National Laboratory Impact Initiative

    Broader source: Energy.gov [DOE]

    The National Laboratory Impact Initiative supports the relationship between the Office of Energy Efficiency & Renewable Energy and the national laboratory enterprise.  The national laboratories...

  13. National Security Complex | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    Security Complex Y-12 National Security Complex Completes W69 Dismantlement

  14. National Security Facility (NSF) | Argonne National Laboratory

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

    National Security Facility (NSF) National Security Facility (NSF) Argonne National Laboratory's National Security Facility (NSF) is a flexible, state-of-the-art secure user facility that contains multiple national security networks, video teleconference capability, high-resolution graphics support, a fully powered and cooled data center, multi-level training facilities, and conferencing facilities. The NSF provides tools and resources to enable and strengthen connections between government

  15. National Postdoctoral Association | Argonne National Laboratory

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

    National Postdoctoral Association The National Postdoctoral Association (NPA) is a member-driven organization that provides a unique, national voice for postdoctoral scholars. Since 2003, we have taken on the ambitious agenda to enhance the quality of the postdoctoral experience in the U.S. We have assumed a leadership role in addressing the many issues confronting the postdoctoral community that are national in scope and requiring action beyond the local level. Read more. Argonne National Lab

  16. Safety overview of the National Ignition Facility

    SciTech Connect (OSTI)

    Brereton, S.J.; McLouth, L.; Odell, B.; Singh, M.; Tobin, M.; Trent, M.

    1996-05-23

    The National Ignition Facility (NIF) is a proposed US Department of Energy inertial confinement laser fusion facility. The candidate sites for locating the NIF are: Los Alamos National Laboratory, Sandia National Laboratory, the Nevada Test Site, and Lawrence Livermore National Laboratory (LLNL), the preferred site. The NIF will operate by focusing 192 laser beams onto a tiny deuterium- tritium target located at the center of a spherical target chamber. The NIF mission is to achieve inertial confinement fusion (ICF) ignition, access physical conditions in matter of interest to nuclear weapons physics, provide an above ground simulation capability for nuclear weapons effects testing, and contribute to the development of inertial fusion for electrical power production. The NIF has been classified as a radiological, low hazard facility on the basis of a preliminary hazards analysis and according to the DOE methodology for facility classification. This requires that a safety analysis be prepared under DOE Order 5481.1B, Safety Analysis and Review System. A draft Preliminary Safety Analysis Report (PSAR) has been written, and this will be finalized later in 1996. This paper summarizes the safety issues associated with the operation of the NIF. It provides an overview of the hazards, estimates maximum routine and accidental exposures for the preferred site of LLNL, and concludes that the risks from NIF operations are low.

  17. Safety overview of the National Ignition Facility

    SciTech Connect (OSTI)

    Brereton, S.; McLouth, L.; Odell, B.; Singh, M.; Tobin, M.; Trent, M.; Yatabe, J.

    1996-12-31

    The National Ignition Facility (NIF) is a proposed U.S. Department of Energy inertial confinement laser fusion facility. The candidate sites for locating the NIF are: Los Alamos National Laboratory, Sandia National Laboratory - New Mexico, the Nevada Test Site, and Lawrence Livermore National Laboratory (LLNL), the preferred site. The NIF will operate by focusing 192 laser beams onto a tiny deuterium-tritium target located at the center of a spherical target chamber. The NIF has been classified as a radiological, low hazard facility on the basis of a preliminary hazards analysis and according to the DOE methodology for facility classification. This requires that a safety analysis be prepared under DOE Order 5481.1B, Safety Analysis and Review System. A draft Preliminary Safety Analysis Report (PSAR) has been written, and this will be finalized later in 1996, after independent review. This paper summarizes the safety issues associated with the construction and operation of the NIF. It provides an overview of the hazards, estimates maximum routine and accidental exposures for the preferred site of LLNL, and concludes that the risks from NIF operations are low. 9 refs., 2 figs., 2 tabs.

  18. Sphericity and symmetry breaking in the formation of Frank–Kasper phases from one component materials

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

    Lee, Sangwoo; Leighton, Chris; Bates, Frank S.

    2014-11-05

    Frank–Kasper phases are tetrahedrally packed structures occurring in numerous materials, from elements to intermetallics to self-assembled soft materials. They exhibit complex manifolds of Wigner–Seitz cells with many-faceted polyhedra, forming an important bridge between the simple close-packed periodic and quasiperiodic crystals. The recent discovery of the Frank–Kasper σ-phase in diblock and tetrablock polymers stimulated the experiments reported here on a poly(isoprene-b-lactide) diblock copolymer melt. Thus, analysis of small-angle X-ray scattering and mechanical spectroscopy exposes an undiscovered competition between the tendency to form self-assembled particles with spherical symmetry, and the necessity to fill space at uniform density within the framework imposed bymore » the lattice. We thus deduce surprising analogies between the symmetry breaking at the body-centered cubic phase to σ-phase transition in diblock copolymers, mediated by exchange of mass, and the symmetry breaking in certain metals and alloys (such as the elements Mn and U), mediated by exchange of charge. Similar connections are made between the role of sphericity in real space for polymer systems, and the role of sphericity in reciprocal space for metallic systems such as intermetallic compounds and alloys. These findings establish new links between disparate materials classes, provide opportunities to improve the understanding of complex crystallization by building on synergies between hard and soft matter, and, perhaps most significantly, challenge the view that the symmetry breaking required to form reduced symmetry structures (possibly even quasiperiodic crystals) requires particles with multiple predetermined shapes and/or sizes.« less

  19. Sphericity and symmetry breaking in the formation of Frank–Kasper phases from one component materials

    SciTech Connect (OSTI)

    Lee, Sangwoo; Leighton, Chris; Bates, Frank S.

    2014-11-05

    Frank–Kasper phases are tetrahedrally packed structures occurring in numerous materials, from elements to intermetallics to self-assembled soft materials. They exhibit complex manifolds of Wigner–Seitz cells with many-faceted polyhedra, forming an important bridge between the simple close-packed periodic and quasiperiodic crystals. The recent discovery of the Frank–Kasper σ-phase in diblock and tetrablock polymers stimulated the experiments reported here on a poly(isoprene-b-lactide) diblock copolymer melt. Thus, analysis of small-angle X-ray scattering and mechanical spectroscopy exposes an undiscovered competition between the tendency to form self-assembled particles with spherical symmetry, and the necessity to fill space at uniform density within the framework imposed by the lattice. We thus deduce surprising analogies between the symmetry breaking at the body-centered cubic phase to σ-phase transition in diblock copolymers, mediated by exchange of mass, and the symmetry breaking in certain metals and alloys (such as the elements Mn and U), mediated by exchange of charge. Similar connections are made between the role of sphericity in real space for polymer systems, and the role of sphericity in reciprocal space for metallic systems such as intermetallic compounds and alloys. These findings establish new links between disparate materials classes, provide opportunities to improve the understanding of complex crystallization by building on synergies between hard and soft matter, and, perhaps most significantly, challenge the view that the symmetry breaking required to form reduced symmetry structures (possibly even quasiperiodic crystals) requires particles with multiple predetermined shapes and/or sizes.

  20. ABAREX -- A neutron spherical optical-statistical-model code -- A user`s manual

    SciTech Connect (OSTI)

    Smith, A.B.; Lawson, R.D.

    1998-06-01

    The contemporary version of the neutron spherical optical-statistical-model code ABAREX is summarized with the objective of providing detailed operational guidance for the user. The physical concepts involved are very briefly outlined. The code is described in some detail and a number of explicit examples are given. With this document one should very quickly become fluent with the use of ABAREX. While the code has operated on a number of computing systems, this version is specifically tailored for the VAX/VMS work station and/or the IBM-compatible personal computer.

  1. Spherical cavity-expansion forcing function in PRONTO 3D for application to penetration problems

    SciTech Connect (OSTI)

    Warren, T.L.; Tabbara, M.R.

    1997-05-01

    In certain penetration events the primary mode of deformation of the target can be approximated by known analytical expressions. In the context of an analysis code, this approximation eliminates the need for modeling the target as well as the need for a contact algorithm. This technique substantially reduces execution time. In this spirit, a forcing function which is derived from a spherical-cavity expansion analysis has been implemented in PRONTO 3D. This implementation is capable of computing the structural and component responses of a projectile due to three dimensional penetration events. Sample problems demonstrate good agreement with experimental and analytical results.

  2. Machine imparting complex rotary motion for lapping a spherical inner diameter

    DOE Patents [OSTI]

    Carroll, T.A.; Yetter, H.H.

    1985-01-30

    An apparatus for imparting complex rotary motion is used to lap an inner spherical diameter surface of a workpiece. A lapping tool consists of a dome and rod mounted along the dome's vertical axis. The workpiece containing the lapping tool is held in a gimbal which uses power derived from a secondary takeoff means to impart rotary motion about a horizontal axis. The gimbal is rotated about a vertical axis by a take means while mounted at a radially outward position on a rotating arm.

  3. Machine imparting complex rotary motion for lapping a spherical inner diameter

    DOE Patents [OSTI]

    Carroll, Thomas A.; Yetter, Harold H.

    1986-01-01

    An apparatus for imparting complex rotary motion is used to lap an inner spherical diameter surface of a workpiece. A lapping tool consists of a dome and rod mounted along the dome's vertical axis. The workpiece containing the lapping tool is held in a gimbal which uses power derived from a secondary takeoff means to impart rotary motion about a horizontal axis. The gimbal is rotated about a vertical axis by a take means while mounted at a radially outward position on a rotating arm.

  4. CORRELATED AND ZONAL ERRORS OF GLOBAL ASTROMETRIC MISSIONS: A SPHERICAL HARMONIC SOLUTION

    SciTech Connect (OSTI)

    Makarov, V. V.; Dorland, B. N.; Gaume, R. A.; Hennessy, G. S.; Berghea, C. T.; Dudik, R. P.; Schmitt, H. R.

    2012-07-15

    We propose a computer-efficient and accurate method of estimating spatially correlated errors in astrometric positions, parallaxes, and proper motions obtained by space- and ground-based astrometry missions. In our method, the simulated observational equations are set up and solved for the coefficients of scalar and vector spherical harmonics representing the output errors rather than for individual objects in the output catalog. Both accidental and systematic correlated errors of astrometric parameters can be accurately estimated. The method is demonstrated on the example of the JMAPS mission, but can be used for other projects in space astrometry, such as SIM or JASMINE.

  5. SPHERICALLY SYMMETRIC NLTE MODEL ATMOSPHERES OF HOT HYDROGEN-HELIUM FIRST STARS

    SciTech Connect (OSTI)

    Kubat, Jiri

    2012-12-15

    We present results of our calculations of NLTE model stellar atmospheres for hot Population III stars composed of hydrogen and helium. We use our own computer code for the calculation of spherically symmetric NLTE model atmospheres in hydrostatic and radiative equilibrium. The model atmospheres are then used for the calculation of emergent fluxes. These fluxes serve to evaluate the flow of high-energy photons for energies higher than ionization energies of hydrogen and helium, the so-called ionizing photon fluxes. We also present the time evolution of the ionizing photon fluxes.

  6. National Ignition Facility | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    National Ignition Facility Glass amplifiers in Laser Bay 2 at the National Ignition Facility. The construction of the 192-beam 1.8 MJ UV NIF, the world's most energetic laser, was ...

  7. Los Alamos National Lab: National Security Science

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

    more.. Charlie McMillan, Director of Los Alamos National Laboratory 1:08 Charlie McMillan, Director of Los Alamos National Laboratory, describes how the Lab provides...

  8. Spherical collapse in Galileon gravity: fifth force solutions, halo mass function and halo bias

    SciTech Connect (OSTI)

    Barreira, Alexandre; Li, Baojiu; Baugh, Carlton M.; Pascoli, Silvia E-mail: liqb@mail.ihep.ac.cn E-mail: silvia.pascoli@durham.ac.uk

    2013-11-01

    We study spherical collapse in the Quartic and Quintic Covariant Galileon gravity models within the framework of the excursion set formalism. We derive the nonlinear spherically symmetric equations in the quasi-static and weak-field limits, focusing on model parameters that fit current CMB, SNIa and BAO data. We demonstrate that the equations of the Quintic model do not admit physical solutions of the fifth force in high density regions, which prevents the study of structure formation in this model. For the Quartic model, we show that the effective gravitational strength deviates from the standard value at late times (z?<1), becoming larger if the density is low, but smaller if the density is high. This shows that the Vainshtein mechanism at high densities is not enough to screen all of the modifications of gravity. This makes halos that collapse at z?<1 feel an overall weaker gravity, which suppresses halo formation. However, the matter density in the Quartic model is higher than in standard ?CDM, which boosts structure formation and dominates over the effect of the weaker gravity. In the Quartic model there is a significant overabundance of high-mass halos relative to ?CDM. Dark matter halos are also less biased than in ?CDM, with the difference increasing appreciably with halo mass. However, our results suggest that the bias may not be small enough to fully reconcile the predicted matter power spectrum with LRG clustering data.

  9. Nonlinear effects in the extraction of laminar flame speeds from expanding spherical flames

    SciTech Connect (OSTI)

    Kelley, A.P.; Law, C.K.

    2009-09-15

    Various factors affecting the determination of laminar flames speeds from outwardly propagating spherical flames in a constant-pressure combustion chamber were considered, with emphasis on the nonlinear variation of the stretched flame speed to the flame stretch rate, and the associated need to nonlinearly extrapolate the stretched flame speed to yield an accurate determination of the laminar flame speed and Markstein length. Experiments were conducted for lean and rich n-butane/air flames at 1atm initial pressure, demonstrating the complex and nonlinear nature of the dynamics of flame evolution, and the strong influences of the ignition transient and chamber confinement during the initial and final periods of the flame propagation, respectively. These experimental data were analyzed using the nonlinear relation between the stretched flame speed and stretch rate, yielding laminar flame speeds that agree well with data determined from alternate flame configurations. It is further suggested that the fidelity in the extraction of the laminar flame speed from expanding spherical flames can be facilitated by using small ignition energy and a large combustion chamber. (author)

  10. Region with trapped surfaces in spherical symmetry, its core, and their boundaries

    SciTech Connect (OSTI)

    Bengtsson, Ingemar; Senovilla, Jose M. M.

    2011-02-15

    We consider the region T in spacetime containing future-trapped closed surfaces and its boundary B, and derive some of their general properties. We then concentrate on the case of spherical symmetry, but the methods we use are general and applicable to other situations. We argue that closed trapped surfaces have a nonlocal property, ''clairvoyance'', which is inherited by B. We prove that B is not a marginally trapped tube in general, and that it can have portions in regions whose whole past is flat. For asymptotically flat black holes, we identify a general past barrier, well inside the event horizon, to the location of B under physically reasonable conditions. We also define the core Z of the trapped region as that part of T which is indispensable to sustain closed trapped surfaces. We prove that the unique spherically symmetric dynamical horizon is the boundary of such a core, and we argue that this may serve to single it out. To illustrate the results, some explicit examples are discussed, namely, Robertson-Walker geometries and the imploding Vaidya spacetime.

  11. New model of calculating the energy transfer efficiency for the spherical theta-pinch device

    SciTech Connect (OSTI)

    Xu, G.; Hock, C.; Loisch, G.; Jacoby, J.; Xiao, G.; Zhao, Y.; Weyrich, K.; Li, Y.

    2015-05-15

    Ion-beam-plasma-interaction plays an important role in the field of warm dense matter and inertial confinement fusion. A spherical theta pinch is proposed to act as a plasma target in various applications including a plasma stripper cell. One key parameter for such applications is the free electron density. A linear dependency of this density to the amount of energy transferred into the plasma from an energy storage was found by Teske. Since the amount of stored energy is known, the energy transfer efficiency is a reliable parameter for the design of a spherical theta pinch device. As the main assumption of a constant reflected plasma resistance is contradictory by the measured data, the traditional two models of energy transfer efficiency will lead to wrong results. From measurements, the parasitic resistance is derived as constant. Based on this key parameter, a new model is proposed. Due to no assumption, the new model is considered as exact. Further, a comparison of these three different models is given at a fixed operation voltage for the full range of working gas pressures. Due to the inappropriate assumptions included in the traditional models, one owns a tendency to overestimate the energy transfer efficiency whereas the other leads to an underestimation. Applying our new model to a wide spread set of operation voltages and gas pressures, an overall picture of the energy transfer efficiency results.

  12. Method for producing solid or hollow spherical particles of chosen chemical composition and of uniform size

    DOE Patents [OSTI]

    Hendricks, Charles D.

    1988-01-01

    A method is provided for producing commercially large quantities of high melting temperature solid or hollow spherical particles of a predetermined chemical composition and having a uniform and controlled size distribution. An end (18, 50, 90) of a solid or hollow rod (20, 48, 88) of the material is rendered molten by a laser beam (14, 44, 82). Because of this, there is no possibility of the molten rod material becoming contaminated with extraneous material. In various aspects of the invention, an electric field is applied to the molten rod end (18, 90), and/or the molten rod end (50, 90) is vibrated. In a further aspect of the invention, a high-frequency component is added to the electric field applied to the molten end of the rod (90). By controlling the internal pressure of the rod, the rate at which the rod is introduced into the laser beam, the environment of the process, the vibration amplitude and frequency of the molten rod end, the electric field intensity applied to the molten rod end, and the frequency and intensity of the component added to the electric field, the uniformity and size distribution of the solid or hollow spherical particles (122) produced by the inventive method is controlled. The polarity of the electric field applied to the molten rod end can be chosen to eliminate backstreaming electrons, which tend to produce run-away heating in the rod, from the process.

  13. Quantum superposition principle and gravitational collapse: Scattering times for spherical shells

    SciTech Connect (OSTI)

    Ambrus, M.; Hajicek, P.

    2005-09-15

    A quantum theory of spherically symmetric thin shells of null dust and their gravitational field is studied. In Nucl. Phys. B603, 555 (2001), it has been shown how superpositions of quantum states with different geometries can lead to a solution of the singularity problem and black hole information paradox: the shells bounce and re-expand and the evolution is unitary. The corresponding scattering times will be defined in the present paper. To this aim, a spherical mirror of radius R{sub m} is introduced. The classical formula for scattering times of the shell reflected from the mirror is extended to quantum theory. The scattering times and their spreads are calculated. They have a regular limit for R{sub m}{yields}0 and they reveal a resonance at E{sub m}=c{sup 4}R{sub m}/2G. Except for the resonance, they are roughly of the order of the time the light needs to cross the flat space distance between the observer and the mirror. Some ideas are discussed of how the construction of the quantum theory could be changed so that the scattering times become considerably longer.

  14. National Laboratory]; Chertkov, Michael [Los Alamos National...

    Office of Scientific and Technical Information (OSTI)

    Chertkov, Michael Los Alamos National Laboratory Construction and Facility Engineering; Energy Conservation, Consumption, & Utilization(32); Energy Planning, Policy, &...

  15. Chemist, Sandia National Laboratories | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration | (NNSA) Chemist, Sandia National Laboratories Jerilyn Timlin Jerilyn Timlin October 2009 National Institutes of Health (NIH) New Innovator Award Jerilyn Timlin, a chemist at Sandia National Laboratories, has been presented by the National Institutes of Health (NIH) with a New Innovator Award, one of 55 such awards granted by the NIH this year. The award encourages researchers to explore bold ideas that have the potential to catapult fields forward and speed the translation of

  16. Cognitive Informatics, Pacific Northwest National Laboratory | National

    National Nuclear Security Administration (NNSA)

    Nuclear Security Administration | (NNSA) Cognitive Informatics, Pacific Northwest National Laboratory Frank Greitzer Frank Greitzer Frank Greitzer was invited to be one of six "provocateurs," selected internationally by the National Science Foundation (NSF) and the National Institute of Standards and Technology (NIST), to participate in planning of, and present to a National Academies workshop on Usability, Security, and Privacy of Computer Systems Workshop held July 20-22, 2009 in

  17. Sandia National Laboratories: National Security Programs

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

    Nuclear Weapons Defense Systems International, Homeland, & Nuclear Security Energy and Climate Facebook Twitter YouTube Flickr RSS Programs National Security Programs We strive to become the laboratory that the U.S. turns to first for technology solutions to the most challenging problems that threaten peace and freedom for our nation and the globe. At Sandia, national security is our business. We apply advanced science and engineering to help our nation and allies detect, repel, defeat, or

  18. National Security Photo Gallery | Argonne National Laboratory

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

    Competition | National Nuclear Security Administration | (NNSA) Solicitation National Security Campus Management and Operating (M&O) Contract Competition Contract Competition Home Page Welcome to the National Nuclear Security Administration's website for the National Security Campus (NSC) Management and Operating Contract Competition. The NSC in Kansas City, MO, is situated on approximately 177 acres. The facility is leased for the NNSA by the General Services Administration. Satellite

  19. Lawrence Berkeley National Laboratory | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration Berkeley National Laboratory NNSA engineer teaches young people STEM, makes mark on Livermore lab communities. Rick Roses Job: Federal fire protection engineer and explosives safety engineer Educational background: Bachelor's degree in mechanical engineering, University of California, Berkeley (1984) and a master's in national resource strategy, National Defense University (2010). Rick Roses,... Lab employees, officials, business leaders dedicate Livermore Solar Center

  20. Linear stability of spherically symmetric and wormhole solutions supported by the sine-Gordon ghost scalar field

    SciTech Connect (OSTI)

    Dzhunushaliev, Vladimir; Folomeev, Vladimir; Singleton, Douglas; Myrzakulov, Ratbay

    2010-08-15

    In this paper we investigate wormhole and spherically symmetric solutions in four-dimensional gravity plus a matter source consisting of a ghost scalar field with a sine-Gordon potential. For the wormhole solutions we also include the possibility of electric and/or magnetic charges. For both types of solutions we perform a linear stability analysis and show that the wormhole solutions are stable and that when one turns on the electric and/or magnetic field the solution remains stable. The linear stability analysis of the spherically symmetric solutions indicates that they can be stable or unstable depending on one of the parameters of the system. This result for the spherically symmetric solution is nontrivial since a previous investigation of four-dimensional gravity plus a ghost scalar field with a {lambda}{phi}{sup 4} interaction found only unstable spherically symmetric solutions. Both the wormhole and spherically symmetric solutions presented here asymptotically go to anti-de Sitter space-time.

  1. Method for making fine and ultrafine spherical particles of zirconium titanate and other mixed metal oxide systems

    DOE Patents [OSTI]

    Hu, Michael Z.

    2006-05-23

    Disclosed is a method for making amorphous spherical particles of zirconium titanate and crystalline spherical particles of zirconium titanate comprising the steps of mixing an aqueous solution of zirconium salt and an aqueous solution of titanium salt into a mixed solution having equal moles of zirconium and titanium and having a total salt concentration in the range from 0.01 M to about 0.5 M. A stearic dispersant and an organic solvent is added to the mixed salt solution, subjecting the zirconium salt and the titanium salt in the mixed solution to a coprecipitation reaction forming a solution containing amorphous spherical particles of zirconium titanate wherein the volume ratio of the organic solvent to aqueous part is in the range from 1 to 5. The solution of amorphous spherical particles is incubated in an oven at a temperature .ltoreq.100.degree. C. for a period of time .ltoreq.24 hours converting the amorphous particles to fine or ultrafine crystalline spherical particles of zirconium titanate.

  2. News Archive | Princeton Plasma Physics Lab

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

    Archive Subscribe to Princeton Plasma Physics Laboratory News September 2, 2016 PPPL intern creates software for snapshot of plasma in NSTX-U By Jeanne Jackson DeVoe Max Wallace, a Community College intern from Laney College in Oakland, California, shows fellow intern Priya Jaglal a poster on his research during a student poster session at PPPL on Aug. 10. Wallace developed software to allow scientists to get a quick snapshot of experiments on the National Spherical Torus Experiment-Upgrade

  3. Princeton University Energy Scholars report focuses on fusion energy |

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

    Princeton Plasma Physics Lab Princeton University Energy Scholars report focuses on fusion energy By Jeanne Jackson DeVoe July 28, 2016 Tweet Widget Google Plus One Share on Facebook Adam Cohen, at left, former deputy director for operations at PPPL, with Princeton Energy Scholars in the National Spherical Torus Experiment-Upgrade Control Room during a tour of PPPL in June 2014. (Photo by Elle Starkman/PPPL Office of Communications) Adam Cohen, at left, former deputy director for operations

  4. A New Era Begins | Princeton Plasma Physics Lab

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

    A New Era Begins Welcome to the first major addition to the U.S. fusion program of the 21st century. The U.S. Department of Energy's Princeton Plasma Physics Laboratory's (PPPL) new $94 million National Spherical Torus Experiment-Upgrade (NSTX-U) is the most powerful fusion facility of its kind on Earth and a device poised to bring the world closer to a bold new energy age. Publication File: PDF icon NSTX-U_presskit_print_NewEra

  5. NSTX-U Digital Coil Protection System Software Detailed Design

    SciTech Connect (OSTI)

    2014-06-01

    The National Spherical Torus Experiment (NSTX) currently uses a collection of analog signal processing solutions for coil protection. Part of the NSTX Upgrade (NSTX-U) entails replacing these analog systems with a software solution running on a conventional computing platform. The new Digital Coil Protection System (DCPS) will replace the old systems entirely, while also providing an extensible framework that allows adding new functionality as desired.

  6. News | Princeton Plasma Physics Lab

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

    Developing the digital safeguard that protects the National Spherical Torus Experiment-Upgrade at PPPL Click on an image below to view the high resolution image. Then right click on the image and select "Save Image" or "Save Image As..." Members of the team that developed the DCPS, from left: Gretchen Zimmer, Kevin Lamb, Greg Tchillingarian, Paul Sichta, John Lawson, Tim Stevenson, Stefan Gerhardt and Roman Rozenblat. Not shown: Vince Mastrocola, John Dong, Gary Gibilisco.

  7. News | Princeton Plasma Physics Lab

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

    Princeton University Energy Scholars report focuses on fusion energy Click on an image below to view the high resolution image. Then right click on the image and select "Save Image" or "Save Image As..." Adam Cohen, at left, former deputy director for operations at PPPL, with Princeton Energy Scholars in the National Spherical Torus Experiment-Upgrade Control Room during a tour of PPPL in June 2014

  8. Quest Magazine Summer 2016 | Princeton Plasma Physics Lab

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

    Quest Magazine Summer 2016 It is my pleasure to welcome readers to the fourth annual edition of Quest, the Laboratory's research magazine. Research has begun full bore on the National Spherical Torus Experiment-Upgrade (NSTX-U), our flagship fusion facility, whose construction was completed in 2015 after nearly four years of building and a cost of $94 million. Image: Quest 2016 Publication File: PDF icon Quest Magazine Summer 2016 Publication Type: Quest

  9. T

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

    wo major new components power the National Spherical Torus Experiment-Upgrade: A widened center stack that doubles the magnetic field strength and plasma current and quintuples the length of fusion experiments, and a second neutral beam injector that doubles the tokamak's heating power. Taken together, the new parts boost the NSTX-U operating conditions closer to those that will be found in a commercial fusion power plant. "This project was more complex than building the NSTX in the first

  10. Electromagnetic Transport From Microtearing Mode Turbulence

    SciTech Connect (OSTI)

    Guttenfelder, W; Kaye, S M; Nevins, W M; Wang, E; Bell, R E; Hammett, G W; LeBlanc, B P; Mikkelsen, D R

    2011-03-23

    This Letter presents non-linear gyrokinetic simulations of microtearing mode turbulence. The simulations include collisional and electromagnetic effects and use experimental parameters from a high beta discharge in the National Spherical Torus Experiment (NSTX). The predicted electron thermal transport is comparable to that given by experimental analysis, and it is dominated by the electromagnetic contribution of electrons free streaming along the resulting stochastic magnetic field line trajectories. Experimental values of flow shear can significantly reduce the predicted transport.

  11. Los Alamos National Laboratory

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

    Administration | (NNSA) Los Alamos National Lab Performance Evaluations FY 2016 FY 2016 Performance Evaluation Plan, Los Alamos National Security, LLC FY 2015 FY 2015 Performance Evaluation Report, Los Alamos National Security, LLC FY 2015 Performance Evaluation Report, Fee Determination Letter, Los Alamos National Security, LLC FY 2015 Performance Evaluation Plan, Los Alamos National Security, LLC FY 2014 FY 2014 Performance Evaluation Report, Los Alamos National Security, LLC FY 2014

  12. National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    U.S. Department of Energy National Nuclear Security Administration Federal Equal ... A. Name and Address of Agency National Nuclear Security Administration Office of ...

  13. National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    U.S. Department of Energy National Nuclear Security Administration Federal Equal ... A. Name and Address of Agency National Nuclear Security Administration 1000 Independence ...

  14. National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    15 National Nuclear Security Administration FY 2013 PER Babcock & Wilcox Technical ... The National Nuclear Security Administration (NNSA) Production Office (NPO) took into ...

  15. National Science Bowl Finals

    ScienceCinema (OSTI)

    None

    2010-09-01

    National Science Bowl finals and awards at the National Building Museum in Washington D.C. Monday 5/3/2010

  16. First National Technology Center

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

    First National Technology First National Technology Center Center Electronic Equipment - manufactured to withstand 8 milliseconds of voltage disruption CBEMA Curve - Chips ...

  17. National Nuclear Security Administration

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

    Prepared by U.S. Department of Energy National Nuclear Security Administration Nevada Field Office . Environmental Management Operations February 2015 Nevada National Security ...

  18. Level: National Data;

    U.S. Energy Information Administration (EIA) Indexed Site

    (Fuel and Nonfuel), 2006; Level: National Data; Row: Energy Sources and Shipments, ... (Fuel and Nonfuel), 2006; Level: National Data; Row: Energy Sources and Shipments, ...

  19. Spherically symmetric cosmological spacetimes with dust and radiation — numerical implementation

    SciTech Connect (OSTI)

    Lim, Woei Chet; Regis, Marco; Clarkson, Chris E-mail: regis@to.infn.it

    2013-10-01

    We present new numerical cosmological solutions of the Einstein Field Equations. The spacetime is spherically symmetric with a source of dust and radiation approximated as a perfect fluid. The dust and radiation are necessarily non-comoving due to the inhomogeneity of the spacetime. Such a model can be used to investigate non-linear general relativistic effects present during decoupling or big-bang nucleosynthesis, as well as for investigating void models of dark energy with isocurvature degrees of freedom. We describe the full evolution of the spacetime as well as the redshift and luminosity distance for a central observer. After demonstrating accuracy of the code, we consider a few example models, and demonstrate the sensitivity of the late time model to the degree of inhomogeneity of the initial radiation contrast.

  20. Method of simulating spherical voids for use as a radiographic standard

    DOE Patents [OSTI]

    Foster, Billy E.

    1977-01-01

    A method of simulating small spherical voids in metal is provided. The method entails drilling or etching a hemispherical depression of the desired diameter in each of two sections of metal, the sections being flat plates or different diameter cylinders. A carbon bead is placed in one of the hemispherical voids and is used as a guide to align the second hemispherical void with that in the other plate. The plates are then bonded together with epoxy, tape or similar material and the two aligned hemispheres form a sphere within the material; thus a void of a known size has been created. This type of void can be used to simulate a pore in the development of radiographic techniques of actual voids (porosity) in welds and serve as a radiographic standard.

  1. Effect of calcium modification on the microstructure and oxidation property of submicron spherical palladium powders

    SciTech Connect (OSTI)

    Che, S.; Sakurai, O.; Funakubo, H.; Shinozaki, K.; Mizutani, N.

    1997-02-01

    Ca-modified spherical palladium particles were prepared from the mixed solution of Pd(NO{sub 3}){sub 2} and Ca(NO{sub 3}){sub 2} by ultrasonic spray pyrolysis. Pure palladium powder and that modified with less than 55 ppm Ca were composed of single crystal particles. However, Ca addition of more than 550 ppm resulted in polycrystalline particles. Crystallite size of the particles decreased with the increase of Ca addition and changed dramatically at the addition of some hundred ppm. Ca additive did not form solid solution with palladium but formed CaPd{sub 3}O{sub 4} on the surface and grain boundary of the particles. 50 ppm{endash}1{percent} of Ca addition significantly reduced the oxidization of palladium powder. More addition of Ca resulted in excess oxidation due to the reaction between palladium and calcium oxide. {copyright} {ital 1997 Materials Research Society.}

  2. Critical radius for sustained propagation of spark-ignited spherical flames

    SciTech Connect (OSTI)

    Kelley, Andrew P.; Jomaas, Grunde; Law, Chung K.

    2009-05-15

    An experimental study was performed to determine the requirements for sustained propagation of spark-ignited hydrogen-air and butane-air flames at atmospheric and elevated pressures. Results show that sustained propagation is always possible for mixtures whose Lewis number is less than unity, as long as a flame can be initially established. However, for mixtures whose Lewis number is greater than unity, sustained propagation depends on whether the initially ignited flame can attain a minimum radius. This minimum radius was determined for mixtures of different equivalence ratios and pressures, and was found to agree moderately well with the theoretically predicted critical radius beyond which there is no solution for the adiabatic, quasi-steady propagation of the spherical flame. The essential roles of pressure, detailed chemistry, and the need to use local values in the quantitative evaluation of the flame response parameters are emphasized. (author)

  3. Microscopic description of spherical to {gamma}-soft shape transitions in Ba and Xe nuclei

    SciTech Connect (OSTI)

    Li, Z. P.; Niksic, T.; Vretenar, D.; Meng, J.

    2010-03-15

    The rapid transition between spherical and {gamma}-soft shapes in Ba and Xe nuclei in the mass region A>=130 is analyzed using excitation spectra and collective wave functions obtained by diagonalization of a five-dimensional Hamiltonian for quadrupole vibrational and rotational degrees of freedom, with parameters determined by constrained self-consistent relativistic mean-field calculations for triaxial shapes. The results reproduce the characteristic evolution of excitation spectra and E2 transition probabilities, and in general, a good agreement with available data is obtained. The calculated spectra display fingerprints of a second-order shape phase transition that can approximately be described by analytic solutions corresponding to the E(5) dynamical symmetry.

  4. Asymptotic behavior of dynamical variables and naked singularity formation in spherically symmetric gravitational collapse

    SciTech Connect (OSTI)

    Kawakami, Hayato; Mitsuda, Eiji; Nambu, Yasusada; Tomimatsu, Akira

    2009-07-15

    In considering the gravitational collapse of matter, it is an important problem to clarify what kind of conditions leads to the formation of naked singularity. For this purpose, we apply the 1+3 orthonormal frame formalism introduced by Uggla et al. to the spherically symmetric gravitational collapse of a perfect fluid. This formalism allows us to construct an autonomous system of evolution and constraint equations for scale-invariant dynamical variables normalized by the volume expansion rate of the timelike orthonormal frame vector. We investigate the asymptotic evolution of such dynamical variables towards the formation of a central singularity and present a conjecture that the steep spatial gradient for the normalized density function is a characteristic of the naked singularity formation.

  5. Calculation of the fast ion tail distribution for a spherically symmetric hot spot

    SciTech Connect (OSTI)

    McDevitt, C. J.; Tang, X.-Z.; Guo, Z.; Berk, H. L.

    2014-10-15

    The fast ion tail for a spherically symmetric hot spot is computed via the solution of a simplified Fokker-Planck collision operator. Emphasis is placed on describing the energy scaling of the fast ion distribution function in the hot spot as well as the surrounding cold plasma throughout a broad range of collisionalities and temperatures. It is found that while the fast ion tail inside the hot spot is significantly depleted, leading to a reduction of the fusion yield in this region, a surplus of fast ions is observed in the neighboring cold plasma region. The presence of this surplus of fast ions in the neighboring cold region is shown to result in a partial recovery of the fusion yield lost in the hot spot.

  6. Measurements of the divergence of fast electrons in laser-irradiated spherical targets

    SciTech Connect (OSTI)

    Yaakobi, B.; Solodov, A. A.; Myatt, J. F.; Delettrez, J. A.; Stoeckl, C.; Froula, D. H.

    2013-09-15

    In recent experiments using directly driven spherical targets on the OMEGA laser system, the energy in fast electrons was found to reach ?1% of the laser energy at an irradiance of ?1.1 10{sup 15} W/cm{sup 2}. The fraction of these fast electrons absorbed in the compressed fuel shell depends on their angular divergence. This paper describes measurements of this divergence deduced from a series of shots where Mo-coated shells of increasing diameter (D) were suspended within an outer CH shell. The intensity of the MoK? line and the hard x-ray radiation were found to increase approximately as ?D{sup 2}, indicating wide divergence of the fast electrons. Alternative interpretations of these results (electron scattering, radiation excitation of K?, and an electric field due to return current) are shown to be unimportant.

  7. Analysis of plasma density profiles and thermal transport in laser-irradiated spherical targets

    SciTech Connect (OSTI)

    Fechner, W.B.; Shepard, C.L.; Busch, G.E.; Schroeder, R.J.; Tarvin, J.A.

    1984-06-01

    Measurements are presented for plasma density profiles, critical surface trajectories, and mass-ablation rates, as obtained from experiments in which layered spherical targets were irradiated with 1.05-..mu..m laser light at intensities between 1 x 10/sup 14/ and 1 x 10/sup 15/ W/cm/sup 2/. The targets were designed to allow study of thermal transport in overdense plasmas. They were from 70 to 110 ..mu..m in diameter, with a variable thickness parylene ablator and an aluminum substrate. Simulated results are consistent with all three sets of data if transport of both thermal and suprathermal electrons is severely inhibited, with a flux limiter of 0.03< or =f< or =0.06 being appropriate.

  8. In-Flight Measurements of Capsule Adiabats in Laser Driven Spherical Implosions

    SciTech Connect (OSTI)

    Kritcher, A L; Doppner, T; Fortman, C; Ma, T; Landen, O L; Wallace, R; Glenzer, S H

    2011-03-07

    We present the first x-ray Thomson scattering measurements of temperature and density from spherically imploding matter. The shape of the Compton downscattered spectrum provides a first-principles measurement of the electron velocity distribution function, dependent on T{sub e} and the Fermi temperature T{sub F} {approx} n{sub e}{sup 2/3}. In flight compressions of Be and CH targets reach 6-13 times solid density, with T{sub e}/T{sub F} {approx} 0.4-0.7, resulting in minimum adiabats of {approx}1.6-2. These measurements are consistent with low-entropy implosions and predictions by simulations using radiation-hydrodynamic modeling.

  9. Quasi-spherical direct drive fusion simulations for the Z machine and future accelerators.

    SciTech Connect (OSTI)

    VanDevender, J. Pace; McDaniel, Dillon Heirman; Roderick, Norman Frederick; Nash, Thomas J.

    2007-11-01

    We explored the potential of Quasi-Spherical Direct Drive (QSDD) to reduce the cost and risk of a future fusion driver for Inertial Confinement Fusion (ICF) and to produce megajoule thermonuclear yield on the renovated Z Machine with a pulse shortening Magnetically Insulated Current Amplifier (MICA). Analytic relationships for constant implosion velocity and constant pusher stability have been derived and show that the required current scales as the implosion time. Therefore, a MICA is necessary to drive QSDD capsules with hot-spot ignition on Z. We have optimized the LASNEX parameters for QSDD with realistic walls and mitigated many of the risks. Although the mix-degraded 1D yield is computed to be {approx}30 MJ on Z, unmitigated wall expansion under the > 100 gigabar pressure just before burn prevents ignition in the 2D simulations. A squeezer system of adjacent implosions may mitigate the wall expansion and permit the plasma to burn.

  10. Movable multi-probes for plasma boundary measurement in sino-united spherical tokamak

    SciTech Connect (OSTI)

    Chai, Song Wang, Wenhao; Tan, Yi; Gao, Zhe

    2014-11-15

    A novel movable multi-probes is developed to get local magnetic and electrostatic profiles on Sino-UNIted Spherical Tokamak (SUNIST). This multi-probes combines a four-tips Langmuir probe, a magnetic coil, and a retarding field energy analyzer (RFEA). It can be used to simultaneously measure the poloidal magnetic field B{sub p}, electric field E{sub r}, electron temperature T{sub e}, electron density n{sub e}, and ion temperature T{sub i}. Its small overall size (20 × 20 × 38 mm{sup 3}) enables the movable multi-probes to measure the magnetic and electrostatic profiles in high spatial resolution, with negligible impact to plasma in SUNIST. This paper presents the design of the movable multi-probes, in particular, details of RFEA for reliable ion energy measurements. Preliminary experimental results of the movable multi-probes are given as well.

  11. MAGNETIC ENERGY CASCADE IN SPHERICAL GEOMETRY. I. THE STELLAR CONVECTIVE DYNAMO CASE

    SciTech Connect (OSTI)

    Strugarek, A.; Brun, A. S.; Mathis, S.

    2013-02-20

    We present a method to characterize the spectral transfers of magnetic energy between scales in simulations of stellar convective dynamos. The full triadic transfer functions are computed thanks to analytical coupling relations of spherical harmonics based on the Clebsch-Gordan coefficients. The method is applied to mean field {alpha}{Omega} dynamo models as benchmark tests. From a physical standpoint, the decomposition of the dynamo field into primary and secondary dynamo families proves very instructive in the {alpha}{Omega} case. The same method is then applied to a fully turbulent dynamo in a solar convection zone, modeled with the three-dimensional MHD Anelastic Spherical Harmonics code. The initial growth of the magnetic energy spectrum is shown to be non-local. It mainly reproduces the kinetic energy spectrum of convection at intermediate scales. During the saturation phase, two kinds of direct magnetic energy cascades are observed in regions encompassing the smallest scales involved in the simulation. The first cascade is obtained through the shearing of the magnetic field by the large-scale differential rotation that effectively cascades magnetic energy. The second is a generalized cascade that involves a range of local magnetic and velocity scales. Non-local transfers appear to be significant, such that the net transfers cannot be reduced to the dynamics of a small set of modes. The saturation of the large-scale axisymmetric dipole and quadrupole is detailed. In particular, the dipole is saturated by a non-local interaction involving the most energetic scale of the magnetic energy spectrum, which points to the importance of the magnetic Prandtl number for large-scale dynamos.

  12. A novel process route for the production of spherical SLS polymer powders

    SciTech Connect (OSTI)

    Schmidt, Jochen; Sachs, Marius; Blümel, Christina; Winzer, Bettina; Toni, Franziska; Wirth, Karl-Ernst; Peukert, Wolfgang

    2015-05-22

    Currently, rapid prototyping gradually is transferred to additive manufacturing opening new applications. Especially selective laser sintering (SLS) is promising. One drawback is the limited choice of polymer materials available as optimized powders. Powders produced by cryogenic grinding show poor powder flowability resulting in poor device quality. Within this account we present a novel process route for the production of spherical polymer micron-sized particles of good flowability. The feasibility of the process chain is demonstrated for polystyrene e. In a first step polymer microparticles are produced by a wet grinding method. By this approach the mean particle size and the particle size distribution can be tuned between a few microns and several 10 microns. The applicability of this method will be discussed for different polymers and the dependencies of product particle size distribution on stressing conditions and process temperature will be outlined. The comminution products consist of microparticles of irregular shape and poor powder flowability. An improvement of flowability of the ground particles is achieved by changing their shape: they are rounded using a heated downer reactor. The influence of temperature profile and residence time on the product properties will be addressed applying a viscous-flow sintering model. To further improve the flowability of the cohesive spherical polymer particles nanoparticles are adhered onto the microparticles’ surface. The improvement of flowability is remarkable: rounded and dry-coated powders exhibit a strongly reduced tensile strength as compared to the comminution product. The improved polymer powders obtained by the process route proposed open new possibilities in SLS processing including the usage of much smaller polymer beads.

  13. The importance of electrothermal terms in Ohm's law for magnetized spherical implosions

    SciTech Connect (OSTI)

    Davies, J. R.; Betti, R.; Chang, P. -Y.; Fiksel, G.

    2015-11-06

    The magnetohydrodynamics (MHD) of magnetic-field compression in laser-driven spherical targets is considered. Magnetic-field evolution is cast in terms of an effective fluid velocity, a convective term resulting from resistivity gradients, a resistive diffusion term, and a source term. Effective velocity is the sum of fluid velocity, drift velocity, and heat-flux velocity, given by electron heat flux divided by electron enthalpy density, which has two components: the perpendicular or Nernst velocity and the cross-field velocity. The Nernst velocity compresses the magnetic field as a heat front moves into the gas. The cross-field velocity leads to dynamo generation of an azimuthal magnetic field. It is proposed that the heat-flux velocity should be flux limited using a “Nernst” flux limiter independent of the thermal flux limiter but should not exceed it. The addition of MHD routines to the 1-D, Lagrangian hydrocode LILAC and the Eulerian version of the 2-D hydrocode DRACO is described, and the codes are used to model a magnetized spherical compression on the OMEGA laser. Thermal flux limiting at a shock front is found to cause unphysical electron temperature gradients that lead to large, unphysical magnetic fields caused by the resistivity gradient, so thermal flux limiting in the gas is removed. The Nernst term reduces the benefits of magnetization in inertial fusion. In addition, a Nernst flux limiter ≤ 0.12 is required in the gas in order to agree with measured neutron yield and increases in the neutron-averaged ion temperature caused by magnetization. This corresponds to maintaining the Nernst velocity below the shock velocity, which prevents significant decoupling of the magnetic field and gas compression.

  14. The importance of electrothermal terms in Ohm's law for magnetized spherical implosions

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

    Davies, J. R.; Betti, R.; Chang, P. -Y.; Fiksel, G.

    2015-11-06

    The magnetohydrodynamics (MHD) of magnetic-field compression in laser-driven spherical targets is considered. Magnetic-field evolution is cast in terms of an effective fluid velocity, a convective term resulting from resistivity gradients, a resistive diffusion term, and a source term. Effective velocity is the sum of fluid velocity, drift velocity, and heat-flux velocity, given by electron heat flux divided by electron enthalpy density, which has two components: the perpendicular or Nernst velocity and the cross-field velocity. The Nernst velocity compresses the magnetic field as a heat front moves into the gas. The cross-field velocity leads to dynamo generation of an azimuthal magneticmore » field. It is proposed that the heat-flux velocity should be flux limited using a “Nernst” flux limiter independent of the thermal flux limiter but should not exceed it. The addition of MHD routines to the 1-D, Lagrangian hydrocode LILAC and the Eulerian version of the 2-D hydrocode DRACO is described, and the codes are used to model a magnetized spherical compression on the OMEGA laser. Thermal flux limiting at a shock front is found to cause unphysical electron temperature gradients that lead to large, unphysical magnetic fields caused by the resistivity gradient, so thermal flux limiting in the gas is removed. The Nernst term reduces the benefits of magnetization in inertial fusion. In addition, a Nernst flux limiter ≤ 0.12 is required in the gas in order to agree with measured neutron yield and increases in the neutron-averaged ion temperature caused by magnetization. This corresponds to maintaining the Nernst velocity below the shock velocity, which prevents significant decoupling of the magnetic field and gas compression.« less

  15. Engineer, Sandia National Laboratories | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration | (NNSA) Engineer, Sandia National Laboratories Clifford Ho Clifford Ho February 2010 Asian American Engineer of the Year Clifford Ho, a Sandia engineer, has been selected by the Chinese Institute of Engineers - USA to receive the Asian American Engineer of the Year Award. The honor is presented each year to the nation's most outstanding Asian American engineers and scientists who make significant, lasting and global contributions to the nation. Ho was recognized for his

  16. Lawrence Livermore National Laboratory | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration | (NNSA) Lawrence Livermore National Laboratory Lawrence Livermore National Laboratory DE-AC52-07NA27344 Operated by Lawrence Livermore National Security, LLC BASIC Contract (Official) Modifications (Official) Funding Mods Available Upon Request Conformed Contract (Unofficial) LLNL Sec A (SF33) (pdf, 91KB) See Modifications Section under Conformed Contract Link LLNS Conformed Contract (weblink) LLNL Sec B-H (pdf, 306KB) LLNL Sec I pdf 687KB LLNL Sec J Appx A (pdf, 67KB) LLNL

  17. Pacific Northwest National Laboratory | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration Pacific Northwest National Laboratory NNSA deputy visits PNNL to see radiochemistry and threat detection capabilities NNSA Principal Deputy Administrator Madelyn Creedon visited the Pacific Northwest National Laboratory (PNNL) in Washington this month to see the work it does for the agency, focusing on radiochemistry and threat detection. NNSA hosts international CTBT on-site inspection experts at Nevada National Security Site This month, NNSA hosted a Comprehensive

  18. national security | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    security Klotz visits Y-12 to see progress on new projects and ongoing work on NNSA's national security missions Last week, NNSA Administrator Lt. Gen. Frank Klotz (Ret.) visited the Y-12 National Security Complex to check on the status of ongoing projects like the Uranium Processing Facility as well as the site's continuing uranium operations. He also met with the Region 2 volunteers of the Radiogical... Managing the data deluge for national security analysts ALBUQUERQUE, N.M. - After a

  19. Lawrence Livermore National Laboratory | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration | (NNSA) Lawrence Livermore National Laboratory Lawrence Livermore National Laboratory (LLNL) is a design laboratory that is responsible for the safety and reliability of the nuclear explosives package in nuclear weapons. It supports surveillance, assessment, and refurbishment of the nuclear weapons stockpile. LLNL also possesses unique high-energy-density physics capabilities and scientific computing assets. The lab is managed by Lawrence Livermore National Security, LLC and

  20. National Nuclear Security Administration Los Alamos National

    National Nuclear Security Administration (NNSA)

    National Nuclear Security Administration Los Alamos National Security, LLC Fiscal Year 2014 Performance Evaluation Report (PER) NNSA Los Alamos Field Office Performance Period: October 2013 - September 2014 November 14, 2014 NA-LA November 14, 2014 Executive Summary This Performance Evaluation Report (PER) provides the assessment of Los Alamos National Security, LLC performance for the period of October 1, 2013 through September 30, 2014, as evaluated against the objectives defined in the Fiscal

  1. National Science Bowl | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    Science Bowl Texas students win regional National Science Bowl competition, secure spot in finals in nation's capital More than 200 students from 37 from High schools across the Texas Panhandle gathered together with a few hundred volunteers for a meeting and competition of the minds: The Pantex Science Bowl 2016. Set up like a game show with buzzers, toss up and bonus questions, these groups of four students... Amarillo Students Win Regional National Science Bowl Competition, Secure Spot in

  2. sandia national laboratory | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    sandia national laboratory Sandia California celebrates 60 years On March 8, Sandia/California celebrates its 60th anniversary. The site, which began with a singular nuclear weapons mission, now supports all Sandia mission areas. Nuclear weapons still accounts for nearly half of the site's work, along with strong programs in homeland security, transportation... Managing the data deluge for national security analysts ALBUQUERQUE, N.M. - After a disaster or national tragedy, bits of information

  3. National Lab Impact Initiative

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

    Lab Impact Initiative Energy Efficiency & Renewable Energy EERE National Lab Impact Summit Driving American Energy Innovation and Competitiveness May 4, 2016 | 7:30 am-7:00 pm National Renewable Energy Laboratory Golden, Colorado EERE National Lab Impact Summit // i ` http://www.cyclotronroad.org/home TABLE OF CONTENTS Department of Energy National Lab Abbreviations .........................................................................................................ii Welcome Letter

  4. First National Technology Center

    Office of Energy Efficiency and Renewable Energy (EERE)

    Speaker presentation prepared by Dennis Hughes, a lead property manager with First National Buildings Inc.

  5. National Security Science | Los National Alamos Laboratory

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

    LANSCE: Mission-Critical for National Security Nuclear Energy for Our Challenging Future The Invisible Neutron Threat Blasting Missiles Out of the Sky LANL and the Air Force: ...

  6. National Renewable Energy Laboratory | National Nuclear Security...

    National Nuclear Security Administration (NNSA)

    National Renewable Energy Laboratory NNSA lab recognized for innovation to power electric ... Annual Merit Review Awards recognized significant achievements in the Department of Energy

  7. National Ignition Facility Reaches Milestone Early | National...

    National Nuclear Security Administration (NNSA)

    Reaches Milestone Early | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile Preventing Proliferation Powering the...

  8. Previous Sandia National Laboratories | National Nuclear Security...

    National Nuclear Security Administration (NNSA)

    Apply for Our Jobs Our Jobs Working at NNSA Blog Home About Us Our Operations Acquisition and Project Management M & O Support Department Sandia National Laboratories ...

  9. Sandia National Laboratory Performance Evaluations | National...

    National Nuclear Security Administration (NNSA)

    Sandia National Laboratory Performance Evaluations FY 2016 FY 2016 Performance Evaluation Plan, Sandia Corporation FY 2015 FY 2015 Performance Evaluation Report, Sandia Corporation ...

  10. Lawrence Livermore National Laboratory | National Nuclear Security...

    National Nuclear Security Administration (NNSA)

    Life Extension Program Bay Area national labs team to tackle long-standing automotive hydrogen storage challenge SOLAR POWER PURCHASE FOR DOE LABORATORIES More about LLNL...

  11. Manager, Sandia National Laboratories | National Nuclear Security...

    National Nuclear Security Administration (NNSA)

    of New Mexico's Anderson School of Management's Hall of Fame Inductee Jim Novak from Sandia National Laboratories will be inducted into the University of New Mexico's ...

  12. sandia national lab | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    sandia national lab NNSA Researchers Advance Technology for Remote Reactor Monitoring NNSA's Defense Nuclear Nonproliferation Research and Development Program drives the innovation ...

  13. national labs | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    and hackers engage innovation and partnerships NNSA's labs change the world everyday through cutting-edge developments in support of NNSA's critical national security missions. ...

  14. National Nuclear Security Administration | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration | (NNSA) National Nuclear Security Administration FY15 Year End Report Semi Annual Report FY14 Year End Report Semi Annual

  15. Researcher, Sandia National Laboratories | National Nuclear Security...

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

    Laboratories Award: Fellow of the Institute of Electrical & Electronics Engineers (IEEE) Profile: Paul Dodd, a Sandia National Laboratories researcher, has been named a Fellow...

  16. National Security, Weapons Science

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

    National Security, Weapons Science National Security, Weapons Science National security depends on science and technology. The United States relies on Los Alamos National Laboratory for the best of both. No place on Earth pursues a broader array of world-class scientific endeavors. CoMuEx» Explosives Center» Dual-Axis Radiographic Hydrodynamic Test Facility (DARHT) The Dual-Axis Radiographic Hydrodynamic Test Facility at Los Alamos National Laboratory is part of the DOE's stockpile stewardship

  17. Foreign-national Investigators

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

    foreign national investigators Foreign-national Investigators Foreign National Investigators must have access to B174 shown on their badge. Foreign National Investigators must notify Beth Mariotti by e-mail of their first intended presence in B174. By September 2009, it is expected that there will be no restrictions on computer use by Foreign National Investigators at JLF. However, LLNL prohibits the use of personally-owned computers on-site

  18. Argonne National Laboratory | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    Argonne National Laboratory First-of-its-Kind NNSA Capability to Support Study of Materials at Extreme Conditions for Stockpile Stewardship WASHINGTON - A new first-of-its-kind-worldwide research capability will help unravel the mysteries of material behavior at extreme conditions and short time scales in support of the Department of Energy's National Nuclear Security Administration's (DOE/NNSA's) vital

  19. Sandia National Laboratories: Sandia National Laboratories: Missions:

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

    Defense Systems & Assessments: Accomplishments Accomplishments About Defense Systems & Assessments Program Areas Accomplishments Archives Cybersecurity Programs Accomplishments Protecting the nation Sandia lasers test and calibrate sensors on U.S. satellites Sandia's scientists and engineers have a significant impact on national security and continually deliver results, including these noteworthy successes from fiscal year 2012: AHW Launch Advanced Hypersonic Weapon test flight

  20. National Supplemental Screening Program | Argonne National Laboratory

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

    National Supplemental Screening Program The National Supplemental Screening Program (NSSP) offers medical screenings at no charge for former U.S. Department of Energy (DOE) site workers who may have been exposed to hazardous substances at work. For more information, see the documents below. PDF icon Retiree_Benefits_NSSPbrochure.pdf PDF icon Retiree_Benefits_newtest.pdf PDF icon Retiree_Benefits_NSSPemployees

  1. sandia national labotartory | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    sandia national labotartory Sandia National Laboratory Sandia Field Office Contact the Field Office Contract Administration & Business Management Emergency Information Facilities & Projects Nuclear Operations Environment, Safety & Health Public Affairs Safeguards & Security Performance and Quality Assurance Programs NEPA Reading Room

  2. Effects of radiation and compression on propagating spherical flames of methane/air mixtures near the lean flammability limit

    SciTech Connect (OSTI)

    Chen, Zheng [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China)

    2010-12-15

    Large discrepancies between the laminar flame speeds and Markstein lengths measured in experiments and those predicted by simulations for ultra-lean methane/air mixtures bring a great concern for kinetic mechanism validation. In order to quantitatively explain these discrepancies, a computational study is performed for propagating spherical flames of lean methane/air mixtures in different spherical chambers using different radiation models. The emphasis is focused on the effects of radiation and compression. It is found that the spherical flame propagation speed is greatly reduced by the coupling between thermal effect (change of flame temperature or unburned gas temperature) and flow effect (inward flow of burned gas) induced by radiation and/or compression. As a result, for methane/air mixtures near the lean flammability limit, the radiation and compression cause large amounts of under-prediction of the laminar flame speeds and Markstein lengths extracted from propagating spherical flames. Since radiation and compression both exist in the experiments on ultra-lean methane/air mixtures reported in the literature, the measured laminar flame speeds and Markstein lengths are much lower than results from simulation and thus cannot be used for kinetic mechanism validation. (author)

  3. Role of negatively charged ions in plasma on the growth and field emission properties of spherical carbon nanotube tip

    SciTech Connect (OSTI)

    Tewari, Aarti; Walia, Ritu; Sharma, Suresh C.

    2012-01-15

    The role of negatively charged ions in plasma on growth (without catalyst) and field emission properties of spherical carbon nanotube (CNT) tip has been theoretically investigated. A theoretical model of charge neutrality, including the kinetics of electrons, negatively and positively charged ions, neutral atoms, and the energy balance of various species has been developed. Numerical calculations of the spherical CNT tip radius for different relative density of negatively charged ions {epsilon}{sub r}(=n{sub SF{sub 6{sup -}}}/n{sub C{sup +}}, where n{sub SF{sub 6{sup -}}} and n{sub C}{sup +} are the equilibrium densities of sulphur hexafluoride and carbon ions, respectively) have been carried out for the typical glow discharge plasma parameters. It is found that the spherical CNT tip radius decreases with {epsilon}{sub r} and hence the field emission of electrons from the spherical CNT tip increases. Some of our theoretical results are in accordance with the existing experimental observations.

  4. A Star on Earth

    ScienceCinema (OSTI)

    Prager, Stewart; Zwicker, Andrew; Hammet, Greg; Tresemer, Kelsey; Diallo, Ahmed

    2014-06-06

    At the Energy Department's Princeton Plasma Physics Lab, scientists are trying to accomplish what was once considered the realm of science fiction: create a star on Earth. The National Spherical Torus Experiment (NSTX) is a magnetic fusion device that is used to study the physics principles of spherically shaped plasmas -- hot ionized gases in which, under the right conditions, nuclear fusion will occur. Fusion is the energy source of the sun and all of the stars. Not just limited to theoretical work, the NSTX is enabling cutting-edge research to develop fusion as a future energy source.

  5. A Star on Earth

    SciTech Connect (OSTI)

    Prager, Stewart; Zwicker, Andrew; Hammet, Greg; Tresemer, Kelsey; Diallo, Ahmed

    2014-03-05

    At the Energy Department's Princeton Plasma Physics Lab, scientists are trying to accomplish what was once considered the realm of science fiction: create a star on Earth. The National Spherical Torus Experiment (NSTX) is a magnetic fusion device that is used to study the physics principles of spherically shaped plasmas -- hot ionized gases in which, under the right conditions, nuclear fusion will occur. Fusion is the energy source of the sun and all of the stars. Not just limited to theoretical work, the NSTX is enabling cutting-edge research to develop fusion as a future energy source.

  6. Engineer, Sandia National Laboratories | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration | (NNSA) Engineer, Sandia National Laboratories Sandra Begay-Campbell Sandra Begay-Campbell Ely S. Parker Award Sandra Begay-Campbell, a Sandia National Laboratories engineer and a member of the Navajo Nation, was selected for the prestigious Ely S. Parker Award by the American Indian Science and Engineering Society at an honors banquet Oct. 31 in Portland, Ore. Begay-Campbell, who has worked at Sandia for 17 years and is a principal member of the technical staff, received the

  7. National Energy Education Summit

    Broader source: Energy.gov [DOE]

    The National Energy Education Summit is organized by the Council of Energy Research and Education Leaders (CEREL) and will serve as a first-of-its-kind national forum for energy educators, subject...

  8. Sandia National Laboratories

    National Nuclear Security Administration (NNSA)

    feet underground.

    Bay Area national labs team to tackle long-standing automotive hydrogen storage challenge http:www.nnsa.energy.govblogbay-area-national-labs-team-tackle-...

  9. Nevada National Security Site

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

    April 24, 2014 Cultural Artifacts Cross Eras at the Nevada National Security Site It is well known that the Nevada National Security Site (NNSS) is home to many artifacts from the ...

  10. Nevada National Security Site

    Office of Energy Efficiency and Renewable Energy (EERE)

    HISTORYIn 1950, President Truman established what is now known as the Nevada National Security Site (NNSS) to perform nuclear weapons testing activities.  In support of national defense initiatives...

  11. National Geothermal Summit

    Broader source: Energy.gov [DOE]

    The Geothermal Energy Association (GEA) will be holding it’s fifth annual National Geothermal Summit on June 3-4 at the Grand Sierra Resort and Casino in Reno, NV. The National Geothermal Summit is...

  12. Los Alamos National Laboratory

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

    participates in National Lab Day to increase awareness of science across the nation April 29, 2010 Events planned May 4-5 at Bradbury Science Museum LOS ALAMOS, New Mexico, April...

  13. 2012 National Electricity Forum

    Broader source: Energy.gov [DOE]

    At the 2012 National Electricity Forum, held February 8-9, 2012 and jointly organized by DOE's Office of Electricity Delivery & Energy Reliability (OE) and the National Association of...

  14. nevada national security site

    National Nuclear Security Administration (NNSA)

    7%2A en Nevada National Security Site operator recognized for green fleet http:www.nnsa.energy.govblognevada-national-security-site-operator-recognized-green-fleet

    The...

  15. National Environmental Research Parks

    SciTech Connect (OSTI)

    Not Available

    1994-07-01

    The National Environmental Research Parks are outdoor laboratories that provide opportunities for environmental studies on protected lands that act as buffers around Department of Energy (DOE) facilities. The research parks are used to evaluate the environmental consequences of energy use and development as well as the strategies to mitigate these effects. They are also used to demonstrate possible environmental and land-use options. The seven parks are: Fermilab National Environmental Research Park; Hanford National Environmental Research Park; Idaho National Environmental Research Park; Los Alamos National Environmental Research Park; Nevada National Environmental Research Park; Oak Ridge National Environmental Research Park; and Savannah River National Environmental Research Park. This document gives an overview of the events that led to the creation of the research parks. Its main purpose is to summarize key points about each park, including ecological research, geological characteristics, facilities, and available databases.

  16. Facilities | Argonne National Laboratory

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

    Facilities Some of the nation's most powerful and sophisticated facilities for energy research Argonne National Laboratory is home to some of the nation's most powerful and sophisticated research facilities. As a U.S. Department of Energy national laboratory, Argonne offers access to the facilities listed below through a variety of arrangements. Advanced Powertrain Research Facility Center for Transportation Research Materials Engineering Research Facility Distributed Energy Research Center

  17. Seneca Nation- 2007 Project

    Broader source: Energy.gov [DOE]

    On the three territories of the Seneca Nation, there exist opportunities for energy development from both renewable and nonrenewable resources.

  18. National User Facilities

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

    National User Facilities Our Vision National User Facilities Research Areas In Focus Global Solutions ⇒ Navigate Section Our Vision National User Facilities Research Areas In Focus Global Solutions Berkeley Lab's User Facilities-Engines of Discovery Berkeley Lab's User Facilities provide state-of-the-art resources for scientists across the nation and around the world. About 10,000 researchers a year use these facilities, representing nearly one third of the total for all Department of Energy

  19. National Renewable Energy Laboratory

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

    Tribal Energy Program Review Roger Taylor Manger State, Local & Tribal Integrated Application Group National Renewable Energy Laboratory November 5-8, 2007 Major DOE National Laboratories Brookhaven Brookhaven Pacific Northwest Pacific Northwest Lawrence Berkeley Lawrence Berkeley Lawrence Livermore Lawrence Livermore h h h h h INEL INEL National Renewable National Renewable Energy Laboratory Energy Laboratory Los Alamos Los Alamos Sandia Sandia Argonne Argonne Oak Ridge Oak Ridge Defense

  20. Los Alamos National Laboratory

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

    scientists will codirect $14.5 million National Center for Systems Biology July 28, 2009 Lab contributes computer modeling, antibody engineering capabilities Los Alamos, New Mexico, July 28, 2009- Los Alamos National Laboratory scientists will codirect a new National Center for Systems Biology located at the University of New Mexico in Albuquerque. The new Spatiotemporal Modeling Center (STMC) is funded by a $14.5 million, five- year grant from the National Institute for General Medical Sciences

  1. National Hydropower Map

    Broader source: Energy.gov [DOE]

    High-resolution map produced by Oak Ridge National Laboratory showing hydropower resources throughout the United States.

  2. Management | Argonne National Laboratory

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

    Chemical Sciences & Engineering Focus: Understanding & Control of Interfacial Processes Web Site Michael Thackeray Michael Thackeray (Deputy Director) Argonne National Laboratory...

  3. Downloads | Argonne National Laboratory

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

    --Environmental policy & planning --Geochemistry ... -Decision science --Emergency & disaster management ... the nation to solve society's complex scientific problems. ...

  4. National Geothermal Summit

    Broader source: Energy.gov [DOE]

    The Geothermal Energy Association hosts its annual National Geothermal Summit in Reno, Nevada, June 3-4, 2015.

  5. Alamos National Laboratory's 2013

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

    .1 million pledged during Los Alamos National Laboratory's 2013 employee giving campaign December 17, 2012 LOS ALAMOS, NEW MEXICO, December 17, 2012-Los Alamos National Laboratory employees have again demonstrated concern for their communities and those in need by pledging a record $2.13 million to United Way and other eligible nonprofit programs. Los Alamos National Security, LLC, which manages and operates the Laboratory for the National Nuclear Security Administration, plans to prorate its $1

  6. Alamos National Security, LLC

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

    Eleven nonprofit organizations receive community giving grants from Los Alamos National Security, LLC December 15, 2009 Los Alamos, New Mexico, December 15, 2009- Eleven local nonprofit organizations with projects supported by Los Alamos National Laboratory employee volunteers received $75,000 in Community Giving grants from Los Alamos National Security, LLC, the company that manages the Lab for the National Nuclear Security Administration. The organizations are located in Los Alamos, Española,

  7. Photos | Argonne National Laboratory

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

    -Arms control & nonproliferation --Research reactor conversion -Biometrics -Biotechnology for national security -Cyber security -Facility security -Decision science ...

  8. Videos | Argonne National Laboratory

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

    -Arms control & nonproliferation --Research reactor conversion -Biometrics -Biotechnology for national security -Cyber security -Facility security -Decision science ...

  9. National SCADA Testbed

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

    Lab Photovoltaic Systems Evaluation Laboratory PV Regional ... Facility Geomechanics and Drilling Labs National ... Health Monitoring Offshore Wind High-Resolution ...

  10. NATIONAL SECURITY TECHNOLOGIES - NEVADA NATIONAL SECURITY SITE

    National Nuclear Security Administration (NNSA)

    - NEVADA NATIONAL SECURITY SITE FISCAL YEARS 2009 THRU 2015 SMALL BUSINESS PROGRAM RESULTS & FORECAST CATEGORY Total Procurement Total SB Small Disad. Bus Woman-Owned SB Hub-Zone ...

  11. lasers. National Ignition Facility | National Nuclear Security...

    National Nuclear Security Administration (NNSA)

    target shot of fiscal year 2015 WASHINGTON - Last week, the National Ignition Facility (NIF) fired its 300th laser target shot in fiscal year (FY) 2015, meeting the year's goal...

  12. Linear stability and nonlinear dynamics of the fishbone mode in spherical tokamaks

    SciTech Connect (OSTI)

    Wang, Feng; Liu, J. Y. [School of Physics and Optoelectronic Engineering, Dalian University of Technology, Dalian 116024 (China)] [School of Physics and Optoelectronic Engineering, Dalian University of Technology, Dalian 116024 (China); Fu, G. Y.; Breslau, J. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2013-10-15

    Extensive linear and nonlinear simulations have been carried out to investigate the energetic particle-driven fishbone instability in spherical tokamak plasmas with weakly reversed q profile and the q{sub min} slightly above unity. The global kinetic-MHD hybrid code M3D-K is used. Numerical results show that a fishbone instability is excited by energetic beam ions preferentially at higher q{sub min} values, consistent with the observed appearance of the fishbone before the long-lived mode in MAST and NSTX experiments. In contrast, at lower q{sub min} values, the fishbone tends to be stable. In this case, the beam ion effects are strongly stabilizing for the non-resonant kink mode. Nonlinear simulations show that the fishbone saturates with strong downward frequency chirping as well as radial flattening of the beam ion distribution. An (m, n) = (2, 1) magnetic island is found to be driven nonlinearly by the fishbone instability, which could provide a trigger for the (2, 1) neoclassical tearing mode sometimes observed after the fishbone instability in NSTX.

  13. Propagation of transient signals from a spherical source in a half-space with surface layers

    SciTech Connect (OSTI)

    Norwood, F.R.

    1993-01-01

    The title problem is of particular interest for the analysis of seismic signals arising from underground nuclear explosions. Previous attempts at the solution have indicated that, although cylindrical symmetry exists, conventional methods cannot be applied because of the existence of plane and spherical boundaries. The present paper develops a ray-grouping technique for finding the solution to the title problem. This technique allows the separation of the problem into a series of canonical problems. Each such problem deals with a given boundary condition (e.g., continuity conditions at a material interface). Using this technique, one may follow waves along ray paths. It is easy to identify, after n reflections, (a) rays which arrive simultaneously at a given point and (b) the terms in the solution which need to be included at a given time. It is important to note that a cylindrical coordinate system is not employed, even though the problem is axially symmetric. Instead, the equations are carefully transformed making it possible to use a Cartesian coordinate system. This results in a spectral representation of the solution in terms of algebraic expressions in lieu of Bessel functions.

  14. Propagation of transient signals from a spherical source in a half-space with surface layers

    SciTech Connect (OSTI)

    Norwood, F.R.

    1993-06-01

    The title problem is of particular interest for the analysis of seismic signals arising from underground nuclear explosions. Previous attempts at the solution have indicated that, although cylindrical symmetry exists, conventional methods cannot be applied because of the existence of plane and spherical boundaries. The present paper develops a ray-grouping technique for finding the solution to the title problem. This technique allows the separation of the problem into a series of canonical problems. Each such problem deals with a given boundary condition (e.g., continuity conditions at a material interface). Using this technique, one may follow waves along ray paths. It is easy to identify, after n reflections, (a) rays which arrive simultaneously at a given point and (b) the terms in the solution which need to be included at a given time. It is important to note that a cylindrical coordinate system is not employed, even though the problem is axially symmetric. Instead, the equations are carefully transformed making it possible to use a Cartesian coordinate system. This results in a spectral representation of the solution in terms of algebraic expressions in lieu of Bessel functions.

  15. HYDRODYNAMICS OF CORE-COLLAPSE SUPERNOVAE AT THE TRANSITION TO EXPLOSION. I. SPHERICAL SYMMETRY

    SciTech Connect (OSTI)

    Fernandez, Rodrigo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)

    2012-04-20

    We study the transition to runaway expansion of an initially stalled core-collapse supernova shock. The neutrino luminosity, mass accretion rate, and neutrinospheric radius are all treated as free parameters. In spherical symmetry, this transition is mediated by a global non-adiabatic instability that develops on the advection time and reaches nonlinear amplitude. Here, we perform high-resolution, time-dependent hydrodynamic simulations of stalled supernova shocks with realistic microphysics to analyze this transition. We find that radial instability is a sufficient condition for runaway expansion if the neutrinospheric parameters do not vary with time and if heating by the accretion luminosity is neglected. For a given unstable mode, transition to runaway occurs when fluid in the gain region reaches positive specific energy. We find approximate instability criteria that accurately describe the behavior of the system over a wide region of parameter space. The threshold neutrino luminosities are in general different than the limiting value for a steady-state solution. We hypothesize that multidimensional explosions arise from the excitation of unstable large-scale modes of the turbulent background flow, at threshold luminosities that are lower than in the laminar case.

  16. A spherical shell target scheme for laser-driven neutron sources

    SciTech Connect (OSTI)

    He, Min-Qing Zhang, Hua; Wu, Si-Zhong; Wu, Jun-Feng; Chen, Mo; Cai, Hong-Bo Zhou, Cang-Tao; Cao, Li-Hua; Zheng, Chun-Yang; Zhu, Shao-Ping; He, X. T.; Dong, Quan-Li; Sheng, Zheng-Ming; Pei, Wen-Bing

    2015-12-15

    A scheme for neutron production is investigated in which an ultra-intense laser is irradiated into a two-layer (deuterium and aurum) spherical shell target through the cone shaped entrance hole. It is found that the energy conversion efficiency from laser to target can reach as high as 71%, and deuterium ions are heated to a maximum energy of several MeV from the inner layer surface. These ions are accelerated towards the center of the cavity and accumulated finally with a high density up to tens of critical density in several picoseconds. Two different mechanisms account for the efficient yield of the neutrons in the cavity: (1) At the early stage, the neutrons are generated by the high energy deuterium ions based on the “beam-target” approach. (2) At the later stage, the neutrons are generated by the thermonuclear fusion when the most of the deuterium ions reach equilibrium in the cavity. It is also found that a large number of deuterium ions accelerated inward can pass through the target center and the outer Au layer and finally stopped in the CD{sub 2} layer. This also causes efficient yield of neutrons inside the CD{sub 2} layer due to “beam-target” approach. A postprocessor has been designed to evaluate the neutron yield and the neutron spectrum is obtained.

  17. Geometrical properties of the trans-spherical solutions in higher dimensions

    SciTech Connect (OSTI)

    Kang, Gungwon; Kim, Hyeong-Chan; Lee, Jungjai

    2009-06-15

    We investigate the geometrical properties of static vacuum p-brane solutions of Einstein gravity in D=n+p+3 dimensions, which have spherical symmetry of S{sup n+1} orthogonal to the p directions and which are invariant under the translation along them. The solutions are characterized by the mass density and p number of tension densities. The causal structure of the higher-dimensional solutions is essentially the same as that of the five-dimensional ones. Namely, a naked singularity appears for most solutions except for the Schwarzschild black p-brane and the Kaluza-Klein bubble. We show that some important geometric properties such as the area of S{sup n+1} and the total spatial volume are characterized only by the three parameters (the mass density, the sum of tension densities, and the sum of tension density squares), rather than individual tension densities. These geometric properties are analyzed in detail in this parameter space and are compared with those of the five-dimensional case.

  18. Subsurface failure in spherical bodies. A formation scenario for linear troughs on Vesta’s surface

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

    Stickle, Angela M.; Schultz, P. H.; Crawford, D. A.

    2014-10-13

    Many asteroids in the Solar System exhibit unusual, linear features on their surface. The Dawn mission recently observed two sets of linear features on the surface of the asteroid 4 Vesta. Geologic observations indicate that these features are related to the two large impact basins at the south pole of Vesta, though no specific mechanism of origin has been determined. Furthermore, the orientation of the features is offset from the center of the basins. Experimental and numerical results reveal that the offset angle is a natural consequence of oblique impacts into a spherical target. We demonstrate that a set ofmore » shear planes develops in the subsurface of the body opposite to the point of first contact. Moreover, these subsurface failure zones then propagate to the surface under combined tensile-shear stress fields after the impact to create sets of approximately linear faults on the surface. Comparison between the orientation of damage structures in the laboratory and failure regions within Vesta can be used to constrain impact parameters (e.g., the approximate impact point and likely impact trajectory).« less

  19. Bubble nucleation in simple and molecular liquids via the largest spherical cavity method

    SciTech Connect (OSTI)

    Gonzalez, Miguel A.; Abascal, José L. F.; Valeriani, Chantal; Bresme, Fernando

    2015-04-21

    In this work, we propose a methodology to compute bubble nucleation free energy barriers using trajectories generated via molecular dynamics simulations. We follow the bubble nucleation process by means of a local order parameter, defined by the volume of the largest spherical cavity (LSC) formed in the nucleating trajectories. This order parameter simplifies considerably the monitoring of the nucleation events, as compared with the previous approaches which require ad hoc criteria to classify the atoms and molecules as liquid or vapor. The combination of the LSC and the mean first passage time technique can then be used to obtain the free energy curves. Upon computation of the cavity distribution function the nucleation rate and free-energy barrier can then be computed. We test our method against recent computations of bubble nucleation in simple liquids and water at negative pressures. We obtain free-energy barriers in good agreement with the previous works. The LSC method provides a versatile and computationally efficient route to estimate the volume of critical bubbles the nucleation rate and to compute bubble nucleation free-energies in both simple and molecular liquids.

  20. Subsurface failure in spherical bodies. A formation scenario for linear troughs on Vestas surface

    SciTech Connect (OSTI)

    Stickle, Angela M.; Schultz, P. H.; Crawford, D. A.

    2014-10-13

    Many asteroids in the Solar System exhibit unusual, linear features on their surface. The Dawn mission recently observed two sets of linear features on the surface of the asteroid 4 Vesta. Geologic observations indicate that these features are related to the two large impact basins at the south pole of Vesta, though no specific mechanism of origin has been determined. Furthermore, the orientation of the features is offset from the center of the basins. Experimental and numerical results reveal that the offset angle is a natural consequence of oblique impacts into a spherical target. We demonstrate that a set of shear planes develops in the subsurface of the body opposite to the point of first contact. Moreover, these subsurface failure zones then propagate to the surface under combined tensile-shear stress fields after the impact to create sets of approximately linear faults on the surface. Comparison between the orientation of damage structures in the laboratory and failure regions within Vesta can be used to constrain impact parameters (e.g., the approximate impact point and likely impact trajectory).

  1. The influence of primordial magnetic fields on the spherical collapse model in cosmology

    SciTech Connect (OSTI)

    Shibusawa, Y.; Ichiki, K.; Kadota, K. E-mail: ichiki@a.phys.nagoya-u.ac.jp

    2014-08-01

    Despite the ever growing observational evidence for the existence of the large scale magnetic fields, their origin and the evolution are not fully understood. If the magnetic fields are of primordial origin, they result in the generation of the secondary matter density perturbations and the previous studies show that such density perturbations enhance the number of dark matter halos. We extend the conventional spherical collapse model by including the Lorentz force which has not been implemented in the previous analysis to study the evolution of density perturbations produced by primordial magnetic fields. The critical over-density δ{sub c} characterizing the halo mass function turns out to be a bigger value, δ{sub c}≅ 1.78, than the conventional one δ{sub c}≅ 1.69 for the perturbations evolved only by the gravitational force. The difference in δ{sub c} between our model and the fully matter dominated cosmological model is small at a low redshift and, hence, only the high mass tail of the mass function is affected by the magnetic fields. At a high redshift, on the other hand, the difference in δ{sub c} becomes large enough to suppress the halo abundance over a wide range of mass scales. The halo abundance is reduced for instance by as large a factor as ∼10{sup 5} at z=9.

  2. A quasi-Bohmian approach for a homogeneous spherical solid body based on its geometric structure

    SciTech Connect (OSTI)

    Koupaei, Jalaledin Yousefi; Institutes for Theoretical Physics and Mathematics , Tehran ; Golshani, Mehdi; Department of Physics, Sharif University of Technology, Tehran

    2013-12-15

    In this paper we express the space of rotation as a Riemannian space and try to generalize the classical equations of motion of a homogeneous spherical solid body in the domain of quantum mechanics. This is done within Bohm's view of quantum mechanics, but we do not use the Schrödinger equation. Instead, we assume that in addition to the classical potential there is an extra potential and try to obtain it. In doing this, we start from a classical picture based on Hamilton-Jacobi formalism and statistical mechanics but we use an interpretation which is different from the classical one. Then, we introduce a proper action and extremize it. This procedure gives us a mathematical identity for the extra potential that limits its form. The classical mechanics is a trivial solution of this method. In the simplest cases where the extra potential is not a constant, a mathematical identity determines it uniquely. In fact the first nontrivial potential, apart from some constant coefficients which are determined by experiment, is the usual Bohmian quantum potential.

  3. Literature Review of Spherical Resorcinol-Formaldehyde for Cesium Ion Exchange

    SciTech Connect (OSTI)

    Brown, Garrett N.

    2014-09-30

    The current report summarizes work performed throughout the scientific community and DOE complex as reported in the open literature and DOE-sponsored reports to evaluate the Cs+ ion exchange (CIX) characteristics of SRF resin. King (2007) completed a similar literature review in support of material selection for the Small Column Ion Exchange (SCIX) project. Josephson et al. (2010) and Sams et al. (2009) provided a similar brief review of SRF CIX for the near-tank Cs+ removal (NTCR) project. Thorson (2008a) documented the basis for recommending SRF over SuperLigTM 644 as the primary CIX resin in the WTP. The current review expands on previous work, summarizes additional work completed to date, and provides a broad view of the literature without focusing on a specific column system. Although the focus of the current review is the SRF resin, many cited references include multiple materials such as the non-spherical GGRF and SuperLigTM 644 organic resins and crystalline silicotitanate (CST) IONSIVTM IE-911, a non-elutable inorganic material. This report summarizes relevant information provided in the literature.

  4. Response of a water-filled spherical vessel to an internal explosion

    SciTech Connect (OSTI)

    Lewis, M.W.; Wilson, T.L.

    1997-06-01

    Many problems of interest to the defense community involve fluid-structure interaction (FSI). Such problems include underwater blast loading of structures, bubble dynamics and jetting around structures, and hydrodynamic ram events. These problems may involve gas, fluid, and solid dynamics, nonlinear material behavior, cavitation, reaction kinetics, material failure, and nonlinearity that is due to varying geometry and contact conditions within a structure or between structures. Here, the authors model the response of a water-filled, thick-walled, spherical steel vessel to an internal explosion of 30 grams of C-4 with FSI2D--a two-dimensional coupled finite element and finite volume hydrodynamics code. The gas phase detonation products were modeled with a Becker-Kistiakowsky-Wilson high-explosive equation of state. Predictions from a fully coupled model were compared to experimental results in the form of strain gauge traces. Agreement was reasonably good. Additionally, the calculation was run in an uncoupled mode to understand the importance of fluid-structure interaction in this problem. The uncoupled model results in an accumulation of nonphysical energy in the vessel.

  5. Redirection of the spherical expanding shock wave on the interface with plasma

    SciTech Connect (OSTI)

    Markhotok, A.; Popovic, S.

    2014-02-15

    We study a strong spherical expanding shock wave interacting with the finite-gradient interface between neutral cold gas and weakly ionized plasma. We want to see how the interaction with the interface can alter the shock structure compared to the case of its free propagation through the media with the exponentially varying density. From our comparative calculations based on the 2D model, we found substantial difference in the shock structure including strong deformation of the shock front followed with its gradual flattening and the redirection in its propagation. There are a number of factors that can be used to control this phenomenon in order to strengthen or lessen the effect. The calculations can be made on any scale, limited with the requirement for the shock wave to be strong. The study points at the possibility in certain applications to avoid the shock wave with its redirection rather than attenuation. The results can be applicable to optimization of the energy deposition into the supersonic flux, the drag reduction in hypersonic flight, in the detonation theory, and combustion through the control of the ignition conditions, and for environmental improvements through sonic boom reduction. Cartesian coordinates were used in order to visualize the phenomenon.

  6. National SCADA Test Bed

    Broader source: Energy.gov [DOE]

    The National SCADA Test Bed (NSTB) is a one-of-a-kind national resource that draws on the integrated expertise and capabilities of the Argonne, Idaho, Lawrence Berkeley, Los Alamos, Oak Ridge, Pacific Northwest, and Sandia National Laboratories to address the cybersecurity challenges of energy delivery systems.

  7. Sandia National Laboratories | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    Sandia National Laboratories Sandia employee dubbed a master at locking down NNSA's enterprise NNSA's primary missions include keeping dangerous materials out of the wrong hands while protecting and maintaining the nation's nuclear deterrent. It's no surprise, then, that NNSA's labs and sites employ the best experts available in security. At NNSA's Sandia... On Womens Equality Day, we celebrate NNSA's talented Women in STEM Sandia California hosts Military Academic Collaboration students Sandia

  8. Sandia National Laboratories | National Nuclear Security Administration |

    National Nuclear Security Administration (NNSA)

    (NNSA) Sandia National Laboratories NNSA's Sandia National Laboratories are responsible for the development, testing, and production of specialized nonnuclear components and quality assurance and systems engineering for all of the United States' nuclear weapons. Sandia has locations in Albuquerque, NM; Livermore, CA; Kauai, HI; and Tonopah, NV. The labs are operated by Sandia Corporation. Visit our website Z-Machine Z-Machine Related News Sandia employee dubbed a master at locking down

  9. Physicist, Lawrence Livermore National Laboratory | National Nuclear

    National Nuclear Security Administration (NNSA)

    Security Administration | (NNSA) Physicist, Lawrence Livermore National Laboratory Kennedy Reed Kennedy Reed July 2009 Presidential Award for Excellence in Science and Engineering Mentoring President Obama has named Lawrence Livermore National Laboratory physicist Kennedy Reed as a recipient of the prestigious Presidential Award for Excellence in Science and Engineering Mentoring. Reed is a theoretical physicist at the laboratory, conducting research on atomic collisions in high temperature

  10. Researcher, Lawrence Livermore National Laboratory | National Nuclear

    National Nuclear Security Administration (NNSA)

    Security Administration | (NNSA) Researcher, Lawrence Livermore National Laboratory Placeholder for Bruce Macintosh image Bruce Macintosh February 2010 AAAS Newcomb Cleveland Prize A Lawrence Livermore National Laboratory researcher's paper published in November 2008 is co-winner of this year's American Association for the Advancement of Science (AAAS) Newcomb Cleveland Prize. The Paper is one of two outstanding papers published in Science from June 1, 2008 through May 31, 2009. Bruce

  11. Researcher, Lawrence Livermore National Laboratory | National Nuclear

    National Nuclear Security Administration (NNSA)

    Security Administration | (NNSA) Researcher, Lawrence Livermore National Laboratory Placeholder for Mike Fitzgerald image Mike Fitzgerald February 2010 AAAS Newcomb Cleveland Prize A Lawrence Livermore National Laboratory researcher's paper published in November 2008 is co-winner of this year's American Association for the Advancement of Science (AAAS) Newcomb Cleveland Prize. The Paper is one of two outstanding papers published in Science from June 1, 2008 through May 31, 2009. Another

  12. Sandia National Laboratories | National Nuclear Security Administration |

    National Nuclear Security Administration (NNSA)

    (NNSA) Sandia National Laboratories Allison Davis Allison Davis October 2009 NNSA Defense Programs Award of Excellence Two individuals and nine teams received the NNSA Defense Programs Awards of Excellence at ceremonies this year at Sandia National Laboratories in New Mexico and California. The NNSA Defense Programs Awards of Excellence were created in the early 1980s to give special recognition to those at the laboratories and plants directly associated with the stockpile modernization

  13. Sandia National Laboratories | National Nuclear Security Administration |

    National Nuclear Security Administration (NNSA)

    (NNSA) Sandia National Laboratories Kevin Eklund Kevin Eklund May 2010 NNSA Defense Programs Awards of Excellence Two individuals and nine teams received the NNSA Defense Programs Awards of Excellence at ceremonies this year at Sandia National Laboratories in New Mexico and California. The NNSA Defense Programs Awards of Excellence were created in the early 1980s to give special recognition to those at the laboratories and plants directly associated with the stockpile modernization program.

  14. Lawrence Livermore National Laboratories | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration Livermore National Laboratories NNSA, Air Force Complete Successful B61-12 Life Extension Program Instrumented Flight Tests WASHINGTON, D.C. - The National Nuclear Security Administration (NNSA) and United States Air Force completed eight successful B61-12 Life Extension Program (LEP) Vibration Fly Around/ Instrumented Measurement Vehicle (VFA/IMV) tests at Eglin Air Force Base and Edwards Air Force Base during July to

  15. Sandia National Laboratory | National Nuclear Security Administration |

    National Nuclear Security Administration (NNSA)

    (NNSA) Sandia National Laboratory NNSA's Sandia National Laboratories are responsible for the development, testing, and production of specialized nonnuclear components and quality assurance and systems engineering for all of the United States' nuclear weapons. Sandia has locations in Albuquerque, New Mexico; Livermore, California; Kauai, Hawaii; and Tonopah, Nevada. Sandia Field Office Contact the Field Office Contract Administration & Business Management Emergency Information Facilities

  16. Los Alamos National Security, LLC Los Alamos National Laboratory...

    Office of Environmental Management (EM)

    Security, LLC Los Alamos National Laboratory (LANL) Voluntary Protection Program (VPP) Assessment Los Alamos National Security, LLC Los Alamos National Laboratory (LANL) Voluntary...

  17. Los Alamos National Laboratory participates in National Lab Day...

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

    Lab Day Los Alamos National Laboratory participates in National Lab Day to increase awareness of science across the nation Connecting teachers and students with scientists,...

  18. Modified theory of secondary electron emission from spherical particles and its effect on dust charging in complex plasma

    SciTech Connect (OSTI)

    Misra, Shikha [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi-110016 (India); Mishra, S. K. [Institute for Plasma Research, Gandhinagar-382428 (India); Sodha, M. S. [Department of Education Building, University of Lucknow, Lucknow-226007 (India)

    2013-01-15

    The authors have modified Chow's theory of secondary electron emission (SEE) to take account of the fact that the path length of a primary electron in a spherical particle varies between zero to the diameter or x{sub m} the penetration depth depending on the distance of the path from the centre of the particle. Further by including this modified expression for SEE efficiency, the charging kinetics of spherical grains in a Maxwellian plasma has been developed; it is based on charge balance over dust particles and number balance of electrons and ionic species. It is seen that this effect is more pronounced for smaller particles and higher plasma temperatures. Desirable experimental work has also been discussed.

  19. Schneider National | Open Energy Information

    Open Energy Info (EERE)

    National Jump to: navigation, search Name: Schneider National Place: Denver, CO Website: www.schneidernational.com References: Schneider National1 Information About Partnership...

  20. cygnus | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    and operated with National Securities Technologies and Los Alamos National Laboratory (LANL) at the Nevada National Security Site (NNSS), has fired its 3,000th shot. Originally...

  1. The fluxes of CN neutrinos from the Sun in case of mixing in a spherical layer in the solar core

    SciTech Connect (OSTI)

    Kopylov, Anatoly; Petukhov, Valery E-mail: beril@inr.ru

    2012-03-01

    The results of the calculation are presented for the fluxes of CN neutrinos from the Sun in case of mixing in a spherical layer in the solar core, consistent with the seismic data and with the measured solar neutrino fluxes. It is shown that a substantial increase of the flux of {sup 13}N neutrinos can be gained in this case. The possible implications for experiment are discussed.

  2. String loops in the field of braneworld spherically symmetric black holes and naked singularities

    SciTech Connect (OSTI)

    Stuchlk, Z.; Kolo, M. E-mail: martin.kolos@fpf.slu.cz

    2012-10-01

    We study motion of current-carrying string loops in the field of braneworld spherically symmetric black holes and naked singularities. The spacetime is described by the Reissner-Nordstrm geometry with tidal charge b reflecting the non-local tidal effects coming from the external dimension; both positive and negative values of the spacetime parameter b are considered. We restrict attention to the axisymmetric motion of string loops when the motion can be fully governed by an appropriately defined effective potential related to the energy and angular momentum of the string loops. In dependence on these two constants of the motion, the string loops can be captured, trapped, or can escape to infinity. In close vicinity of stable equilibrium points at the centre of trapped states the motion is regular. We describe how it is transformed to chaotic motion with growing energy of the string loop. In the field of naked singularities the trapped states located off the equatorial plane of the system exist and trajectories unable to cross the equatorial plane occur, contrary to the trajectories in the field of black holes where crossing the equatorial plane is always admitted. We concentrate our attention to the so called transmutation effect when the string loops are accelerated in the deep gravitational field near the black hole or naked singularity by transforming the oscillatory energy to the energy of the transitional motion. We demonstrate that the influence of the tidal charge can be substantial especially in the naked singularity spacetimes with b > 1 where the acceleration to ultrarelativistic velocities with Lorentz factor ? ? 100 can be reached, being more than one order higher in comparison with those obtained in the black hole spacetimes.

  3. Dynamics of a spherical particle in an acoustic field: A multiscale approach

    SciTech Connect (OSTI)

    Xie, Jin-Han, E-mail: J.H.Xie@ed.ac.uk; Vanneste, Jacques [School of Mathematics and Maxwell Institute for Mathematical Sciences, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom)

    2014-10-15

    A rigid spherical particle in an acoustic wave field oscillates at the wave period but has also a mean motion on a longer time scale. The dynamics of this mean motion is crucial for numerous applications of acoustic microfluidics, including particle manipulation and flow visualisation. It is controlled by four physical effects: acoustic (radiation) pressure, streaming, inertia, and viscous drag. In this paper, we carry out a systematic multiscale analysis of the problem in order to assess the relative importance of these effects depending on the parameters of the system that include wave amplitude, wavelength, sound speed, sphere radius, and viscosity. We identify two distinguished regimes characterised by a balance among three of the four effects, and we derive the equations that govern the mean particle motion in each regime. This recovers and organises classical results by King [On the acoustic radiation pressure on spheres, Proc. R. Soc. A 147, 212240 (1934)], Gor'kov [On the forces acting on a small particle in an acoustical field in an ideal fluid, Sov. Phys. 6, 773775 (1962)], and Doinikov [Acoustic radiation pressure on a rigid sphere in a viscous fluid, Proc. R. Soc. London A 447, 447466 (1994)], clarifies the range of validity of these results, and reveals a new nonlinear dynamical regime. In this regime, the mean motion of the particle remains intimately coupled to that of the surrounding fluid, and while viscosity affects the fluid motion, it plays no part in the acoustic pressure. Simplified equations, valid when only two physical effects control the particle motion, are also derived. They are used to obtain sufficient conditions for the particle to behave as a passive tracer of the Lagrangian-mean fluid motion.

  4. Ions confined in spherical dielectric cavities modeled by a splitting field-theory

    SciTech Connect (OSTI)

    Lue, Leo; Linse, Per

    2015-04-14

    The properties of ions confined within spherical dielectric cavities are examined by a splitting field-theory and Monte Carlo simulations. Three types of cavities are considered: one possessing a uniform surface charge density, one with a uniform volume charge density, and one containing mobile ions. In all cases, mobile counterions are present within the dielectric sphere. The splitting theory is based on dividing the electrostatic interaction into long- and short-wavelength contributions and applying different approximations on the two contributions. The splitting theory works well for the case where the dielectric constant of the confining sphere is equal to or less than that of the medium external to the sphere. Nevertheless, by extending the theory with a virial expansion, the predictions are improved. However, when the dielectric constant of the confining sphere is greater than that of the medium outside the sphere, the splitting theory performs poorly, only qualitatively agreeing with the simulation data. In this case, the strong-coupling expansion does not seem to work well, and a modified mean-field theory where the counterions interact directly with only their own image charge gives improved predictions. The splitting theory works best for the system with a uniform surface charge density and worst for the system with a uniform volume charge density. Increasing the number of ions within the sphere, at a fixed radius, tends to increase the ion density near the surface of the sphere and leads to a depletion region in the sphere interior; however, varying the ion number does not lead to any qualitative changes in the performance of the splitting theory.

  5. SNL Los Alamos National Laboratory | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration SNL Los Alamos National Laboratory

  6. National Ignition Facility | National Nuclear Security Administration |

    National Nuclear Security Administration (NNSA)

    (NNSA) National Ignition Facility Glass amplifiers in Laser Bay 2 at the National Ignition Facility. The construction of the 192-beam 1.8 MJ UV NIF, the world's most energetic laser, was completed in March 2009. Current experiments are focusing on using the NIF laser and other ICF high energy density facilities leading to demonstrate fusion ignition and thermonuclear burn in the laboratory. The NIF is also being used to support basic science and SSP experiments. By the end of FY 2012, the

  7. Sandia National Laboratories | National Nuclear Security Administration |

    National Nuclear Security Administration (NNSA)

    (NNSA) Sandia National Laboratories Sandia National Laboratories DE-AC04-94AL85000 Operated by Sandia Corporation a Subsidiary of Lockheed Martin Corporation Contract Conformed 09/30/2015 to Modification 0588. View previous Sandia Contract and Mods (M081-A201). BASIC Contract (Official) Modifications (Official) Funding Mods Available Upon Request Conformed Contract (Updated 09/30/2015 to Mod 0588) (Unofficial) SNL M202 Section A (Supersedes Basic and all Mods) (pdf, 397KB) SNL M216 (9/15/04)

  8. Overview of the preliminary safety analysis of the National Ignition Facility

    SciTech Connect (OSTI)

    Brereton, S.; McLouth, L.; Odell, B.

    1997-06-01

    The National Ignition Facility (NIF) is a proposed U.S. Department of Energy inertial confinement laser fusion facility. The candidate sites for locating the NIF are: Los Alamos National Laboratory, Sandia National Laboratory, New Mexico, the Nevada Test Site, and Lawrence Livermore National Laboratory (LLNL), the preferred site. The NIF will operate by focusing 192 individual laser beams onto a tiny deuterium-tritium target located at the center of a spherical target chamber. The NIF has been classified as a low hazard, radiological facility on the basis of a preliminary hazards analysis and according to the DOE methodology for facility classification. This requires that a safety analysis report be prepared under DOE Order 5481.1B, Safety Analysis and Review System. A Preliminary Safety Analysis Report (PSAR) has been approved, which documents and evaluates the safety issues associated with the construction, operation, and decommissioning of the NIF. 10 refs., 6 figs., 4 tabs.

  9. Sandia National Laboratories: News

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

    News 2016 PPM work featured in book chapter PPM Team Member Highlighted in 2016 Sandia Recruiting Video 2015 PPM Member receives national recognition PPM Member serves on national roadmapping study for modeling across length scales Members of PPM speak at the National Academies Workshop on Additive Manufacturing 2014 Studying materials at the breaking point. May 2014 Computer model used in softening steel. April 2014 2013 Density Functional Theory (DFT) provides ab-initio, electronica structure

  10. National Hydrogen Energy Roadmap

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

    HYDROGEN ENERGY ROADMAP NATIONAL HYDROGEN ENERGY ROADMAP . . Toward a More Secure and Cleaner Energy Future for America Based on the results of the National Hydrogen Energy Roadmap Workshop Washington, DC April 2-3, 2002 United States Department of Energy November 2002 PRODUCTION * DELIVERY * STORAGE * CONVERSION * APPLICATIONS * PUBLIC EDUCATION AND OUTREACH PRODUCTION * DELIVERY * STORAGE * CONVERSION * APPLICATIONS * PUBLIC EDUCATION AND OUTREACH vii As we act on President Bush's National

  11. National Hydrogen Learning Demonstration

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

    Keith Wipke, Sam Sprik, Jennifer Kurtz, Todd Ramsden, Chris Ainscough, Genevieve Saur February 6, 2012 DOE's Informational Webinar Series National Hydrogen Learning Demonstration Status This presentation does not contain any proprietary, confidential, or otherwise restricted information NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy operated by the Alliance for Sustainable Energy, LLC v8 National Renewable Energy Laboratory 2

  12. National Renewable Energy Laboratory

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

    8 Annual Review Roger Taylor November 17, 2008 National Renewable Energy Laboratory Innovation for Our Energy Future Major DOE National Laboratories Brookhaven Pacific Northwest Lawrence Berkeley Lawrence Livermore          INEL National Renewable Energy Laboratory Los Alamos Sandia Argonne Oak Ridge   Defense Program Labs  Office of Science Labs  Energy Efficiency and Renewable Energy Lab  Environmental Management Lab  Fossil Energy Lab NETL 

  13. Pacific Northwest National Laboratory,

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

    Administration Pacific Northwest National Laboratory NNSA deputy visits PNNL to see radiochemistry and threat detection capabilities NNSA Principal Deputy Administrator Madelyn Creedon visited the Pacific Northwest National Laboratory (PNNL) in Washington this month to see the work it does for the agency, focusing on radiochemistry and threat detection. NNSA hosts international CTBT on-site inspection experts at Nevada National Security Site This month, NNSA hosted a Comprehensive

  14. Los Alamos National Laboratory

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

    Los Alamos National Laboratory i Table of Contents Letter from the Division Director 1 Innovation Prize Nominations 2 Innovation Prize Winner 5 About the Feynman Center for Innovation 6 Innovation Assets 7 Strategic Sponsored Work 8 National High Magnetic Field Laboratory 9 Licensing 10 SOLVE 11 Economic Development 12 STAR Cryoelectronics 13 Partnership 14 Verdesian Life Sciences 15 R&D 100 Awards 16 Federal Laboratory Consortium Awards 17 Los Alamos National Laboratory 1 As scientists and

  15. Idaho_National_Laboratory

    Office of Environmental Management (EM)

    Stacey Francis Small Business Program Manager Idaho National Laboratory 2 Idaho National Laboratory Prime Contractors * Idaho National Laboratory - Managed and Operated by Battelle Energy Alliance, LLC - Office of Nuclear Energy * Idaho Cleanup Project - Managed by Fluor Idaho, LLC - Office of Environmental Management * Naval Reactor Facility - Managed by Bechtel Marine Propulsion Corporation - Naval Nuclear Propulsion Program Department of Energy - Idaho 3 We Maintain: * 890 square miles * 111

  16. Sandia National Laboratories: Publications

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

    Facebook Twitter YouTube Flickr RSS Pathfinder Airborne ISR Systems Publications Sandia National Laboratories: Synthetic Aperature Radar (SAR): Publications Reports authored by Sandia National Laboratories 63 results OSTI ID Report No. Type Title Authors Pub. Date Researcher Sponsor 1121978 Full Text Available SAND2013-10619 Technical Report Window taper functions for subaperture processing. Doerry, Armin Walter Dec. 2013 Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

  17. Savannah River National Laboratory

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

    Savannah River National Laboratory srnl.doe.gov SRNL is a DOE National Laboratory operated by Savannah River Nuclear Solutions. At a glance 'Tin whiskers' suppression method Researchers at the Savannah River National Laboratory (SRNL) have identified a treatment method that slows or prevents the formation of whiskers in lead-free solder. Tin whiskers spontaneously grow from thin films of tin, often found in microelectronic devices in the form of solders and platings. Background This problem was

  18. Mentoring | Argonne National Laboratory

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

    Mentoring Why mentoring? As one of the largest laboratories in the nation for science and engineering research, Argonne National Laboratory is home to some of the most prolific and well-renowned scientists and engineers. To maintain an environment that fosters innovative research, we are committed to ensuring the success of our major players on the frontlines of our research-our Postdoctoral Scientists. The Argonne National Laboratory has a long-standing reputation as a place that offers

  19. Alamos National Laboratory's 2014

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

    $2 million pledged during Los Alamos National Laboratory's 2014 employee giving campaign December 17, 2013 "I Give Because..." theme focuses on unique role Lab plays in local communities LOS ALAMOS, N.M., Dec. 17, 2013-Nearly $2 million has been pledged by Los Alamos National Laboratory employees to United Way and other eligible nonprofit programs during the Laboratory's 2014 Employee Giving Campaign. Los Alamos National Security, LLC, which manages and operates the Laboratory for the

  20. Alamos National Security, LLC

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

    200 nonprofit organizations to receive monetary donations from Los Alamos National Security, LLC June 7, 2010 Employee volunteer efforts to be recognized LOS ALAMOS, New Mexico, June 7, 2010-Nonprofit organizations are receiving more than $117,000 from Los Alamos National Security, LLC during a recognition event beginning at 9 a.m. Wednesday at Fuller Lodge in downtown Los Alamos. The monetary donations are being made to the nonprofits as a result of the volunteer efforts of Los Alamos National

  1. Nevada National Security Site Performance Evaluations | National Nuclear

    National Nuclear Security Administration (NNSA)

    Security Administration | (NNSA) Nevada National Security Site Performance Evaluations FY 2016 FY 2016 Performance Evaluation Plan, National Security Technologies, LLC FY 2015 FY 2015 Performance Evaluation Report, National Security Technologies, LLC FY 2015 Performance Evaluation Report, Fee Determination Letter, National Security Technologies, LLC FY 2015 Performance Evaluation Plan, National Security Technologies, LLC FY 2014 FY 2014 Performance Evaluation Report, National Security

  2. National Day of Remembrance

    SciTech Connect (OSTI)

    2010-01-01

    Ames Laboratory observed the National Day of Remembrance for weapons workers from the Cold War era with a ceremony held Oct. 27, 2009 at the Ames Public Library.

  3. National Geothermal Student Competition

    Office of Energy Efficiency and Renewable Energy (EERE)

    The Energy Department's National Geothermal Student Competition (GSC) seeks students interested in building and showcasing scientific research, communication and leadership skills to convey the...

  4. National RES Las Vegas

    Broader source: Energy.gov [DOE]

    RES Las Vegas is another multifaceted event from The National Center which will feature unparalleled access to respected tribal leaders, members of congress, federal agency representatives, state...

  5. SANDIA NATIONAL LABORATORIES

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

    Impacts on Sandia and the Nation 2 SANDIA NATIONAL LABORATORIES 3 LDRD Impacts on Sandia and the Nation For further information, contact: Wendy R. Cieslak Senior Manager, Science, Technology, and Engineering Strategic Initiatives wrciesl@sandia.gov (505) 844-8633 or Henry R. Westrich LDRD Program Manager hrwestr@sandia.gov 505-844-9092 LDRD Impacts on Sandia and the Nation ABOUT THE COVER: Images from some of the case studies in this brochure: a near-UV light- emitting diode (LED), a cell

  6. National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    the University of California for violations of nuclear safety rules at the Los Alamos National Laboratory (LANL) in New Mexico. The University of California operates LANL for ...

  7. " Level: National Data;" " ...

    U.S. Energy Information Administration (EIA) Indexed Site

    5 Reasons that Made Residual Fuel Oil Unswitchable, 2006;" " Level: National Data;" " Row: ... barrels." ,,,,"Reasons that Made Residual Fuel Oil Unswitchable" " "," ",,,..." " ...

  8. Los Alamos National Laboratory

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

    70th anniversary app for iPhone, iPads June 5, 2013 LOS ALAMOS, N.M., June 4, 2013-Los Alamos National Laboratory has launched its first app for iPhones and iPads as part of the Laboratory's yearlong celebration of 70 years serving the nation. The free application is available from the Apple Store (search for Los Alamos National Lab). The app enables users to learn more about the Laboratory's national security mission, cutting edge research, unique history, top-flight scientists and the many

  9. Careers | Argonne National Laboratory

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

    identity, genetic information, marital status, national origin, pregnancy, race, religion, sexual orientation, veteran status or any other characteristic protected by law. EEO...

  10. National Security Education Center

    SciTech Connect (OSTI)

    Hurd, Alan J.

    2015-04-22

    Information about the National Security Education Center is given. Information about the Center’s history and current practices, including its facilities and its practicality are outlined.

  11. 2015 SACNAS National Conference

    Broader source: Energy.gov [DOE]

    Location: The Gaylord Conventiona Center at The National Harbor, Prince George's County, MD POC: Recruitment@doe.gov Website: 2015 SACNAS Conference

  12. National Laboratory's Weapons Program

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

    National Security, LLC, began managing the Laboratory. Prior to joining the Laboratory, McMillan served in a variety of research and management positions at Lawrence Livermore...

  13. 2015 APPA National Conference

    Broader source: Energy.gov [DOE]

    The American Public Power Association (APPA) is hosting their national conference that covers the political, economic, and technological trends shaping the electric utility industry.

  14. Sandia National Laboratories

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

    of, or supplemental to, this entry is a fair and accurate representation of this ... Sandia National Laboratories' (Sandia) Xyce Parallel Circuit Simulator is the world's ...

  15. National Energy Awareness Month

    Broader source: Energy.gov [DOE]

    October is National Energy Awareness Month. It's also a chance to talk about our country’s energy security and its clean energy future.

  16. Seneca Nation- 2014 Project

    Broader source: Energy.gov [DOE]

    The Seneca Nation of Indians (SNI) will install one 1.8-megawatt (MW) wind turbine on tribal common lands near Lake Erie in New York.

  17. Los Alamos National Laboratory

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

    3, 2015 Projects save taxpayer dollars, promote environmental stewardship, sustainability LOS ALAMOS, N.M., April 22, 2015-Nearly 400 Los Alamos National Laboratory employees on 32...

  18. National Laboratory Photovoltaics Research

    Office of Energy Efficiency and Renewable Energy (EERE)

    DOE supports photovoltaic (PV) research and development and facilities at its national laboratories to accelerate progress toward achieving the SunShot Initiative's technological and economic...

  19. Los Alamos National Laboratory

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

    million National Center for Systems Biology July 28, 2009 Lab contributes computer ... Center for Systems Biology located at the University of New Mexico in Albuquerque. ...

  20. Los alamos national laboratory

    National Nuclear Security Administration (NNSA)

    hosted representatives from 11StatesParties to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and one representative from the United Nations Office for...

  1. Los Alamos National Laboratory

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

    sustainability award October 14, 2010 LOS ALAMOS, New Mexico, October 14, 2010-Los Alamos National Laboratory recently received an Environmental Sustainability (EStar) ...

  2. Los Alamos National Laboratory

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

    6th Hazmat Challenge July 31, 2012 Competition tests skills of hazardous materials response teams LOS ALAMOS, New Mexico, July 31, 2012 What: Los Alamos National Laboratory (LANL)...

  3. National Women's History Month

    Broader source: Energy.gov [DOE]

    NATIONAL WOMEN’S HISTORY MONTH is an annual declared month that highlights the contributions of women to events in history and contemporary society.

  4. Mentoring | Argonne National Laboratory

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

    Argonne National Laboratory About Safety News Careers Education Community Diversity Directory Energy Environment Security User Facilities Science Work with Argonne Careers Apply ...

  5. Nevada National Security Site

    National Nuclear Security Administration (NNSA)

    ... and Beyond - National Security - Non-Proliferation - Environmental Management Defense ... explosive devices and to detect the proliferation of weapons of mass destruction. * ...

  6. BROADER National Security Missions

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

    We use our nuclear materials and forensics expertise to help solve national security ... materials, security and consequence management, and manufacturing and technical ...

  7. National Day of Remembrance

    ScienceCinema (OSTI)

    None

    2013-03-01

    Ames Laboratory observed the National Day of Remembrance for weapons workers from the Cold War era with a ceremony held Oct. 27, 2009 at the Ames Public Library.

  8. National Drive Electric Week

    Office of Energy Efficiency and Renewable Energy (EERE)

    Celebrate National Drive Electric Week with ways to make your all-electric or plug-in hybrid cars even greener!

  9. National Laboratory Geothermal Publications

    Broader source: Energy.gov [DOE]

    You can find publications, including technical papers and reports, about geothermal technologies, research, and development at the following U.S. Department of Energy national laboratories.

  10. Alamos National Laboratory

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

    short-pulse laser, scientists from Los Alamos, the Technical University of Darmstadt, Germany, and Sandia National Laboratories focus high-intensity light on an ultra-thin...

  11. National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    The Department of Energy (DOE), the National Nuclear Security Administration (NNSA) and the University of California (UC) have agreed on new management and operations contracts for ...

  12. Awards | Argonne National Laboratory

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

    Performance Award, 2013 (with two other researchers) U.S. Department of Energy Vehicle Technologies Office R&D Award, 2013 Argonne National Laboratory Distinguished...

  13. National Transportation Stakeholders Forum

    Office of Environmental Management (EM)

    National Transportation Stakeholders Forum OSRP * NNSA Contractors transporting in commerce, are required law to comply with applicable regulations required law to comply with ...

  14. Resources | Argonne National Laboratory

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

    Career Postdoctoral Factsheet: Before You Arrive Newsletters Professional Development Mentoring Resources Postdoctoral Society of Argonne LinkedIn Group National Postdoctoral...

  15. Sandia National Laboratories: Sandia National Laboratories: Missions:

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

    Defense Systems & Assessments: Accomplishments Top Archives About Defense Systems & Assessments Program Areas Accomplishments Archives Cybersecurity Programs Archives Sandia's scientists and engineers have a significant impact on national security and continually deliver results. View our previous accomplishments: 2011 Archives: View our 2011 Accomplishments 2010 Archives: View our 2010 Accomplishments

  16. [GUIRR workshops on national competitiveness

    SciTech Connect (OSTI)

    Mayo, M. J.

    2003-12-30

    GUIRR conducted several projects in the area of national competitiveness, including a workshop on DOE National Laboratories and Universities Collaboration.

  17. ssp | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    for Computation at NNSA's Lawrence Livermore National Laboratory (LLNL), announced ... Administration's (NNSA's) Lawrence Livermore National Laboratory today announced the ...

  18. Jianguo Wen | Argonne National Laboratory

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

    Jianguo Wen Materials Scientist Education BS, Physics Department, Wuhan University Ph.D., Institute of Physics, Chinese Academy of Sciences Postdoctoral Fellow, Delft University of Technology, The Netherlands Research Interests Research focuses on development and application of spherical and chromatic aberration-corrected transmission electron microscopy techniques to solve materials problems in catalysts, battery materials, photovoltaic films, and ferroelectric, piezolectric, and

  19. Formalism for testing theories of gravity using lensing by compact objects: Static, spherically symmetric case

    SciTech Connect (OSTI)

    Keeton, Charles R.; Petters, A.O.

    2005-11-15

    We are developing a general, unified, and rigorous analytical framework for using gravitational lensing by compact objects to test different theories of gravity beyond the weak-deflection limit. In this paper we present the formalism for computing corrections to lensing observables for static, spherically symmetric gravity theories in which the corrections to the weak-deflection limit can be expanded as a Taylor series in one parameter, namely, the gravitational radius of the lens object. We take care to derive coordinate-independent expressions and compute quantities that are directly observable. We compute series expansions for the observables that are accurate to second order in the ratio {epsilon}={theta} /{theta}{sub E} of the angle subtended by the lens's gravitational radius to the weak-deflection Einstein radius, which scales with mass as {epsilon}{proportional_to}M {sup 1/2}. The positions, magnifications, and time delays of the individual images have corrections at both first and second order in {epsilon}, as does the differential time delay between the two images. Interestingly, we find that the first-order corrections to the total magnification and centroid position vanish in all gravity theories that agree with general relativity in the weak-deflection limit, but they can remain nonzero in modified theories that disagree with general relativity in the weak-deflection limit. For the Reissner-Nordstroem metric and a related metric from heterotic string theory, our formalism reveals an intriguing connection between lensing observables and the condition for having a naked singularity, which could provide an observational method for testing the existence of such objects. We apply our formalism to the galactic black hole and predict that the corrections to the image positions are at the level of 10 {mu}arc s (microarcseconds), while the correction to the time delay is a few hundredths of a second. These corrections would be measurable today if a pulsar were

  20. A nonlinear eigenvalue problem for self-similar spherical force-free magnetic fields

    SciTech Connect (OSTI)

    Lerche, I.; Low, B. C.

    2014-10-15

    An axisymmetric force-free magnetic field B(r, ?) in spherical coordinates is defined by a function r?sin??B{sub ?}=Q(A) relating its azimuthal component to its poloidal flux-function A. The power law r?sin??B{sub ?}=aA|A|{sup 1/n}, n a positive constant, admits separable fields with A=(A{sub n}(?))/(r{sup n}) , posing a nonlinear boundary-value problem for the constant parameter a as an eigenvalue and A{sub n}(?) as its eigenfunction [B. C. Low and Y. Q Lou, Astrophys. J. 352, 343 (1990)]. A complete analysis is presented of the eigenvalue spectrum for a given n, providing a unified understanding of the eigenfunctions and the physical relationship between the field's degree of multi-polarity and rate of radial decay via the parameter n. These force-free fields, self-similar on spheres of constant r, have basic astrophysical applications. As explicit solutions they have, over the years, served as standard benchmarks for testing 3D numerical codes developed to compute general force-free fields in the solar corona. The study presented includes a set of illustrative multipolar field solutions to address the magnetohydrodynamics (MHD) issues underlying the observation that the solar corona has a statistical preference for negative and positive magnetic helicities in its northern and southern hemispheres, respectively; a hemispherical effect, unchanging as the Sun's global field reverses polarity in successive eleven-year cycles. Generalizing these force-free fields to the separable form B=(H(?,?))/(r{sup n+2}) promises field solutions of even richer topological varieties but allowing for ?-dependence greatly complicates the governing equations that have remained intractable. The axisymmetric results obtained are discussed in relation to this generalization and the Parker Magnetostatic Theorem. The axisymmetric solutions are mathematically related to a family of 3D time-dependent ideal MHD solutions for a polytropic fluid of index ??=?4/3 as discussed in the Appendix.

  1. Sandia National Laboratories: Research

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

    Research Bioscience Investigating cellular and biomolecular processes for bioenergy and biodefense. Computing and information science Developing essential tools for solving the world's most difficult problems. Engineering science Applying predictive simulation to engineering design and decision-making. Materials science Leading the nation in the knowledge of materials engineering, processing, and aging. Nanodevices and microsystems Developing and delivering custom microsystems and national

  2. National Nanotechnology Initiative

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

    National Nanotechnology Initiative (NNI) Basic Energy Sciences (BES) BES Home About Research Materials Sciences & Engineering (MSE) Chemical Sciences, Geosciences, and Biosciences (CSGB) Accelerator and Detector Research Research Conduct Policies DOE Energy Innovation Hubs Energy Frontier Research Centers National Nanotechnology Initiative (NNI) Nanomaterials ES&H Facilities Science Highlights Benefits of BES Funding Opportunities Basic Energy Sciences Advisory Committee (BESAC)

  3. Kaw Nation- 2002 Project

    Broader source: Energy.gov [DOE]

    The study will assess the feasibility of a commercial wind facility on lands selected and owned by the Kaw Nation adjacent to the vacant Chilocco Indian School campus. The Kaw Nation will examine the potential for integration of the wind facility into a redevelopment plan for the property.

  4. Idaho National Laboratory

    Office of Energy Efficiency and Renewable Energy (EERE)

    The Snake River Geothermal Consortium (SRGC) is a research partnership focused on advancing geothermal energy. Hosted by the Idaho National Laboratory (INL), SRGC proposes establishing FORGE as a resource for technology development, deployment, and validation. Their team includes members from national laboratories, universities, industry, and state and federal agencies. The technical team consists of members from Baker Hughes, the Center for Advanced Energy Studies (CAES) – Idaho National Laboratory, University of Idaho, Idaho State University, Boise State University, University of Wyoming - Campbell Scientific, Chena Power, Geothermal Resources Group, Idaho Department of Water Resources, Idaho Geologic Survey, Lawrence Livermore National Laboratory, Mink GeoHydro, National Renewable Energy Laboratory, University of Oklahoma, University of Utah, U.S. Geothermal, and the U.S. Geological Survey (USGS).

  5. Consent Order, Lawrence Livermore National National Security, LLC -

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

    WCO-2010-01 | Department of Energy Lawrence Livermore National National Security, LLC - WCO-2010-01 Consent Order, Lawrence Livermore National National Security, LLC - WCO-2010-01 October 29, 2010 Issued to Lawrence Livermore National Security, LLC for deficiencies associated with the Lawrence Livermore National Laboratory Chronic Beryllium Disease Prevention Program On October 29, 2010, the U.S. Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) issued a

  6. Major next steps for fusion energy based on the spherical tokamak design |

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

    (NNSA) Maintaining the Stockpile NNSA ensures the Nation sustains a safe, secure, and effective nuclear deterrent through the application of science, technology, engineering, and manufacturing. To deal with the changing face of nuclear deterrence and more-widely dispersed nuclear knowledge, NNSA also ensures the United States maintains excellence in nuclear science and technology that is second to none. Within the Nuclear Security Enterprise, the central mission which includes maintaining

  7. National Ignition Facility | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    Ignition Facility Former Army Ranger wins Sandia-sponsored student of the year award Former Army Ranger Damon Alcorn recently received the Sandia National Laboratories-Livermore Chamber of Commerce Student of the Year Award. Presented at the Chamber's State of the City Luncheon last month, the annual award highlights a Las Positas College student with exemplary academic... NNSA makers and hackers engage innovation and partnerships NNSA's labs change the world everyday through cutting-edge

  8. Physicist, Lawrence Livermore National Laboratory | National Nuclear

    National Nuclear Security Administration (NNSA)

    Security Administration | (NNSA) Physicist, Lawrence Livermore National Laboratory Omar Hurricane Omar Hurricane Ernest Orlando Lawrence Award Omar Hurricane has been named as a recipient of the Department of Energy's prestigious Ernest Orlando Lawrence Award. He is honored for his scientific leadership to advance understanding in a long-standing nuclear weapons physics anomaly and his contribution to nuclear weapons stockpile stewardship. He will be honored at a ceremony in Washington, D.C.

  9. Researcher, Sandia National Laboratories | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration | (NNSA) Researcher, Sandia National Laboratories David Haaland David Haaland December 2009 Fellows of the American Association for the Advancement of Science Sandia researchers David Haaland and David Myers have been elected Fellows of the American Association for the Advancement of Science. Election as a Fellow is an honor bestowed upon AAAS members by their peers. Haaland was cited for "distinguished contributions in the area of chemometrics and spectral imaging,

  10. Researcher, Sandia National Laboratories | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration | (NNSA) Researcher, Sandia National Laboratories David Myers David Myers December 2009 Fellow of the American Association for the Advancement of Science Sandia researchers David Haaland and David Myers have been elected Fellows of the American Association for the Advancement of Science. Election as a Fellow is an honor bestowed upon AAAS members by their peers. Myers was cited for "contributions to the science, management, and early application of ion implantation,

  11. Sandia National Laboratories: National Security Missions: International

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

    Homeland and Nuclear Security: Homeland Defense and Force Protection Programs Homeland Defense & Force Protection HDPF We design and implement advanced systems for intrusion detection and denial. We anticipate new threats and develop responses and countermeasures. We field technologies for protecting security forces and military personnel. We are committed to providing a Center of Excellence for Physical Security to support the DOE and DOD in ensuring the security of the nation's

  12. Sandia National Laboratories: National Security Missions: International

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

    Homeland and Nuclear Security: Remote Sensing and Verification Programs Remote Sensing and Verification Remote Sensing and Verification Image We extend Sandia's 60-year heritage in nuclear detonation detection to develop, deliver, and provide mission expertise for advanced remote sensing systems to monitor worldwide activities of consequence to national security. We design and build satellite sensor payloads and ground-based systems for the detection of nuclear detonations. We develop and

  13. Sandia National Laboratories: Sandia National Laboratories: Missions:

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

    Defense Systems & Assessments: About Us Defense Systems About Defense Systems & Assessments Program Areas Accomplishments Cybersecurity Programs About Defense Systems & Assessments soldier silhouetted by a sunset Defense Systems & Assessments supports guardians of peace and freedom on the battlefield and in the laboratory by applying engineering, science, and technology solutions to deter, detect, defeat, and defend threats to our national security. We analyze and exploit the

  14. Sandia National Laboratories: Sandia National Laboratories: Missions:

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

    Nuclear Weapons: About About Nuclear Weapons at Sandia Weapons Researcher World-class scientists and engineers come to Sandia to conduct breakthrough research in nuclear weapons. Sandia designs more than 6,300 parts of a modern nuclear weapon's 6,500 components. Our state-of-the-art laboratories facilitate large-scale testing and computer simulation. Sandia's work is of the highest consequence and those doing the work face awesome responsibilities. Unlike other national labs, which focus on

  15. Nevada National Security Site

    National Nuclear Security Administration (NNSA)

    Nevada National Security Site Proud Past, Exciting Future Nevada National Security Site Pre-Proposal Meeting November 19, 2015 Agenda * 8:30 am Welcome * 9:00 am Overview of NNSS and NFO * 10:00 am Break * 10:30 am NNSS Video * 11:00 am Questions * 11:30 am Lunch * 1:00 pm Solicitation Overview * 2:15 pm Break * 2:45 pm Questions * 4:00 pm Conclusion The Nevada National Security Site * Large geographically diverse outdoor laboratory - 1,360 square miles of federally owned and controlled land -

  16. Los Alamos National Laboratory

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

    remembers former director Harold Agnew September 30, 2013 Manhattan Project pioneer was LANL director from 1970-1979 LOS ALAMOS, N.M., Sept. 30, 2013-Los Alamos National Laboratory Director Charlie McMillan today remembered Harold Agnew as a national treasure who transformed the Laboratory into what it is in the 21st century. "His contributions to the Laboratory made us the institution we are today," McMillan said. "It was his vision - decades ago - that recognized that national

  17. Los Alamos National Laboratory's

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

    (NNSA) Los Alamos National Laboratory Los Alamos National Laboratory DE-AC52-06NA25396 Operated by Los Alamos National Security, LLC Conformed to Modification 0341 dated 02/29/2016 BASIC Contract (Official) Modifications (Official) Funding Mods Available Upon Request Conformed Contract (Unofficial) LANL Basic Contract dated 12/21/05 (pdf, 5,501KB) LANL A004 (8/11/06) (pdf, 501KB) LANL Conformed Contract (Conformed to to Modification 0341 dated 02/29/2016) LANL A008 (9/29/06) (pdf, 485KB)

  18. AMERICA'S NATIONAL LABS

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

    AMERICA'S NATIONAL LABS by 50 50 M A D E IN U S A B r e a k t h r o u g h s America's National Laboratory system has been changing and improving the lives of millions for more than 80 years. Born at a time of great societal need, this network of Department of Energy Laboratories has now grown into 17 facilities, working together as engines of prosperity and invention. As this list of 50 Break- throughs attests, National Laboratory discoveries have spawned industries, saved lives, generated new

  19. Foreign National New Hires

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

    Foreign Nationals Foreign National New Hires All foreign nationals including students and postdocs must complete this process. Contact (505) 667-4451, Option 6 Email The new-hire process, including the official pre-arrival period, does not begin until you receive and accept your written offer letter. Pre-Arrival New Hire Process Benefit Options New Employee App For your convenience, download the New Employee App from iTunes (IOS devices) or Google Play (Android devices). You can access new hire

  20. Sandia National Laboratories

    National Nuclear Security Administration (NNSA)

    National Laboratories Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Sand 2011-4582 P. ENERGY U.S. DEPARTMENT OF Albuquerque N e w M e x i c o Sandia Mountains Q Q ApproximatelyQ8,800QacresQQ ofQDOE-ownedQandQQ permittedQland Q Q LocatedQwithinQtheQQ KirtlandQAirQForceQQ