Sample records for torus experiment nstx

  1. Strike Point Control for the National Spherical Torus Experiment (NSTX)

    SciTech Connect (OSTI)

    Kolemen, E.; Gates, D. A.; Rowley, C. W.; Kasdin, N. J.; Kallman, J.; Gerhardt, S.; Soukhanovskii, V.; Mueller, D.

    2010-07-09T23:59:59.000Z

    This paper presents the first control algorithm for the inner and outer strike point position for a Spherical Torus (ST) fusion experiment and the performance analysis of the controller. A liquid lithium divertor (LLD) will be installed on NSTX which is believed to provide better pumping than lithium coatings on carbon PFCs. The shape of the plasma dictates the pumping rate of the lithium by channeling the plasma to LLD, where strike point location is the most important shape parameter. Simulations show that the density reduction depends on the proximity of strike point to LLD. Experiments were performed to study the dynamics of the strike point, design a new controller to change the location of the strike point to desired location and stabilize it. The most effective PF coils in changing inner and outer strike points were identified using equilibrium code. The PF coil inputs were changed in a step fashion between various set points and the step response of the strike point position was obtained. From the analysis of the step responses, PID controllers for the strike points were obtained and the controller was tuned experimentally for better performance. The strike controller was extended to include the outer-strike point on the inner plate to accommodate the desired low outer-strike points for the experiment with the aim of achieving "snowflake" divertor configuration in NSTX.

  2. 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

    2009-01-05T23:59:59.000Z

    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: results of lithium coating experiments, momentum confinement studies, scrape-off layer width scaling, demonstration of divertor heat load mitigation in strongly shaped plasmas, and coupling of CHI plasmas to OH ramp-up. These results advance the ST towards next step fusion energy devices such as NHTX and ST-CTF.

  3. National Spherical Torus Experiment (NSTX) and Planned Research

    SciTech Connect (OSTI)

    Kaye, S.; Neumeyer, C.; Ono, M.; Peng, M.

    1999-11-13T23:59:59.000Z

    The U.S. fusion energy sciences program began in 1996 to increase emphasis on confinement concept innovation. The NSTX [1,2] is being built at PPPL as a national fusion science research facility in response to this emphasis. NSTX is to test fusion science principles of the Spherical Torus (ST) plasmas, which include: (1) High plasma pressure in low magnetic field for high fusion power density, (2) Good energy confinement is a small-size plasma, (3) Nearly fully self-driven (bootstrap) plasma current, (4) Dispersed heat and particle fluxes, and (5) Plasma startup without complicated inboard solenoid magnet. These properties of the ST plasma, if verified, would lead to possible future fusion devices of high fusion performance, small size, feasible power handling, and improved economy. The design of NSTX is depicted in Fig.1. The device is designed to study plasmas with major radius up to 85 cm, minor radius up to 68 cm, elongation up to 2, with flexibility in forming double-null, single-null, and inboard limited plasmas. The nominal operation calls for a toroidal field of 0.3 T for 5 s at the major radius, and a plasma current at 1 MA with q {approximately} 10 at edge. It features a compact center stack containing the inner legs of the toroidal field coils, a full size solenoid capable of delivering 0.6 Wb induction, inboard vacuum vessel, and composite carbon tiles. The center stack can be replaced without disturbing the main device, diagnostics, and auxiliary systems. The vessel will be covered fully with graphite tiles and can be baked to 350 C. Other wall conditioning techniques are also planned.

  4. National Spherical Torus Experiment (NSTX) Center Stack Upgrade

    SciTech Connect (OSTI)

    Neumeyer, C; Chrzanowski, J; Dudek, L; Fan, H; Hatcher, R; Heitzenroeder, P; Menard, J; Ono, M; Ramakrishnan, S; Titus, P; Woolley, R

    2009-09-24T23:59:59.000Z

    The purpose of the NSTX Center Stack Upgrade project is to expand the NSTX operational space and thereby the physics basis for next-step ST facilities. The plasma aspect ratio (ratio of plasma major to minor radius) of the upgrade is increased to 1.5 from the original value of 1.26, which increases the cross sectional area of the center stack by a factor of ~ 3 and makes possible higher levels of performance and pulse duration.

  5. Efficient Coupling of Thermal Electron Bernstein Waves to the Ordinary Electromagnetic Mode on the National Spherical Torus Experiment (NSTX)

    SciTech Connect (OSTI)

    G. Taylor; P.C. Efthimion; B.P. LeBlanc; M.D. Carter; J.B. Caughman; J.B. Wilgen; J. Preinhaelter; R.W. Harvey; S.A. Sabbagh

    2005-02-02T23:59:59.000Z

    Efficient coupling of thermal electron Bernstein waves (EBW) to ordinary mode (Omode) electromagnetic radiation has been measured in plasmas heated by energetic neutral beams and high harmonic fast waves in the National Spherical Torus Experiment (NSTX) [M. Ono, S. Kaye, M. Peng, et al., Proceedings 17th IAEA Fusion Energy Conference (IAEA, Vienna, Austria, 1999), Vol.3, p. 1135]. The EBW to electromagnetic mode coupling efficiency was measured to be 0.8 {+-} 0.2, compared to a numerical EBW modeling prediction of 0.65. The observation of efficient EBW coupling to O-mode, in relatively good agreement with numerical modeling, is a necessary prerequisite for implementing a proposed high power EBW current drive system on NSTX.

  6. Configuration and Heating Power Dependence of Edge Parameters and H-mode Dynamics in National Spherical Torus Experiment (NSTX)

    SciTech Connect (OSTI)

    C.E. Bush; M.G. Bell; R.E. Bell; J. Boedo; E.D. Fredrickson; S.M. Kaye; S. Kubota; B.P. LeBlanc; R. Maingi; R.J. Maqueda; S.A. Sabbagh; V.A. Soukhanovskii; D. Stutman; D.W. Swain; J.B. Wilgen; S.J. Zweben; W.M. Davis; D.A. Gates; D.W. Johnson; R. Kaita; H.W. Kugel; D. Mastrovito; S. Medley; J.E. Menard; D. Mueller; M. Ono; F. Paoletti; S.J. Paul; Y-K.M. Peng; R. Raman; P.G. Roney; A.L. Roquemore; C.H. Skinner; E.J. Synakowski; G. Taylor; the NSTX Team

    2003-01-09T23:59:59.000Z

    Edge parameters play a critical role in H-mode (high-confinement mode) access, which is a key component of plasma discharge optimization in present-day toroidal confinement experiments and the design of next-generation devices. Because the edge magnetic topology of a spherical torus (ST) differs from a conventional aspect ratio tokamak, H-modes in STs exhibit important differences compared with tokamaks. The dependence of the NSTX (National Spherical Torus Experiment) edge plasma on heating power, including the L-H transition requirements and the occurrence of edge-localized modes (ELMs), and on divertor configuration is quantified. Comparisons between good L-modes (low-confinement modes) and H-modes show greater differences in the ion channel than the electron channel. The threshold power for the H-mode transition in NSTX is generally above the predictions of a recent ITER (International Thermonuclear Experimental Reactor) scaling. Correlations of transition and ELM phenomena with turbulent fluctuations revealed by Gas Puff Imaging (GPI) and reflectometry are observed. In both single-null and double-null divertor discharges, the density peaks off-axis, sometimes developing prominent ''ears'' which can be sustained for many energy confinement times, tau subscript ''E'', in the absence of ELMs. A wide variety of ELM behavior is observed, and ELM characteristics depend on configuration and fueling.

  7. Confinement and Local Transport in the National Spherical Torus Experiment NSTX

    SciTech Connect (OSTI)

    Kaye, S M; Stutman, D; Tritz, K; Yuh, H; Bell, M G; Bell, R E; Domier, C W; Gates, D; Horton, W; Kim, J; LeBlanc, B P; Luhmann Jr, N C; Maingi, R; Mazzucato, E; Menard, J E; Mikkelsen, D; Mueller, D; Park, H; Rewoldt, G; Sabbagh, S A; Smith, D R

    2007-03-15T23:59:59.000Z

    NSTX operates at low aspect ratio (R/a~1.3) and high beta (up to 40%), allowing tests of global confinement and local transport properties that have been established from higher aspect ratio devices. NSTX plasmas are heated by up to 7 MW of deuterium neutral beams with preferential electron heating as expected for ITER. Confinement scaling studies indicate a strong ?? dependence, with a current dependence that is weaker than that observed at higher aspect ratio. Dimensionless scaling experiments indicate a strong increase of confinement with decreasing collisionality and a weak degradation with beta. The increase of confinement with ?? is due to reduced transport in the electron channel, while the improvement with plasma current is due to reduced transport in the ion channel related to the decrease in the neoclassical transport level. Improved electron confinement has been observed in plasmas with strong reversed magnetic shear, showing the existence of an electron internal transport barrier (eITB). The development of the eITB may be associated with a reduction in the growth of microtearing modes in the plasma core. Perturbative studies show that while L-mode plasmas with reversed magnetic shear and an eITB exhibit slow changes of L?e across the profile after the pellet injection, H-mode plasmas with a monotonic q-profile and no eITB show no change in this parameter after pellet injection, indicating the existence of a critical gradient that may be related to the q-profile. Both linear and non-linear simulations indicate the potential importance of ETG modes at the lowest ??. Localized measurements of high-? fluctuations exhibit a sharp decrease in signal amplitude levels across the L-H transition, associated with a decrease in both ion and electron transport, and a decrease in calculated linear microinstability growth rates across a wide ?-range, from the ITG/TEM regime up to the ETG regime.

  8. Vessel Eddy Current Measurement for the National Spherical Torus Experiment (NSTX)

    SciTech Connect (OSTI)

    D.A. Gates; J. Menard; R. Marsala

    2004-11-19T23:59:59.000Z

    A simple analog circuit that measures the NSTX axisymmetric eddy current distribution has been designed and constructed. It is based on simple circuit model of the NSTX vacuum vessel that was calibrated using a special axisymmetric eddy current code which was written so that accuracy was maintained in the vicinity of the current filaments. The measurement and the model have been benchmarked against data from numerous vacuum shots and they are in excellent agreement. This is an important measurement that helps give more accurate equilibrium reconstructions.

  9. Vessel eddy current measurement for the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Gates, D.A.; Menard, J.E.; Marsala, R.J. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States)

    2004-12-01T23:59:59.000Z

    A simple analog circuit that measures the National Spherical Torus Experiment (NSTX) axisymmetric eddy current distribution has been designed and constructed. It is based on simple circuit model of the NSTX vacuum vessel that was calibrated using a special axisymmetric eddy current code which was written so that accuracy was maintained in the vicinity of the current filaments [J. Menard, J. Fusion Tech. (to be published)]. The measurement and the model have been benchmarked against data from numerous vacuum shots and they are in excellent agreement. This is an important measurement that helps give more accurate equilibrium reconstructions.

  10. 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.

    2009-10-21T23:59:59.000Z

    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.

  11. Divertor Heat Flux Mitigation in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Soukhanovskii, V A; Maingi, R; Gates, D A; Menard, J E; Paul, S F; Raman, R; Roquemore, A L; Bell, M G; Bell, R E; Boedo, J A; Bush, C E; Kaita, R; Kugel, H W; LeBlanc, B P; Mueller, D

    2008-08-04T23:59:59.000Z

    Steady-state handling of divertor heat flux is a critical issue for both ITER and spherical torus-based devices with compact high power density divertors. Significant reduction of heat flux to the divertor plate has been achieved simultaneously with favorable core and pedestal confinement and stability properties in a highly-shaped lower single null configuration in the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 2000] using high magnetic flux expansion at the divertor strike point and the radiative divertor technique. A partial detachment of the outer strike point was achieved with divertor deuterium injection leading to peak flux reduction from 4-6 MW m{sup -2} to 0.5-2 MW m{sup -2} in small-ELM 0.8-1.0 MA, 4-6 MW neutral beam injection-heated H-mode discharges. A self-consistent picture of outer strike point partial detachment was evident from divertor heat flux profiles and recombination, particle flux and neutral pressure measurements. Analytic scrape-off layer parallel transport models were used for interpretation of NSTX detachment experiments. 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 injection, and nearly impossible to achieve with main electron density, divertor neutral density or recombination increases alone.

  12. Engineering design of the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    C. Neumeyer; P. Heitzenroeder; J. Spitzer, J. Chrzanowski; et al

    2000-05-11T23:59:59.000Z

    NSTX is a proof-of-principle experiment aimed at exploring the physics of the ``spherical torus'' (ST) configuration, which is predicted to exhibit more efficient magnetic confinement than conventional large aspect ratio tokamaks, amongst other advantages. The low aspect ratio (R/a, typically 1.2--2 in ST designs compared to 4--5 in conventional tokamaks) decreases the available cross sectional area through the center of the torus for toroidal and poloidal field coil conductors, vacuum vessel wall, plasma facing components, etc., thus increasing the need to deploy all components within the so-called ``center stack'' in the most efficient manner possible. Several unique design features have been developed for the NSTX center stack, and careful engineering of this region of the machine, utilizing materials up to their engineering allowables, has been key to meeting the desired objectives. The design and construction of the machine has been accomplished in a rapid and cost effective manner thanks to the availability of extensive facilities, a strong experience base from the TFTR era, and good cooperation between institutions.

  13. 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

    2011-06-03T23:59:59.000Z

    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.

  14. 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

    2008-02-29T23:59:59.000Z

    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.

  15. Hardwired Control Changes For NSTX DC Power Feeds

    SciTech Connect (OSTI)

    Ramakrishnan, S.

    2013-06-28T23:59:59.000Z

    The National Spherical Torus Experiment (NSTX) has been designed and installed in the existing facilities at Princeton Plasma Physics Laboratory (PPPL). Most of the hardware, plant facilities, auxiliary sub-systems, and power systems originally used for the Tokamak Fusion Test Reactor (TFTR) have been used with suitable modifications to reflect NSTX needs. The original TFTR Hardwired Control System (HCS) with electromechanical relays was used for NSTX DC Power loop control and protection during NSTX operations. As part of the NSTX Upgrade, the HCS is being changed to a PLC-based system with the same control logic. This paper gives a description of the changeover to the new PLC-based system __________________________________________________

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

    SciTech Connect (OSTI)

    none,

    2014-06-01T23:59:59.000Z

    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.

  17. Conceptual design for the NSTX Central Instrumentation and Control System

    SciTech Connect (OSTI)

    Bashore, D.; Oliaro, G. Roney, P.; Sichta, P.; Tindall, K.

    1997-09-01T23:59:59.000Z

    The design and construction phase for the National Spherical Torus Experiment (NSTX) is under way at the Princeton Plasma Physics Laboratory (PPPL). Operation is scheduled to begin on April 30, 1999. This paper describes the conceptual design for the NSTX Central Instrumentation and Control (I and C) System. Major elements of the Central I and C System include the Process Control System, Plasma Control System, Network System, Data Acquisition System, and Synchronization System to support the NSTX experimental device.

  18. A Megawatt-level 28z GHz Heating System For The National Spherical Torus Experiment Upgrade

    SciTech Connect (OSTI)

    Taylor, Gary

    2014-04-01T23:59:59.000Z

    The National Spherical Torus Experiment Upgrade (NSTX-U) will operate at axial toroidal fields of < 1 T and plasma currents, Ip < 2 MA. The development of non-inductive (NI) plasmas is a major long-term research goal for NSTX-U. Time dependent numerical simulations of 28 GHz electron cyclotron (EC) heating of low density NI start-up plasmas generated by Coaxial Helicity Injection (CHI) in NSTX-U predict a significant and rapid increase of the central electron temperature (Te(0)) before the plasma becomes overdense. The increased Te(0) will significantly reduce the Ip decay rate of CHI plasmas, allowing the coupling of fast wave heating and neutral beam injection. A megawatt-level, 28 GHz electron heating system is planned for heating NI start-up plasmas in NSTX-U. In addition to EC heating of CHI start-up discharges, this system will be used for electron Bernstein wave (EBW) plasma start-up, and eventually for EBW heating and current drive during the Ip flattop.

  19. The Impact Of Lithium Wall Coatings On NSTX Discharges And The Engineering Of The Lithium Tokamak eXperiment (LTX)

    SciTech Connect (OSTI)

    R. Majeski, H. Kugel and R. Kaita

    2010-03-18T23:59:59.000Z

    Recent experiments on the National Spherical Torus eXperiment (NSTX) have shown the benefits of solid lithium coatings on carbon PFC's to diverted plasma performance, in both Land H- mode confinement regimes. Better particle control, with decreased inductive flux consumption, and increased electron temperature, ion temperature, energy confinement time, and DD neutron rate were observed. Successive increases in lithium coverage resulted in the complete suppression of ELM activity in H-mode discharges. A liquid lithium divertor (LLD), which will employ the porous molybdenum surface developed for the LTX shell, is being installed on NSTX for the 2010 run period, and will provide comparisons between liquid walls in the Lithium Tokamak eXperiment (LTX) and liquid divertor targets in NSTX. LTX, which recently began operations at the Princeton Plasma Physics Laboratory, is the world's first confinement experiment with full liquid metal plasma-facing components (PFCs). All materials and construction techniques in LTX are compatible with liquid lithium. LTX employs an inner, heated, stainless steel-faced liner or shell, which will be lithium-coated. In order to ensure that lithium adheres to the shell, it is designed to operate at up to 500 - 600 oC to promote wetting of the stainless by the lithium, providing the first hot wall in a tokamak to operate at reactor-relevant temperatures. The engineering of LTX will be discussed.

  20. Modeling of Spherical Torus Plasmas for Liquid Lithium Wall Experiments

    SciTech Connect (OSTI)

    R. Kaita; S. Jardin; B. Jones; C. Kessel; R. Majeski; J. Spaleta; R. Woolley; L. Zakharo; B. Nelson; M. Ulrickson

    2002-01-29T23:59:59.000Z

    Liquid metal walls have the potential to solve first-wall problems for fusion reactors, such as heat load and erosion of dry walls, neutron damage and activation, and tritium inventory and breeding. In the near term, such walls can serve as the basis for schemes to stabilize magnetohydrodynamic (MHD) modes. Furthermore, the low recycling characteristics of lithium walls can be used for particle control. Liquid lithium experiments have already begun in the Current Drive eXperiment-Upgrade (CDX-U). Plasmas limited with a toroidally localized limiter have been investigated, and experiments with a fully toroidal lithium limiter are in progress. A liquid surface module (LSM) has been proposed for the National Spherical Torus Experiment (NSTX). In this larger ST, plasma currents are in excess of 1 MA and a typical discharge radius is about 68 cm. The primary motivation for the LSM is particle control, and options for mounting it on the horizontal midplane or in the divertor region are under consideration. A key consideration is the magnitude of the eddy currents at the location of a liquid lithium surface. During plasma start up and disruptions, the force due to such currents and the magnetic field can force a conducting liquid off of the surface behind it. The Tokamak Simulation Code (TSC) has been used to estimate the magnitude of this effect. This program is a two dimensional, time dependent, free boundary simulation code that solves the MHD equations for an axisymmetric toroidal plasma. From calculations that match actual ST equilibria, the eddy current densities can be determined at the locations of the liquid lithium. Initial results have shown that the effects could be significant, and ways of explicitly treating toroidally local structures are under investigation.

  1. 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

    2010-05-19T23:59:59.000Z

    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.

  2. National Spherical Torus Experiment (NSTX) Construction, Commissioning, and Initial Operations

    E-Print Network [OSTI]

    supplies, and RF sources, cooling water systems, etc., is made to minimize the overall cost 350 C PFCs, 150C VV PROGRESS AND ACCOMPLISHMENTS Tremendous progress was made during the past year

  3. National Spherical Torus Experiment (NSTX) Construction, Commissioning, and Initial Operations

    E-Print Network [OSTI]

    magnet power supplies, and RF sources, cooling water systems, etc., is made to minimize the overall cost 350 C PFCs, 150C VV PROGRESS AND ACCOMPLISHMENTS Tremendous progress was made during the past year

  4. National Spherical Torus Experiment (NSTX) Center Stack Upgrade

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    ) coil surrounded by an ohmic heating (OH) solenoid and a several poloidal field (PF) shaping coils, all

  5. National Spherical Torus Experiment (NSTX) | Princeton Plasma Physics Lab

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated CodesTransparency VisitSilver Toyota1Resource forNationalA National

  6. National Spherical Torus Experiment NSTX CENTER STACK UPGRADE

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Analysis (FMEA) 14 2.6.3 Structural Design Criteria 15 2.7 Material Selection 15 2.8 General Electrical

  7. Study of Turbulent Fluctuations Driven by the Electron Temperature Gradient in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Mazzucato, E.; Bell, R. E.; Ethier, S.; Hosea, J. C.; Kaye, S. M.; LeBlanc, B. P.; Lee, W. W.; Ryan, P. M.; Smith, D. R.; Wang, W. X.; Wilson, J. R.

    2009-03-26T23:59:59.000Z

    Various theories and numerical simulations support the conjecture that the ubiquitous problem of anomalous electron transport in tokamaks may arise from a short-scale turbulence driven by the electron temperature gradient. To check whether this turbulence is present in plasmas of the National Spherical Torus Experiment (NSTX), measurements of turbulent fluctuations were performed with coherent scattering of electromagnetic waves. Results from plasmas heated by high harmonic fast waves (HHFW) show the existence of density fluctuations in the range of wave numbers k??e=0.1-0.4, corresponding to a turbulence scale length of the order of the collisionless skin depth. Experimental observations and agreement with numerical results from the linear gyro-kinetic GS2 code indicate that the observed turbulence is driven by the electron temperature gradient. These turbulent fluctuations were not observed at the location of an internal transport barrier driven by a negative magnetic shear.

  8. NSTX Weekly Report (May 21, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Diagnostics for Liquid Lithium Divertor Studies on the National Spherical Torus Experiment" by V University), "Modeling the Polarization Properties of Propagating Electromagnetic Waves in NSTX" by J. Zhang Plasma Physics and Plasma Material Interactions in the Fusion Power Plant Regime" 20-21 May 2010 at UC

  9. Intermittent Divertor Filaments in the National Spherical Torus Experiment and Their Relation to Midplane Blobs

    SciTech Connect (OSTI)

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

    2010-05-19T23:59:59.000Z

    While intermittent filamentary structures, also known as blobs, are routinely seen in the low-field-side scrape-off layer of the National Spherical Torus Experiment (NSTX) (Ono et al 2000 Nucl. Fusion 40 557), fine structured filaments are also seen on the lower divertor target plates of NSTX. These filaments, not associated with edge localized modes, correspond to the interaction of the turbulent blobs seen near the midplane with the divertor plasma facing components. The fluctuation level of the neutral lithium light observed at the divertor, and the skewness and kurtosis of its probability distribution function, is similar to that of midplane blobs seen in D?; e.g. increasing with increasing radii outside the outer strike point (OSP) (separatrix). In addition, their toroidal and radial movement agrees with the typical movement of midplane blobs. Furthermore, with the appropriate magnetic topology, i.e. mapping between the portion of the target plates being observed into the field of view of the midplane gas puff imaging diagnostic, very good correlation is observed between the blobs and the divertor filaments. The correlation between divertor plate filaments and midplane blobs is lost close to the OSP. This latter observation is consistent with the existence of ‘magnetic shear disconnection’ due to the lower X-point, as proposed by Cohen and Ryutov (1997 Nucl. Fusion 37 621).

  10. Control System for the NSTX Lithium Pellet Injector

    SciTech Connect (OSTI)

    P. Sichta; J. Dong; R. Gernhardt; G. Gettelfinger; H. Kugel

    2003-10-27T23:59:59.000Z

    The Lithium Pellet Injector (LPI) is being developed for the National Spherical Torus Experiment (NSTX). The LPI will inject ''pellets'' of various composition into the plasma in order to study wall conditioning, edge impurity transport, liquid limiter simulations, and other areas of research. The control system for the NSTX LPI has incorporated widely used advanced technologies, such as LabVIEW and PCI bus I/O boards, to create a low-cost control system which is fully integrated into the NSTX computing environment. This paper will present the hardware and software design of the computer control system for the LPI.

  11. Ramp-up of CHI Initiated Plasmas on NSTX

    SciTech Connect (OSTI)

    Mueller, D; Bell, R E; LeBlanc, B; Roquemore, A L; Raman, R; Jarboe, T R; Nelson, B A

    2009-10-29T23:59:59.000Z

    Experiments on the National Spherical Torus (NSTX) have now demonstrated flux savings using transient coaxial helicity injection (CHI). In these discharges, the discharges initiated by CHI are ramped up with an inductive transformer and exhibit higher plasma current than discharges without the benefit of CHI initiation.

  12. Effects of Toroidal Rotation Sshear on Toroidicity-induced Alfven Eigenmodes in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Podesta, M; Fredrickson, E D; Gorelenkov, N N; LeBlanc, B P; Heidbrink, W W; Crocker, N A; Kubota, S

    2010-08-19T23:59:59.000Z

    The effects of a sheared toroidal rotation on the dynamics of bursting Toroidicity-induced Alfven eigenmodes are investigated in neutral beam heated plasmas on the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40 557 (2000)]. The modes have a global character, extending over most of the minor radius. A toroidal rotation shear layer is measured at the location of maximum drive for the modes. Contrary to results from other devices, no clear evidence of increased damping is found. Instead, experiments with simultaneous neutral beam and radio-frequency auxiliary heating show a strong correlation between the dynamics of the modes and the instability drive. It is argued that kinetic effects involving changes in the mode drive and damping mechanisms other than rotation shear, such as continuum damping, are mostly responsible for the bursting dynamics of the modes.

  13. The NSTX Central Instrumentation and Control System

    SciTech Connect (OSTI)

    G. Oliaro; J. Dong; K. Tindall; P. Sichta

    1999-12-17T23:59:59.000Z

    Earlier this year the National Spherical Torus Experiment (NSTX) at the Princeton Plasma Physics Laboratory achieved ''first plasma''. The Central Instrumentation and Control System was used to support plasma operations. Major elements of the system include the Process Control System, Plasma Control System, Network System, Data Acquisition System, and Synchronization System. This paper will focus on the Process Control System. Topics include the architecture, hardware interface, operator interface, data management, and system performance.

  14. Dynamical Evolution of Pedestal Parameters in ELMy H-mode in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Diallo, A; Kubota, S; Sontag, A; Osborne, T; Podesta, M; Bell, R E; LeBlanc, B P; Menard, J

    2011-07-27T23:59:59.000Z

    Characterizations of the pedestal parameter dynamics throughout the edge localized modes(ELM) cycles are performed on the National Spherical Torus Experiment (NSTX, [M. Ono et al., Nucl. Fusion 40, 557 (2000)]). A clear buildup of the pedestal height is observed between ELMs for three di erent plasma currents, which tends to saturate prior to the onset of ELM at low and medium plasma current. Similarly, the pedestal width increases with no clear evidence of saturation during an ELM cycle. The maximum pedestal gradient increases as a function of plasma current, reaches a nominal value after the ELM crash, and remains constant until the end of the ELM cycle. The pedestal height just prior to the onset of ELM is shown to increase quadratically with plasma current. The pedestal width ? is proportional to the square-root of the poloidal ? at the top of the pedestal. Coherent density uctuations strongly increasing at the plasma edge are observed to be maximum after the ELM crash and to decay during the rest of the ELM cycle. Finally, the pedestal parameters evolution during the ELM cycle as well as the scaling with Ip of the pedestal pressure prior to the onset ELM are found to be qualitatively consistent with the peeling ballooning theory.

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

    SciTech Connect (OSTI)

    Ali Asgarian, M., E-mail: maliasgarian@ph.iut.ac.ir, E-mail: maa@msu.edu [Physics Department, Isfahan University of Technology, Isfahan 84156 (Iran, Islamic Republic of); Department of Electrical and Computer Engineering, Michigan State University, Michigan 48824-1226 (United States); Parvazian, A.; Abbasi, M. [Physics Department, Isfahan University of Technology, Isfahan 84156 (Iran, Islamic Republic of); Verboncoeur, J. P. [Department of Electrical and Computer Engineering, Michigan State University, Michigan 48824-1226 (United States)

    2014-09-15T23:59:59.000Z

    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.

  16. November 10, 1998 Physics Design of the National Spherical Torus

    E-Print Network [OSTI]

    1 Abstract The mission of the National Spherical Torus Experiment (NSTX) is to prove the principles an attractive path to a reactor or Volumetric Neutron Source (VNS). The ST fusion core would be small, economic and is presently under construction. Various reactor concepts have been advanced for the ST, 7,8 and these have

  17. A feasibility study for the spherical torus experiment

    SciTech Connect (OSTI)

    Lazarus, E [Oak Ridge National Laboratory (ORNL); Peng, Yueng Kay Martin [ORNL

    1985-10-01T23:59:59.000Z

    Oak Ridge National Laboratory (ORNL) proposes to build the Spherical Torus Experiment (STX), a very low aspect ratio toroidal confinement device. This proposal concentrates on tokamak operation of the experiment; however, it can in principle be operated as a pinch or reversed-field pinch as well. As a tokamak, the spherical torus confines a plasma that is characterized by high toroidal beta, low poloidal beta, large natural elongation, high plasma current for a given edge q, and strong paramagnetism. These features combine to offer the possibility of a compact, low-field fusion device. The figure below shows that when compared to a conventional tokamak the spherical torus represents a major change in geometry. The primary goals of the experiment will be to demonstrate a capability for high beta (20%) in the first stability regime, to extend our knowledge of tokamak confinement scaling, and to test oscillating-field current drive. The experiment will operate in the high-beta, collisionless regime, which is achieved in STX at low temperatures because of the geometry. At a minimum, operation of STX will help to resolve fundamental questions regarding the scaling of beta and confinement in tokamaks. Complete success in this program would have a significant impact on toroidal fusion research in that it would demonstrate solutions to the problems of beta and steady-state operation in the tokamak. The proposed device has a major radius of 0.45 m, a toroidai field of 0.5 T, a plasma current of 900 kA, and heating by neutral beam injection. We estimate 30 months for design, construction, and assembly. The budget estimate, including contingency and escalation, is $6.8 million.

  18. Startup of the experimental physics industrial control system at NSTX

    SciTech Connect (OSTI)

    Sichta, P.; Dong, J.

    1999-12-17T23:59:59.000Z

    The Experimental Physics Industrial Control System (EPICS) is a set of software which is being used as the basis of the National Spherical Torus Experiment's (NSTX) Process Control System, a major element of the NSTX's Central Instrumentation and Control System. EPICS is a result of a co-development effort started by several US Department of Energy National Laboratories. EPICS is actively supported through an international collaboration made up of government and industrial users. EPICS' good points include portability, scalability, and extensibility. A drawback for small experiments is that a wide range of software skills are necessary to get the software tools running for the process engineers. The authors' experience in designing, developing, operating, and maintaining NSTX's EPICS (system) will be reviewed.

  19. National Spherical Torus Experiment-Upgrade SAFETY ASSESSMENT DOCUMENT

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    -00 Revision 6 DECEMBER 2014 Prepared by: _______________________ Jerry Levine Head, PPPL ESH&S Reviewed by Chair, PPPL ES&H Executive Board #12;#12;NSTX-U SAFETY ASSESSMENT DOCUMENT (SAD) Table of Contents 1

  20. Implementation of BN Control in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Gerhardt, S; Bell, M G; Cropper, M; Gates, D A; Koleman, E; Lawson, J; Marsala, B; Menard, J E; Mueller, D

    2012-09-15T23:59:59.000Z

    We have designed and constructed a system for control of 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 of B N (from realtime equilibrium reconstruction) and a time-dependent request, in order to calculate the required injected power. This injected power request is then turned into modulations of the neutral beams. The details of this algorithm are described, including the techniques used to develop the appropriate control gains. Example uses of the system are shown

  1. Plasma Response to Lithium-Coated Plasma-Facing Components in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    M.G. Bell, H.W. Kugel, R. Kaita, L.E. Zakharov, H. Schneider, B.P. LeBlanc, D. Mansfield, R.E. Bell, R. Maingi, S. Ding, S.M. Kaye, S.F. Paul, S.P. Gerhardt, J.M. Canik, J.C. Hosea, G. Taylor and the NSTX Research Team

    2009-08-20T23:59:59.000Z

    Experiments in the National Spherical Torus Experiment (NSTX) have shown beneficial effects on the performance of divertor plasmas as a result of applying lithium coatings on the graphite and carbonfiber- composite plasma-facing components. These coatings have mostly been applied by a pair of lithium evaporators mounted at the top of the vacuum vessel which inject collimated streams of lithium vapor towards the lower divertor. In NBI-heated, deuterium H-mode plasmas run immediately after the application of lithium, performance modifications included decreases in the plasma density, particularly in the edge, and inductive flux consumption, and increases in the electron and ion temperatures and the energy confinement time. Reductions in the number and amplitude of ELMs were observed, including complete ELM suppression for periods up to 1.2 s, apparently as a result of altering the stability of the edge. However, in the plasmas where ELMs were suppressed, there was a significant secular increase in the effective ion charge Zeff and the radiated power as a result of increases in the carbon and medium-Z metallic impurities, although not of lithium itself which remained at a very low level in the plasma core, <0.1%. The impurity buildup could be inhibited by repetitively triggering ELMs with the application of brief pulses of an n = 3 radial field perturbation. The reduction in the edge density by lithium also inhibited parasitic losses through the scrape-off layer of ICRF power coupled to the plasma, enabling the waves to heat electrons in the core of H-mode plasmas produced by NBI. Lithium has also been introduced by injecting a stream of chemically stabilized, fine lithium powder directly into the scrape-off layer of NBI-heated plasmas. The lithium was ionized in the SOL and appeared to flow along the magnetic field to the divertor plates. This method of coating produced similar effects to the evaporated lithium but at lower amounts.

  2. Analysis Efforts Supporting NSTX Upgrades

    SciTech Connect (OSTI)

    H.Zhang, P. Titus, P. Rogoff, A.Zolfaghari, D. Mangra, M. Smith

    2010-11-29T23:59:59.000Z

    The National Spherical Torus Experiment (NSTX) is a low aspect ratio, spherical torus (ST) configuration device which is located at Princeton Plasma Physics Laboratory (PPPL) This device is presently being updated to enhance its physics by doubling the TF field to 1 Tesla and increasing the plasma current to 2 Mega-amperes. The upgrades include a replacement of the centerstack and addition of a second neutral beam. The upgrade analyses have two missions. The first is to support design of new components, principally the centerstack, the second is to qualify existing NSTX components for higher loads, which will increase by a factor of four. Cost efficiency was a design goal for new equipment qualification, and reanalysis of the existing components. Showing that older components can sustain the increased loads has been a challenging effort in which designs had to be developed that would limit loading on weaker components, and would minimize the extent of modifications needed. Two areas representing this effort have been chosen to describe in more details: analysis of the current distribution in the new TF inner legs, and, second, analysis of the out-of-plane support of the existing TF outer legs.

  3. Measurement of Poloidal Velocity on the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Ronald E. Bell and Russell Feder

    2010-06-04T23:59:59.000Z

    A diagnostic suite has been developed to measure impurity poloidal flow using charge exchange recombination spectroscopy on the National Spherical Torus Experiment. Toroidal and poloidal viewing systems measure all quantities required to determine the radial electric field. Two sets of up/down symmetric poloidal views are used to measure both active emission in the plane of the neutral heating beams and background emission in a radial plane away from the neutral beams. Differential velocity measurements isolate the line-integrated poloidal velocity from apparent flows due to the energy-dependent chargeexchange cross section. Six f/1.8 spectrometers measure 276 spectra to obtain 75 active and 63 background channels every 10 ms. Local measurements from a similar midplane toroidal viewing system are mapped into two dimensions to allow the inversion of poloidal line-integrated measurements to obtain local poloidal velocity profiles. Radial resolution after inversion is 0.6-1.8 cm from the plasma edge to the center.

  4. Electron Bernstein Wave Experiment on the Madison Symmetric Torus

    SciTech Connect (OSTI)

    Anderson, J. K.; Burke, D. R.; Forest, C. B.; Goetz, J. A.; Kaufman, M. C.; Seltzman, A. H. [Department of Physics, University of Wisconsin, Madison WI 53706 (United States)

    2009-11-26T23:59:59.000Z

    A system to heat electrons and possibly drive off-axis field-aligned current is under development on the Madison Symmetric Torus RFP. Staged experiments have reached an input power of 150 kW at 3.6G Hz and have produced a localized increase in SXR emission during rf injection. This measured emission is consistent with modeling in its location, energy spectrum and dependence on radial diffusion within the plasma. The emission is strongest in the region where ray tracing predicts deposition of the injected power. The multi-chord SXR camera used is sensitive to 4-7 keV photons. Enhanced emission in this energy range is consistent with Fokker-Plank modeling of EBW injection. The enhanced SXR emission vanishes quickly when radial diffusion in the plasma is high (as indicated by m = 0 magnetic activity); this is also consistent with Fokker-Plank modeling. An increase of boron emission (and presumably boron within the plasma) is also observed during EBW injection. This presents an alternative explanation to the enhanced SXR emission. Subsequent experiments with a different antenna at 100 kW input showed a small increase in SXR emission near 3 keV. A higher frequency experiment (5.5 GHz) with more input power available is currently under construction. Initial tests are centered on a circular waveguide launcher which requires only a 5 cm circular port in the vacuum vessel and has a target launch power of 400 kW.

  5. Divertor Heat Flux Mitigation in High-Performance H-mode Plasmas in the National Spherical Torus Experiment.

    SciTech Connect (OSTI)

    Soukhanovskii, V A; Maingi, R; Gates, D; Menard, J; Paul, S F; Raman, R; Roquemore, A L; Bell, R E; Bush, C; Kaita, R

    2008-09-22T23:59:59.000Z

    Experiments conducted in high-performance 1.0-1.2 MA 6 MW NBI-heated H-mode plasmas with a high flux expansion radiative divertor in NSTX demonstrate that significant divertor peak heat flux reduction and access to detachment may be facilitated naturally in a highly-shaped spherical torus (ST) configuration. Improved plasma performance with high {beta}{sub p} = 15-25%, a high bootstrap current fraction f{sub BS} = 45-50%, longer plasma pulses, and an H-mode regime with smaller ELMs has been achieved in the lower single null configuration with higher-end elongation 2.2-2.4 and triangularity 0.6-0.8. Divertor peak heat fluxes were reduced from 6-12 MW/m{sup 2} to 0.5-2 MW/m{sup 2} in ELMy H-mode discharges using high magnetic flux expansion and partial detachment of the outer strike point at several D{sub 2} injection rates, while good core confinement and pedestal characteristics were maintained. The partially detached divertor regime was characterized by a 30-60% increase in divertor plasma radiation, a peak heat flux reduction by up to 70%, measured in a 10 cm radial zone, a five-fold increase in divertor neutral pressure, and a significant volume recombination rate increase.

  6. 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. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)] [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States); Bell, R. E.; Diallo, A.; Gerhardt, S. P.; LeBlanc, B. P.; Manickam, J.; Menard, J. E.; Podestà, M. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Betti, R. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)] [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2014-05-15T23:59:59.000Z

    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.

  7. Parametric Dependence Of Fast-ion Transport Events On The National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Fredrickson, Erik; Gorelenkov, N. N.; Podesta, M.; Gerhardt, S. P.; Bell, R. E.; Diallo, A.; LeBlanc, B. [Princeton Plasma Physics Lab., NJ (United States)] [Princeton Plasma Physics Lab., NJ (United States); Bortolon, A. [Univ. of Tennessee, Knoxville, TN (United States)] [Univ. of Tennessee, Knoxville, TN (United States)

    2014-03-31T23:59:59.000Z

    Neutral-beam heated tokamak plasmas commonly have more than one third of the plasma kinetic energy in the non-thermal energetic beam ion population. This population of fast ions heats the plasma, provides some of the current drive, and can affect the stability (positively or negatively) of magnetohydrodynamic instabilities. This population of energetic ions is not in thermodynamic equilibrium, thus there is free-energy available to drive instabilities, which may lead to redistribution of the fast ion population. Understanding under what conditions beam-driven instabilities arise, and the extent of the resulting perturbation to the fast ion population, is important for predicting and eventually demonstrating non-inductive current ramp-up and sustainment in NSTX-U, as well as the performance of future fusion plasma experiments such as ITER. This paper presents an empirical approach towards characterizing the stability boundaries for some common energetic-ion-driven instabilities seen on NSTX.

  8. National Spherical Torus Experiment (NSTX) | U.S. DOE Office of Science

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire Solar EnergyKambaraorRENEWABLE Mobile

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

    SciTech Connect (OSTI)

    None

    2013-08-27T23:59:59.000Z

    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.

  10. Lithium Pellet Injector Development for NSTX

    SciTech Connect (OSTI)

    G. Gettelfinger; J. Dong; R. Gernhardt; H. Kugel; P. Sichta; J. Timberlake

    2003-12-04T23:59:59.000Z

    A pellet injector suitable for the injection of lithium and other low-Z pellets of varying mass into plasmas at precise velocities from 5 to 500 m/s is being developed for use on NSTX (National Spherical Torus Experiment). The ability to inject low-Z impurities will significantly expand NSTX experimental capability for a broad range of diagnostic and operational applications. The architecture employs a pellet-carrying cartridge propelled through a guide tube by deuterium gas. Abrupt deceleration of the cartridge at the end of the guide tube results in the pellet continuing along its intended path, thereby giving controlled reproducible velocities for a variety of pellets materials and a reduced gas load to the torus. The planned injector assembly has four hundred guide tubes contained in a rotating magazine with eight tubes provided for injection into plasmas. A PC-based control system is being developed as well and will be described elsewhere in these Proceedings. The development path and mechanical performance of the injector will be described.

  11. Divertor Heat Flux Mitigation in High-Performance H-mode Discharges in the National Spherical Torus Experiment.

    SciTech Connect (OSTI)

    Soukhanovskii, V A; Maingi, R; Gates, D; Menard, J

    2008-12-31T23:59:59.000Z

    Experiments conducted in high-performance 1.0 MA and 1.2 MA 6 MW NBI-heated H-mode discharges with a high magnetic flux expansion radiative divertor in NSTX demonstrate that significant divertor peak heat flux reduction and access to detachment may be facilitated naturally in a highly-shaped spherical torus (ST) configuration. Improved plasma performance with high {beta}{sub t} = 15-25%, a high bootstrap current fraction f{sub BS} = 45-50%, longer plasma pulses, and an H-mode regime with smaller ELMs has been achieved in the strongly-shaped lower single null configuration with elongation {kappa} = 2.2-2.4 and triangularity {delta} = 0.6-0.8. Divertor peak heat fluxes were reduced from 6-12 MW/m{sup 2} to 0.5-2 MW/m{sup 2} in ELMy H-mode discharges using the inherently high magnetic flux expansion f{sub m} = 16-25 and the partial detachment of the outer strike point at several D{sub 2} injection rates. A good core confinement and pedestal characteristics were maintained, while the core carbon concentration and the associated Z{sub eff} were reduced. The partially detached divertor regime was characterized by an increase in divertor radiated power, a reduction of ion flux to the plate, and a large neutral compression ratio. Spectroscopic measurements indicated a formation of a high-density, low temperature region adjacent to the outer strike point, where substantial increases in the volume recombination rate and CII, CIII emission rates was measured.

  12. Addressing the challenges of plasma-surface interactions in NSTX-U*

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

    Kaita, Robert; Abrams, Tyler; Jaworski, Michael; Lucia, Matthew; Nichols, Jacob H.; Skinner, Charles H.; Stotler, Daren; Allain, Jean Paul; Bedoya, Felipe

    2015-04-01T23:59:59.000Z

    The importance of conditioning plasma-facing components (PFCs) has long been recognized as a critical element in obtaining high-performance plasmas in magnetic confinement devices. Lithium coatings, for example, have been used for decades for conditioning PFCs. Since the initial studies on the Tokamak Fusion Test Reactor, experiments on devices with different aspect ratios and magnetic geometries like the National Spherical Torus Experiment (NSTX) continue to show the relationship between lithium PFCs and good confinement and stability. While such results are promising, their empirical nature do not reflect the detailed relationship between PFCs and the dynamic conditions that occur in the tokamakmore »environment. A first step developing an understanding such complexity will be taken in the upgrade to NSTX (NSTX-U) that is nearing completion. New measurement capabilities include the Materials Analysis and Particle Probe (MAPP) for in situ surface analysis of samples exposed to tokamak plasmas. The OEDGE suite of codes, for example, will provide a new way to model the underlying mechanisms for such material migration in NSTX-U. This will lead to a better understanding of how plasma-facing surfaces evolve during a shot, and how the composition of the plasma facing surface influences the discharge performance we observe. This paper will provide an overview of these capabilities, and highlight their importance for NSTX-U plans to transition from carbon to high-Z PFCs.« less

  13. Addressing the challenges of plasma-surface interactions in NSTX-U*

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

    Kaita, Robert [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Abrams, Tyler [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Jaworski, Michael [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Lucia, Matthew [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Nichols, Jacob H. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Skinner, Charles H. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Stotler, Daren [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Allain, Jean Paul [University of Illinois, Urbana, IL (United States); Bedoya, Felipe [University of Illinois, Urbana, IL (United States)

    2015-04-01T23:59:59.000Z

    The importance of conditioning plasma-facing components (PFCs) has long been recognized as a critical element in obtaining high-performance plasmas in magnetic confinement devices. Lithium coatings, for example, have been used for decades for conditioning PFCs. Since the initial studies on the Tokamak Fusion Test Reactor, experiments on devices with different aspect ratios and magnetic geometries like the National Spherical Torus Experiment (NSTX) continue to show the relationship between lithium PFCs and good confinement and stability. While such results are promising, their empirical nature do not reflect the detailed relationship between PFCs and the dynamic conditions that occur in the tokamak environment. A first step developing an understanding such complexity will be taken in the upgrade to NSTX (NSTX-U) that is nearing completion. New measurement capabilities include the Materials Analysis and Particle Probe (MAPP) for in situ surface analysis of samples exposed to tokamak plasmas. The OEDGE suite of codes, for example, will provide a new way to model the underlying mechanisms for such material migration in NSTX-U. This will lead to a better understanding of how plasma-facing surfaces evolve during a shot, and how the composition of the plasma facing surface influences the discharge performance we observe. This paper will provide an overview of these capabilities, and highlight their importance for NSTX-U plans to transition from carbon to high-Z PFCs.

  14. Edge ion heating by launched high harmonic fast waves in the National Spherical Torus Experiment

    E-Print Network [OSTI]

    Biewer, Theodore

    Edge ion heating by launched high harmonic fast waves in the National Spherical Torus Experiment T al., Fusion Technology 30, 1337 (1996)] measures the velocity distribution of ions in the plasma edge power High Harmonic Fast Wave (HHFW) rf heating in helium plasmas, with the poloidal ion temperature

  15. Dependence of Recycling and Edge Profiles on Lithium Evaporation in High Triangularity, High Performance NSTX H-mode Discharges

    SciTech Connect (OSTI)

    Maingi, R [PPPL; Osborne, T H [General Atomics; Bell, M G [PPPL; Bell, R E [PPPL; Boyle, D P [PPPL; Canik, J M [ORNL; Dialla, A [PPPL; Kaita, R [PPPL; Kaye, S M [PPPL; Kugel, H W [PPPL; LeBlanc, B P [PPPL; Sabbagh, S A [Applied Physics and Applied Math Dept., Columbia University, New York, NY 10027 USA; Skinner, C H [PPPL; Soukhanovskii, V A [LLNL

    2014-04-01T23:59:59.000Z

    In this paper, the effects of a pre-discharge lithium evaporation scan on highly shaped discharges in the National Spherical Torus Experiment (NSTX) are documented. Lithium wall conditioning ('dose') was routinely applied onto graphite plasma facing components between discharges in NSTX, partly to reduce recycling. Reduced D[sub]? emission from the lower and upper divertor and center stack was observed, as well as reduced midplane neutral pressure; the magnitude of reduction increased with the pre-discharge lithium dose. Improved energy confinement, both raw ?[sub]E and H-factor normalized to scalings, with increasing lithium dose was also observed. At the highest doses, we also observed elimination of edge-localized modes. The midplane edge plasma profiles were dramatically altered, comparable to lithium dose scans at lower shaping, where the strike point was farther from the lithium deposition centroid. This indicates that the benefits of lithium conditioning should apply to the highly shaped plasmas planned in NSTX-U.

  16. The Role of Lithium Conditioning in Achieving High Performance, Long Pulse H-mode Discharges in the NSTX and EAST Devices

    SciTech Connect (OSTI)

    Maingi, Rajesh [PPPL; Mansfield, D. K. [PPPL; Gong, X. Z. [IPPCAS; Sun, Z. [IPPCAS; Bell, M. G. [PPPL

    2014-10-01T23:59:59.000Z

    In this paper, the role of lithium wall conditioning on the achievement of high performance, long pulse discharges in the National Spherical Torus Experiment (NSTX) and the Experimental Advanced Superconducting Tokamak (EAST) is documented. Common observations include recycling reduction and elimination of ELMs. In NSTX, lithium conditioning typically resulted in ELM-free operation with impurity accumulation, which was ameliorated e.g. with pulsed 3D fields to trigger controlled ELMs. Active lithium conditioning in EAST discharges has overcome this problem, producing an ELM-free Hmode with controlled density and impurities.

  17. Aspect ratio effects on neoclassical tearing modes from comparison between DIII-D and National Spherical Torus Experiment

    SciTech Connect (OSTI)

    La Haye, R. J.; Buttery, R. J. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Gerhardt, S. P. [Princeton Plasma Physics Laboratory, P.O. Box 451 Princeton, New Jersey 08543 (United States); Sabbagh, S. A. [Columbia University, 2960 Broadway, New York, New York 10027-6900 (United States); Brennan, D. P. [University of Tulsa, 800 South Tucker Drive, Tulsa, Oklahoma 74104 (United States)

    2012-06-15T23:59:59.000Z

    Neoclassical tearing mode islands are sustained by helically perturbed bootstrap currents arising at finite beta from toroidal effects that trap a fraction of the particles in non-circulating orbits. DIII-D and NSTX are here operated with similar shape and cross-sectional area but almost a factor of two difference in inverse aspect ratio a/R. In these experiments, destabilized n=1 tearing modes were self-stabilized (reached the 'marginal point') by reducing neutral-beam power and thus beta. The measure of the marginal island gives information on the small-island stabilizing physics that in part (with seeding) governs onset. The marginal island width on NSTX is found to be about three times the ion banana width and agrees with that measured in DIII-D, except for DIII-D modes closer to the magnetic axis, which are about two times the ion banana width. There is a balance of the helically perturbed bootstrap term with small island effects with the sum of the classical and curvature terms in the modified Rutherford equation for tearing-mode stability at the experimental marginal point. Empirical evaluation of this sum indicates that while the stabilizing effect of the curvature term is negligible in DIII-D, it is important in NSTX. The mode temporal behavior from the start of neutral-beam injection reduction also suggests that NSTX operates closer to marginal classical tearing stability; this explains why there is little hysteresis in beta between mode onset, saturation, and self-stabilization (while DIII-D has large hysteresis in beta). NIMROD code module component calculations based on DIII-D and NSTX reconstructed experimental equilibria are used to diagnose and confirm the relative importance of the stabilizing curvature effect, an advantage for low aspect ratio; the relatively greater curvature effect makes for less susceptibility to NTM onset even if the classical tearing stability index is near marginal.

  18. NSTX High Temperature Sensor Systems

    SciTech Connect (OSTI)

    B.McCormack; H.W. Kugel; P. Goranson; R. Kaita; et al

    1999-11-01T23:59:59.000Z

    The design of the more than 300 in-vessel sensor systems for the National Spherical Torus Experiment (NSTX) has encountered several challenging fusion reactor diagnostic issues involving high temperatures and space constraints. This has resulted in unique miniature, high temperature in-vessel sensor systems mounted in small spaces behind plasma facing armor tiles, and they are prototypical of possible high power reactor first-wall applications. In the Center Stack, Divertor, Passive Plate, and vessel wall regions, the small magnetic sensors, large magnetic sensors, flux loops, Rogowski Coils, thermocouples, and Langmuir Probes are qualified for 600 degrees C operation. This rating will accommodate both peak rear-face graphite tile temperatures during operations and the 350 degrees C bake-out conditions. Similar sensor systems including flux loops, on other vacuum vessel regions are qualified for 350 degrees C operation. Cabling from the sensors embedded in the graphite tiles follows narrow routes to exit the vessel. The detailed sensor design and installation methods of these diagnostic systems developed for high-powered ST operation are discussed.

  19. Te (R,t) Measurements using Electron Bernstein Wave Thermal Emission on NSTX

    SciTech Connect (OSTI)

    Diem, S J; Efthimion, P C; LeBlanc, B P; Carter, M; Caughman, J; Wilgen, J B; Harvey, R W; Preinhaelter, J; Urban, J

    2006-06-09T23:59:59.000Z

    The National Spherical Torus Experiment (NSTX) routinely studies overdense plasmas with ne of (1–5) X 1019 m-3 and total magnetic field of <0.6 T, so that the first several electron cyclotron harmonics are overdense. The electrostatic electron Bernstein wave (EBW) can propagate in overdense plasmas, exhibits strong absorption, and is thermally emitted at electron cyclotron harmonics. These properties allow thermal EBW emission to be used for local Te measurement. A significant upgrade to the previous NSTX EBW emission diagnostic to measure thermal EBW emission via the oblique B-X-O mode conversion process has been completed. The new EBW diagnostic consists of two remotely steerable, quad-ridged horn antennas, each of which is coupled to a dual channel radiometer. Fundamental (8–18 GHz) and second and third harmonic (18–40 GHz) thermal EBW emission and polarization measurements can be obtained simultaneously.

  20. Two-dimensional AXUV-based radiated power density diagnostics on NSTX-U

    SciTech Connect (OSTI)

    Faust, I.; Parker, R. R. [MIT - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Delgado-Aparicio, L.; Bell, R. E.; Diallo, A.; Gerhardt, S. P.; LeBlanc, B.; Kozub, T. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Tritz, K. [The Johns Hopkins University, Baltimore, Maryland 21209 (United States); Stratton, B. C. [MIT - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States)

    2014-11-15T23:59:59.000Z

    A new set of radiated-power-density diagnostics for the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak have been designed to measure the two-dimensional poloidal structure of the total photon emissivity profile in order to perform power balance, impurity transport, and magnetohydrodynamic studies. Multiple AXUV-diode based pinhole cameras will be installed in the same toroidal angle at various poloidal locations. The local emissivity will be obtained from several types of tomographic reconstructions. The layout and response expected for the new radially viewing poloidal arrays will be shown for different impurity concentrations to characterize the diagnostic sensitivity. The radiated power profile inverted from the array data will also be used for estimates of power losses during transitions from various divertor configurations in NSTX-U. The effect of in-out and top/bottom asymmetries in the core radiation from high-Z impurities will be addressed.

  1. Physics Design Requirements for the National Spherical Torus Experiment Liquid Lithium Divertor

    SciTech Connect (OSTI)

    Kugel, W.; Bell, M.; Berzak,L.; Brooks, A.; Ellis, R.; Gerhardt, S.; Harjes, H.; Kaita, R.; Kallman, J.; Maingi, R.; Majeski, R.; Mansfield, D.; Menard, J.; Nygren,R. E.; Soukhanovskii, V.; Stotler, D.; Wakeland, P.; Zakharov L. E.

    2008-09-26T23:59:59.000Z

    Recent NSTX high power divertor experiments have shown significant and recurring benefits of solid lithium coatings on PFC's to the performance of divertor plasmas in both L- and H- mode confinement regimes heated by high-power neutral beams. The next step in this work is installation of a liquid lithium divertor (LLD) to achieve density control for inductionless current drive capability (e.g., about a 15-25% ne decrease from present highest non-inductionless fraction discharges which often evolve toward the density limit, ne/nGW~1), to enable ne scan capability (x2) in the H-mode, to test the ability to operate at significantly lower density for future ST-CTF reactor designs (e.g., ne/nGW = 0.25), and eventually to investigate high heat-flux power handling (10 MW/m2) with longpulse discharges (>1.5s). The first step (LLD-1) physics design encompasses the desired plasma requirements, the experimental capabilities and conditions, power handling, radial location, pumping capability, operating temperature, lithium filling, MHD forces, and diagnostics for control and characterization.

  2. 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.

    2011-01-10T23:59:59.000Z

    Fluctuations in the edge and scrape-off layer (SOL) of L-mode plasmas in the National Spherical Torus Experiment (NSTX) [S. M. Kaye et al.,Phys. Plasmas 8, 1977 (2001)] 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 D? light contained inmore »the SOL, which acts as a measure of turbulent 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

  3. 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. [Univ. of Colorado, Boulder, CO (United States); Munsat, T. [Univ. of Colorado, Boulder, CO (United States); D’Ippolito, D. A. [Lodestar Research Corp., Boulder, CO (United States); Maqueda, R. J. [Princeton Plasma Physics Lab., NJ (United States); Myra, J. R. [Lodestar Research Corp., Boulder, CO (United States); Russell, D. [Lodestar Research Corp., Boulder, CO (United States); Zweben, S. J. [Princeton Plasma Physics Lab., NJ (United States)

    2011-01-10T23:59:59.000Z

    Fluctuations in the edge and scrape-off layer (SOL) of L-mode plasmas in the National Spherical Torus Experiment (NSTX) [S. M. Kaye et al.,Phys. Plasmas 8, 1977 (2001)] 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 D? light contained in the SOL, which acts as a measure of turbulent 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.

  4. Non-inductive Solenoid-less Plasma Current Start-up in NSTX Using Transient CHI

    SciTech Connect (OSTI)

    Raman, R; Jarboe, T R; Nelson, B A; Bell, M G; Ono, M; Bigelow, T; Kaita, R; LeBlanc, B; Lee, K C; Maqueda, R; Menard, J; Paul, S

    2007-05-23T23:59:59.000Z

    Coaxial Helicity Injection (CHI) has been successfully used in the National Spherical Torus Experiment (NSTX) for a demonstration of closed flux current generation without the use of the central solenoid. The favorable properties of the Spherical Torus (ST) arise from its very small aspect ratio. However, small aspect ratio devices have very restricted space for a substantial central solenoid. Thus methods for initiating the plasma current without relying on induction from a central solenoid are essential for the viability of the ST concept. CHI is a promising candidate for solenoid-free plasma startup in a ST. The method has now produced closed flux current up to 160 kA verifying the high current capability of this method in a large ST built with conventional tokamak components.

  5. Surface Treatment of a Lithium Limiter for Spherical Torus Plasma Experiments

    SciTech Connect (OSTI)

    Kaita, R.; Majeski, R.; Doerner, R.; Antar, G.; Timberlake, J.; Spaleta, J.; Hoffman, D.; Jones, B.; Munsat, T.; Kugel, H.; Taylor, G.; Stutman, D.; Soukhanovskii, V.; Maingi, R.; Molesa, S.; Efthimion, P.; Menard, J.; Finkenthal, M.; Luckhardt, S.

    2001-03-20T23:59:59.000Z

    The concept of a flowing lithium first wall for a fusion reactor may lead to a significant advance in reactor design, since it could virtually eliminate the concerns with power density and erosion, tritium retention, and cooling associated with solid walls. As part of investigations to determine the feasibility of this approach, plasma interaction questions in a toroidal plasma geometry are being addressed in the Current Drive eXperiment-Upgrade (CDX-U) spherical torus (ST). The first experiments involved a toroidally local lithium limiter (L3). Measurements of pumpout rates indicated that deuterium pumping was greater for the L3 compared to conventional boron carbide limiters. The difference in the pumpout rates between the two limiter types decreased with plasma exposure, but argon glow discharge cleaning was able to restore the pumping effectiveness of the L3. At no point, however, was the extremely low recycling regime reported in previous lithium experiments achieved. This may be due to the much larger lithium surfaces that were exposed to the plasma in the earlier work. The possibility will be studied in the next set of CDX-U experiments, which are to be conducted with a large area, fully toroidal lithium limiter.

  6. Physics Design of the National High-power Advanced Torus Experiment

    SciTech Connect (OSTI)

    Menard, J E; Fu, G -Y; Gorelenkov, N; Kaye, S M; Kramer, G; Maingi, R; Neumeyer, C L; Sabbagh, S A; Soukhanovskii, V A

    2007-07-18T23:59:59.000Z

    Moving beyond ITER toward a demonstration power reactor (Demo) will require the integration of stable high fusion gain in steady-state, advanced methods for dissipating very high divertor heat-fluxes, and adherence to strict limits on in-vessel tritium retention. While ITER will clearly address the issue of high fusion gain, and new and planned long-pulse experiments (EAST, JT60-SA, KSTAR, SST-1) will collectively address stable steady-state highperformance operation, none of these devices will adequately address the integrated heat-flux, tritium retention, and plasma performance requirements needed for extrapolation to Demo. Expressing power exhaust requirements in terms of Pheat/R, future ARIES reactors are projected to operate with 60-200MW/m, a Component Test Facility (CTF) or Fusion Development Facility (FDF) for nuclear component testing (NCT) with 40-50MW/m, and ITER 20-25MW/m. However, new and planned long-pulse experiments are currently projected to operate at values of Pheat/R no more than 16MW/m. Furthermore, none of the existing or planned experiments are capable of operating with very high temperature first-wall (Twall = 600-1000C) which may be critical for understanding and ultimately minimizing tritium retention with a reactor-relevant metallic first-wall. The considerable gap between present and near-term experiments and the performance needed for NCT and Demo motivates the development of the concept for a new experiment — the National High-power advanced-Torus eXperiment (NHTX) — whose mission is to study the integration of a fusion-relevant plasma-material interface with stable steady-state high-performance plasma operation.

  7. Analysis of NSTX Upgrade OH Magnet and Center Stack

    SciTech Connect (OSTI)

    A. Zolfaghari, P. Titus, J. Chrzanowski, A. Salehzadeh, F. Dahlgren

    2010-11-30T23:59:59.000Z

    The new ohmic heating (OH) coil and center stack for the National Spherical Torus Experiment (NSTX) upgrade are required to meet cooling and structural requirements for operation at the enhanced 1 Tesla toroidal field and 2 MA plasma current. The OH coil is designed to be cooled in the time between discharges by water flowing in the center of the coil conductor. We performed resistive heating and thermal hydraulic analyses to optimize coolant channel size to keep the coil temperature below 100 C and meet the required 20 minute cooling time. Coupled electromagnetic, thermal and structural FEA analyses were performed to determine if the OH coil meets the requirements of the structural design criteria. Structural response of the OH coil to its self-field and the field from other coils was analyzed. A model was developed to analyze the thermal and electromagnetic interaction of centerstack components such as the OH coil, TF inner legs and the Bellville washer preload mechanism. Torsional loads from the TF interaction with the OH and poloidal fields are transferred through the TF flag extensions via a torque transfer coupling to the rest of the tokamak structure. A 3D FEA analysis was performed to qualify this design. The results of these analyses, which will be presented in this paper, have led to the design of OH coil and centerstack components that meet the requirements of the NSTX-upgrade structural design criteria.

  8. Solenoid-free Plasma Startup in NSTX using Coaxial Helicity Injection

    SciTech Connect (OSTI)

    Roger Raman; Thomas R. Jarboe; Michael G. Bell; Dennis Mueller; Brian A. Nelson; Benoit LeBlanc; Charles Bush; Masayoshi Nagata; Ted Biewer

    2005-01-03T23:59:59.000Z

    The favorable properties of the Spherical Torus (ST) arise from its very small aspect ratio. However, small aspect ratio devices have very restricted space for a substantial central solenoid. Thus methods for initiating the plasma current without relying on induction from a central solenoid are essential for the viability of the ST concept. Coaxial Helicity Injection (CHI) is a promising candidate for solenoid-free plasma startup in a ST. Recent experiments on the HIT-II ST at the University of Washington, have demonstrated the capability of a new method, referred to as transient CHI, to produce a high quality, closed-flux equilibrium that has then been coupled to induction, with a reduced requirement for transformer flux [R. Raman, T.R. Jarboe, B.A. Nelson, et al., Phys. Rev. Lett. 90 (February 2003) 075005-1]. An initial test of this method on the National Spherical Torus Experiment (NSTX) has produced about 140 kA of toroidal current. Modifications are now underway to improve capability for transient CHI in NSTX.

  9. Recent Progress on Spherical Torus Research

    SciTech Connect (OSTI)

    Ono, Masayuki [PPPL; Kaita, Robert [PPPL

    2014-01-01T23:59:59.000Z

    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 ? (radio of plasma to magnetic pressure) stability limit increases rapidly, approximately as ? ~ 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 ?, 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.

  10. The Relationships Between ELM Suppression, Pedestal Profiles, and Lithium Wall Coatings in NSTX

    SciTech Connect (OSTI)

    D.P. Boyle, R. Maingi, P.B. Snyder, J. Manickam, T.H. Osborne, R.E. Bell, B.P. LeBlanc, and the NSTX Team

    2012-08-17T23:59:59.000Z

    Recently in the National Spherical Torus Experiment (NSTX), increasing lithium wall coatings suppressed edge localized modes (ELMs), gradually but not quite monotonically. This work details profile and stability analysis as ELMs disappeared throughout the lithium scan. While the quantity of lithium deposited between discharges did not uniquely determine the presence of ELMs, profile analysis demonstrated that lithium was correlated to wider density and pressure pedestals with peak gradients farther from the separatrix. Moreover, the ELMy and ELM-free discharges were cleanly separated by their density and pedestal widths and peak gradient locations. Ultimately, ELMs were only suppressed when lithium caused the density pedestal to widen and shift inward. These changes in the density gradient were directly reflected in the pressure gradient and calculated bootstrap current. This supports the theory that ELMs in NSTX are caused by peeling and/or ballooning modes, as kink/peeling modes are stabilized when the edge current and pressure gradient shift away from the separatrix. Edge stability analysis using ELITE corroborated this picture, as reconstructed equilibria from ELM-free discharges were generally farther from their kink/peeling stability boundaries than ELMy discharges. We conclude that density profile control provided by lithium is the key first step to ELM suppression in NSTX

  11. 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.

    2011-01-01T23:59:59.000Z

    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

  12. 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. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Fredrickson, E. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Guttadora, L. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Kaita, R. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Kugel, H. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Menard, J. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Takahashi, H. [Princeton Fusion Research LLC, Princeton, NJ (United States)

    2011-10-06T23:59:59.000Z

    This paper describes techniques for measuring halo currents, and their associated toroidal peaking, in the National Spherical Torus Experiments [M. Ono, et. al, Nuclear Fusion 40, 557 (2000)]. 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 peaking 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.

  13. NSTX Weekly Report (November 19, 2010) FY 2011 NSTX plasma operations started on October 4, 2010

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Inductance Plasmas and First RWM State Space Control Experiments in NSTX" by Steve Sabbagh (Columbia. The ovens are presently under argon for assessment of required maintenance. · Molybdenum Inner Divertor

  14. Fast ion absorption of the high harmonic fast wave in the National Spherical Torus Experiment a...

    E-Print Network [OSTI]

    Egedal, Jan

    the high harmonic fast wave #HHFW# and energetic particles in a spherical torus #ST# #Ref. 1# is a new, Princeton, New Jersey 08543 R. W. Harvey CompX, Del Mar, California 92014 T. K. Mau University of California, Columbia University, New York, New York 10027 J. Egedal Plasma Science and Fusion Center, Massachusetts

  15. Snowflake divertor configuration studies for NSTX-Upgrade

    SciTech Connect (OSTI)

    Soukhanovskii, V A

    2011-11-12T23:59:59.000Z

    Snowflake divertor experiments in NSTX provide basis for PMI development toward NSTX-Upgrade. Snowflake configuration formation was followed by radiative detachment. Significant reduction of steady-state divertor heat flux observed in snowflake divertor. Impulsive heat loads due to Type I ELMs are partially mitigated in snowflake divertor. Magnetic control of snowflake divertor configuration is being developed. Plasma material interface development is critical for NSTX-U success. Four divertor coils should enable flexibility in boundary shaping and control in NSTX-U. Snowflake divertor experiments in NSTX provide good basis for PMI development in NSTX-Upgrade. FY 2009-2010 snowflake divertor experiments in NSTX: (1) Helped understand control of magnetic properties; (2) Core H-mode confinement unchanged; (3) Core and edge carbon concentration reduced; and (4) Divertor heat flux significantly reduced - (a) Steady-state reduction due to geometry and radiative detachment, (b) Encouraging results for transient heat flux handling, (c) Combined with impurity-seeded radiative divertor. Outlook for snowflake divertor in NSTX-Upgrade: (1) 2D fluid modeling of snowflake divertor properties scaling - (a) Edge and divertor transport, radiation, detachment threshold, (b) Compatibility with cryo-pump and lithium conditioning; (2) Magnetic control development; and (3) PFC development - PFC alignment and PFC material choice.

  16. November 10, 1998 Physics Design of the National Spherical Torus

    E-Print Network [OSTI]

    NSTX is to prove the principles of spherical torus physics by producing high- t plasmas that are non an attractive path to a reactor or VolumetricNeutron Source VNS.The ST fusion core would be small under construction. Various reactor concepts have been advanced for the ST,7,8 and these have identi ed

  17. Large Area Divertor Temperature Measurements Using A High-speed Camera With Near-infrared FiIters in NSTX

    SciTech Connect (OSTI)

    Lyons, B C; Zweben, S J; Gray, T K; Hosea, J; Kaita, R; Kugel, H W; Maqueda, R J; McLean, A G; Roquemore, A L; Soukhanovskii, V A

    2011-04-05T23:59:59.000Z

    Fast cameras already installed on the National Spherical Torus Experiment (NSTX) have be equipped with near-infrared (NIR) filters in order to measure the surface temperature in the lower divertor region. Such a system provides a unique combination of high speed (> 50 kHz) and wide fi eld-of-view (> 50% of the divertor). Benchtop calibrations demonstrated the system's ability to measure thermal emission down to 330 oC. There is also, however, signi cant plasma light background in NSTX. Without improvements in background reduction, the current system is incapable of measuring signals below the background equivalent temperature (600 - 700 oC). Thermal signatures have been detected in cases of extreme divertor heating. It is observed that the divertor can reach temperatures around 800 oC when high harmonic fast wave (HHFW) heating is used. These temperature profiles were fi t using a simple heat diffusion code, providing a measurement of the heat flux to the divertor. Comparisons to other infrared thermography systems on NSTX are made.

  18. Transient Enhancement (?Spike-on-Tail?) Observed on Neutral-Beam-Injected Energetic Ion Spectra Using the E||B Neutral Particle Analyzer in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    S. S. Medley, N. N. Gorelenkov, R. E. Bell, E. D. Fredrickson, S. P. Gerhardt, B. P. LeBlanc, M. Podestà, A. L. Roquemore, and the NSTX Team

    2010-06-09T23:59:59.000Z

    An increase of up to four-fold in the E||B Neutral Particle Analyzer (NPA) charge exchange neutral flux localized at the Neutral Beam (NB) injection full energy is observed in the National Spherical Torus Experiment (NSTX). Termed the High-Energy Feature (HEF), it appears on the NB-injected energetic ion spectrum only in discharges where tearing or kink-type modes (f < 10 kHz) are absent, TAE activity (f ~ 10-150 kHz) is weak (?Brms < 75 mGauss) and CAE/GAE activity (f ~ 400 – 1200 kHz) is robust. The feature exhibits a growth time of ~ 20 - 80 ms and occasionally develops a slowing down distribution that continues to evolve over periods of 100?s of milliseconds, a time scale long compared with the typical ~ 10?s ms equilibration time of the NB injected particles. The HEF is observed only in H-mode (not L-mode) discharges with injected NB power of 4 MW or greater and in the field pitch range v||/v ~ 0.7 – 0.9; i.e. only for passing (never trapped) energetic ions. The HEF is suppressed by vessel conditioning using lithium deposition at rates ~ 100 mg/shot, a level sufficient to suppress ELM activity. Increases of ~ 10 - 30 % in the measured neutron yield and total stored energy are observed to coincide with the feature along with broadening of measured Te(r), Ti(r) and ne(r) profiles. However, TRANSP analysis shows that such increases are driven by plasma profile changes and not the HEF phenomenon itself. Though a definitive mechanism has yet to be developed, the HEF appears to be caused by a form of TAE/CAE wave-particle interaction that distorts of the NB fast ion distribution in phase space.

  19. Biasing, Acquisition and Interpretation of a Dense Langmuir Probe Array in NSTX

    SciTech Connect (OSTI)

    Jaworski, M. A.; Kallman, J.; Kaita, R.; Kugel, H.; LeBlanc, B.; Marsala, R.; Ruzic, D.

    2010-09-22T23:59:59.000Z

    A dense array of 99 Langmuir probes has been installed in the lower divertor region of the National Spherical Torus Experiments (NSTX). This array is instrumented with a system of elec- tronics that allows flexibility in the choice of probes to bias as well as the type of measurement (including standard swept, single probe, triple probe and operation as passive floating potential and scrape-off-layer (SOL) current monitors). The use of flush-mounted probes requires careful inter- pretation. The time dependent nature of the SOL makes swept-probe traces difficult to interpret. To overcome these challenges, the single- and triple-Langmuir probe signals are used in comple- mentary fashion to determine the temperature and density at the probe location. A comparison to mid-plane measurements is made. Work is supported by DOE contracts DE-AC02-09CHI1466 and DE-PS02-07ER07-29.

  20. Mass changes in NSTX Surface Layers with Li Conditioning as Measured by Quartz Microbalances

    SciTech Connect (OSTI)

    C.H. Skinner, H.W. Kugel, A. L. Roquemore, PS. Krstic and A. Beste

    2008-06-09T23:59:59.000Z

    Dynamic retention, lithium deposition, and the stability of thick deposited layers were measured by three quartz crystal microbalances (QMB) deployed in plasma shadowed areas at the upper and lower divertor and outboard midplane in the National Spherical Torus Experiment (NSTX). Deposition of 185 {micro}/g/cm{sup 2} over 3 months in 2007 was measured by a QMB at the lower divertor while a QMB on the upper divertor, that was shadowed from the evaporator, received an order of magnitude less deposition. During helium glow discharge conditioning both neutral gas collisions and the ionization and subsequent drift of Li{sup +} interrupted the lithium deposition on the lower divertor. We present calculations of the relevant mean free paths. Occasionally strong variations in the QMB frequency were observed of thick lithium films suggesting relaxation of mechanical stress and/or flaking or peeling of the deposited layers.

  1. Design of interferometer system for Keda Torus eXperiment using terahertz solid-state diode sources

    SciTech Connect (OSTI)

    Xie, Jinlin, E-mail: jlxie@ustc.edu.cn; Wang, Haibo; Li, Hong; Lan, Tao; Liu, Adi; Liu, Wandong; Yu, Changxuan [School of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Ding, Weixing [School of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); University of California-Los Angeles, P. O. Box 957099, Los Angeles, California 90095-7099 (United States)

    2014-11-15T23:59:59.000Z

    A solid-state source based terahertz (THz) interferometer diagnostic system has been designed and characterized for the Keda Torus eXperiment (KTX). The THz interferometer utilizes the planar diodes based frequency multiplier (X48) to provide the probing beam at fixed frequency 0.650 THz, and local oscillator is provided by an independent solid-state diode source with tunable frequency (0.650 THz +/? 10 MHz). Both solid-state sources have approximately 1 mW power. The planar-diode mixers optimized for high sensitivity, ?750 mV/mW, are used in the heterodyne detection system, which permits multichannel interferometer on KTX with a low phase noise. A sensitivity of {sub min} = 4.5 × 10{sup 16} m{sup ?2} and a temporal resolution of 0.2 ?s have been achieved during the initial bench test.

  2. NSTX LTXPEGASUS Compact CTF

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    isotope retention. ST-CTF Compact ST-CTF at ~ 10 MA range provide a compact nuclear component test to NSTX. Large vacuum vessel, no stabilizing plates, excellent set of profile and boundary diagnostics

  3. NSTX-U Advances in Real-time C++11 on Linux

    SciTech Connect (OSTI)

    Erickson, Keith G

    2014-04-01T23:59:59.000Z

    Programming languages like C and Ada combined with proprietary embedded operating systems have dominated the real-time application space for decades. The new C++11standard includes native, language-level support for concurrency, a required feature for any nontrivial event-oriented real-time software. Threads, Locks, and Atomics now exist to provide the necessary tools to build the structures that make up the foundation of a complex real-time system. The National Spherical Torus Experiment Upgrade (NSTX-U) at the Princeton Plasma Physics Laboratory (PPPL) is breaking new ground with the language as applied to the needs of fusion devices. A new Digital Coil Protection System (DCPS) will serve as the main protection mechanism for the magnetic coils, and it is written entirely in C++11 running on Concurrent Computer Corporation's real-time operating system, RedHawk Linux. It runs over 600 algorithms in a 5 kHz control loop that determine whether or not to shut down operations before physical damage occurs. To accomplish this, NSTX-U engineers developed software tools that do not currently exist elsewhere, including real-time atomic synchronization, real-time containers, and a real-time logging framework. Together with a recent (and carefully configured) version of the GCC compiler, these tools enable data acquisition, processing, and output using a conventional operating system to meet a hard real-time deadline (that is, missing one periodic is a failure) of 200 microseconds.

  4. H-mode fueling optimization with the supersonic deuterium jet in NSTX

    SciTech Connect (OSTI)

    Soukhanovskii, V A; Bell, M G; Bell, R E; Gates, D A; Kaita, R; Kugel, H W; LeBlanc, B P; Lundberg, D P; Maingi, R; Menard, J E; Raman, R; Roquemore, A L; Stotler, D P

    2008-06-18T23:59:59.000Z

    High-performance, long-pulse 0.7-1.2 MA 6-7 MW NBI-heated small-ELM H-mode plasma discharges are developed in the National Spherical Torus Experiment (NSTX) as prototypes for confinement and current drive extrapolations to future spherical tori. It is envisioned that innovative lithium coating techniques for H-mode density pumping and a supersonic deuterium jet for plasma refueling will be used to achieve the low pedestal collisionality and low n{sub e}/n{sub G} fractions (0.3-0.6), both of which being essential conditions for maximizing the non-inductive (bootstrap and beam driven) current fractions. The low field side supersonic gas injector (SGI) on NSTX consists of a small converging-diverging graphite Laval nozzle and a piezoelectric gas valve. The nozzle is capable of producing a deuterium jet with Mach number M {le} 4, estimated gas density at the nozzle exit n {le} 5 x 10{sup 23} m{sup -3}, estimated temperature T {ge} 70 K, and flow velocity v = 2:4 km/s. The nozzle Reynolds number Reis {approx_equal} 6000. The nozzle and the valve are enclosed in a protective carbon fiber composite shroud and mounted on a movable probe at a midplane port location. Despite the beneficial L-mode fueling experience with supersonic jets in limiter tokamaks, there is a limited experience with fueling of high-performance H-mode divertor discharges and the associated density, MHD stability, and MARFE limits. In initial supersonic deuterium jet fueling experiments in NSTX, a reliable H-mode access, a low NBI power threshold, P{sub LH} {le} 2 MW, and a high fueling efficiency (0.1-0.4) have been demonstrated. Progress has also been made toward a better control of the injected fueling gas by decreasing the uncontrolled high field side (HFS) injector fueling rate by up to 95 % and complementing it with the supersonic jet fueling. These results motivated recent upgrades to the SGI gas delivery and control systems. The new SGI-Upgrade (SGI-U) capabilities include multi-pulse ms-scale controls and a reservoir gas pressure up to P{sub 0} = 5000 Torr. In this paper we summarize recent progress toward optimization of H-mode fueling in NSTX using the SGI-U.

  5. NSTX-U Control System Upgrades

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

    Erickson, K G; Gates, D A; Gerhardt, S P; Lawson, J E; Mozulay, R; Sichta, P; Tchilinguirian, G J

    2014-06-01T23:59:59.000Z

    The National Spherical Tokamak Experiment (NSTX) is undergoing a wealth of upgrades (NSTX-U). These upgrades, especially including an elongated pulse length, require broad changes to the control system that has served NSTX well. A new fiber serial Front Panel Data Port input and output (I/O) stream will supersede the aging copper parallel version. Driver support for the new I/O and cyber security concerns require updating the operating system from Redhat Enterprise Linux (RHEL) v4 to RedHawk (based on RHEL) v6. While the basic control system continues to use the General Atomics Plasma Control System (GA PCS), the effort to forward port the entire software package to run under 64-bit Linux instead of 32-bit Linux included PCS modifications subsequently shared with GA and other PCS users. Software updates focused on three key areas: (1) code modernization through coding standards (C99/C11), (2) code portability and maintainability through use of the GA PCS code generator, and (3) support of 64-bit platforms. Central to the control system upgrade is the use of a complete real time (RT) Linux platform provided by Concurrent Computer Corporation, consisting of a computer (iHawk), an operating system and drivers (RedHawk), and RT tools (NightStar). Strong vendor support coupled with an extensive RT toolset influenced this decision. The new real-time Linux platform, I/O, and software engineering will foster enhanced capability and performance for NSTX-U plasma control.

  6. NSTX Weekly Report (Mar. 19, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    experiments in NSTX that provided support for this plasma-material interface (PMI) concept (http" divertor configuration may be a viable PMI solution for future conventional and spherical tokamaks. Initial was completed, and preparations started for its leak checking. · Plasma Materials Interaction (PMI) Probe - J. P

  7. Reconciliation of Measured and TRANSP-calculated Neutron Emission Rates in the National Spherical Torus Experiment: Circa 2002-2005

    SciTech Connect (OSTI)

    S.S. Medley; D.S. Darrow; A.L. Roquemore

    2005-06-15T23:59:59.000Z

    A change in the response of the neutron detectors on the National Spherical Torus Experiment occurred between the 2002-2003 and 2004 experimental run periods. An analysis of this behavior by investigating the neutron diagnostic operating conditions and comparing measured and TRANSP-calculated neutron rates is presented. Also a revised procedure for cross calibration of the neutron scintillator detectors with the fission chamber detectors was implemented that delivers good agreement amongst the measured neutron rates for all neutron detectors and all run periods. For L-mode discharges, the measured and TRANSP-calculated neutron rates now match closely for all run years. For H-mode discharges over the entire 2002-2004 period, the 2FG scintillator and fission chamber measurements match each other but imply a neutron deficit of 11.5% relative to the TRANSP-calculated neutron. The results of this report impose a modification on all of the previously used calibration factors for the entire neutron detector suite over the 2002-2004 period. A tabular summary of the new calibration factors is provided including certified calibration factors for the 2005 run.

  8. Varying the Pre-discharge Lithium Wall Coatings to Alter the Characteristics of the ELM-free H-mode Pedestal in NSTX

    SciTech Connect (OSTI)

    D.P. Boyle, J.M. Canik, R. Maing, P.B. Snyder, T.H. Osborne, and the NSTX Team

    2012-06-28T23:59:59.000Z

    A previous experiment in the National Spherical Torus Experiment (NSTX) showed pre-discharge lithium deposition gradually suppresed edge-localized modes (ELMs) and had nearly continuous relationships with reduced recycling and transport. In this paper, additional data filled gaps in the earlier experiment, and demonstrates that recycling, confinement, and pedestal structure continued to improve with additional lithium, even after ELMs were completely suppressed. New analysis shows that toroidal rotation and ion temperature also increased continuously with additional lithium. Besides its evolution with additional lithium, we also characterize the time evolution of the ELM-free H-mode pedestal as average density rose and impurities accumulated. We find that the pedestal structure, divertor heat flux and Dalpha profiles, and inferred recycling coefficient did not change significantly, at least until radiative losses become dominant. This suggests that the low-recycling properties of lithium were not significantly degraded over the duration of the discharge.

  9. Novel Use of Water Soluble "Aquapour" As A Temporary Spacer During Coil Winding For The NSTX-U Centerstack

    SciTech Connect (OSTI)

    Mardenfeld, Michael

    2013-07-01T23:59:59.000Z

    A major facility upgrade to the National Spherical Torus eXperiment (NSTX-U) is currently underway at Princeton Plasma Physics Laboratory (PPPL). A key component of NSTX-U is the fabrication of a new, higher field centerstack (CS). In order to simultaneously provide robust joints between the inner and outer legs of the Toroidal Field Coils (TF) and minimize radial build, the NSTX-U CS design requires that the Ohmic Heating solenoid (OH) be wound directly on the inner TF bundle. To protect the OH against thermal expansion stress during scenarios where the inner TF bundle is hot but the OH is relatively cool, the completed CS will have a 0.100 inch annular gap between the outer diameter of the TF bundle and the inner diameter of the OH solenoid. "Aquapour", a proprietary material produced by the Advanced Ceramics Manufacturing Company will be used during manufacture to produce this gap. After the TF bundle is vacuum pressure impregnated and cured, a cylindrical "clam shell" mold will be assembled around it, and a slurry of powdered Aquapour and water will be pumped into the annular space between the mold and TF bundle. Subsequent baking will turn the Aquapour solid, and a protective layer of wet lay-up fiberglass and resin will be added. The OH solenoid will be wound directly on this wet lay-up shell. After vacuum pressure impregnation of the OH, the water soluble Aquapour will be washed away, leaving the required radial clearance between the TF and OH. This paper will describe prototyping and testing of this process, and plans for use on the actual CS fabrication.

  10. Reduced model prediction of electron temperature profiles in microtearing-dominated National Spherical Torus eXperiment plasmas

    SciTech Connect (OSTI)

    Kaye, S. M., E-mail: skaye@pppl.gov; Guttenfelder, W.; Bell, R. E.; Gerhardt, S. P.; LeBlanc, B. P.; Maingi, R. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

    2014-08-15T23:59:59.000Z

    A representative H-mode discharge from the National Spherical Torus eXperiment is studied in detail to utilize it as a basis for a time-evolving prediction of the electron temperature profile using an appropriate reduced transport model. The time evolution of characteristic plasma variables such as ?{sub e},??{sub e}{sup ?}, the MHD ? parameter, and the gradient scale lengths of T{sub e}, T{sub i}, and n{sub e} were examined as a prelude to performing linear gyrokinetic calculations to determine the fastest growing micro instability at various times and locations throughout the discharge. The inferences from the parameter evolutions and the linear stability calculations were consistent. Early in the discharge, when ?{sub e} and ?{sub e}{sup ?} were relatively low, ballooning parity modes were dominant. As time progressed and both ?{sub e} and ?{sub e}{sup ?} increased, microtearing became the dominant low-k{sub ?} mode, especially in the outer half of the plasma. There are instances in time and radius, however, where other modes, at higher-k{sub ?}, may, in addition to microtearing, be important for driving electron transport. Given these results, the Rebut-Lallia-Watkins (RLW) electron thermal diffusivity model, which is based on microtearing-induced transport, was used to predict the time-evolving electron temperature across most of the profile. The results indicate that RLW does a good job of predicting T{sub e} for times and locations where microtearing was determined to be important, but not as well when microtearing was predicted to be stable or subdominant.

  11. Final Scientific/Technical Report, USDOE Award DE-FG-02ER54684, Recipient: CompX, Project Title: Fokker-Planck/Ray Tracing for Electron Bernstein and Fast Wave Modeling in Support of NSTX.

    SciTech Connect (OSTI)

    R.W. Harvey, CompX, Del Mar, CA 92014

    2009-11-12T23:59:59.000Z

    This DOE grant supported fusion energy research, a potential long-term solution to the world's energy needs. Magnetic fusion, exemplified by confinement of very hot ionized gases, i.e., plasmas, in donut-shaped tokamak vessels is a leading approach for this energy source. Thus far, a mixture of hydrogen isotopes has produced 10's of megawatts of fusion power for seconds in a tokamak reactor at Princeton Plasma Physics Laboratory in New Jersey. The research grant under consideration, ER54684, uses computer models to aid in understanding and projecting efficacy of heating and current drive sources in the National Spherical Torus Experiment, a tokamak variant, at PPPL. The NSTX experiment explores the physics of very tight aspect ratio, almost spherical tokamaks, aiming at producing steady-state fusion plasmas. The current drive is an integral part of the steady-state concept, maintaining the magnetic geometry in the steady-state tokamak. CompX further developed and applied models for radiofrequency (rf) heating and current drive for applications to NSTX. These models build on a 30 year development of rf ray tracing (the all-frequencies GENRAY code) and higher dimensional Fokker-Planck rf-collisional modeling (the 3D collisional-quasilinear CQL3D code) at CompX. Two mainline current-drive rf modes are proposed for injection into NSTX: (1) electron Bernstein wave (EBW), and (2) high harmonic fast wave (HHFW) modes. Both these current drive systems provide a means for the rf to access the especially high density plasma--termed high beta plasma--compared to the strength of the required magnetic fields. The CompX studies entailed detailed modeling of the EBW to calculate the efficiency of the current drive system, and to determine its range of flexibility for driving current at spatial locations in the plasma cross-section. The ray tracing showed penetration into NSTX bulk plasma, relatively efficient current drive, but a limited ability to produce current over the whole radial plasma cross-section. The actual EBW experiment will cost several million dollars, and remains in the proposal stage. The HHFW current drive system has been experimentally implemented on NSTX, and successfully drives substantial current. The understanding of the experiment is to be accomplished in terms of general concepts of rf current drive, and also detailed modeling of the experiment which can discern the various competing processes which necessarily occur simultaneously in the experiment. An early discovery of the CompX codes, GENRAY and CQL3D, was that there could be significant interference between the neutral beam injection fast ions in the machine (injected for plasma heating) and the HHFW energy. Under many NSTX experimental conditions, power which could go to the fast ions would then be unavailable for current drive by the desired HHFW interaction with electrons. This result has been born out by experiments; the modeling helps in understanding difficulties with HHFW current drive, and has enabled adjustment of the experiment to avoid interaction with neutral beam injected fast ions thereby achieving stronger HHFW current drive. The detailed physics modeling of the various competing processes is almost always required in fusion energy plasma physics, to ensure a reasonably accurate and certain interpretation of the experiment, enabling the confident design of future, more advanced experiments and ultimately a commercial fusion reactor. More recent work entails detailed investigation of the interaction of the HHFW radiation for fast ions, accounting for the particularly large radius orbits in NSTX, and correlations between multiple HHFW-ion interactions. The spherical aspect of the NSTX experiment emphasized particular physics such as the large orbits which are present to some degree in all tokamaks, but gives clearer clues on the resulting physics phenomena since competing physics effects are reduced.

  12. NSTX Failure Modes & Effects Analysis / NSTX-FMEA-71-10 / p. 1 of 115 FAILURE MODES AND EFFECTS ANALYSIS

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    NSTX Failure Modes & Effects Analysis / NSTX-FMEA-71-10 / p. 1 of 115 NSTX FAILURE MODES AND EFFECTS ANALYSIS (FMEA) Revision 10 Dated: November 2014 Prepared By: Name/WBS Signature Name: ________________________________________________ Ron Strykowsky, NSTX Upgrade Project Manager #12;NSTX Failure Modes & Effects Analysis / NSTX-FMEA-71

  13. Divertor Heat Flux Amelioration in Highly-Shaped Plasma in NSTX

    SciTech Connect (OSTI)

    Soukhanovskii, V; Maingi, R; Gates, D; Menard, J; Raman, R; Bell, R; Bush, C; Kaita, R; Kugel, H; LeBlanc, B; Paul, S; Roquemore, A

    2007-07-02T23:59:59.000Z

    Steady-state handling of divertor heat flux is a critical issue for both the International Thermonuclear Experimental Reactor and spherical torus (ST) based devices with compact high power density divertors. The ST compact divertor with a small plasma volume, a small plasma-wetted area, and a short parallel connection length can reduce the operating space of heat flux dissipation techniques based on induced edge and/or scrape-off layer (SOL) power and momentum loss, such as the radiative and dissipative divertors and radiative mantles. Access to these regimes is studied in the National Spherical Torus Experiment (NSTX) with an open geometry horizontal carbon plate divertor in 2-6 MW NBI-heated H-mode plasmas in a lower single null (LSN) configuration in a range of elongations {kappa} = 1.8-2.4 and triangularities {delta}= 0.40-0.75. Experiments conducted in a lower end {kappa}{approx}1.8-2.0 and {delta}{approx} 0.4-0.5 LSN shape using deuterium injection in the divertor region have achieved the outer strike point (OSP) peak heat flux reduction from 4-6 MW/m2 to a manageable level of 1-2 MW/m2. However, only the high-recycling radiative divertor (RD) regime was found to be compatible with good performance and H-mode confinement. A partially detached divertor (PDD) could only be obtained at a high D2 injection rate that led to an X-point MARFE formation and confinement degradation. Also in the low {kappa}{approx} 2,{delta}{approx} 0.45 shape, peak heat flux q{sub pk} and heat flux width {lambda}{sub q} scaling studies have been conducted. Similar to tokamak divertor studies, q{sub pk} was found to be a strong function of input power PNBI and plasma current Ip, and the heat flux midplane scale length {lambda}{sub q} was found to be large as compared with simple SOL models. In this paper, we report on the first experiments to assess steady-state divertor heat flux amelioration in highly shaped plasmas in NSTX.

  14. NSTX-U Control System Upgrades

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

    Erickson, K. G.; Gates, D. A.; Gerhardt, S. P.; Lawson, J. E.; Mozulay, R.; Sichta, P.; Tchilinguirian, G. J.

    2014-06-01T23:59:59.000Z

    The National Spherical Tokamak Experiment (NSTX) is undergoing a wealth of upgrades (NSTX-U). These upgrades, especially including an elongated pulse length, require broad changes to the control system that has served NSTX well. A new fiber serial Front Panel Data Port input and output (I/O) stream will supersede the aging copper parallel version. Driver support for the new I/O and cyber security concerns require updating the operating system from Redhat Enterprise Linux (RHEL) v4 to RedHawk (based on RHEL) v6. While the basic control system continues to use the General Atomics Plasma Control System (GA PCS), the effort to forwardmore »port the entire software package to run under 64-bit Linux instead of 32-bit Linux included PCS modifications subsequently shared with GA and other PCS users. Software updates focused on three key areas: (1) code modernization through coding standards (C99/C11), (2) code portability and maintainability through use of the GA PCS code generator, and (3) support of 64-bit platforms. Central to the control system upgrade is the use of a complete real time (RT) Linux platform provided by Concurrent Computer Corporation, consisting of a computer (iHawk), an operating system and drivers (RedHawk), and RT tools (NightStar). Strong vendor support coupled with an extensive RT toolset influenced this decision. The new real-time Linux platform, I/O, and software engineering will foster enhanced capability and performance for NSTX-U plasma control.« less

  15. Progress In Understanding The Enhanced Petestal H-mode In NSTX

    SciTech Connect (OSTI)

    Gerhardt, S. P.; Canik, J. M.; Maingi, R.; Battaglia, D.; Bell, R. E.; Guttenfelder, W.; LeBlanc, B. P.; Smith, D. R.; Yuh, H.; Sabbagh, S.

    2014-06-26T23:59:59.000Z

    ThIS paper describes the enhanced pedestal (EP) H-mode observed in the National Spherical Torus Experiment (NSTX). The defining characteristics of EP H-mode are given, namely i)transition after the L- to H-mode transition, ii) region of very steep ion temperature gradient, and iii) associated region of strong rotational shear. A newly observed long-pulse EP H-mode example shows quiescent behavior for as long as the heating and current drive sources are maintained. Cases are shown where the region of steep ion temperature gradient is located at the very edge, and cases where it is shifted up to 10 cm inward from the plasma edge; these cases are united by a common dependence of the ion temperature gradient on the toroidal rotation frequency shear. EP H-mode examples have been observed across a wide range of q95 and pedestal collisionality. No strong changes in the fluctuation amplitudes have been observed following the eP H-mode transition, and transport analysis indicates that the ion t hermal transport is comparable to or less than anticipated from a simple neoclassical transport model. Cases are shown where EP H-modes were reliably generated, through these low-q95 examples were difficult to sustain. A case where an externally triggered ELM precipitates the transition to EP H-mode is also shown, though an initial experiment designed to trigger EP-H-modes in this fashion was successful.

  16. Progress in understanding the enhanced pedestal H-mode in NSTX

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

    Gerhardt, S.P.; Canik, J.M; Maingi, R.; Battaglia, D.; Bell, R.E.; Guttenfelder, W.; LeBlanc, B.P.; Smith, D.R.; Yuh, H.; Sabbagh, S.

    2014-08-01T23:59:59.000Z

    The paper describes the enhanced pedestal (EP) H-mode observed in the National Spherical Torus Experiment (NSTX). The defining characteristics of EP H-mode are given, namely i)transition after the L- to H-mode transition, ii) region of very steep ion temperature gradient, and iii) associated region of strong rotational shear. A newly observed long-pulse EP H-mode example shows quiescent behavior for as long as the heating and current drive sources are maintained. Cases are shown where the region of steep ion temperature gradient is located at the very edge, and cases where it is shifted up to 10 cm inward from the plasma edge; these cases are united by a common dependence of the ion temperature gradient on the toroidal rotation frequency shear. EP H-mode examples have been observed across a wide range of q95 and pedestal collisionality. No strong changes in the fluctuation amplitudes have been observed following the eP H-mode transition, and transport analysis indicates that the ion t hermal transport is comparable to or less than anticipated from a simple neoclassical transport model. Cases are shown where EP H-modes were reliably generated, through these low-q95 examples were difficult to sustain. A case where an externally triggered ELM precipitates the transition to EP H-mode is also shown, though an initial experiment designed to trigger EP-H-modes in this fashion was successful.

  17. Progress in understanding the enhanced pedestal H-mode in NSTX

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

    Gerhardt, S.P.; Canik, J.M; Maingi, R.; Battaglia, D.; Bell, R.E.; Guttenfelder, W.; LeBlanc, B.P.; Smith, D.R.; Yuh, H.; Sabbagh, S.

    2014-08-01T23:59:59.000Z

    The paper describes the enhanced pedestal (EP) H-mode observed in the National Spherical Torus Experiment (NSTX). The defining characteristics of EP H-mode are given, namely i)transition after the L- to H-mode transition, ii) region of very steep ion temperature gradient, and iii) associated region of strong rotational shear. A newly observed long-pulse EP H-mode example shows quiescent behavior for as long as the heating and current drive sources are maintained. Cases are shown where the region of steep ion temperature gradient is located at the very edge, and cases where it is shifted up to 10 cm inward from themore »plasma edge; these cases are united by a common dependence of the ion temperature gradient on the toroidal rotation frequency shear. EP H-mode examples have been observed across a wide range of q95 and pedestal collisionality. No strong changes in the fluctuation amplitudes have been observed following the eP H-mode transition, and transport analysis indicates that the ion t hermal transport is comparable to or less than anticipated from a simple neoclassical transport model. Cases are shown where EP H-modes were reliably generated, through these low-q95 examples were difficult to sustain. A case where an externally triggered ELM precipitates the transition to EP H-mode is also shown, though an initial experiment designed to trigger EP-H-modes in this fashion was successful.« less

  18. 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 [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of) [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2014-02-15T23:59:59.000Z

    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.

  19. Dependence of various SOL widths on plasma current and density in NSTX H-mode plasmas

    SciTech Connect (OSTI)

    Ahn, J; Maingi, R; Boedo, J; Soukhanovskii, V A

    2009-02-12T23:59:59.000Z

    The dependence of various SOL widths on the line-averaged density ({ovr n}{sub e}) and plasma current (l{sub p}) for the quiescent H-mode plasmas with Type-V ELMs in the National Spherical Torus Experiment (NSTX) was investigated. It is found that the heat flux SOL width ({lambda}{sub q}), measured by the IR camera, is virtually insensitive to {ovr n}{sub e} and has a strong negative dependence on l{sub p}. This insensitivity of {lambda}{sub q} to {ovr n}{sub e} is consistent with the scaling law from JET H-mode plasmas that shows a very weak dependence on the upstream density. The electron temperature, ion saturation current density, electron density, and electron pressure decay lengths ({lambda}{sub Te}, {lambda}{sub jsat}, {lambda}{sub ne}, and {lambda}{sub pe}, respectively) measured by the probe showed that {lambda}{sub Te} and {lambda}{sub jsat} have strong negative dependence on l{sub p}, whereas {lambda}{sub ne} and {lambda}{sub pe} revealed only a little or no dependence. The dependence of {lambda}{sub Te} on l{sub p} is consistent with the scaling law in the literature while {lambda}{sub ne} and {lambda}{sub pe} dependence shows a different trend.

  20. Torus instability

    E-Print Network [OSTI]

    B. Kliem; T. Toeroek

    2006-08-04T23:59:59.000Z

    The expansion instability of a toroidal current ring in low-beta magnetized plasma is investigated. Qualitative agreement is obtained with experiments on spheromak expansion and with essential properties of solar coronal mass ejections, unifying the two apparently disparate classes of fast and slow coronal mass ejections.

  1. NSTX Organization 2009 Heating Systems

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Erik Perry Central I&C Paul Sichta Power Systems John Lacenere Auxiliary Systems Bill Blanchard Physics Analysis and Simulation Stan Kaye Advanced Scenarios and Control David Gates, Jon Menard Modeling1 NSTX Organization ­ 2009 Heating Systems Tim Stevenson Device Operation Al von Halle Construction

  2. NSTX Plasma Response to Lithium Coated Divertor

    SciTech Connect (OSTI)

    H.W. Kugel, M.G. Bell, J.P. Allain, R.E. Bell, S. Ding, S.P. Gerhardt, M.A. Jaworski, R. Kaita, J. Kallman, S.M. Kaye, B.P. LeBlanc, R. Maingi, R. Majeski, R. Maqueda, D.K. Mansfield, D. Mueller, R. Nygren, S.F. Paul, R. Raman, A.L. Roquemore, S.A. Sabbagh, H. Schneider, C.H. Skinner, V.A. Soukhanovskii, C.N. Taylor, J.R. Timberlak, W.R. Wampler, L.E. Zakharov, S.J. Zweben, and the NSTX Research Team

    2011-01-21T23:59:59.000Z

    NSTX experiments have explored lithium evaporated on a graphite divertor and other plasma facing components in both L- and H- mode confinement regimes heated by high-power neutral beams. Improvements in plasma performance have followed these lithium depositions, including a reduction and eventual elimination of the HeGDC time between discharges, reduced edge neutral density, reduced plasma density, particularly in the edge and the SOL, increased pedestal electron and ion temperature, improved energy confinement and the suppression of ELMs in the H-mode. However, with improvements in confinement and suppression of ELMs, there was a significant secular increase in the effective ion charge Zeff and the radiated power in H-mode plasmas as a result of increases in the carbon and medium-Z metallic impurities. Lithium itself remained at a very low level in the plasma core, <0.1%. Initial results are reported from operation with a Liquid Lithium Divertor (LLD) recently installed.

  3. Lithium Wall Conditioning And Surface Dust Detection On NSTX

    SciTech Connect (OSTI)

    Skinner, C H; Bell, M G; Friesen, F.Q.L.; Heim, B; Jaworski, M A; Kugel, H; Maingi, R; Rais, B

    2011-05-23T23:59:59.000Z

    Lithium evaporation onto NSTX plasma facing components (PFC) has resulted in improved energy confinement, and reductions in the number and amplitude of edge-localized modes (ELMs) up to the point of complete ELM suppression. The associated PFC surface chemistry has been investigated with a novel plasma material interface probe connected to an in-vacuo surface analysis station. Analysis has demonstrated that binding of D atoms to the polycrystalline graphite material of the PFCs is fundamentally changed by lithium - in particular deuterium atoms become weakly bonded near lithium atoms themselves bound to either oxygen or the carbon from the underlying material. Surface dust inside NSTX has been detected in real-time using a highly sensitive electrostatic dust detector. In a separate experiment, electrostatic removal of dust via three concentric spiral-shaped electrodes covered by a dielectric and driven by a high voltage 3-phase waveform was evaluated for potential application to fusion reactors

  4. Lithium Surface Coatings for Improved Plasma Performance in NSTX

    SciTech Connect (OSTI)

    Kugel, H W; Ahn, J -W; Allain, J P; Bell, R; Boedo, J; Bush, C; Gates, D; Gray, T; Kaye, S; Kaita, R; LeBlanc, B; Maingi, R; Majeski, R; Mansfield, D; Menard, J; Mueller, D; Ono, M; Paul, S; Raman, R; Roquemore, A L; Ross, P W; Sabbagh, S; Schneider, H; Skinner, C H; Soukhanovskii, V; Stevenson, T; Timberlake, J; Wampler, W R

    2008-02-19T23:59:59.000Z

    NSTX high-power divertor plasma experiments have shown, for the first time, significant and frequent benefits from lithium coatings applied to plasma facing components. Lithium pellet injection on NSTX introduced lithium pellets with masses 1 to 5 mg via He discharges. Lithium coatings have also been applied with an oven that directed a collimated stream of lithium vapor toward the graphite tiles of the lower center stack and divertor. Lithium depositions from a few mg to 1 g have been applied between discharges. Benefits from the lithium coating were sometimes, but not always seen. These improvements sometimes included decreases plasma density, inductive flux consumption, and ELM frequency, and increases in electron temperature, ion temperature, energy confinement and periods of MHD quiescence. In addition, reductions in lower divertor D, C, and O luminosity were measured.

  5. NSTX Disruption Simulations of Detailed Divertor and Passive Plate Models by Vector Potential Transfer from OPERA Global Analysis Results

    SciTech Connect (OSTI)

    P. H. Titus, S. Avasaralla, A.Brooks, R. Hatcher

    2010-09-22T23:59:59.000Z

    The National Spherical Torus Experiment (NSTX) project is planning upgrades to the toroidal field, plasma current and pulse length. This involves the replacement of the center-stack, including the inner legs of the TF, OH, and inner PF coils. A second neutral beam will also be added. The increased performance of the upgrade requires qualification of the remaining components including the vessel, passive plates, and divertor for higher disruption loads. The hardware needing qualification is more complex than is typically accessible by large scale electromagnetic (EM) simulations of the plasma disruptions. The usual method is to include simplified representations of components in the large EM models and attempt to extract forces to apply to more detailed models. This paper describes a more efficient approach of combining comprehensive modeling of the plasma and tokamak conducting structures, using the 2D OPERA code, with much more detailed treatment of individual components using ANSYS electromagnetic (EM) and mechanical analysis. This capture local eddy currents and resulting loads in complex details, and allows efficient non-linear, and dynamic structural analyses.

  6. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX Upgrade Project Subtotal 888 03MAY10A 03: Period of Performance: $949 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Budget: Labik Approvals Signature Date NSTX-U Project Manager R. Strykowsky 4- WBS Dictionary sheet

  7. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX Upgrade Project Subtotal 500 01OCT12 01: Period of Performance: $1,174 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work 2014 Authorized Budget: Perry Functional Manager L. Dudek Approvals Signature Date NSTX-U Project

  8. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX Upgrade Project Subtotal 1,401 23FEB09A: Period of Performance: $2,984 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Account Manager Stevenson Functional Manager M.Williams Approvals Signature Date NSTX-U Project Manager R

  9. CTI in NSTX, Proposal for Compact Toroid Injection in NSTX

    SciTech Connect (OSTI)

    R. Raman

    2008-11-04T23:59:59.000Z

    This is the final Report summarizing the activities of the proposal to invetigate the potential of deep fueling a spherical torus or tokamak using high velocity injection of compact toroids.

  10. 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

    2010-11-22T23:59:59.000Z

    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.

  11. Simulation of Diffusive Lithium Evaporation Onto the NSTX Vessel Walls

    SciTech Connect (OSTI)

    Stotler, D. P.; Skinner, C. H.; Blanchard, W. R.; Krstic, P. S.; Kugel, H. W.; Schneider, H.; Zakharov, L. E.

    2010-12-09T23:59:59.000Z

    A model for simulating the diffusive evaporation of lithium into a helium filled NSTX vacuum vessel is described and validated against an initial set of deposition experiments. The DEGAS 2 based model consists of a three-dimensional representation of the vacuum vessel, the elastic scattering process, and a kinetic description of the evaporated atoms. Additional assumptions are required to account for deuterium out-gassing during the validation experiments. The model agrees with the data over a range of pressures to within the estimated uncertainties. Suggestions are made for more discriminating experiments that will lead to an improved model.

  12. Spherical torus fusion reactor

    DOE Patents [OSTI]

    Martin Peng, Y.K.M.

    1985-10-03T23:59:59.000Z

    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.

  13. Comparison of Gas Puff Imaging Data in NSTX with the DEGAS 2 Simulation

    SciTech Connect (OSTI)

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

    2012-11-08T23:59:59.000Z

    Gas-Puff-Imaging (GPI) is a two dimensional diagnostic which measures the edge D? light emission from a neutral D2 gas puff nears the outer mid-plane of NSTX. DEGAS 2 is a 3-D Monte Carlo code used to model neutral transport and atomic physics in tokamak plasmas. In this paper we compare measurements of the D? light emission obtained by GPI on NSTX with DEGAS 2 simulations of D? light emission for specific experiments. Both the simulated spatial distribution and absolute intensity of the D? light emission agree well with the experimental data obtained between ELMs in H-mode. __________________________________________________

  14. Comparison of Gas Puff Imaging Data in NSTX with the DEGAS 2 Simulation

    SciTech Connect (OSTI)

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

    2012-10-27T23:59:59.000Z

    Gas-Puff-Imaging (GPI) is a two dimensional diagnostic which measures the edge D? light emission from a neutral D2 gas puff nears the outer mid-plane of NSTX. DEGAS 2 is a 3-D Monte Carlo code used to model neutral transport and atomic physics in tokamak plasmas. In this paper we compare measurements of the D? light emission obtained by GPI on NSTX with DEGAS 2 simulations of D? light emission for specific experiments. Both the simulated spatial distribution and absolute intensity of the D? light emission agree well with the experimental data obtained between ELMs in H-mode.

  15. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    will therefore aim to develop a basis for predictive understanding to advance long-pulse high performance plasma research on NSTX, and to strengthen the scientific basis for the ITER hybrid mode operation. 3

  16. NSTX PLASMA START-UP USING TRANSIENT COAXIAL HELICITY INJECTION D. Mueller1

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    experimental measurements made on NSTX include fast time-scale visible imaging of the entire process. I generation of ST experiments, and essential for an ST reactor, that the central solenoid be replaced by other schematically in Fig. 2. When gas is introduced into the volume below the lower divertor gap and a voltage (1

  17. NSTX Weekly Report (Jan. 15, 2009) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    preparations to close and pump-down the NSTX vacuum vessel. Some rework and testing of the Beam Emission duct is scheduled for next week, and will be followed by vessel pump-down. Access to the NSTX test cell published in Nuclear Fusion. The paper describes high beta stability sustainment to resistive wall modes

  18. NSTX Weekly Report (November 24, 2010) FY 2011 NSTX plasma operations started on October 4, 2010

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    in NSTX" by V. A. Soukhanovskii (LLNL) et al. has been accepted for publication in Nuclear Fusion Operations (A. von Halle, C. Neumeyer) The NSTX outage continued this past week with in-vessel diagnostic removed and brought to the Vacuum Prep Lab for transmission testing. A water leak was discovered

  19. NSTX Weekly Report (Apr. 2, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    NSTX Weekly Report (Apr. 2, 2010) FY 2010 NSTX plasma operations Planned: Total - 15 run weeks experimental operations began this week with the completion of machine proposals (XMP's) to evaluate machine was used extensively this week, as well as neutral beam injection and machine's error field control. HHFW

  20. Recent Progress in the NSTX/NSTX-U Lithium Program and Prospects for Reactor-Relevant Liquid-Lithium Based Divertor Development

    SciTech Connect (OSTI)

    M. Ono, et al.

    2012-10-27T23:59:59.000Z

    Developing a reactor compatible divertor has been identified as a particularly challenging technology problem for magnetic confinement fusion. While tungsten has been identified as the most attractive solid divertor material, the NSTX/NSTX-U lithium (Li) program is investigating the viability of liquid lithium (LL) as a potential reactor compatible divertor plasma facing component (PFC) . In the near term, operation in NSTX-U is projected to provide reactor-like divertor heat loads < 40 MW/m^2 for 5 s. During the most recent NSTX campaign, ~ 0.85 kg of Li was evaporated onto the NSTX PFCs where a ~50% reduction in heat load on the Liquid Lithium Divertor (LLD) was observed, attributable to enhanced divertor bolometric radiation. This reduced divertor heat flux through radiation observed in the NSTX LLD experiment is consistent with the results from other lithium experiments and calculations. These results motivate an LL-based closed radiative divertor concept proposed here for NSTX-U and fusion reactors. With an LL coating, the Li is evaporated from the divertor strike point surface due to the intense heat. The evaporated Li is readily ionized by the plasma due to its low ionization energies, and the ionized Li ions can radiate strongly, resulting in a significant reduction in the divertor heat flux. Due to the rapid plasma transport in divertor plasma, the radiation values can be significantly enhanced up to ~ 11 MJ/cc of LL. This radiative process has the desired function of spreading the focused divertor heat load to the entire divertor chamber facilitating the divertor heat removal. The LL divertor surface can also provide a "sacrificial" surface to protect the substrate solid material from transient high heat flux such as the ones caused by the ELMs. The closed radiative LLD concept has the advantages of providing some degree of partition in terms of plasma disruption forces on the LL, Li particle divertor retention, and strong divertor pumping action from the Li-coated divertor chamber wall. By operating at a lower temperature than the first wall, the LLD can serve to purify the entire reactor chamber, as impurities generally migrate toward lower temperature Li-condensed surfaces. To maintain the LL purity, a closed LL loop system with a modest capacity (e.g., ~ 1 Liter/sec for ~ 1% level "impurities") is envisioned for a steady-state 1 GW-electric class fusion power plant.

  1. NSTX Program Governance, Research Support and Facility Operation

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    of DPP, 3 PU faculty) · Graduate students & post-doc (from PU) · Engineering expertise: designNSTX Program Governance, Research Support and Facility Operation Office of Science M.G. Bell, PPPL for the NSTX Research Team NSTX 5 Year Plan Review for 2009-13 Princeton Plasma Physics Laboratory July 28

  2. Data Analysis Tools for NSTX-U Physics Meeting

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Data Analysis Tools for NSTX-U Bill Davis Stan Kaye Physics Meeting B-318 Aug. 26, 2013 NSTX LLC #12;NSTX-U Monday Physics Meeting­ Data Analysis Tools, Bill Davis (8/26/2013) 2 Overview ·Web Tools in depth · Overlaying in different ways · Browsing Fast Camera data ·EFITmovies and EFITviewer

  3. Theory needs for NSTX-U and ITER J. Menard, S. Kaye, and the

    E-Print Network [OSTI]

    Theory needs for NSTX-U and ITER J. Menard, S. Kaye, and the NSTX-U Topical Science Group Leaders PPPL Theory Department Retreat Princeton University and PPPL September 24-25 and 27, 2012 NSTX Wisconsin X Science LLC #12;NSTX-U PPPL Theory Department Retreat ­ September 24, 25, 27 2 Outline · NSTX

  4. Spherical torus fusion reactor

    DOE Patents [OSTI]

    Peng, Yueng-Kay M. (Oak Ridge, TN)

    1989-01-01T23:59:59.000Z

    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.

  5. Diagnostic options for radiative divertor feedback control on NSTX-U

    SciTech Connect (OSTI)

    Soukhanovskii, V. A.; McLean, A. G. [Lawrence Livermore National Laboratory, Livermore, California, 94550 (United States); Gerhardt, S. P.; Kaita, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Raman, R. [University of Washington, Seattle, Washington 98195 (United States)

    2012-10-15T23:59:59.000Z

    A radiative divertor technique is used in present tokamak experiments and planned for ITER to mitigate high heat loads on divertor plasma-facing components (PFCs) to prevent excessive material erosion and thermal damage. In NSTX, a large spherical tokamak with lithium-coated graphite PFCs and high divertor heat flux (q{sub peak} Less-Than-Or-Slanted-Equal-To 15 MW/m{sup 2}), radiative divertor experiments have demonstrated a significant reduction of divertor peak heat flux simultaneously with good core H-mode confinement using pre-programmed D{sub 2} or CD{sub 4} gas injections. In this work diagnostic options for a new real-time feedback control system for active radiative divertor detachment control in NSTX-U, where steady-state peak divertor heat fluxes are projected to reach 20-30 MW/m{sup 2}, are discussed. Based on the NSTX divertor detachment measurements and analysis, the control diagnostic signals available for NSTX-U include divertor radiated power, neutral pressure, spectroscopic deuterium recombination signatures, infrared thermography of PFC surfaces, and thermoelectric scrape-off layer current. In addition, spectroscopic 'security' monitoring of possible confinement or pedestal degradation is recommended. These signals would be implemented in a digital plasma control system to manage the divertor detachment process via an actuator (impurity gas seeding rate).

  6. Overview of Innovative PMI Research on NSTX-U and Associated PMI Facilities at PPPL

    SciTech Connect (OSTI)

    M. Ono, M. Jaworski, R. Kaita, C. N. Skinner, J.P. Allain, R. Maingi, F. Scotti, V.A. Soukhanovskii, and the NSTX-U Team

    2012-09-19T23:59:59.000Z

    Developing a reactor compatible divertor and managing the associated plasma material interaction (PMI) has been identified as a high priority research area for magnetic confinement fusion. Accordingly on NSTXU, the PMI research has received a strong emphasis. With ~ 15 MW of auxiliary heating power, NSTX-U will be able to test the PMI physics with the peak divertor plasma facing component (PFC) heat loads of up to 40-60 MW/m2 . To support the PMI research, a comprehensive set of PMI diagnostic tools are being implemented. The snow-flake configuration can produce exceptionally high divertor flux expansion of up to ~ 50. Combined with the radiative divertor concept, the snow-flake configuration has reduced the divertor heat flux by an order of magnitude in NSTX. Another area of active PMI investigation is the effect of divertor lithium coating (both in solid and liquid phases). The overall NSTX lithium PFC coating results suggest exciting opportunities for future magnetic confinement research including significant electron energy confinement improvements, Hmode power threshold reduction, the control of Edge Localized Modes (ELMs), and high heat flux handling. To support the NSTX-U/PPPL PMI research, there are also a number of associated PMI facilities implemented at PPPL/Princeton University including the Liquid Lithium R&D facility, Lithium Tokamak Experiment, and Laboratories for Materials Characterization and Surface Chemistry.

  7. Reduction of plasma density in the Helicity Injected Torus with Steady Inductance experiment by using a helicon pre-ionization source

    SciTech Connect (OSTI)

    Hossack, Aaron C.; Jarboe, Thomas R.; Victor, Brian S. [Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195 (United States)] [Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195 (United States); Firman, Taylor; Prager, James R.; Ziemba, Timothy [Eagle Harbor Technologies, Inc., 119 W. Denny Way, Suite 210, Seattle, Washington 98119 (United States)] [Eagle Harbor Technologies, Inc., 119 W. Denny Way, Suite 210, Seattle, Washington 98119 (United States); Wrobel, Jonathan S. [979B West Moorhead Circle, Boulder, Colorado 80305 (United States)] [979B West Moorhead Circle, Boulder, Colorado 80305 (United States)

    2013-10-15T23:59:59.000Z

    A helicon based pre-ionization source has been developed and installed on the Helicity Injected Torus with Steady Inductance (HIT-SI) spheromak. The source initiates plasma breakdown by injecting impurity-free, unmagnetized plasma into the HIT-SI confinement volume. Typical helium spheromaks have electron density reduced from (2–3) × 10{sup 19} m{sup ?3} to 1 × 10{sup 19} m{sup ?3}. Deuterium spheromak formation is possible with density as low as 2 × 10{sup 18} m{sup ?3}. The source also enables HIT-SI to be operated with only one helicity injector at injector frequencies above 14.5 kHz. A theory explaining the physical mechanism driving the reduction of breakdown density is presented.

  8. The Columbia Non-neutral Torus

    SciTech Connect (OSTI)

    Thomas Sunn Pedersen

    2009-09-23T23:59:59.000Z

    Final report for the Columbia Non-neutral Torus. This details the results from the design, construction and initial operation of the Columbia Non-neutral Torus.

  9. NSTX Weekly Report (Jan. 29, 2009) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    of flat line density via ELM triggering and gas fueling optimization. (R. Maingi) · The article vessel bake. Access to the NSTX test cell will be restricted during the 1st shift this coming week during MPTS diagnostic operations. R

  10. 5/28/08 6:03 PMPrinceton University -PPPL to phase out compact stellarator experiment, upgrade spherical torus program Page 1 of 2http://www.princeton.edu/main/news/archive/S21/15/04A97/index.xml?section=topstories

    E-Print Network [OSTI]

    in an underestimation of its cost and a more prolonged construction process. An 18-month series of project reviews spherical torus program Page 1 of 2http://www.princeton.edu/main/news/archive/S21/15/04A97/index://www.pppl.gov/> (PPPL) will phase out construction of the National Compact Stellarator Experiment (NCSX) and instead

  11. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Research Operations Chit Review Board (designated by Run Coordinator) MINOR MODIFICATIONS (Approved-mounted Langmuir probe and two small magnetic coils for Br and Bz measurements. The assembly is mounted measurements [6, 7] using the supersonic Releigh-Pitot law. Initial NSTX SGI results obtained in the end of FY

  12. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Float Budgeted Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX: Period of Performance: $700 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Tresemer

  13. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX Upgrade Project: Period of Performance: $251 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Titus

  14. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX Upgrade Project: Period of Performance: $4,516 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Denault

  15. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Float Budgeted Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX: Period of Performance: $2,595 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Chrzanowski

  16. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX Upgrade Project: Period of Performance: $102 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Blanchard

  17. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Float Budgeted Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX: Period of Performance: $79 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Raki

  18. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX Upgrade Project: Period of Performance: $442 Control Account Manager: Revision #: Revision Date: CLOSED Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Chrzanowski

  19. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Float Budgeted Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX: Period of Performance: $388 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Blanchard

  20. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX Upgrade Project Subtotal 1,401 23FEB09A: Period of Performance: $3,335 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Raki

  1. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX Upgrade Project Subtotal 1,240 23FEB09A: Period of Performance: $2,260 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Denault

  2. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX Upgrade Project Subtotal 1,366 23FEB09A: Period of Performance: $1,860 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Denault

  3. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX Upgrade Project Subtotal 1: Period of Performance: $3,618 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Perry

  4. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Float Budgeted Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) NSTX: Period of Performance: $338 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Chrzanowski

  5. Driving EHOs in NSTX Rob Goldston

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Driving EHOs in NSTX Rob Goldston September 8, 2010 #12;Houston, We have a Problem · Lithium rises. · This is not good, but it is not because the lithium is not pumping deuterium. · In the absence in most respects to RWM interactions - but in rotating frame. · Being examined by J-K Park and A. Boozer

  6. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    for improved pedestal data while ensuring heat load on HHFW antenna is acceptable 4. Increase evaporation rate pulse-durations. High elongation + EFC + LITER have produced record poloidal beta and record low flux-consumption in NSTX. Further decreases in flux consumption are possible with increased non-inductive fraction and

  7. NSTX Upgrade Program Advisory Committee Meeting April 17-19, 2012

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    , collaboration, 5 year plan 3:15 Coffee Break 3:30 Masa Ono NSTX Upgrade Project Status, Facility and Diagnostic PPPL Charge Agenda Presentations NSTX FY2011 year-end report NSTX-U FY2012-14 Milestones Budget Planning Meeting Presentation NSTX-U PAC-31 members Previous PAC reports: PAC-30 Final Report PAC-29 Final

  8. Improvement in Plasma Performance with Lithium Coatings in NSTX

    SciTech Connect (OSTI)

    Kaita, R

    2009-02-17T23:59:59.000Z

    Lithium as a plasma-facing material has attractive features, including a reduction in the recycling of hydrogenic species and the potential for withstanding high heat and neutron fluxes in fusion reactors. Dramatic effects on plasma performance with lithium-coated plasma-facing components (PFC's) have been demonstrated on many fusion devices, including TFTR, T-11M, and FT-U. Using a liquid-lithium-filled tray as a limiter, the CDX-U device achieved very significant enhancement in the confinement time of ohmically heated plasmas. The recent NSTX experiments reported here have demonstrated, for the first time, significant and recurring benefits of lithium PFC coatings on divertor plasma performance in both L- and H- mode regimes heated by neutral beams.

  9. Improvement in Plasma Performance with Lithium Coatings in NSTX

    SciTech Connect (OSTI)

    Kaita, R; Ahn, J -W; Allain, J P; Bell, M G; Bell, R; Boedo, J; Bush, C; Mansfield, D; Menard, J; Mueller, D; Ono, M; Paul, S; Raman, R; Roquemore, A L; Ross, P W; Sabbagh, S; Schneider, H; Skinner, C H; Soukhanovskii, V; Stevenson, T; Stotler, D; Timberlake, J; Wampler, W R; Wilgen, J B

    2008-09-12T23:59:59.000Z

    Lithium as a plasma-facing material has attractive features, including a reduction in the recycling of hydrogenic species and the potential for withstanding high heat and neutron fluxes in fusion reactors. Dramatic effects on plasma performance with lithium-coated plasma-facing components (PFCOs) have been demonstrated on many fusion devices, including TFTR, [1] T-11M, [2] and FT-U. [3] Using a liquid-lithium-filled tray as a limiter, the CDX-U device achieved very significant enhancement in the confinement time of ohmically heated plasmas. [4] The recent NSTX experiments reported here have demonstrated, for the first time, significant and recurring benefits of lithium PFC coatings on divertor plasma performance in both L- and H- mode regimes heated by neutral beams.

  10. Reduced model simulations of the scrape-off-layer heat-flux width and comparison with experiment

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

    Myra, J. R. [Lodestar Research Corporation, Boulder, CO (United States); Russell, D. A. [Lodestar Research Corporation, Boulder, CO (United States); D'Ippolito, D. A. [Lodestar Research Corporation, Boulder, CO (United States); Ahn, J- W [Oak Ridge National Lab., TN (United States); Maingi, R. [Oak Ridge National Lab., TN (United States); Maqueda, R. J. [Princeton Plasma Physics Lab., NJ (United States); Lundberg, D. P. [Princeton Plasma Physics Lab., NJ (United States); Stotler, D. P. [Princeton Plasma Physics Lab., NJ (United States); Zweben, S. J. [Princeton Plasma Physics Lab., NJ (United States); Boedo, J. [Univ. of California at San Diego, CA (United States); Umansky, M. [Lawrence Livermore National Lab., Livermore, CA (United States)

    2011-01-10T23:59:59.000Z

    Reduced model simulations of turbulence in the edge and scrape-off-layer (SOL) region of a spherical torus or tokamak plasma are employed to address the physics of the scrape-off-layer heat flux width. The simulation model is an electrostatic two-dimensional fluid turbulence model, applied in the plane perpendicular to the magnetic field at the outboard midplane of the torus. The model contains curvature-driven-interchange modes, sheath losses, and both perpendicular turbulent diffusive and convective (blob) transport. These transport processes compete with classical parallel transport to set the SOL width. Midplane SOL profiles of density, temperature and parallel heat flux are obtained from the simulation and compared with experimental results from the National Spherical Torus Experiment (NSTX) [S. M. Kaye, et al., Phys. Plasmas 8, 1977 (2001)] to study the scaling of the heat flux width with power and plasma current. It is concluded that midplane turbulence is the main contributor to the SOL heat flux width for the low power H-mode discharges studied, while additional physics is required to explain the plasma current scaling of the SOL heat flux width observed experimentally in higher power discharges. Intermittent separatrix spanning convective cells are found to be the main mechanism that sets the near-SOL width in the simulations. The roles of sheared flows and blob trapping vs. emission are discussed.

  11. Reduced model simulations of the scrape-off-layer heat-flux width and comparison with experiment

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

    Myra, J. R.; Russell, D. A.; D’Ippolito, D. A.; Ahn, J.-W.; Maingi, R.; Maqueda, R. J.; Lundberg, D. P.; Stotler, D. P.; Zweben, S. J.; Boedo, J.; et al

    2011-01-01T23:59:59.000Z

    Reduced model simulations of turbulence in the edge and scrape-off-layer (SOL) region of a spherical torus or tokamak plasma are employed to address the physics of the scrape-off-layer heat flux width. The simulation model is an electrostatic two-dimensional fluid turbulence model, applied in the plane perpendicular to the magnetic field at the outboard midplane of the torus. The model contains curvature-driven-interchange modes, sheath losses, and both perpendicular turbulent diffusive and convective (blob) transport. These transport processes compete with classical parallel transport to set the SOL width. Midplane SOL profiles of density, temperature and parallel heat flux are obtained from themore »simulation and compared with experimental results from the National Spherical Torus Experiment (NSTX) to study the scaling of the heat flux width with power and plasma current. It is concluded that midplane turbulence is the main contributor to the SOL heat flux width for the low power H-mode discharges studied, while additional physics is required to explain the plasma current scaling of the SOL heat flux width observed experimentally in higher power discharges. Intermittent separatrix spanning convective cells are found to be the main mechanism that sets the near-SOL width in the simulations. The roles of sheared flows and blob trapping vs. emission are discussed.« less

  12. NSTX Real-Time Control GUI User's Guide

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    the use of the Power Supply Real-Time Control (PSRTC) Graphical User Interface (GUI), shown below. AsideNSTX Real-Time Control GUI User's Guide March 28, 2008 #12;This document is meant to describe from the PCS, the NSTX control system is made up of several executables/applications that each function

  13. NSTX Computing and Controls Paul Sichta

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Center #12;#12; EPICS MDSplus Plasma Control Software from General Atomics SharedAppVNC System Imager Cooling He Refrig #12;#12;FY12-13-14 NSTX-Upgrade Project * Pulse Length: 1.8 6.5 sec Ip: 1 2 MA 2nd NBI-based Data Repository 2 MDSplus servers: 1 uses CAMAC 30 trees, 4000 signals, > 60000 nodes (I haven

  14. Progress in Simulating Turbulent Electron Thermal Transport in NSTX

    SciTech Connect (OSTI)

    Guttenfelder, Walter; Kaye, S. M.; Ren, Y.; Bell, R. E.; Hammett, G. W.; LeBlanc, B. P.; Mikkelsen, D. R. [Princeton Plasma Physics Lab., Princeton, NJ (United States); Peterson, J. L.; Nevins, W. M. [Lawrence Livermore National Lab., Livermore, CA (United States); Candy, J. [General Atomics, San Diego, CA (United States); Yuh, H. [Nova Photonics, Princeton, NJ (United States)

    2013-07-17T23:59:59.000Z

    Nonlinear simulations based on multiple NSTX discharge scenarios have progressed to help differentiate unique instability mechanisms and to validate with experimental turbulence and transport data. First nonlinear gyrokinetic simulations of microtearing (MT) turbulence in a high-beta NSTX H-mode discharge predict experimental levels of electron thermal transport that are dominated by magnetic flutter and increase with collisionality, roughly consistent with energy confinement times in dimensionless collisionality scaling experiments. Electron temperature gradient (ETG) simulations predict significant electron thermal transport in some low and high beta discharges when ion scales are suppressed by E x B shear. Although the predicted transport in H-modes is insensitive to variation in collisionality (inconsistent with confinement scaling), it is sensitive to variations in other parameters, particularly density gradient stabilization. In reversed shear (RS) Lmode discharges that exhibit electron internal transport barriers, ETG transport has also been shown to be suppressed nonlinearly by strong negative magnetic shear, s<<0. In many high beta plasmas, instabilities which exhibit a stiff beta dependence characteristic of kinetic ballooning modes (KBM) are sometimes found in the core region. However, they do not have a distinct finite beta threshold, instead transitioning gradually to a trapped electron mode (TEM) as beta is reduced to zero. Nonlinear simulations of this "hybrid" TEM/KBM predict significant transport in all channels, with substantial contributions from compressional magnetic perturbations. As multiple instabilities are often unstable simultaneously in the same plasma discharge, even on the same flux surface, unique parametric dependencies are discussed which may be useful for distinguishing the different mechanisms experimentally.

  15. Efficient Subtorus Processor Allocation in a Multi-Dimensional Torus

    SciTech Connect (OSTI)

    Weizhen Mao; Jie Chen; William Watson

    2005-11-30T23:59:59.000Z

    Processor allocation in a mesh or torus connected multicomputer system with up to three dimensions is a hard problem that has received some research attention in the past decade. With the recent deployment of multicomputer systems with a torus topology of dimensions higher than three, which are used to solve complex problems arising in scientific computing, it becomes imminent to study the problem of allocating processors of the configuration of a torus in a multi-dimensional torus connected system. In this paper, we first define the concept of a semitorus. We present two partition schemes, the Equal Partition (EP) and the Non-Equal Partition (NEP), that partition a multi-dimensional semitorus into a set of sub-semitori. We then propose two processor allocation algorithms based on these partition schemes. We evaluate our algorithms by incorporating them in commonly used FCFS and backfilling scheduling policies and conducting simulation using workload traces from the Parallel Workloads Archive. Specifically, our simulation experiments compare four algorithm combinations, FCFS/EP, FCFS/NEP, backfilling/EP, and backfilling/NEP, for two existing multi-dimensional torus connected systems. The simulation results show that our algorithms (especially the backfilling/NEP combination) are capable of producing schedules with system utilization and mean job bounded slowdowns comparable to those in a fully connected multicomputer.

  16. NSTX Weekly Report (Feb. 26, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    of the NSTX vacuum vessel. Also this week, testing of the field coil power conversion system safety interlocks Lithium Divertor (LLD) - A vacuum chamber mockup of an LLD plate air cooling feedthrough connected that the vacuum seal and interior welds performed successfully. Cyclic thermal testing is in progress. · LLD

  17. NSTX Weekly Report (May 28, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    . Twelve papers have been submitted for publication in Journal of Nuclear Materials. The poster given Lithium Evaporation onto the NSTX Vessel Walls" by D. Stotler, "Macroscopic Motion of Liquid Metal Plasma operations resumed this past week after completion of combined field power testing, leading to the successful

  18. NSTX Weekly Report (June 04, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Kolemen completed an Experimental Machine Proposal "Relay Control" to test a "relay control" algorithm experimental campaign. The dropper control system was tested in place and eventually used briefly to inject) diagnostic continued with the successful local testing of the vacuum vessel shutters. Access to the NSTX test

  19. NSTX Weekly Report (Jan. 22, 2009) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    research team attended the 2nd NIFS-CRF International Symposium on Plasma-Surface Interactions on Jan. 18 presentations: "Lithium coatings on NSTX plasma facing components and its effects on plasma performance -invited," by H. Kugel, "A Simple Apparatus for the Injection of Lithium Aerosol into the Scrape-off Layer

  20. NSTX Weekly Report (July 23, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    insulation, and the integrated system testing for restoring TF/OH operations. Access to the NSTX test cell building. Research Operations (M. Bell) Boundary Physics Operations (H. Kugel) Alignments and spatial and six old optical fibers viewing the LLD. (V. Soukhanovskii) Testing of a new automated filling

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

    SciTech Connect (OSTI)

    Brown, T; Goldston, R J; El-Guebaly, L; Kessel, C; Neilson, G H; Malang, S; Menard, J E; Prager, S; Scott, S; Titus, P; Waganer, L

    2012-09-26T23:59:59.000Z

    A fusion pilot plant study was initiated to clarify the development needs in moving from ITER to a first of a kind fusion power plant. The mission of the pilot plant was set to encompass component test and fusion nuclear science missions yet produce net electricity with high availability in a device designed to be prototypical of the commercial device. The objective of the study was to evaluate three different magnetic configuration options, the advanced tokamak (AT), spherical tokamak (ST) and compact stellarator (CS) in an effort to establish component characteristics, maintenance features and the general arrangement of each candidate device. With the move to look beyond ITER the fusion community is now beginning to embark on DEMO reactor studies with an emphasis on defining configuration arrangements that can meet a high availability goal. This paper reviews the AT pilot plant design, detailing the selected maintenance approach, the device arrangement and sizing of the in-vessel components. Details of interfacing auxiliary systems and services that impact the ability to achieve high availability operations will also be discussed.

  2. Edge Turbulence Velocity Changes with Lithium Coating on NSTX

    SciTech Connect (OSTI)

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

    2012-08-10T23:59:59.000Z

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

  3. NSTX-U | Princeton Plasma Physics Lab

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated CodesTransparency VisitSilver Toyota PriusNSR Key Number RetrievalNSTX-U

  4. The torus instability

    E-Print Network [OSTI]

    Kliem, B

    2006-01-01T23:59:59.000Z

    The expansion instability of a toroidal current ring in low-beta magnetized plasma is investigated. Qualitative agreement is obtained with experiments on spheromak expansion and with essential properties of solar coronal mass ejections (CMEs), unifying the two apparently disparate classes of fast and slow CMEs.

  5. The Condensate from Torus Knots

    E-Print Network [OSTI]

    A. Gorsky; A. Milekhin; N. Sopenko

    2015-06-22T23:59:59.000Z

    We discuss recently formulated instanton-torus knot duality in $\\Omega$-deformed 5D SQED on $\\mathbb{R}^4 \\times S^1$ focusing at the microscopic aspects of the condensate formation in the instanton ensemble. Using the chain of dualities and geometric transitions we embed the SQED with a surface defect into the $SU(2)$ SQCD with $N_f=4$ and identify the numbers $(n,m)$ of the torus $T_{n,m}$ knot as instanton charge and electric charge. The HOMFLY torus knot invariants in the fundamental representation provide entropic factor in the condensate of the massless flavor counting the degeneracy of the instanton--W-boson web with instanton and electric numbers $(n,m)$ but different spin and flavor content. Using the inverse geometrical transition we explain how our approach is related to the evaluation of the HOMFLY invariants in terms of Wilson loop in 3d CS theory. The reduction to 4D theory is briefly considered and some analogy with baryon vertex is conjectured.

  6. Plasma Performance Improvement with Lithium-Coated Plasma-Facing Components in NSTX

    SciTech Connect (OSTI)

    Kaita, R; Kugel, H; Bell, M G; Bell, R; Boedo, J; Bush, C; Ellis, R; Gates, D; Gerhardt, S; Gray, T; Kallman, J; Kaye, S; LeBlanc, B; Majeski, R; Maingi, R; Mansfield, D; Menard, J; Mueller, D; Ono, M; Paul, S; Raman, R; Roquemore, A L; Ross, P W; Sabbagh, S; Schneider, H; Skinner, S H; Soukhanovskii, V; Stevenson, T; Stotler, D; Timberlake, J; Zakharov, L; Ahn, J; Allain, J P; Wampler, W R

    2009-01-08T23:59:59.000Z

    Lithium as a plasma-facing material has many attractive features, including a reduction in the recycling of hydrogenic species and the potential for withstanding high heat and neutron fluxes in fusion reactors. Recent NSTX experiments have shown, for the first time, significant and recurring benefits of lithium coatings on plasma-facing components (PFC's) to the performance of divertor plasmas in both L- and H- mode confinement regimes heated by high-power neutral beams. They included decreases in the plasma density and inductive flux consumption, and increases in the electron temperature, ion temperature, energy confinement time, and DD neutron rate. Extended periods of MHD quiescence were also achieved, and measurements of the visible emission from the lower divertor showed a reduction in the deuterium, carbon, and oxygen line emission. Other salient results with lithium evaporation included a broadening of the electron temperature profile, and changes in edge density gradients that benefited electron Bernstein wave coupling. There was also a reduction in ELM frequency and amplitude, followed by a period of complete ELM suppression. In general, it was observed that both the best and the average confinement occurred after lithium deposition and that the increase in WMHD occurs mostly through an increase in We. In addition, a liquid lithium divertor (LLD) is being installed on NSTX this year. As the first fully-toroidal liquid metal divertor target, experiments with the LLD can provide insight into the behavior of metallic ITER PFC's should they liquefy during high-power divertor tokamak operations. The NSTX lithium coating and LLD experiments are important near-term steps in demonstrating the potential of liquid lithium as a solution to the first-wall problem for both magnetic and inertial fusion reactors.

  7. Plasma Performance Improvement with Lithium-Coated Plasma-Facing Components in NSTX

    SciTech Connect (OSTI)

    Kaita, R., et. al.

    2008-09-29T23:59:59.000Z

    Lithium as a plasma-facing material has many attractive features, including a reduction in the recycling of hydrogenic species and the potential for withstanding high heat and neutron fluxes in fusion reactors. Recent NSTX experiments have shown, for the first time, significant and recurring benefits of lithium coatings on plasma-facing components (PFC's) to the performance of divertor plasmas in both L- and H- mode confinement regimes heated by high-power neutral beams. They included decreases in the plasma density and inductive flux consumption, and increases in the electron temperature, ion temperature, energy confinement time, and DD neutron rate. Extended periods of MHD quiescence were also achieved, and measurements of the visible emission from the lower divertor showed a reduction in the deuterium, carbon, and oxygen line emission. Other salient results with lithium evaporation included a broadening of the electron temperature profile, and changes in edge density gradients that benefited electron Bernstein wave coupling. There was also a reduction in ELM frequency and amplitude, followed by a period of complete ELM suppression. In general, it was observed that both the best and the average confinement occurred after lithium deposition and that the increase in WMHD occurs mostly through an increase in We. In addition, a liquid lithium divertor (LLD) is being installed on NSTX this year. As the first fully-toroidal liquid metal divertor target, experiments with the LLD can provide insight into the behavior of metallic ITER PFC's should they liquefy during high-power divertor tokamak operations. The NSTX lithium coating and LLD experiments are important near-term steps in demonstrating the potential of liquid lithium as a solution to the first-wall problem for both magnetic and inertial fusion reactors.

  8. BPM, 3/12-13/02 NSTX Research Plan Supported by

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    BPM, 3/12-13/02 NSTX Research Plan Supported by Martin Peng Oak Ridge National Laboratory, UT to accelerate research in FY03-04 to meet the FESAC 5-year Objective on ST #12;BPM, 3/12-13/02 NSTX Research programs #12;BPM, 3/12-13/02 NSTX Research Plan U.S. Collaborative Team members make crucial contributions

  9. Turbo Pump Magnetic Shielding Analysis NSTX-CALC-24-04-00

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    NSTX Turbo Pump Magnetic Shielding Analysis NSTX-CALC-24-04-00 March 16, 2011 Prepared By turbo pump to reduce the fringe field from NSTX coils at the pump location to below 50 gauss to be at least 12 inches longer than the pump (6 inches above the top and below the bottom of the turbo pump

  10. Supported by National Spherical Torus Experiment

    E-Print Network [OSTI]

    -Materials Interactions, Advanced Physics, Nuclear Component Testing Burning Plasma Physics ST offers compact geometry / ITER Operations Passive plates Blanket modules Port Control Coils Control Coils ITER vessel ITER plasma

  11. Deuterium Retention in NSTX with Lithium Conditioning

    SciTech Connect (OSTI)

    C.H. Skinner, J.P. Allain, W. Blanchard, H.W. Kugel, R. Maingi, L. Roquemore, V. Soukhanovskii, C.N. Taylor

    2010-06-02T23:59:59.000Z

    High (? 90%) deuterium retention was observed in NSTX gas balance measurements both withand without lithiumization of the carbon plasma facing components. The gas retained in ohmic discharges was measured by comparing the vessel pressure rise after a discharge to that of a gasonly pulse with the pumping valves closed. For neutral beam heated discharges the gas input and gas pumped by the NB cryopanels were tracked. The discharges were followed by outgassing of deuterium that reduced the retention. The relationship between retention and surface chemistry was explored with a new plasma-material interface probe connected to an in-vacuo surface science station that exposed four material samples to the plasma. XPS and TDS analysis showed that the binding of D atoms is fundamentally changed by lithium - in particular atoms are weakly bonded in regions near lithium atoms bound to either oxygen or the carbon matrix.

  12. Developments to Supplant CAMAC with Industry Standard Technology at NSTX

    SciTech Connect (OSTI)

    Sichta, P.; Dong, J.; Marsala, R.; Oliaro, G.; Wertenbaker, J.

    2003-07-31T23:59:59.000Z

    NSTX, like other research programs, is facing an inevitable crisis due to end-of-life issues for its 20-year-old CAMAC instrumentation. In many cases replacement components are not available, effectively rendering a CAMAC module unusable after a failure. The proliferation of high-performance, reliable, low-cost commodity computing hardware and software based on industry standard technology can provide the basis for a new generation of instrumentation. At NSTX, there have been several advances towards developing a PCI-based model for data acquisition and control systems. New hardware developments include a High Performance Signal Conditioning board and an FPGA-based Multifunction Timing System. Extensible software interfaces have been developed to integrate these boards into the NSTX computing environment. This paper will illustrate these developments and how they could be used to benefit collaborative fusion research.

  13. MHD Induced Neutral Beam Ion Loss from NSTX Plasmas

    SciTech Connect (OSTI)

    D.S. Darrow, E.D. Fredrickson, N.N. Gorelenkov, A.L. Roquemore, and K. Shinohara

    2007-12-13T23:59:59.000Z

    Bursts of ~60 kHz activity on Mirnov coils occur frequently in NSTX plasmas and these are accompanied by bursts of neutral beam ion loss over a range in pitch angles. These losses have been measured with a scintillator type loss probe imaged with a high speed (>10,000 frames/s) video camera, giving the evolution of the energy and pitch angle distributions of the lost neutral beam ions over the course of the events. The instability occurs below the TAE frequency in NSTX (~100 kHz) in high beta plasmas and may be a beta driven Alfvén acoustic (BAAE) mode.

  14. Simulations of NSTX with a Liquid Lithium Divertor Module

    SciTech Connect (OSTI)

    D. P. Stotler, R. Maingi, H.W. Kugel, A. Yu. Pigarov, T.D. Rognlien, V.A. Soukhanovskii

    2008-07-08T23:59:59.000Z

    The UEDGE edge plasma transport code is used to model the effect of the reduced recycling provided by the Liquid Lithium Divertor (LLD) module that will be installed in NSTX. UEDGE's transport coefficients are calibrated against an existing NSTX shot using midplane and divertor diagnostic data. The LLD is then incorporated into the simulations as a reduction in the recycling coefficient over the outer divertor. Heat transfer calculations performed using the resulting heat flux profiles indicate that lithium evaporation will be negligible for pulse lengths < 2 s at low (? 2 MW) input power. At high input power (? 7 MW), the pulse length may have to be restricted.

  15. Reactor assessments of advanced bumpy torus configurations

    SciTech Connect (OSTI)

    Uckan, N.A.; Owen, L.W.; Spong, D.A.; Miller, R.L.; Ard, W.B.; Pipkins, J.F.; Schmitt, R.J.

    1983-01-01T23:59:59.000Z

    Recently, several configurational approaches and concept improvement schemes were introduced for enhancing the performance of the basic ELMO Bumpy Torus (EBT) concept and for improving its reactor potential. These configurations include planar racetrack and square geometries, Andreoletti coil systems, and bumpy torus-stellarator hybrids (which include twisted racetrack and helical axis stellarator-snakey torus). Preliminary evaluations of reactor implications of each of these configurations have been carried out based on magnetics (vacuum) calculations, transport and scaling relationships, and stability properties. Results indicate favorable reactor projections with a significant reduction in reactor physical size as compared to conventional EBT reactor designs carried out in the past.

  16. Evaporated Lithium Surface Coatings in NSTX

    SciTech Connect (OSTI)

    Kugel, H. W.; Mansfield, D.; Maingi, R.; Bel, M. G.; Bell, R. E.; Allain, J. P.; Gates, D.; Gerhardt, S.; Kaita, R.; Kallman, J.; Kaye, S.; LeBlanc, B.; Majeski, R.; Menard, J.; Mueller, D.; Ono, M.

    2009-04-09T23:59:59.000Z

    Two lithium evaporators were used to evaporate more than 100 g of lithium on to the NSTX lower divertor region. Prior to each discharge, the evaporators were withdrawn behind shutters, where they also remained during the subsequent HeGDC applied for periods up to 9.5 min. After the HeGDC, the shutters were opened and the LITERs were reinserted to deposit lithium on the lower divertor target for 10 min, at rates of 10-70 mg/min, prior to the next discharge. The major improvements in plasma performance from these lithium depositions include: 1) plasma density reduction as a result of lithium deposition; 2) suppression of ELMs; 3) improvement of energy confinement in a low-triangularity shape; 4) improvement in plasma performance for standard, high-triangularity discharges; 5) reduction of the required HeGDC time between discharges; 6) increased pedestal electron and ion temperature; 7) reduced SOL plasma density; and 8) reduced edge neutral density.

  17. Dynamics of the Disruption Halo Current Toroidal Asymmetry in NSTX

    SciTech Connect (OSTI)

    S.P. Gerhardt

    2012-09-27T23:59:59.000Z

    This paper describes the dynamics of disruption halo current non-axisymmetries in the lower divertor of the National Spherical Torus Experiment [M. Ono, et al. Nuclear Fusion 40, 557 (2000)]. While. The halo currents typically have a strongly asymmetric structure where they enter the divertor floor, and this asymmetry has been observed to complete up to 7 toroidal revolutions over the duration of the halo current pulse. However, the rotation speed and toroidal extend of the asymmetry can vary significantly during the pulse. The rotation speed, halo current pulse duration, and total number of revolutions tend to be smaller in cases with large halo currents. The halo current pattern is observed to become toroidally symmetric at the end of the halo current pulse. It is proposed that this symmeterization is due to the loss of most or all of the closed field line geometry in the final phase of the vertical displacement event.

  18. NSTX Data Usage and Publication Agreement NSTX Research is carried out by a multi-institutional collaborative Research Team. All Research Team

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    -institutional collaborative Research Team. All Research Team members are offered full access to NSTX data as it is collected and analyzed. This privilege entails responsibility by the Research Team members, both on-site and off for the provided measurements, systems operations, and analyses. The undersigned member of the NSTX Research Team

  19. Methanol in the L1551 Circumbinary Torus

    E-Print Network [OSTI]

    Glenn J. White; C. W. M. Fridlund; P. Bergman; A. Beardsmore; Rene Liseau; R. R. Phillips

    2006-09-25T23:59:59.000Z

    We report observations of gaseous methanol in an edge-on torus surrounding the young stellar object L1551 IRS5. The peaks in the torus are separated by ~ 10,000 AU from L1551 IRS5, and contain ~ 0.03 earth masses of cold methanol. We infer that the methanol abundance increases in the outer part of the torus, probably as a result of methanol evaporation from dust grain surfaces heated by the shock luminosity associated with the shocks associated with the jets of an externally located x-ray source. Any methanol released in such a cold environment will rapidly freeze again, spreading methanol throughout the circumbinary torus to nascent dust grains, planitesimals, and primitive bodies. These observations probe the initial chemical conditions of matter infalling onto the disk.

  20. 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 

  1. Implications of NSTX Lithium Results for Magnetic Fusion Research

    SciTech Connect (OSTI)

    M. Ono, M.G. Bell, R.E. Bell, R. Kaita, H.W. Kugel, B.P. LeBlanc, J.M. Canik, S. Diem, S.P.. Gerhardt, J. Hosea, S. Kaye, D. Mansfield, R. Maingi, J. Menard, S. F. Paul, R. Raman, S.A. Sabbagh, C.H. Skinner, V. Soukhanovskii, G. Taylor, and the NSTX Research Team

    2010-01-14T23:59:59.000Z

    Lithium wall coating techniques have been experimentally explored on NSTX for the last five years. The lithium experimentation on NSTX started with a few milligrams of lithium injected into the plasma as pellets and it has evolved to a lithium evaporation system which can evaporate up to ~ 100 g of lithium onto the lower divertor plates between lithium reloadings. The unique feature of the lithium research program on NSTX is that it can investigate the effects of lithium in H-mode divertor plasmas. This lithium evaporation system thus far has produced many intriguing and potentially important results; the latest of these are summarized in a companion paper by H. Kugel. In this paper, we suggest possible implications and applications of the NSTX lithium results on the magnetic fusion research which include electron and global energy confinement improvements, MHD stability enhancement at high beta, ELM control, H-mode power threshold reduction, improvements in radio frequency heating and non-inductive plasma start-up performance, innovative divertor solutions and improved operational efficiency.

  2. Easy Web Interfaces to IDL Code for NSTX Data Analysis W. M. Davisa

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Easy Web Interfaces to IDL Code for NSTX Data Analysis W. M. Davisa * a Princeton Plasma Physics and debugging time. A variety of "Web Tools" for the analysis and display of raw and analyzed physics data are in use on NSTX [1], and new ones can be produced quickly from existing IDL [2] code. A Web Tool with only

  3. Upward-facing Lithium Flash Evaporator for NSTX-U

    SciTech Connect (OSTI)

    Roquemore, A. L.

    2013-07-09T23:59:59.000Z

    NSTX plasma performance has been significantly enhanced by lithium conditioning [1]. To date, the lower divertor and passive plates have been conditioned by downward facing lithium evaporators (LITER) as appropriate for lower null plasmas. The higher power operation expected from NSTX-U requires double null plasma operation in order to distribute the heat flux between the upper and lower divertors making it desirable to coat the upper divertor region with Li as well. An upward aiming LITER (U-LITER) is presently under development and will be inserted into NSTX-U using a horizontal probe drive located in a 6" upper midplane port. In the retracted position the evaporator will be loaded with up to 300 mg of Li granules utilizing one of the calibrated NSTX Li powder droppers[2]. The evaporator will then be inserted into the vessel in a location within the shadow of the RF limiters and will remain in the vessel during the discharge. About 10 seconds before a discharge, it will be rapidly heated and the lithium completely evaporated onto the upper divertor, thus avoiding the complication of a shutter that prevents evaporation during the shot when the diagnostic shutters are open. The minimal time interval between the evaporation and the start of the discharge will avoid the passivation of the lithium by residual gases and enable the study of the conditioning effects of un-passivated Li surfaces [3]. Two methods are being investigated to accomplish the rapid (few second) heating of the lithium. A resistive method relies on passing a large current through a Li filled crucible. A second method requires using a 3 kW e-beam gun to heat the Li. In this paper the evaporator systems will be described and the pros and cons of each heating method will be discussed.

  4. Performance characterization of the Caltech corn act torus injector P. K. Loewenhardt,a) M. R. Browqb) J. Yee, and P. M. Bellan

    E-Print Network [OSTI]

    Brown, Michael R.

    A compact torus (CT), or spheromak, is a toroidal mag- netofluid configuration in which plasma is cot tokamak by the Caltech Spheromak Ijec- tion experiment to study helicity injection and refueling,3

  5. Fast waves and electron current drive in the Irvine Torus

    SciTech Connect (OSTI)

    Platt, R.C.

    1987-01-01T23:59:59.000Z

    This work reports the results of experimental studies of the fast wave with frequencies near the mean gyro-frequency in magnetized, toroidal plasmas with comparison to theory. Experiment investigating fast-wave dispersion and damping, and the use of unidirectional fast waves to drive steady-state electron currents were performed on the Irvine Torus. The wave was excited in the plasmas by a phased array antenna which allowed launching of uni- or bi-directional fast waves around the torus. Probe measurements of the angle of propagation of wave energy, radial wavelengths, and the direction and magnitude of radial wave phase velocities were found to be in good agreement with predictions from cold plasma theory. Measurements of fast-wave damping showed the observed damping lengths to be anomalously short when compared to predictions for electron Landau damping, transit-time magnetic pumping, and collisional damping, but may be explained by effects due to fast-wave scattering from drift-wave density fluctuations. Steady-state electron currents were driven by unidirectional fast waves. Up to 14% of the wave energy was converted to poloidal magnetic field energy. The maximum current observed was found to be in rough agreement with a prediction from quasi-linear theory.

  6. Lithium Coatings on NSTX Plasma Facing Components and Its Effects On Boundary Control, Core Plasma Performance, and Operation

    SciTech Connect (OSTI)

    H.W.Kugel, M.G.Bell, H.Schneider, J.P.Allain, R.E.Bell, R Kaita, J.Kallman, S. Kaye, B.P. LeBlanc, D. Mansfield, R.E. Nygen, R. Maingi, J. Menard, D. Mueller, M. Ono, S. Paul, S.Gerhardt, R.Raman, S.Sabbagh, C.H.Skinner, V.Soukhanovskii, J.Timberlake, L.E.Zakharov, and the NSTX Research Team

    2010-01-25T23:59:59.000Z

    NSTX high-power divertor plasma experiments have used in succession lithium pellet injection (LPI), evaporated lithium, and injected lithium powder to apply lithium coatings to graphite plasma facing components. In 2005, following wall conditioning and LPI, discharges exhibited edge density reduction and performance improvements. Since 2006, first one, and now two lithium evaporators have been used routinely to evaporate lithium onto the lower divertor region at total rates of 10-70 mg/min for periods 5-10 min between discharges. Prior to each discharge, the evaporators are withdrawn behind shutters. Significant improvements in the performance of NBI heated divertor discharges resulting from these lithium depositions were observed. These evaporators are now used for more than 80% of NSTX discharges. Initial work with injecting fine lithium powder into the edge of NBI heated deuterium discharges yielded comparable changes in performance. Several operational issues encountered with lithium wall conditions, and the special procedures needed for vessel entry are discussed. The next step in this work is installation of a Liquid Lithium Divertor surface on the outer part of the lower divertor.

  7. Lithium coatings on NSTX plasma facing components and its effects on boundary control, core plasma performance, and operation

    SciTech Connect (OSTI)

    Kugel, H. W. [Princeton Plasma Physics Laboratory (PPPL); Bell, M. G. [Princeton Plasma Physics Laboratory (PPPL); Maingi, R. [Oak Ridge National Laboratory (ORNL)

    2010-01-01T23:59:59.000Z

    NSTX high power divertor plasma experiments have used in succession lithium pellet injection (LPI), evaporated lithium, and injected lithium powder to apply lithium coatings to graphite plasma facing components. In 2005, following the wall conditioning and LPI, discharges exhibited edge density reduction and performance improvements. Since 2006, first one, and now two lithium evaporators have been used routinely to evaporate lithium onto the lower divertor region at total rates of 10-70 mg/min for periods 5-10 min between discharges. Prior to each discharge, the evaporators are withdrawn behind shutters. Significant improvements in the performance of NBI heated divertor discharges resulting from these lithium depositions were observed. These evaporators are now used for more than 80% of NSTX discharges. Initial work with injecting fine lithium powder into the edge of NBI heated deuterium discharges yielded comparable changes in performance. Several operational issues encountered with lithium wall conditions, and the special procedures needed for vessel entry are discussed. The next step in this work is installation of a liquid lithium divertor surface on the outer part of the lower divertor.

  8. NSTX-U Control System Upgrades | Princeton Plasma Physics Lab

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy: GridTruck PlatooningJefferson Lab |NSTX-U Advances in

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy: GridTruck PlatooningJefferson Lab |NSTX-U Advances inPlasma

  10. PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76CH03073

    E-Print Network [OSTI]

    Spherical Torus Experiment (NSTX) by 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, and S to the extraordinary electromagnetic mode on the National Spherical Torus Experiment (NSTX) G. Taylor, P.C. Efthimion

  11. Zero point energy on extra dimension: Noncommutative Torus

    E-Print Network [OSTI]

    S. Fabi; B. Harms; G. Karatheodoris

    2007-04-25T23:59:59.000Z

    In this paper we calculate the zero point energy density experienced by observers on M^4 due to a massless scalar field defined throughout M^4 x T^2_F, where T^2_F are fuzzy extra dimensions. Using the Green's function approach we calculate the energy density for the commutative torus and the fuzzy torus. We calculate then the energy density for the fuzzy torus using the Hamiltonian approach. Agreement is shown between Green's function and Hamiltonian approaches.

  12. Conceptual design of a divertor Thomson scattering diagnostic for NSTX-U

    SciTech Connect (OSTI)

    McLean, A. G., E-mail: mclean@fusion.gat.com; Soukhanovskii, V. A.; Allen, S. L. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); Carlstrom, T. N. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); LeBlanc, B. P.; Ono, M.; Stratton, B. C. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-11-15T23:59:59.000Z

    A conceptual design for a divertor Thomson scattering (DTS) diagnostic has been developed for the NSTX-U device to operate in parallel with the existing multipoint Thomson scattering system. Higher projected peak heat flux in NSTX-U will necessitate application of advanced magnetics geometries and divertor detachment. Interpretation and modeling of these divertor scenarios will depend heavily on local measurement of electron temperature, T{sub e}, and density, n{sub e}, which DTS provides in a passive manner. The DTS design for NSTX-U adopts major elements from the successful DIII-D DTS system including 7-channel polychromators measuring T{sub e} to 0.5 eV. If implemented on NSTX-U, the divertor TS system would provide an invaluable diagnostic for the boundary program to characterize the edge plasma.

  13. Princeton Plasma Physics Laboratory Procedure Title: Access to NSTX Experimental Areas

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    and Operations Division Energy Conversion Systems Engineering Environmental Restoration & Waste Management NSTX D-Site Caretaking Vacuum Computer Tritium Quality Assurance/Quality Control AC Power Maintenance Division Water Systems Neutral Beam (Heating Systems Branch of Electrical Engineering) Radiofrequency

  14. Raman Spectroscopy of Carbon Dust Samples from NSTX

    SciTech Connect (OSTI)

    Y. Raitses, C.H. Skinner, F. Jiang and T.S. Duffy

    2008-02-21T23:59:59.000Z

    The Raman spectrum of dust particles exposed to the NSTX plasma is different from the spectrum of unexposed particles scraped from an unused graphite tile. For the unexposed particles, the high energy G-mode peak (Raman shift ~1580 cm-1) is much stronger than the defect-induced D-mode peak (Raman shift ~ 1350 cm-1), a pattern that is consistent with Raman spectrum for commercial graphite materials. For dust particles exposed to the plasma, the ratio of G-mode to D-mode peaks is lower and becomes even less than 1. The Raman measurements indicate that the production of carbon dust particles in NSTX involves modifications of the physical and chemical structure of the original graphite material. These modifications are shown to be similar to those measured for carbon deposits from atmospheric pressure helium arc discharge with an ablating anode electrode made from a graphite tile material. We also demonstrate experimentally that heating to 2000-2700 K alone can not explain the observed structural modifications indicating that they must be due to higher temperatures needed for graphite vaporization, which is followed either by condensation or some plasma-induced processes leading to the formation of more disordered forms of carbon material than the original graphite.

  15. NSTX ELECTRICAL POWER SYSTEMS S. Ramakrishnan, C. Neumeyer, E. Baker, R. Hatcher, A. Ilic, R. Marsala, D. O'Neill, A. von Halle

    E-Print Network [OSTI]

    NSTX ELECTRICAL POWER SYSTEMS S. Ramakrishnan, C. Neumeyer, E. Baker, R. Hatcher, A. Ilic, R, auxiliary sub-systems, and power systems originally used for the Tokamak Fusion Test Reactor (TFTR) have and the location of the NSTX device drove the major changes in the Power system hardware. The NSTX has eleven (11

  16. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    at Constant q OP-XP-617 1. Overview of planned experiment Goal: Measure RF power loss properties as a function of magnetic field constant q to elucidate: · RF power loss scaling with B under similar stability conditions of shots around 112699) [J. Hosea et al., 2005 RF Conference]. Thus the RF power loss is significantly

  17. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    width: 1.5, 2.0, 2.5 kA · Control shot: remove SPA pulses to check that LITER rate is sufficient for ELM.4 compared to 2.0. Additionally, the waveform of the n=3 field will be optimized; previous experiments showed. Experimental run plan 1. Produce reference discharge (2 shots) · Reload 132592: Ip=1.0 MA, Bt=0.45 T, =2.2, =0

  18. Arithmetic functions in torus and tree networks

    DOE Patents [OSTI]

    Bhanot, Gyan (Princeton, NJ); Blumrich, Matthias A. (Ridgefield, CT); Chen, Dong (Croton On Hudson, NY); Gara, Alan G. (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Heidelberger, Philip (Cortlandt Manor, NY); Steinmacher-Burow, Burkhard D. (Mount Kisco, NY); Vranas, Pavlos M. (Bedford Hills, NY)

    2007-12-25T23:59:59.000Z

    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.

  19. Plasma-Material Interface Development for Future Spherical Tokamak-based Devices in NSTX.

    SciTech Connect (OSTI)

    et. al, V

    2011-09-24T23:59:59.000Z

    The divertor plasma-material interface (PMI) must be able to withstand steady-state heat fluxes up to 10 MW/m{sup 2} (a limit imposed by the present day divertor material and engineering constraints) with minimal material erosion, as well as to provide impurity control and ion density pumping capabilities. In spherical tokamaks (STs), the compact divertor geometry and the requirement of low core electron collisionality n*{sub e} at n{sub e} < 0.5-0.7 n{sub G} (where n{sub G} is the Greenwald density) for increased neutral beam current drive efficiency impose much greater demands on divertor and first-wall particle and heat flux mitigation solutions. In NSTX, divertor heat flux mitigation and impurity control with an innovative 'snowflake' divertor configuration and ion density pumping by evaporated lithium wall and divertor coatings are studied. Lithium coatings have enabled ion density reduction up to 50% in NSTX through the reduction of wall and divertor recycling rates. The 'snowflake' divertor configuration was obtained in NSTX in 0.8-1 MA 4-6 MW NBI-heated H-mode lithium-assisted discharges using three divertor coils. The snowflake divertor formation was always accompanied by a partial detachment of the outer strike point with an up to 50% increase in divertor radiation from intrinsic carbon, the peak divertor heat flux reduction from 3-6 MW/m{sup 2} to 0.5-1 MW/m{sup 2}, and a significant increase in divertor volume recombination. High core confinement was maintained with the snowflake divertor, evidenced by the t{sub E}, W{sub MHD} and the H98(y,2) factors similar to those of the standard divertor discharges. Core carbon concentration and radiated power were reduced by 30-70%, apparently as a result of reduced divertor physical and chemical sputtering in the snowflake divertor and ELMs. In the SFD discharges, the MHD stability of the H-mode pedestal region was altered leading to the re-appearance of medium size (DW/W = 5-10%), Type I, ELMs otherwise suppressed due to lithium conditioning. Fast divertor measurements showed that impulsive particle and heat fluxes due to the ELMs were significantly dissipated in the high magnetic flux expansion region of the snowflake divertor. The snowflake divertor configuration is being combined in experiments with extrinsic deuterium or impurity gas puffing for increased dissipative divertor power losses, additional upper divertor nulls for increased power sharing between the upper and the lower divertors, and lithium coated plasma facing components for large area ion pumping. These efforts are aimed at the development of an integrated PMI for future ST-based devices for fusion development applications.

  20. Observation of EHO in NSTX and Theoretical Study of its Active Control Using HHFW Antenna

    SciTech Connect (OSTI)

    J.-K. Park, et. al.

    2013-01-14T23:59:59.000Z

    Two important topics in the tokamak ELM control, using the non-axisymmetric (3D) magnetic perturbations, are studied in NSTX and combined envisioning ELM control in the future NSTX-U operation: Experimental observations of the edge harmonic oscillation in NSTX (not necessarily the same as EHOs in DIII-D), and theoretical study of its external drive using the high harmonic fast wave (HHFW) antenna as a 3D field coil. Edge harmonic oscillations were observed particularly well in NSTX ELM-free operation with low n core modes, with various diagnostics confirming n = 4 ~#24; 6 edge-localized and coherent oscillations in 2 ~#24; 8kHz frequency range. These oscillations seem to have a favored operational window in rotational shear, similarly to EHOs in DIII-D QH modes . However, in NSTX, they are not observed to provide particle or impurity control, possibly due to their weak amplitudes, of a few mm displacements, as measured by reflectometry. The external drive of these modes has been proposed in NSTX, by utilizing audio-frequency currents in the HHFW antenna straps. Analysis shows that the HHFW straps can be optimized to maximize n = 4 ~#24; 6 while minimizing n = 1 ~#24; 3. Also, IPEC calculations show that the optimized configuration with only 1kAt current can produce comparable or larger displacements than the observed internal modes. If this optimized external drive can be constructively combined, or further resonated with the internal modes, the edge harmonic oscillations in NSTX may be able to produce sufficient particle control to modify ELMs.

  1. Effect of Lithium PFC Coatings on NSTX Density Control

    SciTech Connect (OSTI)

    Kugel, H W; Bell, M G; Bush, C; Gates, D; Gray, T; Kaita, R; Leblanc, B; Maingi, R; Majeski, R; Mansfield, D; Mueller, D; Raman, R; Roquemore, A L; Sabbagh, S; Skinner, C H; Soukhanovskii, V; Stevenson, T; Zakharov, L

    2006-08-21T23:59:59.000Z

    Lithium coatings on the graphite plasma facing components (PFCs) in NSTX are being investigated as a tool for density profile control and reducing the recycling of hydrogen isotopes. Repeated lithium pellet injection into Center Stack Limited and Lower Single Null Ohmic Helium Discharges were used to coat graphite surfaces that had been pre-conditioned with Ohmic Helium Discharges of the same shape to reduce their contribution to hydrogen isotope recycling. The following deuterium NBI reference discharges exhibited a reduction in density by a factor of about 3 for limited and 2 for diverted plasmas respectively, and peaked density profiles. Recently, a lithium evaporator has been used to apply thin coatings on conditioned and unconditioned PFCs. Effects on the plasma density and the impurities were obtained by pre-conditioning the PFCs with ohmic helium discharges, and performing the first deuterium NBI discharge as soon as possible after applying the lithium coating.

  2. R t f N l C t T ti Di i GReport of Nuclear Component Testing Discussion Group National Spherical Torus ProgramNational Spherical Torus Program

    E-Print Network [OSTI]

    Abdou, Mohamed Fusion nuclear technology, VNS UCLA Gates, Dave NSTX plasma experimentation PPPL Hegna 100 IEA ST Agreement, FPCC, 2/27-28/07 3 Tritium self-sufficiency goal (%) ~0 ~100 100 # Abdou et al

  3. Torus CLAS12-Superconducting Magnet Quench Analysis

    SciTech Connect (OSTI)

    Kashikhin, V S; Elouadhiri, L; Ghoshal, P K; Kashy, D; Makarov, A; Pastor, O; Quettier, L; Velev, G; Wiseman, M

    2014-06-01T23:59:59.000Z

    The JLAB Torus magnet system consists of six superconducting trapezoidal racetrack-type coils assembled in a toroidal configuration. These coils are wound with SSC-36 Nb-Ti superconductor and have the peak magnetic field of 3.6 T. The first coil manufacturing based on the JLAB design began at FNAL. The large magnet system dimensions (8 m diameter and 14 MJ of stored energy) dictate the need for quench protection. Each coil is placed in an aluminum case mounted inside a cryostat and cooled by 4.6 K supercritical helium gas flowing through a copper tube attached to the coil ID. The large coil dimensions and small cryostat thickness drove the design to challenging technical solutions, suggesting that Lorentz forces due to transport currents and eddy currents during quench and various failure scenarios are analyzed. The paper covers the magnet system quench analysis using the OPERA3d Quench code.

  4. Persistent Density Perturbations at Rational q Surfaces Following Pellet Injection in the Joint European Torus

    E-Print Network [OSTI]

    Persistent Density Perturbations at Rational q Surfaces Following Pellet Injection in the Joint European Torus

  5. From Use Cases of the Joint European Torus towards Integrated Commissioning Requirements of the ITER Tokamak

    E-Print Network [OSTI]

    From Use Cases of the Joint European Torus towards Integrated Commissioning Requirements of the ITER Tokamak

  6. Zero point energy on extra dimensions: Noncommutative torus

    SciTech Connect (OSTI)

    Fabi, S.; Harms, B.; Karatheodoris, G. [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, Alabama 35487-0324 (United States)

    2007-09-15T23:59:59.000Z

    In this paper we calculate the zero point energy density experienced by observers on M{sup 4} due to a massless scalar field defined throughout M{sup 4}xT{sub F}{sup 2}, where T{sub F}{sup 2} are fuzzy extra dimensions. Using the Green's function approach we calculate the energy density for the commutative torus and the fuzzy torus. We also calculate the energy density for the fuzzy torus using the Hamiltonian approach. Agreement is shown between the Green's function and Hamiltonian approaches.

  7. Demonstration of Tokamak Ohmic Flux Saving by Transient Coaxial Helicity Injection on NSTX

    SciTech Connect (OSTI)

    R. Raman, D. Mueller, B.A. Nelson, T.R. Jarboe, S. Gerhardt, H.W. Kugel, B. LeBlanc, R. Maingi, J. Menard, M. Ono, S. Paul, L. Roquemore, S. Sabbagh, V. Soukhanovskii, and the NSTX Research Team

    2010-04-23T23:59:59.000Z

    Transient Coaxial Helicity Injection (CHI) started discharges in NSTX have attained peak currents up to 300 kA and when these discharges are coupled to induction, it has produced up to 200 kA additional current over inductive-only operation. CHI in NSTX has shown to be energetically quite efficient, producing a plasma current of about 10 A/Joule of capacitor bank energy. In addition, for the first time, the CHI produced toroidal current that couples to induction continues to increase with the energy supplied by the CHI power supply at otherwise similar values of the injector flux, indicating the potential for substantial current generation capability by CHI in NSTX and in future toroidal devices. __________________________________________________

  8. Advanced tokamak reactors based on the spherical torus (ATR/ST). Preliminary design considerations

    SciTech Connect (OSTI)

    Miller, R.L.; Krakowski, R.A.; Bathke, C.G.; Copenhaver, C.; Schnurr, N.M.; Engelhardt, A.G.; Seed, T.J.; Zubrin, R.M.

    1986-06-01T23:59:59.000Z

    Preliminary design results relating to an advanced magnetic fusion reactor concept based on the high-beta, low-aspect-ratio, spherical-torus tokamak are summarized. The concept includes resistive (demountable) toroidal-field coils, magnetic-divertor impurity control, oscillating-field current drive, and a flowing liquid-metal breeding blanket. Results of parametric tradeoff studies, plasma engineering modeling, fusion-power-core mechanical design, neutronics analyses, and blanket thermalhydraulics studies are described. The approach, models, and interim results described here provide a basis for a more detailed design. Key issues quantified for the spherical-torus reactor center on the need for an efficient drive for this high-current (approx.40 MA) device as well as the economic desirability to increase the net electrical power from the nominal 500-MWe(net) value adopted for the baseline system. Although a direct extension of present tokamak scaling, the stablity and transport of this high-beta (approx.0.3) plasma is a key unknown that is resoluble only by experiment. The spherical torus generally provides a route to improved tokamak reactors as measured by considerably simplified coil technology in a configuration that allows a realistic magnetic divertor design, both leading to increased mass power density and reduced cost.

  9. National Spherical Torus Experiment Upgrade Status and Plans*

    E-Print Network [OSTI]

    ANS 20th Topical Meeting on the Technology of Fusion Energy (TOFE-2012) Nashville, TN USA August 27 confinement physics predictive capability for ITER and beyond · Develop ST as fusion energy system Lithium fusion nuclear environment of copious neutrons to develop an experimental database on: ­ Nuclear

  10. 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. (Wisconsin Univ., Madison, WI (United States)); Assadi, S. (Fermi National Accelerator Lab., Batavia, IL (United States)); Sidikman, K.L. (Oak Ridge National Lab., TN (United States))

    1992-11-01T23:59:59.000Z

    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.

  11. 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.

    1993-04-03T23:59:59.000Z

    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.

  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. [Wisconsin Univ., Madison, WI (United States); Assadi, S. [Fermi National Accelerator Lab., Batavia, IL (United States); Sidikman, K.L. [Oak Ridge National Lab., TN (United States)

    1992-11-01T23:59:59.000Z

    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. Response of NSTX Liquid Lithium divertor to High Heat Loads

    SciTech Connect (OSTI)

    Abrams, Tyler; Kallman, J; Kaitaa, R; Foley, E L; Grayd, T K; Kugel, H; Levinton, F; McLean, A G

    2012-07-18T23:59:59.000Z

    Samples of the NSTX Liquid Lithium Divertor (LLD) with and without an evaporative Li coating were directly exposed to a neutral beam ex-situ at a power of ~1.5 MW/m2 for 1-3 seconds. Measurements of front face and bulk sample temperature were obtained. Predictions of temperature evolution were derived from a 1D heat flux model. No macroscopic damage occurred when the "bare" sample was exposed to the beam but microscopic changes to the surface were observed. The Li-coated sample developed a lithium hydroxide (LiOH) coating, which did not change even when the front face temperature exceeded the pure Li melting point. These results are consistent with the lack of damage to the LLD surface and imply that heating alone may not expose pure liquid Li if the melting point of surface impurities is not exceeded. This suggests that flow and heat are needed for future PFCs requiring a liquid Li surface. __________________________________________________

  14. NSTX Weekly Report (December 17, 2010) FY 2011 NSTX plasma operations started on October 4, 2010

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    . This symposium will include sessions for: 1. Lithium effects on edge and core plasma properties in magnetic confinement devices; 2. Laboratory experiments on plasma-lithium interactions; 3. Technologies for handling and 839 plasma shots The 2nd International Symposium on Lithium Applications for Fusion Devices

  15. Magnetic Diagnostics For Equilibrium Reconstruction And Realtime Plasma Control In NSTX-Upgrade

    SciTech Connect (OSTI)

    Gerhardt, Stefan P. [PPPL; Erickson, Keith [PPPL; Kaita, Robert [PPPL; Lawson, John [PPPL; Mozulay, Robert [PPPL; Mueller, Dennis [PPPL; Que, Weiguo [PPPL; Rahman, Nabidur [PPPL; Schneider, Hans [PPPL; Smalley, Gustav [PPPL; Tresemer, Kelsey [PPPL

    2014-06-01T23:59:59.000Z

    This paper describes aspects of magnetic diagnostics for realtime control in NSTX-U. The sensor arrangement on the upgraded center column is described. New analog and digital circuitry for processing the plasma current rogowski data are presented. An improved algorithm for estimating the plasma vertical velocity for feedback control is presented.

  16. First Observation Of ELM Pacing With Vertical Jogs In A Spherical Torus

    SciTech Connect (OSTI)

    Gerhardt, S P; Canik, J M; Maingi, R; Bell, R; Gates, d; Goldston, R; Hawryluk, R; Le Blanc, B P; Menard, J; Sontag, A C; Sabbagh, S

    2010-07-15T23:59:59.000Z

    Experiments in a number of conventional aspect ratio tokamaks have been successful in pacing edge localized modes (ELMs) by rapid vertical jogging of the plasma. This paper demonstrates the first pacing of ELMs in a spherical torus plasma. Applied 30 Hz vertical jogs synchronized the ELMs with the upward motion of the plasma. 45 Hz jogs also lead to an increase in the ELM frequency, though the synchronization of the ELMs and jogs was unclear. A reduction in the ELM energy was observed at the higher driven ELM frequencies. __________________________________________________

  17. Initial Results from the Lost Alpha Diagnostics on Joint European Torus

    SciTech Connect (OSTI)

    Darrow, Doug; Cecil, Ed; Ellis, Bob; Fullard, Keith; Hill, Ken; Horton, Alan; Kiptily, Vasily; Pedrick, Les; Reich, Matthias

    2007-07-25T23:59:59.000Z

    Two devices have been installed in the Joint European Torus (JET) vacuum vessel near the plasma boundary to investigate the loss of energetic ions and fusion products in general and alpha particles in particular during the upcoming JET experiments. These devices are (i) a set of multichannel thin foil Faraday collectors, and (ii) a well collimated scintillator which is optically connected to a charge-coupled device. Initial results, including the radial energy and poloidal dependence of lost ions from hydrogen and deuterium plasmas during the 2005–06 JET restart campaign, will be presented.

  18. Simulations of LH coupling in the Madison Symmetric Torus Reversed Field Pinch

    SciTech Connect (OSTI)

    Carlsson, J.; Smithe, D. [Tech-X Corporation, Boulder USA (United States); Cartert, M. [Oak Ridge National Laboratory, Oak Ridge (United States); Burke, D.; Kaufman, M.; Goetz, J. [University of Wisconsin, Madison (United States)

    2007-09-28T23:59:59.000Z

    Simulations using several codes are being performed in support of the LH experiment in the Madison Symmetric Torus (MST) Reversed Field Pinch (RFP). Due to the special requirements of the MST RFP configuration (tight-fitting conducting shell in which only minimal portholes can be tolerated), a novel interdigital line slow-wave launch structure is used, mounted below the mid plane on the inboard side. The unusual configuration made it necessary to modify the main RF coupling code, RANT3D/AORSA1D-H, which was primarily developed for tokamak simulations. Preliminary results will be presented.

  19. Cascade of torus doubling bifurcations in a detuned laser

    SciTech Connect (OSTI)

    Krents, A A [S.P. Korolev Samara State Aerospace University, Samara (Russian Federation); Molevich, N E [Samara Branch of the P.N. Lebedev Physical Institute, Russian Academy of Sciences, Samara (Russian Federation)

    2009-08-31T23:59:59.000Z

    By using a simplified system of Maxwell-Bloch equations (with the adiabatically excluded polarisation of the medium), we studied the processes proceeding in the cross section of a light wave propagating in a wide-aperture laser emitting at the frequency detuned from the transition-line centre. It is shown that in the model under study the passage to the chaotic regime during a change in the wave propagation velocity across the aperture occurs via the doubling bifurcations of an ergodic two-dimensional torus. The spectrum of Lyapunov exponents is found and it is established that at bifurcation points a structurally unstable three-dimensional torus is produced, which gives rise to a stable doubled ergodic torus. (nonlinear optical phenomena)

  20. Admissibility condition and nontrivial indices on a noncommutative torus

    SciTech Connect (OSTI)

    Nagao, Keiichi [Theoretical Physics Laboratory, College of Education, Ibaraki University, Mito 310-8512 (Japan)

    2006-03-15T23:59:59.000Z

    We study the index of the Ginsparg-Wilson Dirac operator on a noncommutative torus numerically. To do this, we first formulate an admissibility condition which suppresses the fluctuation of gauge fields. Assuming this condition, we generate gauge configurations randomly, and find various configurations with nontrivial indices. We show one example of configurations with index 1 explicitly. This result provides the first evidence that nontrivial indices can be naturally defined on the noncommutative torus by utilizing the Ginsparg-Wilson relation and the admissibility condition.

  1. Advances in Fast 2-D Camera Data Handling and Analysis on NSTX

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    4.8 800x600 150 32x32 12 Photron Fastcam 750 1500 2.0 1024x1024 120 128x16 10 Miro 2 50 2000 1.2 800 turbulence in gas puffs · The propagation of ELMs and MARFEs · Heat loading on plasma facing components ­ Advances in Fast 2D Cameras on NSTX. Davis. 5June 15-19, 2009 ELM formation with and without background

  2. Prepared for the U.S. Department of Energy under Contract DE-AC02-76CH03073. Princeton Plasma Physics Laboratory

    E-Print Network [OSTI]

    (NSTX) D.A. Gates, R. Maingi, J. Menard, S. Kaye, S.A. Sabbagh, G. Taylor, J.R. Wilson, et al. November2 , G. Taylor1 , J.R. Wilson1 , M.G. Bell1 , R.E. Bell1 , S. Bernabei1 , J. Bialek2 , T. Biewer1 , W in the National Spherical Torus Experiment (NSTX) D. A. Gates1 , R. Maingi4 , J. Menard1 , S. Kaye1 , S.A. Sabbagh

  3. The Gauss-Bonnet Theorem for the noncommutative two torus

    E-Print Network [OSTI]

    Connes, Alain

    2009-01-01T23:59:59.000Z

    In this paper we show that the value at zero of the zeta function of the Laplacian on the non-commutative two torus, endowed with its canonical conformal structure, is independent of the choice of the volume element (Weyl factor) given by a (non-unimodular) state. We had obtained, in the late eighties, in an unpublished computation, a general formula for this value at zero involving modified logarithms of the modular operator of the state. We give here the detailed computation and prove that the result is independent of the Weyl factor as in the classical case, thus proving the analogue of the Gauss-Bonnet theorem for the noncommutative two torus.

  4. Chimera states on a flat torus

    E-Print Network [OSTI]

    Mark J. Panaggio; Daniel M. Abrams

    2012-11-09T23:59:59.000Z

    Discovered numerically by Kuramoto and Battogtokh in 2002, chimera states are spatiotemporal patterns in which regions of coherence and incoherence coexist. These mathematical oddities were recently reproduced in a laboratory setting sparking a flurry of interest in their properties. Here we use asymptotic methods to derive the conditions under which two-dimensional chimeras, similar to those observed in the experiments, can appear in a periodic space. We also use numerical integration to explore the dynamics of these chimeras and determine which are dynamically stable.

  5. Recent Fast Wave Coupling and Heating Studies on NSTX, with Possible Implications for ITER

    SciTech Connect (OSTI)

    J.C. Hosea, R.E. Bell, E. Feibush, R.W. Harvey, E.F. Jaeger, B.P LeBlanc, R. Maingi, C.K. Phillips, L. Roquemore, P.M. Ryan, G. Taylor, K. Tritz, E.J. Valeo, J. Wilgen, J.R. Wilson, and the NSTX Team

    2009-07-21T23:59:59.000Z

    The goal of the high harmonic fast wave (HHFW) research on NSTX is to maximize the coupling of RF power to the core of the plasma by minimizing the coupling of RF power to edge loss processes. HHFW core plasma heating efficiency in helium and deuterium L-mode discharges is found to improve markedly on NSTX when the density 2 cm in front of the antenna is reduced below that for the onset of perpendicular wave propagation (nonset ? B*k|| 2/?). In NSTX, the observed RF power losses in the plasma edge are driven in the vicinity of the antenna as opposed to resulting from multi-pass edge damping. PDI surface losses through ion-electron collisions are estimated to be significant. Recent spectroscopic measurements suggest that additional PDI losses could be caused by the loss of energetic edge ions on direct loss orbits and perhaps result in the observed clamping of the edge rotation. Initial deuterium H-mode heating studies reveal that core heating is degraded at lower k? (- 8 m-1 relative to 13 m-1) as for the Lmode case at elevated edge density. Fast visible camera images clearly indicate that a major edge loss process is occurring from the plasma scrape off layer (SOL) in the vicinity of the antenna and along the magnetic field lines to the lower outer divertor plate. Large type I ELMs, which are observed at both k? values, appear after antenna arcs caused by precursor blobs, low level ELMs, or dust. For large ELMs without arcs, the source reflection coefficients rise on a 0.1 ms time scale, which indicates that the time derivative of the reflection coefficient can be used to discriminate between arcs and ELMs.

  6. NSTX-U Advances in Real-time C++11 on Linux | Princeton Plasma Physics Lab

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy: GridTruck PlatooningJefferson Lab |NSTX-U Advances in Real-time

  7. NSTX-U Digital Coil Protection System Software Detailed Design | Princeton

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy: GridTruck PlatooningJefferson Lab |NSTX-U Advances inPlasma Physics

  8. Beta-induced Alfven-Acoustic Eigenmodes in NSTX and DIII-D Driven by Beam Ions

    E-Print Network [OSTI]

    Beta-induced Alfv´en-Acoustic Eigenmodes in NSTX and DIII-D Driven by Beam Ions N. N. Gorelenkov´en Cascades) · BAAEmodes (Beta-induced Alfv´en- acoustic Eigenmodes) New BAAE modes (Gorelenkov- bilities: · TAE/RSAEs and (toroidicity-induced/ reversed shear AEs - Alfv´en Cascades) · BAAEmodes (Beta

  9. Dynamic evolution of plasma facing surfaces in NSTX: Impact of impurities and substrate composition on fuel recycling

    E-Print Network [OSTI]

    Harilal, S. S.

    interactions in NSTX with liquid lithium on thin porous molyb- denum substrate for the divertor, additional PFC material dynamic properties. High rate of oxygen adsorption from residual gases during lithium deposition, mixing, and overall fuel recycling. Simulation results showed that formed lithium compounds, filling

  10. Dependence of recycling and edge profiles on lithium evaporation in high triangularity, high performance NSTX H-mode discharges

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    1 Dependence of recycling and edge profiles on lithium evaporation in high triangularity, high between discharges in NSTX, partly to reduce recycling. Reduced D emissions from the lower and upper of the recycling light, improvements in global confinement16-19 , along with the appearance of ELM-free regimes20

  11. Spherical Torus Plasma Interactions with Large-area Liquid Lithium Surfaces in CDX-U

    SciTech Connect (OSTI)

    R. Kaita; R. Majeski; M. Boaz; P. Efthimion; B. Jones; D. Hoffman; H. Kugel; J. Menard; T. Munsat; A. Post-Zwicker; V. Soukhanovskii; J. Spaleta; G. Taylor; J. Timberlake; R. Woolley; L. Zakharov; M. Finkenthal; D. Stutman; G. Antar; R. Doerner; S. Luckhardt; R. Maingi; M. Maiorano; S. Smith

    2002-01-18T23:59:59.000Z

    The Current Drive Experiment-Upgrade (CDX-U) device at the Princeton Plasma Physics Laboratory (PPPL) is a spherical torus (ST) dedicated to the exploration of liquid lithium as a potential solution to reactor first-wall problems such as heat load and erosion, neutron damage and activation, and tritium inventory and breeding. Initial lithium limiter experiments were conducted with a toroidally-local liquid lithium rail limiter (L3) from the University of California at San Diego. Spectroscopic measurements showed a clear reduction of impurities in plasmas with the L3, compared to discharges with a boron carbide limiter. The evidence for a reduction in recycling was less apparent, however. This may be attributable to the relatively small area in contact with the plasma, and the presence of high-recycling surfaces elsewhere in the vacuum chamber. This conclusion was tested in subsequent experiments with a fully toroidal lithium limiter that was installed above the floor of the vacuum vessel. The new limiter covered over ten times the area of the L3 facing the plasma. Experiments with the toroidal lithium limiter have recently begun. This paper describes the conditioning required to prepare the lithium surface for plasma operations, and effect of the toroidal liquid lithium limiter on discharge performance.

  12. Calibration of the Joint European Torus energetic ion and alpha particle collective Thomson scattering diagnostic receiver

    E-Print Network [OSTI]

    Egedal, Jan

    Calibration of the Joint European Torus energetic ion and alpha particle collective Thomson is calibrated assuming blackbody emission from the torus vacuum vessel ~VV! and using electron cyclotron emission ~ECE!. The 32 receiver channels are absolutely calibrated with a mechanical chopper

  13. Calibration of the Joint European Torus energetic ion and alpha particle collective Thomson scattering diagnostic receiver

    E-Print Network [OSTI]

    Egedal, Jan

    Calibration of the Joint European Torus energetic ion and alpha particle collective Thomson Torus JET energetic ion and alpha particle collective Thomson scattering diagnostic is calibrated . The 32 receiver channels are absolutely calibrated with a mechanical chopper in the quasioptical arm

  14. Spherical Torus Plasma Interactions with Large-Area Liquid Lithium Surfaces in CDX-U

    E-Print Network [OSTI]

    California at Los Angeles, University of

    - 1 - Spherical Torus Plasma Interactions with Large-Area Liquid Lithium Surfaces in CDX-U R. KAITA of this concept, key liquid lithium-plasma interaction questions are being addressed in the CDX-U device[2 (PPPL) is a spherical torus (ST) dedicated to the exploration of liquid lithium as a potential solution

  15. Low-Recycling Conditions and Improved Core Confinement in Steady-State Operation Scenarios in JET (Joint European Torus)

    E-Print Network [OSTI]

    Low-Recycling Conditions and Improved Core Confinement in Steady-State Operation Scenarios in JET (Joint European Torus)

  16. High-resolution Tangential AXUV Arrays for Radiated Power Density Measurements on NSTX-U

    SciTech Connect (OSTI)

    Delgado-Aparicio, L [PPPL; Bell, R E [PPPL; Faust, I [MIT; Tritz, K [The Johns Hopkins University, Baltimore, MD, 21209, USA; Diallo, A [PPPL; Gerhardt, S P [PPPL; Kozub, T A [PPPL; LeBlanc, B P [PPPL; Stratton, B C [PPPL

    2014-07-01T23:59:59.000Z

    Precise measurements of the local radiated power density and total radiated power are a matter of the uttermost importance for understanding the onset of impurity-induced instabilities and the study of particle and heat transport. Accounting of power balance is also needed for the understanding the physics of various divertor con#12;gurations for present and future high-power fusion devices. Poloidal asymmetries in the impurity density can result from high Mach numbers and can impact the assessment of their flux-surface-average and hence vary the estimates of P[sub]rad (r, t) and (Z[sub]eff); the latter is used in the calculation of the neoclassical conductivity and the interpretation of non-inductive and inductive current fractions. To this end, the bolometric diagnostic in NSTX-U will be upgraded, enhancing the midplane coverage and radial resolution with two tangential views, and adding a new set of poloidally-viewing arrays to measure the 2D radiation distribution. These systems are designed to contribute to the near- and long-term highest priority research goals for NSTX-U which will integrate non-inductive operation at reduced collisionality, with high-pressure, long energy-confinement-times and a divertor solution with metal walls.

  17. NSTX RESEARCH FORUM FOR EXPERIMENTS IN FY2011-12 PPPL -March 15-18, 2011

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    . Click on Submit 3. Click on Participant 4. If you don't already have WebEX on your system you shield under the tool bar and installing ActiveX. 5. Once the WebEx client is installed you will entered

  18. Exponential Time Decay Estimates for the Landau Equation on Torus

    E-Print Network [OSTI]

    Kung-Chien Wu

    2013-01-04T23:59:59.000Z

    We study the time decay estimates for the linearized Landau equation on torus when the initial perturbation is not necessarily smooth. Our result reveals the kinetic and fluid aspects of the equation. We design a Picard-type iteration and Mixture lemma for constructing the increasingly regular kinetic like waves, they are carried by transport equations and have exponential time decay rate. The fluid like waves are constructed as part of the long-wave expansion in the spectrum of the Fourier mode for the space variable and the time decay rate depends on the size of the domain. The Mixture lemma plays an important role in this paper, this lemma is parallel to Boltzmann equation but the proof is more challenge.

  19. Pointwise Behavior of the Linearized Boltzmann Equation on Torus

    E-Print Network [OSTI]

    Kung-Chien Wu

    2013-01-04T23:59:59.000Z

    We study the pointwise behavior of the linearized Boltzmann equation on torus for non-smooth initial perturbation. The result reveals both the fluid and kinetic aspects of this model. The fluid-like waves are constructed as part of the long-wave expansion in the spectrum of the Fourier mode for the space variable, the time decay rate of the fluid-like waves depends on the size of the domain. We design a Picard-type iteration for constructing the increasingly regular kinetic-like waves, which are carried by the transport equations and have exponential time decay rate. Moreover, the mixture lemma plays an important role in constructing the kinetic-like waves, we supply a new proof of this lemma to avoid constructing explicit solution of the damped transport equations

  20. Towards identifying the mechanisms underlying field-aligned edge-loss of HHFW power on NSTX

    SciTech Connect (OSTI)

    Perkins, R. J.; Bell, R. E.; Bertelli, N.; Diallo, A.; Gerhardt, S.; Hosea, J. C.; Jaworski, M. A.; LeBlanc, B. P.; Kramer, G. J.; Maingi, R.; Phillips, C. K.; Podestà, M.; Roquemore, L.; Scotti, F.; Taylor, G.; Wilson, J. R. [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Ahn, J-W.; Gray, T. K.; Green, D. L.; McLean, A. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); and others

    2014-02-12T23:59:59.000Z

    Fast-wave heating will be a major heating scheme on ITER, as it can heat ions directly and is relatively unaffected by the large machine size unlike neutral beams. However, fast-wave interactions with the plasma edge can lead to deleterious effects such as, in the case of the high-harmonic fast-wave (HHFW) system on NSTX, large losses of fast-wave power in the scrape off layer (SOL) under certain conditions. In such scenarios, a large fraction of the lost HHFW power is deposited on the upper and lower divertors in bright spiral shapes. The responsible mechanism(s) has not yet been identified but may include fast-wave propagation in the scrape off layer, parametric decay instability, and RF currents driven by the antenna reactive fields. Understanding and mitigating these losses is important not only for improving the heating and current-drive on NSTX-Upgrade but also for understanding fast-wave propagation across the SOL in any fast-wave system. This talk summarizes experimental results demonstrating that the flow of lost HHFW power to the divertor regions largely follows the open SOL magnetic field lines. This lost power flux is relatively large close to both the antenna and the last closed flux surface with a reduced level in between, so the loss mechanism cannot be localized to the antenna. At the same time, significant losses also occur along field lines connected to the inboard edge of the bottom antenna plate. The power lost within the spirals is roughly estimated, showing that these field-aligned losses to the divertor are significant but may not account for the total HHFW loss. To elucidate the role of the onset layer for perpendicular fast-wave propagation with regards to fast-wave propagation in the SOL, a cylindrical cold-plasma model is being developed. This model, in addition to advanced RF codes such as TORIC and AORSA, is aimed at identifying the underlying mechanism(s) behind these SOL losses, to minimize their effects in NSTX-U, and to predict their importance in ITER.

  1. Charged particle driver for ICF using an accelerated, focused compact torus

    SciTech Connect (OSTI)

    Meeker, D.J.; Hammer, J.H.; Hartman, C.W.

    1986-06-01T23:59:59.000Z

    We report the status of evaluating an accelerated and focused compact torus as a driver for ICF. We are studying the acceleration and focusing aspects experimentally in the RACE facility, a recently completed ring generator coupled to a 260 kJ acceleration bank. Compact torus and ICF target interaction is being investigated with PIC codes and LASNEX, a 2D magneto-hydrodynamics code. Final conditions required of the CT are discussed as well as coupling issues such as superthermal electron production. We conclude with an economic evaluation of a few 100 MW reactor driven by a compact torus. 9 refs., 5 figs., 1 tab.

  2. Prepared for the U.S. Department of Energy under Contract DE-AC02-76CH03073. Princeton Plasma Physics Laboratory

    E-Print Network [OSTI]

    Physics Laboratory Status of the Control System on the National Spherical Torus Experiment (NSTX) D.S. Department of Energy Office of Scientific and Technical Information P.O. Box 62 Oak Ridge, TN 37831-0062 Telephone: (865) 576-8401 Fax: (865) 576-5728 E-mail: reports@adonis.osti.gov National Technical Information

  3. DIMENSIONS of DISCOVERY Sponsored Program Awards

    E-Print Network [OSTI]

    Ginzel, Matthew

    of a Stent Prototype to Induce Closure of Post-Traumatic Blast-Induced Pseudo-Aneurysms; Modification 1) and its Effect on High Performance Plasmas in National Spherical Torus Experiment (NSTX)." Allebach, Jan P." Applegate, Todd J; animal sciences, from Purac, $43,632, "Effect of Form and Dos- age of Lactylate

  4. PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76CH03073

    E-Print Network [OSTI]

    in Calendar Year 2001. The home page for PPPL Reports and Publications is: http://www.pppl.gov/pub_report/ DOE, Princeton, New Jersey 08543, USA Abstract Neutral beam (NB) heating in the National Spherical Torus auxiliary heating. NB heating experiments in NSTX began in September 2000 using up to 5 MW of 80 keV D beams

  5. Observation of Non-Maxwellian Electron Distributions in th e NSTX Divertor

    SciTech Connect (OSTI)

    M.A. Jaworski, et. al.

    2013-03-07T23:59:59.000Z

    The scrape-off layer plasma at the tokamak region is characterized by open field lines and often contains large variations in plasma properties along these field-lines. Proper characterization of local plasma conditions is critical to assessing plasma-material interaction processes occuring at the target. Langmuir probes are frequently employed in tokamak divertors but are challenging to interpretation. A kinetic interpretation for Langmuir probes in NSTX has yielded non-Maxwellian electron distributions in the divertor characterized by cool bulk populations and energetic tail populations with temperatures of 2-4 times the bulk. Spectroscopic analysis and modeling confirms the bulk plasma temperature and density which can only be obtained with the kinetic interpretation

  6. Effect of Deuterium Gas Puff On The Edge Plasma In NSTX

    SciTech Connect (OSTI)

    Zweben, S. J.

    2014-02-20T23:59:59.000Z

    This paper describes a detailed examination of the effects of a relatively small pulsed deuterium gas puff on the edge plasma and edge turbulence in NSTX. This gas puff caused little or no change in the line-averaged plasma density or total stored energy, or in the edge density and electron temperature up to the time of the peak of the gas puff. The radial profile of the D? light emission and the edge turbulence within this gas puff did not vary significantly over its rise and fall, implying that these gas puffs did not significantly perturb the local edge plasma or edge turbulence. These measurements are compared with modeling by DEGAS 2, UEDGE, and with simplified estimates for the expected effects of this gas puff.

  7. NEUTRAL BEAM ARMOR FOR NSTX UPGRADE K. Tresemer, T. Stevenson, C. Priniski, J. Winkelman, L. Bryant, R. Wood

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    in these upgrades are the relocation and upgrade of the NSTX Neutral Beam Armor to capture both sets of beamline in the overlap areas to a rugged 3D carbon- fiber composite (CFC) material, capable of handling thermally.70 43.01 90 kV 3 6 37.88 9.24 28.67 110 kV 1 9 56.82 13.86 23.89 FUSION SCIENCE AND TECHNOLOGY VOL. 60

  8. 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)

    2013-08-15T23:59:59.000Z

    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.

  9. Confinement of pure electron plasmas in the Columbia Non-neutral Torus

    SciTech Connect (OSTI)

    Berkery, John W.; Pedersen, Thomas Sunn; Kremer, Jason P.; Marksteiner, Quinn R.; Lefrancois, Remi G.; Hahn, Michael S.; Brenner, Paul W. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)

    2007-06-15T23:59:59.000Z

    The Columbia Non-neutral Torus (CNT) [T. S. Pedersen, J. P. Kremer, R. G. Lefrancois, Q. Marksteiner, N. Pomphrey, W. Reiersen, F. Dahlgreen, and X. Sarasola, Fusion Sci. Technol. 50, 372 (2006)] is a stellarator used to study non-neutral plasmas confined on magnetic surfaces. A detailed experimental study of confinement of pure electron plasmas in CNT is described here. Electrons are introduced into the magnetic surfaces by placing a biased thermionic emitter on the magnetic axis. As reported previously, the insulated rods holding this and other emitter filaments contribute to the radial transport by charging up negatively and creating ExB convective transport cells. A model for the rod-driven transport is presented and compared to the measured transport rates under a number of different conditions, finding good agreement. Neutrals also drive transport, and by varying the neutral pressure in the experiment, the effects of rod-driven and neutral-driven transport are separated. The neutral-driven electron loss rate scales linearly with neutral pressure. The neutral driven transport, presumably caused by electron-neutral collisions, is much greater than theoretical estimates for neoclassical diffusion in a classical stellarator with strong radial electric fields. In fact the confinement time is on the order of the electron-neutral collision time. Ion accumulation, electron attachment, and other effects are considered, but do not explain the observed transport rates.

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

    SciTech Connect (OSTI)

    Weitzner, Harold [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)] [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)

    2014-02-15T23:59:59.000Z

    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.

  11. An In-situ materials analysis particle probe (MAPP) diagnostic to study particle density control and hydrogenic fuel retention in NSTX

    SciTech Connect (OSTI)

    Allain, Jean Paul [University of Illinois at Urbana-Champaign] (ORCID:000000031348262X)

    2014-09-05T23:59:59.000Z

    A new materials analysis particle probe (MAPP) was designed, constructed and tested to develop understanding of particle control and hydrogenic fuel retention in lithium-based plasma-facing surfaces in NSTX. The novel feature of MAPP is an in-situ tool to probe the divertor NSTX floor during LLD and lithium-coating shots with subsequent transport to a post-exposure in-vacuo surface analysis chamber to measure D retention. In addition, the implications of a lithiated graphite-dominated plasma-surface environment in NSTX on LLD performance, operation and ultimately hydrogenic pumping and particle control capability are investigated in this proposal. MAPP will be an invaluable tool for erosion/redeposition simulation code validation.

  12. FPA Meeting, 10/11-12/05 Status of World ST Research Status of World Spherical Torus Research

    E-Print Network [OSTI]

    and Energy Policy October 11-12, 2005, Washington, DC Supported by Office of Science College W&M Colorado Sch Has a Tradition of Strong Collaboration · Active bilateral exchanges ­ UK-US on NSTX and MAST ­ START options for economical fusion reactor Phase III Target Strategy of the All-Japan ST Research Program (Prof

  13. Fourier Modeling of the Radio Torus Surrounding Supernova 1987A

    E-Print Network [OSTI]

    C. -Y. Ng; B. M. Gaensler; L. Staveley-Smith; R. N. Manchester; M. J. Kesteven; L. Ball; A. K. Tzioumis

    2008-05-27T23:59:59.000Z

    We present detailed Fourier modeling of the radio remnant of Supernova 1987A, using high-resolution 9 GHz and 18 GHz data taken with the Australia Telescope Compact Array over the period 1992 to 2008. We develop a parameterized three-dimensional torus model for the expanding radio shell, in which the emission is confined to an inclined equatorial belt; our model also incorporates both a correction for light travel-time effects and an overall east-west gradient in the radio emissivity. By deriving an analytic expression for the two-dimensional Fourier transform of the projected three-dimensional brightness distribution, we can fit our spatial model directly to the interferometric visibility data. This provides robust estimates to the radio morphology at each epoch. The best-fit results suggest a constant remnant expansion at 4000 +/- 400 km/s over the 16-year period covered by the observations. The model fits also indicate substantial mid-latitude emission, extending to 40 degree on either side of the equatorial plane. This likely corresponds to the extra-planar structure seen in H$\\alpha$ and Ly$\\alpha$ emission from the supernova reverse shock, and broadly supports hydrodynamic models in which the complex circumstellar environment was produced by a progression of interacting winds from the progenitor. Our model quantifies the clear asymmetry seen in the radio images: we find that the eastern half of the radio remnant is consistently ~40 brighter than the western half at all epochs, which may result from an asymmetry in the ejecta distribution between these two hemispheres.

  14. NSTX presentation

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy: GridTruck PlatooningJefferson Lab |

  15. High-resolution tangential absolute extreme ultraviolet arrays for radiated power density measurements on NSTX-U

    SciTech Connect (OSTI)

    Delgado-Aparicio, L.; Bell, R. E.; Diallo, A.; Gerhardt, S. P.; Kozub, T. A.; LeBlanc, B. P.; Stratton, B. C. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Faust, I. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Tritz, K. [The Johns Hopkins University, Baltimore, Maryland 21209 (United States)

    2014-11-15T23:59:59.000Z

    The radiated-power-density diagnostic on the equatorial midplane for the NSTX-U tokamak will be upgraded to measure the radial structure of the photon emissivity profile with an improved radial resolution. This diagnostic will enhance the characterization and studies of power balance, impurity transport, and MHD. The layout and response expected of the new system is shown for different plasma conditions and impurity concentrations. The effect of toroidal rotation driving poloidal asymmetries in the core radiation from high-Z impurities is also addressed.

  16. Comparison of Measurement And Modeling Of Current Profile Changes Due To Neutral Bean Ion Redistribution During TAE Avalanches in NSTX

    SciTech Connect (OSTI)

    Darrow, Douglas

    2013-07-09T23:59:59.000Z

    Brief "avalanches" of toroidal Alfven eigenmodes (TAEs) are observed in NSTX plasmas with several different n numbers simultaneously present. These affect the neutral beam ion distribution as evidenced by a concurrent drop in the neutron rate and, sometimes, beam ion loss. Guiding center orbit modeling has shown that the modes can transiently render portions of the beam ion phase space stochastic. The resulting redistribution of beam ions can also create a broader beam-driven current profile and produce other changes in the beam ion distribution function

  17. Transition to ELM-free improved H-mode by lithium deposition on NSTX graphite divertor surfaces

    SciTech Connect (OSTI)

    Mansfield, D K; Kugel, H W; Maingi, R; Bell, M G; Bell, R; Kaita, R; Kallman, J; Kaye, S; LeBlanc, B; Mueller, D; Paul, S; Raman, R; Roquemore, A L; Sabbagh, S; Schneider, H; Skinner, C H; Soukhanovskii, V A; Timberlake, J; Wilgen, J; Zakharov, L

    2009-02-17T23:59:59.000Z

    Lithium evaporated onto plasma facing components in the NSTX lower divertor has made dramatic improvements in discharge performance. As lithium accumulated, plasmas previously exhibiting robust Type 1 ELMs gradually transformed into discharges with intermittent ELMs and finally into continuously evolving ELM-free discharges. During this sequence, other discharge parameters changed in a complicated manner. As the ELMs disappeared, energy confinement improved and remarkable changes in edge and scrape-off layer plasma properties were observed. These results demonstrate that active modification of plasma surface interactions can preempt large ELMs.

  18. Understanding ion cyclotron harmonic fast wave heating losses in the scrape off layer of tokamak plasmas

    SciTech Connect (OSTI)

    Bertelli, N [PPPL; Jaeger, E F; Hosea, J C; Phillips, C K; Berry, L; Bonoli, P T; Gerhardt, S P [PPPL; Green, D; LeBlanc, B [PPPL; Perkins, R J; Ryan, P M; Taylor, G; Valeo, E J; Wilso, J R; Wright, J C

    2014-07-01T23:59:59.000Z

    Fast waves at harmonics of the ion cyclotron frequency, which have been used successfully on National Spherical Torus Experiment (NSTX), will also play an important role in ITER and are a promising candidate for the Fusion Nuclear Science Facility (FNSF) designs based on spherical torus (ST). Experimental studies of high harmonic fast waves (HHFW) heating on the NSTX have demonstrated that substantial HHFW power loss occurs along the open field lines in the scrape-off layer (SOL), but the mechanism behind the loss is not yet understood. The full wave RF code AORSA, in which the edge plasma beyond the last closed flux surface (LCFS) is included in the solution domain, is applied to specific NSTX discharges in order to predict the effects and possible causes of this power loss. In the studies discussed here, a collisional damping parameter has been implemented in AORSA as a proxy to represent the real, and most likely nonlinear, damping processes. A prediction for the NSTX Upgrade (NSTX-U) experiment, that will begin operation next year, is also presented, indicating a favorable condition for the experiment due to a wider evanescent region in edge density.*Research supported by the U.S. DOE under Contract No. DE-AC02-09CH11466 with Princeton University.

  19. 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

    2015-06-01T23:59:59.000Z

    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

  20. NSTX S.A.Sabbagh IEA Workshop 59 02/15/05 S. A. Sabbagh1, A.C. Sontag1, R. E. Bell2, J. Bialek1, A. Garofalo1, D.A. Gates2,

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    NSTX S.A.Sabbagh ­ IEA Workshop 59 ­ 02/15/05 S. A. Sabbagh1, A.C. Sontag1, R. E. Bell2, J. Bialek1 IPP, Garching U Quebec IEA Workshop 59: Shape and Aspect Ratio Optimization for High Beta, Steady of Sciences, Hefei, China #12;NSTX S.A.Sabbagh ­ IEA Workshop 59 ­ 02/15/05 Physics study of global MHD mode

  1. Calculation of Neoclassical Toroidal Viscosity with a Particle Simulation in the Tokamak Magnetic Breaking Experiments

    SciTech Connect (OSTI)

    Kimin Kim, et al

    2013-04-23T23:59:59.000Z

    Accurate calculation of perturbed distribution function #14;?f and perturbed magnetic fi eld #14;?B is essential to achieve prediction of non-ambipolar transport and neoclassical toroidal viscosity (NTV) in perturbed tokamaks. This paper reports a study of the NTV with a #14;?f particle code (POCA) and improved understanding of magnetic braking in tokamak experiments. POCA calculates the NTV by computing #14;f with guiding-center orbit motion and using #14;B from the ideal perturbed equilibrium code (IPEC). POCA simulations are compared with experimental estimations for NTV, which are measured from angular momentum balance (DIII-D) and toroidal rotational damping rate (NSTX). The calculation shows good agreement in total NTV torque for the DIII-D discharge, where an analytic neoclassical theory also gives a consistent result thanks to relatively large aspect-ratio and slow toroidal rotations. In NSTX discharges, where the aspect-ratio is small and the rotation is fast, the theory only gives a qualitative guide for predicting NTV. However, the POCA simulation largely improves the quantitative NTV prediction for NSTX. It is discussed that a self- consistent calculation of ?#14;B using general perturbed equilibria is eventually necessary since a non-ideal plasma response can change the perturbed eld and thereby the NTV torque.

  2. Predictions of VRF on a Langmuir Probe under the RF Heating Spiral on the Divertor Floor on NSTX-U

    SciTech Connect (OSTI)

    Hosea, J C [PPPL; Perkins, R J [PPPL; Jaworski, M A [PPPL; Kramer, G J [PPPL; Ahn, J-W [ORNL

    2014-07-01T23:59:59.000Z

    RF heating deposition spirals are observed on the divertor plates on NSTX as shown in for a NB plus RF heating case. It has been shown that the RF spiral is tracked quite well by the spiral mapping of the strike points on the divertor plate of magnetic field lines passing in front of the high harmonic fast wave (HHFW) antenna on NSTX. Indeed, both current instrumented tiles and Langmuir probes respond to the spiral when it is positioned over them. In particular, a positive increment in tile current (collection of electrons) is obtained when the spiral is over the tile. This current can be due to RF rectification and/or RF heating of the scrape off layer (SOL) plasma along the magnetic field lines passing in front of the the HHFW antenna. It is important to determine quantitatively the relative contributions of these processes. Here we explore the properties of the characteristics of probes on the lower divertor plate to determine the likelyhood that the primary cause of the RF heat deposition is RF rectification.

  3. DEPLETED MAGNETIC FLUX TUBES AS PROBES OF THE IO TORUS PLASMA

    E-Print Network [OSTI]

    Russell, Christopher T.

    and Astronomy, University of Iowa, Iowa City, IA 52242, USA ABSTRACT On the initial pass by Io the Galileo that they were depleted in their energy content. These tubes have not been seen on every return to the Io torus balance with neighboring flux tubes in steady state. Figure 1 shows such pressure balance. The magnitude

  4. 558: Calculation of Eddy Currents in the ETE Spherical Torus G.O. Ludwig

    E-Print Network [OSTI]

    558: Calculation of Eddy Currents in the ETE Spherical Torus G.O. Ludwig Instituto Nacional de model based on the Green's function method. The distribution of eddy currents is calculated using a thin well with values of the eddy currents measured in ETE. INTRODUCTION This paper presents a magnetostatic

  5. Thermoelectric Rotating Torus for Fusion A. B. Hassam and Yi-Min Huang

    E-Print Network [OSTI]

    Hassam, Adil

    Thermoelectric Rotating Torus for Fusion A. B. Hassam and Yi-Min Huang Institute for Plasma power maintains the rotation and also heats the plasma. The thermoelectric effect from the resultingRevLett.91.195002 PACS numbers: 52.58.­c, 52.30.­q, 52.55.­s In magnetized plasma, thermoelectric currents

  6. An Inexpensive Ohmic Transformer Firing Circuit for the CDXU Spherical Torus

    E-Print Network [OSTI]

    1 An Inexpensive Ohmic Transformer Firing Circuit for the CDX­U Spherical Torus T. Munsat, R designed and modeled a simple, efficient circuit for delivering power to the CDX­U ohmic transformer, spherical tori) have traditionally driven plasma current by using the transformer action of a centrally

  7. An Inexpensive Ohmic Transformer Firing Circuit for the CDX-U Spherical Torus

    E-Print Network [OSTI]

    1 An Inexpensive Ohmic Transformer Firing Circuit for the CDX-U Spherical Torus T. Munsat, R designed and modeled a simple, efficient circuit for delivering power to the CDX-U ohmic transformer, spherical tori) have traditionally driven plasma current by using the transformer action of a centrally

  8. Initial Data for General Relativity Containing a Marginally Outer Trapped Torus

    E-Print Network [OSTI]

    Sascha Husa

    1996-06-15T23:59:59.000Z

    Asymptotically flat, time-symmetric, axially symmetric and conformally flat initial data for vacuum general relativity are studied numerically on $R^3$ with the interior of a standard torus cut out. By the choice of boundary condition the torus is marginally outer trapped, and thus a surface of minimal area. Apart from pure scaling the standard tori are parameterized by a radius $a\\in [0,1]$, where $a=0$ corresponds to the limit where the boundary torus degenerates to a circle and $a=1$ to a torus that touches the axis of symmetry. Noting that these tori are the orbits of a $U(1)\\times U(1)$ conformal isometry allows for a simple scheme to solve the constraint, involving numerical solution of only ordinary differential equations.The tori are unstable minimal surfaces (i.e. only saddle points of the area functional) and thus can not be apparent horizons, but are always surrounded by an apparent horizon of spherical topology, which is analyzed in the context of the hoop conjecture and isoperimetric inequality for black holes.

  9. Physics basis for a spherical torus power plant S.C. Jardin a,

    E-Print Network [OSTI]

    Najmabadi, Farrokh

    Physics basis for a spherical torus power plant S.C. Jardin a, *, C.E. Kessel a , J. Menard a , T for a fusion power plant. A special class of wall-stabilized high-b high-bootstrap fraction low-aspect-ratio tokamak; Fusion power plant; Plasma operating regime 1. Introduction The most significant difference

  10. Local well-posedness for the Zakharov system on multidimensional torus

    E-Print Network [OSTI]

    Kishimoto, Nobu

    2011-01-01T23:59:59.000Z

    The initial value problem of the Zakharov system on two dimensional torus with general period is shown to be locally well-posed in the Sobolev spaces of optimal regularity, including the energy space. Proof relies on a standard iteration argument using the Bourgain norms. The same strategy is also applicable to three and higher dimensional cases.

  11. Fusion alpha-particle diagnostics for DT experiments on the joint European torus

    SciTech Connect (OSTI)

    Kiptily, V. G.; Beaumont, P.; Syme, D. B. [Euratom / CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon (United Kingdom); Belli, F. [Associazione Euratom -ENEA sulla Fusione, C.R. Frascati, C.P. 65, Frascati (Italy); Cecil, F. E.; Riva, M. [Colorado School of Mines, Golden, CO (United States); Conroy, S.; Ericsson, G. [Department of Physics and Astronomy, Uppsala University, BOX 516, Uppsala (Sweden); Craciunescu, T. [Association Euratom -MEdC, National Institute for Laser, Plasma and Radiation Physics (Romania); Garcia-Munoz, M. [Max-Planck-Institut für Plasmaphysik, EURATOM-Association IPP, Garching, D-85748 (Germany); Curuia, M.; Soare, S. [Association Euratom -MEdC, National Institute for Cryogenics and Isotopic Technology (Romania); Darrow, D. [Princeton Plasma Physics Lab, Princeton, NJ (United States); Fernandes, A. M.; Pereira, R. C.; Sousa, J. [Euratom/IST Fusion Association, Centro de Fusão Nuclear, 1049-001 Lisboa (Portugal); Giacomelli, L.; Voitsekhovitch, I. [CNISM, Dipartimento di Fisica, Universita Milano-Bicocca, Milano (Italy); Gorini,; Nocente, M. [CNISM, Dipartimento di Fisica, Universita Milano-Bicocca, Milano, Italy and Associazione Euratom -ENEA sulla Fusione, IFP Milano (Italy); and others

    2014-08-21T23:59:59.000Z

    JET equipped with ITER-like wall (a beryllium wall and a tungsten divertor) can provide auxiliary heating with power up to 35MW, producing a significant population of ?-particles in DT operation. The direct measurements of alphas are very difficult and ?-particle studies require a significant development of dedicated diagnostics. JET now has an excellent set of confined and lost fast particle diagnostics for measuring the ?-particle source and its evolution in space and time, ?-particle energy distribution, and ?-particle losses. This paper describes how the above mentioned JET diagnostic systems could be used for ?-particle measurements, and what options exist for keeping the essential ?-particle diagnostics functioning well in the presence of intense DT neutron flux. Also, ?-particle diagnostics for ITER are discussed.

  12. Advances in High-harmonic Fast Wave Physics in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Taylor, G; Hosea, J C; LeBlanc, B P; Phillips, C K; Podesta, M; Valeo, E J; Wilson, J R; Ahn, J -W; Chen, G; Green, D L; Jaeger, E F; Maingi, R; Ryan, P M; Wilgen, J B; Heidbrink, W W; Liu, D; Bonoli, P T; Brecht, T; Choi, M

    2009-12-01T23:59:59.000Z

    Improved core high-harmonic fast wave (HHFW) heating at longer wavelengths and during start-up and plasma current ramp-up, has now been obtained by lowering the edge density with lithium wall conditioning, thereby moving the critical density for perpendicular fast-wave propagation away from the vessel wall. Lithium conditioning allowed significant HHFW core electron heating of deuterium neutral beam injection (NBI) fuelled H-mode plasmas to be observed for the first time. Large edge localized modes were observed immediately after the termination of rf power. Visible and infrared camera images show that fast wave interactions can deposit considerable rf energy on the outboard divertor. HHFW-generated parametric decay instabilities were observed to heat ions in the plasma edge and may be the cause for a measured drag on edge toroidal rotation during HHFW heating. A significant enhancement in neutron rate and fast-ion profile were measured in NBI-fuelled plasmas when HHFW heating was applied. __________________________________________________

  13. A Star on Earth

    ScienceCinema (OSTI)

    Prager, Stewart; Zwicker, Andrew; Hammet, Greg; Tresemer, Kelsey; Diallo, Ahmed

    2014-06-06T23:59:59.000Z

    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.

  14. A Star on Earth

    SciTech Connect (OSTI)

    Prager, Stewart; Zwicker, Andrew; Hammet, Greg; Tresemer, Kelsey; Diallo, Ahmed

    2014-03-05T23:59:59.000Z

    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.

  15. Please cite this article in press as: J.N. Brooks, et al., Modeling of plasma/lithium-surface interactions in NSTX: Status and key issues. Fusion Eng. Des. (2011), doi:10.1016/j.fusengdes.2011.08.002

    E-Print Network [OSTI]

    Harilal, S. S.

    2011-01-01T23:59:59.000Z

    .elsevier.com/locate/fusengdes Modeling of plasma/lithium-surface interactions in NSTX: Status and key issues J.N. Brooks , A. Hassanein history: Available online xxx Keywords: Lithium NSTX Plasma material interactions Erosion a b s t r a c nuclear science facility or DEMO. Accordingly, we have been analyzing lithium plasma surface interactions

  16. Traces of holomorphic families of operators on the noncommutative torus and on Hilbert modules

    E-Print Network [OSTI]

    Sara Azzali; Cyril Lévy; Carolina Neira Jiménez; Sylvie Paycha

    2015-01-26T23:59:59.000Z

    We revisit traces of holomorphic families of pseudodifferential operators on a closed manifold in view of geometric applications. We then transpose the corresponding analytic constructions to two different geometric frameworks; the noncommutative torus and Hilbert modules. These traces are meromorphic functions whose residues at the poles as well as the constant term of the Laurent expansion at zero (the latter when the family at zero is a differential operator) can be expressed in terms of Wodzicki residues and extended Wodzicki residues involving logarithmic operators. They are therefore local and contain geometric information. For holomorphic families leading to zeta regularised traces, they relate to the heat-kernel asymptotic coefficients via an inverse Mellin mapping theorem. We revisit Atiyah's L^2-index theorem by means of the (extended) Wodzicki residue and interpret the scalar curvature on the noncommutative two torus as an (extended) Wodzicki residue.

  17. High-speed three-wave polarimeter-interferometer diagnostic for Madison symmetric torus

    SciTech Connect (OSTI)

    Deng, B. H.; Brower, D. L.; Ding, W. X.; Wyman, M. D.; Chapman, B. E.; Sarff, J. S. [Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States); Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2006-10-15T23:59:59.000Z

    A high-speed three-wave polarimeter-interferometer diagnostic has been developed on the Madison symmetric torus reversed field pinch to provide simultaneous measurement of electron density and poloidal magnetic field profile evolution. With increased digitizer bandwidth, polarimetry noise due to aliasing and cross-talk is minimized, and time response improved. System performance is demonstrated by measurements of equilibrium profile evolution during fast events such as the sawtooth crash and pellet injection.

  18. Derivation of nuclear parameters for delayed neutron detector measurements for D-D and D-T plasma operation at the Joint European Torus

    SciTech Connect (OSTI)

    Angelone, M. (JET Joint Undertaking Abingdon, Oxon (United Kingdom))

    1993-08-01T23:59:59.000Z

    The first attempt to calculate the parameters for [sup 238]U and [sup 232]Th used in the analysis of delayed neutron counter measurements of the total neutron yield from deuterium-tritium (D-T) plasmas is described. The nuclear theory of systematics is employed, together with nuclear data from the literature. As a check on the methods used, the delayed neutron parameters were also calculated for deuterium-deuterium plasma conditions; the resulting neutron yields agreed within [+-]7% with the results obtained using the experimentally calibrated delayed neutron counter assemblies. After the calculations were completed, the first D-T plasma experiment was performed at the Joint European Torus (JET). Delayed neutron measurements were made using [sup 232]Th samples. The calculated delayed neutron parameters gave neutron yields that agreed within [+-]8% with those obtained with conventional activation methods, using iron and silicon samples. 30 refs., 5 figs., 8 tabs.

  19. Prepared for the U.S. Department of Energy under Contract DE-AC02-76CH03073. Princeton Plasma Physics Laboratory

    E-Print Network [OSTI]

    .K. Mau, J.E. Menard, C.K. Phillips, P.M. Ryan, S.A. Sabbagh, E.J. Synakowski, G. Taylor, R. Wilson. Phillips, P. M. Ryan3 , S. A. Sabbagh4 , E. J. Synakowski, G. Taylor, R. Wilson and the NSTX Research Team Torus Experiment C.E. Kessel, R.E. Bell, M.G. Bell, D.A. Gates, R.W. Harvey, S.M. Kaye, B.P. LeBlanc, T

  20. Topological Invariants and Ground-State Wave Functions of Topological Insulators on a Torus

    E-Print Network [OSTI]

    Zhong Wang; Shou-Cheng Zhang

    2014-01-25T23:59:59.000Z

    We define topological invariants in terms of the ground states wave functions on a torus. This approach leads to precisely defined formulas for the Hall conductance in four dimensions and the topological magneto-electric $\\theta$ term in three dimensions, and their generalizations in higher dimensions. They are valid in the presence of arbitrary many-body interaction and disorder. These topological invariants systematically generalize the two-dimensional Niu-Thouless-Wu formula, and will be useful in numerical calculations of disordered topological insulators and strongly correlated topological insulators, especially fractional topological insulators.

  1. Simulations of lower-hybrid coupling in the Madison Symmetric Torus

    SciTech Connect (OSTI)

    Carlsson, Johan; Smithe, David [Tech-X Corporation, Boulder, Colorado (United States); Carter, Mark [Oak Ridge National Laboratory, Oak Ridge, Tennessee (United States); Kaufman, Mike [University of Wisconsin, Madison, Wisconsin (United States)

    2009-11-26T23:59:59.000Z

    Simulations of Lower Hybrid (LH) coupling in the Madison Symmetric Torus (MST) Reversed Field Pinch (RFP) will be presented. Due to the special requirements of the RFP configuration (tight-fitting conducting shell in which only minimal portholes are acceptable), an unusual interdigital line slow-wave antenna is used, mounted below the mid plane on the inboard side. A number of codes are used, including VORPAL, RANT3D/AORSA1D-H and MWS, each solving different equations and using different algorithms. Output from the different codes will be presented and compared to verify the simulation results.

  2. VOLUME54, NUMBER9 PHYSICAL REVIEW LETTERS 4 MARCH1985 Conversion of Wave Energy to Magnetic Field Energy in a Plasma Torus

    E-Print Network [OSTI]

    Karney, Charles

    VOLUME54, NUMBER9 PHYSICAL REVIEW LETTERS 4 MARCH1985 Conversion of Wave Energy to Magnetic Field on the Princeton Large Torus (PLT)' have converted wave energy to poloidal field energy with the remarkable Energy in a Plasma Torus N. J. Fisch and C. F. F. Karney Plasma Physics Laboratory, Princeton University

  3. 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

    2011-02-24T23:59:59.000Z

    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.

  4. Conformal perturbation theory and higher spin entanglement entropy on the torus

    E-Print Network [OSTI]

    Shouvik Datta; Justin R. David; S. Prem Kumar

    2014-12-12T23:59:59.000Z

    We study the free fermion theory in 1+1 dimensions deformed by chemical potentials for holomorphic, conserved currents at finite temperature and on a spatial circle. For a spin-three chemical potential \\mu, the deformation is related at high temperatures to a higher spin black hole in hs[0] theory on AdS_3 spacetime. We calculate the order \\mu^2 corrections to the single interval Renyi and entanglement entropies on the torus using the bosonized formulation. A consistent result, satisfying all checks, emerges upon carefully accounting for both perturbative and winding mode contributions in the bosonized language. The order \\mu^2 corrections involve integrals that are finite but potentially sensitive to contact term singularities. We propose and apply a prescription for defining such integrals which matches the Hamiltonian picture and passes several non-trivial checks for both thermal corrections and the Renyi entropies at this order. The thermal corrections are given by a weight six quasi-modular form, whilst the Renyi entropies are controlled by quasi-elliptic functions of the interval length with modular weight six. We also point out the well known connection between the perturbative expansion of the partition function in powers of the spin-three chemical potential and the Gross-Taylor genus expansion of large-N Yang-Mills theory on the torus. We note the absence of winding mode contributions in this connection, which suggests qualitatively different entanglement entropies for the two systems.

  5. Solenoid-free Plasma Start-up in NSTX using Transient CHI R. Raman 1), T.R. Jarboe 1), B.A. Nelson 1), D. Mueller 2), M.G. Bell 2), R. Bell 1),

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    1 Solenoid-free Plasma Start-up in NSTX using Transient CHI R. Raman 1), T.R. Jarboe 1), B sustainment and ramp-up of the toroidal plasma current. In these discharges, the central Ohmic transformer by CHI. The coupled discharges have ramped up to >700 kA and transitioned into an H-mode demonstrating

  6. 6/15/00 1 Diagnostics for Liquid Lithium Experiments in CDXU

    E-Print Network [OSTI]

    in fusion reactors. To investigate the interaction of a spherical torus plasma with liquid lithium limiters­Upgrade (CDX­U) where the plasma­wall interactions are dominated by liquid lithium surfaces. Among the unique6/15/00 ­ 1 ­ Diagnostics for Liquid Lithium Experiments in CDX­U R. Kaita, a P. Efthimion, a D

  7. Hydrogen atom in crossed electric and magnetic fields: Phase space topology and torus quantization via periodic orbits

    E-Print Network [OSTI]

    Hydrogen atom in crossed electric and magnetic fields: Phase space topology and torus quantization for the periodic orbits in a strongly coupled multidimen- sional Hamiltonian system, namely the hydrogen atom.15.Gy, 05.45.-a, 45.20.Jj I. INTRODUCTION The hydrogen atom in crossed electric and magnetic fields

  8. Prepared for the U.S. Department of Energy under Contract DE-AC02-76CH03073. Princeton Plasma Physics Laboratory

    E-Print Network [OSTI]

    Experiment (NSTX). In plasmas with high plasma rotation, superthermal flow of carbon produces a near Gaussian

  9. Spectral asymmetry of the massless Dirac operator on a 3-torus

    SciTech Connect (OSTI)

    Downes, Robert J., E-mail: R.Downes@ucl.ac.uk; Vassiliev, Dmitri, E-mail: D.Vassiliev@ucl.ac.uk [Department of Mathematics, University College London, Gower Street, London WC1E 6BT (United Kingdom)] [Department of Mathematics, University College London, Gower Street, London WC1E 6BT (United Kingdom); Levitin, Michael, E-mail: M.Levitin@reading.ac.uk [Department of Mathematics and Statistics, University of Reading, Whiteknights, PO Box 220, Reading RG6 6AX (United Kingdom)] [Department of Mathematics and Statistics, University of Reading, Whiteknights, PO Box 220, Reading RG6 6AX (United Kingdom)

    2013-11-15T23:59:59.000Z

    Consider the massless Dirac operator on a 3-torus equipped with Euclidean metric and standard spin structure. It is known that the eigenvalues can be calculated explicitly: the spectrum is symmetric about zero and zero itself is a double eigenvalue. The aim of the paper is to develop a perturbation theory for the eigenvalue with smallest modulus with respect to perturbations of the metric. Here the application of perturbation techniques is hindered by the fact that eigenvalues of the massless Dirac operator have even multiplicity, which is a consequence of this operator commuting with the antilinear operator of charge conjugation (a peculiar feature of dimension 3). We derive an asymptotic formula for the eigenvalue with smallest modulus for arbitrary perturbations of the metric and present two particular families of Riemannian metrics for which the eigenvalue with smallest modulus can be evaluated explicitly. We also establish a relation between our asymptotic formula and the eta invariant.

  10. Electron cyclotron emission radiometer upgrade on the Joint European Torus (JET) tokamak

    SciTech Connect (OSTI)

    Luna, E. de la; Sanchez, J.; Tribaldos, V.; Conway, G.; Suttrop, W.; Fessey, J.; Prentice, R.; Gowers, C.; Chareau, J. M. [Asociacion EURATOM-CIEMAT para Fusion, CIEMAT, Madrid (Spain); IPP-EURATOM Association, Garching (Germany); EURATOM-UKAEA Fusion Associations, Culham Science Centre, Abingdon (United Kingdom); European Commission, Institute for Transuranium Elements, Karlsruhe (Germany)

    2004-10-01T23:59:59.000Z

    The capabilities of the Joint European Torus (JET) electron cyclotron emission (ECE) diagnostics have recently been extended with an upgrading of the heterodyne radiometer. The number of channels has been doubled to 96 channels, with a frequency separation corresponding to <1 cm for JET magnetic field gradient, and with a frequency response of 1 MHz. This enhancement has increased the radial coverage of the ECE electron temperature measurements in JET to approximately the full plasma column (limited at R>2.6 m for the X-mode due to harmonic overlap) at almost all magnetic field values used at JET (1.7 T

  11. Statistical analysis of variations in impurity ion heating at reconnection events in the Madison Symmetric Torus

    SciTech Connect (OSTI)

    Cartolano, M. S.; Craig, D., E-mail: darren.craig@wheaton.edu [Wheaton College, Wheaton, Illinois 60187 (United States); Den Hartog, D. J.; Kumar, S. T. A.; Nornberg, M. D. [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States) [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, Madison, Wisconsin 53706 (United States)

    2014-01-15T23:59:59.000Z

    The connection between impurity ion heating and other physical processes in the plasma is evaluated by studying variations in the amount of ion heating at reconnection events in the Madison Symmetric Torus (MST). Correlation of the change in ion temperature with individual tearing mode amplitudes indicates that the edge-resonant modes are better predictors for the amount of global ion heating than the core-resonant modes. There is also a strong correlation between ion heating and current profile relaxation. Simultaneous measurements of the ion temperature at different toroidal locations reveal, for the first time, a toroidal asymmetry to the ion heating in MST. These results present challenges for existing heating theories and suggest a stronger connection between edge-resonant tearing modes, current profile relaxation, and ion heating than has been previously thought.

  12. First Studies of Pure Electron Plasmas in the Columbia Non-neutral Torus

    SciTech Connect (OSTI)

    Berkery, J. W.; Pedersen, T. S.; Kremer, J. P.; Lefrancois, R. G.; Marksteiner, Q. R.; Boozer, A. H. [Dept. of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027 (United States); Mynick, H. E.; Pomphrey, N.; Reiersen, W.; Dahlgreen, F. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Himura, H. [Kyoto Institute of Technology, Kyoto (Japan); Sarasola, X. [CIEMAT, Madrid (Spain)

    2006-10-18T23:59:59.000Z

    The first studies of pure electron plasmas confined on magnetic surfaces in the Columbia Non-neutral Torus are overviewed. The electron plasma is created by a thermionic emitter filament and similar filaments mounted on ceramic rods are used as Langmuir and emissive probes. The equilibrium density, temperature and potential profiles are experimentally measured. Numerical calculations of the equilibrium agree well with measurements and also predict a toroidal density variation of a factor of four. The confinement time is found to decrease with increased neutral pressure and emitter bias voltage, and it is presently limited to 20 ms by the insulated emitter and probe rods. A retractable electron emitter and external diagnostics will be used to determine the confinement time in the absence of rods. Ion driven instabilities are observed at high neutral pressure and low magnetic field strength. Further research of these instabilities will be carried out.

  13. Group-Theoretical Quantization of 2+1 Geavity in the Metric-Torus Sector

    E-Print Network [OSTI]

    P. Hajicek

    1997-05-29T23:59:59.000Z

    A symmetry based quantization method of reparametrization invariant systems is described; it will work for all systems that possess complete sets of perennials whose Lie algebras close and which generate a sufficiently large symmetry groups. The construction leads to a quantum theory including a Hilbert space, a complete system of operator observables and a unitary time evolution. The method is applied to the 2+1 gravity. The paper is restricted to the metric-torus sector, zero cosmological constant $\\Lambda$ and it makes strong use of the so-called homogeneous gauge; the chosen algebra of perennials is that due to Martin. Two frequent problems are tackled. First, the Lie algebra of perennials does not generate a group of symmetries. The notion of group completion of a reparametrization invariant system is introduced so that the group does act; the group completion of the physical phase space of our model is shown to add only some limit points to it so that the ranges of observables are not unduly changed. Second, a relatively large number of relations between observables exists; they are transferred to the quantum theory by the well-known methods due to Kostant and Kirillov. In this way, a uniqueness of the physical representation of some extension of Martin's algebra is shown. The Hamiltonian is defined by a systematic procedure due to Dirac; for the torus sector, the result coincides with that by Moncrief. The construction may be extensible to higher genera and non-zero $\\Lambda$ of the 2+1 gravity, because some complete sets of perennials are well-known and there are no obstructions to the closure of the algebra.

  14. Central Safety Factor and #12;ßN Control on NSTX-U via Beam Power and Plasma Boundary Shape Modification, using TRANSP for Closed Loop Simulations

    SciTech Connect (OSTI)

    Boyer, M. D. [PPPL; Andre, R. [PPPL; Gates, David A. [PPPL; Gerhardt, S. [PPPL; Goumiri, I. R. [Princeton University; Menard, Jon [PPPL

    2014-08-01T23:59:59.000Z

    The high-performance operational goals of NSTX-U will require development of advanced feedback control algorithms, including control of ßN and the safety factor profile. In this work, a novel approach to simultaneously controlling #12;ßN and the value of the safety factor on the magnetic axis, q0, through manipulation of the plasma boundary shape and total beam power, is proposed. Simulations of the proposed scheme show promising results and motivate future experimental implementation and eventual integration into a more complex current profile control scheme planned to include actuation of individual beam powers, density, and loop voltage. As part of this work, a flexible framework for closed loop simulations within the high-fidelity code TRANSP was developed. The framework, used here to identify control-design-oriented models and to tune and test the proposed controller, exploits many of the predictive capabilities of TRANSP and provides a means for performing control calculations based on user-supplied data (controller matrices, target waveforms, etc.). The flexible framework should enable high-fidelity testing of a variety of control algorithms, thereby reducing the amount of expensive experimental time needed to implement new control algorithms on NSTX-U and other devices.

  15. Fast-wave Power Flow Along SOL Field Lines In NSTX nd The Associated Power Deposition Profile Across The SOL In Front Of The Antenna

    SciTech Connect (OSTI)

    Perkins, Roy

    2013-06-21T23:59:59.000Z

    Fast-wave heating and current drive efficiencies can be reduced by a number of processes in the vicinity of the antenna and in the scrape off layer (SOL). On NSTX from around 25% to more than 60% of the high-harmonic fast-wave power can be lost to the SOL regions, and a large part of this lost power flows along SOL magnetic field lines and is deposited in bright spirals on the divertor floor and ceiling. We show that field-line mapping matches the location of heat deposition on the lower divertor, albeit with a portion of the heat outside of the predictions. The field-line mapping can then be used to partially reconstruct the profile of lost fast-wave power at the midplane in front of the antenna, and the losses peak close to the last closed flux surface (LCFS) as well as the antenna. This profile suggests a radial standing-wave pattern formed by fast-wave propagation in the SOL, and this hypothesis will be tested on NSTX-U. Advanced RF codes must reproduce these results so that such codes can be used to understand this edge loss and to minimize RF heat deposition and erosion in the divertor region on ITER.

  16. A Description of the Full Particle Orbit Following SPIRAL Code for Simulating Fast-ion Experiments in Tokamaks

    SciTech Connect (OSTI)

    Kramer, G.J.; Budny, R.V.; Bortolon, A.; Fredrickson, E.D.; Fu, G.Y.; Heidbrink, W.W.; Nazikian, R.; Valeo, E.; Van Zeeland, M.A.

    2012-07-27T23:59:59.000Z

    The numerical methods used in the full particle-orbit following SPIRAL code are described and a number of physics studies performed with the code are presented to illustrate its capabilities. The SPIRAL code is a test-particle code and is a powerful numerical tool to interpret and plan fast-ion experiments in Tokamaks. Gyro-orbit effects are important for fast ions in low-field machines such as NSTX and to a lesser extent in DIII-D. A number of physics studies are interlaced between the description of the code to illustrate its capabilities. Results on heat loads generated by a localized error-field on the DIII-D wall are compared to measurements. The enhanced Triton losses caused by the same localized error-field are calculated and compared to measured neutron signals. MHD activity such as tearing modes and Toroidicity-induced Alfven Eigenmodes (TAEs) have a profound effect on the fast-ion content of Tokamak plasmas and SPIRAL can calculate the effects of MHD activity on the confined and lost fast-ion population as illustrated for a burst of TAE activity in NSTX. The interaction between Ion Cyclotron Range of Frequency (ICRF) heating and fast ions depends solely on the gyro-motion of the fast ions and is captured exactly in the SPIRAL code. A calculation of ICRF absorption on beam ions in ITER is presented. The effects of high harmonic fast wave heating on the beam-ion slowing-down distribution in NSTX is also studied.

  17. PPPL-3300, Preprint: May 1998, UC-420,423 Tritium Experience in Large Tokamaks: Application to ITER

    E-Print Network [OSTI]

    experience with the use of tritium fuel in the Tokamak Fusion Test Reactor and the Joint European Torus, together with progress in developing the technical design of the International Thermonuclear Experimental Reactor has expanded the technical knowledge base for tritium issues in fusion. This paper reports

  18. PPPL3300, Preprint: May 1998, UC420,423 Tritium Experience in Large Tokamaks: Application to ITER

    E-Print Network [OSTI]

    experience with the use of tritium fuel in the Tokamak Fusion Test Reactor and the Joint European Torus, together with progress in developing the technical design of the International Thermonuclear Experimental Reactor has expanded the technical knowledge base for tritium issues in fusion. This paper reports

  19. Hydrogen atom in crossed electric and magnetic fields: Phase space topology and torus quantization via periodic orbits

    E-Print Network [OSTI]

    Stephan Gekle; Jörg Main; Thomas Bartsch; T. Uzer

    2006-10-02T23:59:59.000Z

    A hierarchical ordering is demonstrated for the periodic orbits in a strongly coupled multidimensional Hamiltonian system, namely the hydrogen atom in crossed electric and magnetic fields. It mirrors the hierarchy of broken resonant tori and thereby allows one to characterize the periodic orbits by a set of winding numbers. With this knowledge, we construct the action variables as functions of the frequency ratios and carry out a semiclassical torus quantization. The semiclassical energy levels thus obtained agree well with exact quantum calculations.

  20. Demonstration of Tokamak Ohmic Flux Saving by Transient Coaxial Helicity Injection in the National Spherical Torus Experiment

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Demonstration of Tokamak Ohmic Flux Saving by Transient Coaxial Helicity Injection in the National: 52.55.Fa, 52.25.Vy, 52.35.Vd, 52.50.Nr Toroidal magnetic configurations based on the tokamak concept component in conventional tokamak reactor designs could be elimi- nated [1,2]. The central solenoid also

  1. Continuous Improvement of H-Mode Discharge Performance with Progressively Increasing Lithium Coatings in the National Spherical Torus Experiment

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    -wall interactions. Recently, there is growing use of lithium coatings, in particular, to control edge recyclingContinuous Improvement of H-Mode Discharge Performance with Progressively Increasing Lithium September 2011) Lithium wall coatings have been shown to reduce recycling, improve energy confinement

  2. ACCRETION AND OUTFLOW FROM A MAGNETIZED, NEUTRINO COOLED TORUS AROUND THE GAMMA-RAY BURST CENTRAL ENGINE

    SciTech Connect (OSTI)

    Janiuk, Agnieszka; Mioduszewski, Patryk [Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Moscibrodzka, Monika, E-mail: agnes@cft.edu.pl [Department of Physics, University of Nevada Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154 (United States)

    2013-10-20T23:59:59.000Z

    We calculate the structure and short-term evolution of a gamma-ray burst (GRB) central engine in the form of a turbulent torus accreting onto a stellar mass black hole. Our models apply to the short GRB events, in which a remnant torus forms after the neutron star-black hole or a double neutron star merger and is subsequently accreted. We study the two-dimensional, relativistic models and concentrate on the effects of the black hole and flow parameters as well as the neutrino cooling. We compare the resulting structure and neutrino emission to the results of our previous one-dimensional simulations. We find that the neutrino cooled torus launches a powerful mass outflow, which contributes to the total neutrino luminosity and mass loss from the system. The neutrino luminosity may exceed the Blandford-Znajek luminosity of the polar jets and the subsequent annihilation of neutrino-antineutrino pairs will provide an additional source of power to the GRB emission.

  3. An axisymmetric hydrodynamical model for the torus wind in AGN. II: X-ray excited funnel flow

    E-Print Network [OSTI]

    A. Dorodnitsyn; T. Kallman; D. Proga

    2008-06-23T23:59:59.000Z

    We have calculated a series of models of outflows from the obscuring torus in active galactic nuclei (AGN). Our modeling assumes that the inner face of a rotationally supported torus is illuminated and heated by the intense X-rays from the inner accretion disk and black hole. As a result of such heating a strong biconical outflow is observed in our simulations. We calculate 3-dimensional hydrodynamical models, assuming axial symmetry, and including the effects of X-ray heating, ionization, and radiation pressure. We discuss the behavior of a large family of these models, their velocity fields, mass fluxes and temperature, as functions of the torus properties and X-ray flux. Synthetic warm absorber spectra are calculated, assuming pure absorption, for sample models at various inclination angles and observing times. We show that these models have mass fluxes and flow speeds which are comparable to those which have been inferred from observations of Seyfert 1 warm absorbers, and that they can produce rich absorption line spectra.

  4. An axisymmetric hydrodynamical model for the torus wind in AGN. II: X-ray excited funnel flow

    E-Print Network [OSTI]

    Dorodnitsyn, A; Proga, D

    2008-01-01T23:59:59.000Z

    We have calculated a series of models of outflows from the obscuring torus in active galactic nuclei (AGN). Our modeling assumes that the inner face of a rotationally supported torus is illuminated and heated by the intense X-rays from the inner accretion disk and black hole. As a result of such heating a strong biconical outflow is observed in our simulations. We calculate 3-dimensional hydrodynamical models, assuming axial symmetry, and including the effects of X-ray heating, ionization, and radiation pressure. We discuss the behavior of a large family of these models, their velocity fields, mass fluxes and temperature, as functions of the torus properties and X-ray flux. Synthetic warm absorber spectra are calculated, assuming pure absorption, for sample models at various inclination angles and observing times. We show that these models have mass fluxes and flow speeds which are comparable to those which have been inferred from observations of Seyfert 1 warm absorbers, and that they can produce rich absorp...

  5. Calibration of an advanced neutral particle analyzer for the Madison Symmetric Torus reversed-field pinch

    SciTech Connect (OSTI)

    Reusch, J. A.; Anderson, J. K.; Eilerman, S. [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Belykh, V.; Polosatkin, S. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk (Russian Federation); Liu, D. [University of California-Irvine, Irvine, California 92697 (United States); Fiksel, G. [University of Rochester, Rochester, New York 14623 (United States)

    2012-10-15T23:59:59.000Z

    A new E Parallel-To B neutral particle analyzer, which has recently been installed on Madison Symmetric Torus (MST) reversed-field pinch (RFP), has now been calibrated, allowing the measurement of the fast ion density and energy distribution. This diagnostic, dubbed the advanced neutral particle analyzer (ANPA), can simultaneously produce time resolved measurements of the efflux of both hydrogen and deuterium ions from the plasma over a 35 keV energy range with an energy resolution of 2-4 keV and a time resolution of 10 {mu}s. These capabilities are needed to measure both majority ion heating that occurs during magnetic reconnection events in MST and the behavior of the fast ions from the 1 MW hydrogen neutral beam injector on MST. Calibration of the ANPA was performed using a custom ion source that resides in the flight tube between the MST and the ANPA. In this work, the ANPA will be described, the calibration procedure and results will be discussed, and initial measurements of the time evolution of 25 keV neutral beam injection-born fast ions will be presented.

  6. Plasma behaviour at high beta and high density in the Madison Symmetric Torus RFP

    SciTech Connect (OSTI)

    Wyman, M. [University of Wisconsin, Madison; Chapman, B. E. [University of Wisconsin, Madison; Ahn, J. W. [University of Wisconsin, Madison; Almagri, A. F. [University of Wisconsin, Madison; Anderson, J. [University of Wisconsin, Madison; Bonomo, F. [Consorzio RFX, Italy; Bower, D L [University of California, Los Angeles; Combs, Stephen Kirk [ORNL; Craig, D. [University of Wisconsin, Madison; Foust, Charles R [ORNL

    2009-01-01T23:59:59.000Z

    Pellet fuelling of improved confinement Madison Symmetric Torus (MST) plasmas has resulted in high density and high plasma beta. The density in improved confinement discharges has been increased fourfold, and a record plasma beta (beta(tot) = 26%) for the improved confinement reversed-field pinch (RFP) has been achieved. At higher beta, a new regime for instabilities is accessed in which local interchange and global tearing instabilities are calculated to be linearly unstable, but experimentally, no severe effect, e. g., a disruption, is observed. The tearing instability, normally driven by the current gradient, is driven by the pressure gradient in this case, and there are indications of increased energy transport ( as compared with low-density improved confinement). Pellet fuelling is also compared with enhanced edge fuelling of standard confinement RFP discharges for the purpose of searching for a density limit in MST. In standard-confinement discharges, pellet fuelling peaks the density profile where edge fuelling cannot, but transport appears unchanged. For a limited range of plasma current, MST discharges with edge fuelling are constrained to a maximum density corresponding to the Greenwald limit. This limit is surpassed in pellet-fuelled improved confinement discharges.

  7. Liquid Lithium Experiments in CDX-U

    SciTech Connect (OSTI)

    R. Majeski; R. Doerner; R. Kaita; G. Antar; J. Timberlake; et al

    2000-11-15T23:59:59.000Z

    The initial results of experiments involving the use of liquid lithium as a plasma facing component in the Current Drive Experiment-Upgrade (CDX-U) are reported. Studies of the interaction of a steady-state plasma with liquid lithium in the Plasma Interaction with Surface and Components Experimental Simulator (PISCES-B) are also summarized. In CDX-U a solid or liquid lithium covered rail limiter was introduced as the primary limiting surface for spherical torus discharges. Deuterium recycling was observed to be reduced, but so far not eliminated, for glow discharge-cleaned lithium surfaces. Some lithium influx was observed during tokamak operation. The PISCES-B results indicate that the rates of plasma erosion of lithium can exceed predictions by an order of magnitude at elevated temperatures. Plans to extend the CDX-U experiments to large area liquid lithium toroidal belt limiters are also described.

  8. 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

    2013-08-27T23:59:59.000Z

    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.

  9. Radiation fields of disk, BLR and torus in quasars and blazars: implications for gamma-ray absorption

    E-Print Network [OSTI]

    A. -C. Donea; R. J. Protheroe

    2002-02-04T23:59:59.000Z

    The radiation fields external to the jets and originating from within a few parsecs from the black hole, are discussed in this paper. They are the direct radiation from an accretion disk in symbiosis with jets, the radiation field from the broad line region (BLR) surrounding the accretion disk, and the infrared radiation from a dusty torus. The jet/disk symbiosis modifies the energetics in the central parsec of AGN such that for a given accretion rate, a powerful jet would occur at the expense of the disk luminosity, and consequently the disk would less efficiently ionize the BRL clouds or heat the dust in the torus, thereby affecting potentially important target photon fields for interactions of gamma-rays, accelerated electrons and protons along the jet. Motivated by unification schemes of active galactic nuclei, we briefly review the evidence for the existence of broad line regions and small-scale dust tori in BL Lacs and Fanaroff-Riley Class I (FR-I) radio galaxies. We propose that an existing jet-accretion disk symbiosis can be extrapolated to provide a large scale-symbiosis between other important dusty constituents of the blazar/FR-I family. In the present paper, we discuss in the context of this symbiosis interactions of GeV and TeV gamma-rays produced in the jet with the various radiation fields external to the jet in quasars and blazars, taking account the anisotropy of the radiation.

  10. The spatial Lambda-Fleming-Viot process on a large torus: genealogies in the presence of recombination

    E-Print Network [OSTI]

    Etheridge, A M

    2011-01-01T23:59:59.000Z

    We extend the spatial Lambda-Fleming-Viot process introduced in [BEV10] to incorporate recombination. The process models allele frequencies in a population which is distributed over the two-dimensional torus T(L) of sidelength L and is subject to two kinds of reproduction events : small events of radius O(1) and much rarer large events of radius O(L^{alpha}) for some alpha in (0,1]. We investigate the correlation between the times to the most recent common ancestor of alleles at two linked loci for a sample of size two from the population. These individuals are initially sampled from `far apart' on the torus. As L tends to infinity, depending on the frequency of the large events, the recombination rate and the initial distance between the two individuals sampled, we obtain either a complete decorrelation of the coalescence times at the two loci, or a sharp transition between a first period of complete correlation and a subsequent period during which the remaining times needed to reach the most recent common a...

  11. Description NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    30AUG11A 30AUG11A 100 0.00 B 1038 Award Friction Stir Weld Contract 0 30AUG11A 30AUG11A 100 0.00 B FY

  12. PPPL to launch major upgrade of key fusion energy test facility...

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

    to launch major upgrade of key fusion energy test facility NSTX project will produce most powerful spherical torus in the world By John Greenwald January 9, 2012 Tweet Widget...

  13. PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76CH03073

    E-Print Network [OSTI]

    used on NSTX, with an emphasis on the computing controls, data acquisition, and synchronization systems) is about 0.5 seconds. The torus' extremely compact center stack assembly needs about ten minutes to cool of the NSTX Control System by P. Sichta, J. Dong, G. Oliaro, and P. Roney December 2001 #12;PPPL Reports

  14. Accurate evolutions of unequal-mass neutron-star binaries: properties of the torus and short GRB engines

    E-Print Network [OSTI]

    Luciano Rezzolla; Luca Baiotti; Bruno Giacomazzo; David Link; Jose A. Font

    2010-05-13T23:59:59.000Z

    We present new results from accurate and fully general-relativistic simulations of the coalescence of unmagnetized binary neutron stars with various mass ratios. The evolution of the stars is followed through the inspiral phase, the merger and prompt collapse to a black hole, up until the appearance of a thick accretion disk, which is studied as it enters and remains in a regime of quasi-steady accretion. Although a simple ideal-fluid equation of state with \\Gamma=2 is used, this work presents a systematic study within a fully general relativistic framework of the properties of the resulting black-hole--torus system produced by the merger of unequal-mass binaries. More specifically, we show that: (1) The mass of the torus increases considerably with the mass asymmetry and equal-mass binaries do not produce significant tori if they have a total baryonic mass M_tot >~ 3.7 M_sun; (2) Tori with masses M_tor ~ 0.2 M_sun are measured for binaries with M_tot ~ 3.4 M_sun and mass ratios q ~ 0.75-0.85; (3) The mass of the torus can be estimated by the simple expression M_tor(q, M_tot) = [c_1 (1-q) + c_2](M_max-M_tot), involving the maximum mass for the binaries and coefficients constrained from the simulations, and suggesting that the tori can have masses as large as M_tor ~ 0.35 M_sun for M_tot ~ 2.8 M_sun and q ~ 0.75-0.85; (4) Using a novel technique to analyze the evolution of the tori we find no evidence for the onset of non-axisymmetric instabilities and that very little, if any, of their mass is unbound; (5) Finally, for all the binaries considered we compute the complete gravitational waveforms and the recoils imparted to the black holes, discussing the prospects of detection of these sources for a number of present and future detectors.

  15. Anomalous Electron Transport Due to Multiple High Frequency Beam Ion Driven Alfven Eigenmode

    SciTech Connect (OSTI)

    N.N. Gorelenkov, D. Stutman, K. Tritz, A. Boozer, L. Delgardo-Aparicio, E. Fredrickson, S. Kaye, and R. White

    2010-07-13T23:59:59.000Z

    We report on the simulations of recently observed correlations of the core electron transport with the sub-thermal ion cyclotron frequency instabilities in low aspect ratio plasmas of the National Spherical Torus Experiment (NSTX). In order to model the electron transport of the guiding center code ORBIT is employed. A spectrum of test functions of multiple core localized Global shear Alfven Eigenmode (GAE) instabilities based on a previously developed theory and experimental observations is used to examine the electron transport properties. The simulations exhibit thermal electron transport induced by electron drift orbit stochasticity in the presence of multiple core localized GAE.

  16. Suppression of energetic particle driven instabilities with HHFW heating

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

    Fredrickson, E. D.; Taylor, G.; Bertelli, N.; Darrow, D. S.; Gorelenkov, N.; Kramer, G.; Liu, D.; Crocker, N. A.; Kubota, S.; White, R.

    2015-01-01T23:59:59.000Z

    In plasmas in the National Spherical Torus Experiment (NSTX) [Ono et al., Nucl. Fusion 40 (2000) 557] heated with neutral beams, the beam ions typically excite Energetic Particle Modes (EPMs or fishbones), and Toroidal, Global or Compressional Alfvén Eigenmodes (TAE, GAE, CAE). These modes can redistribute the energetic beam ions, altering the beam driven current profile and the plasma heating profile, or they may affect electron thermal transport or cause losses of the beam ions. In this paper we present experimental results where these instabilities, driven by the super-thermal beam ions, are suppressed with the application of High Harmonic Fastmore »Wave heating.« less

  17. Suppression of energetic particle driven instabilities with HHFW heating

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

    Fredrickson, E. D. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Taylor, G. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Bertelli, N. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Darrow, D. S. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Gorelenkov, N. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Kramer, G. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Liu, D. [University of California, Irvine, CA (United States); Crocker, N. A. [University of California, Los Angeles (United States); Kubota, S. [University of California, Los Angeles (United States); White, R. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2015-01-01T23:59:59.000Z

    In plasmas in the National Spherical Torus Experiment (NSTX) [Ono et al., Nucl. Fusion 40 (2000) 557] heated with neutral beams, the beam ions typically excite Energetic Particle Modes (EPMs or fishbones), and Toroidal, Global or Compressional Alfvén Eigenmodes (TAE, GAE, CAE). These modes can redistribute the energetic beam ions, altering the beam driven current profile and the plasma heating profile, or they may affect electron thermal transport or cause losses of the beam ions. In this paper we present experimental results where these instabilities, driven by the super-thermal beam ions, are suppressed with the application of High Harmonic Fast Wave heating.

  18. Effects of Large Area Liquid Lithium Limiters on Spherical Torus Plasmas

    SciTech Connect (OSTI)

    R. Kaita; R. Majeski; M. Boaz; P. Efthimion; G. Gettelfinger; T. Gray; D. Hoffman; S. Jardin; H. Kugel; P. Marfuta; T. Munsat; C. Neumeyer; S. Raftopoulos; V. Soukhanovskii; J. Spaleta; G. Taylor; J. Timberlake; R. Woolley; L. Zakharov; M. Finkenthal; D. Stutman; L. Delgado-Aparicio; R.P. Seraydarian; G. Antar; R. Doerner; S. Luckhardt; M. Baldwin; R.W. Conn; R. Maingi; M. Menon; R. Causey; D. Buchenauer; M. Ulrickson; B. Jones; D. Rodgers

    2004-06-07T23:59:59.000Z

    Use of a large-area liquid lithium surface as a first wall has significantly improved the plasma performance in the Current Drive Experiment-Upgrade (CDX-U) at the Princeton Plasma Physics Laboratory. Previous CDX-U experiments with a partially-covered toroidal lithium limiter tray have shown a decrease in impurities and the recycling of hydrogenic species. Improvements in loading techniques have permitted nearly full coverage of the tray surface with liquid lithium. Under these conditions, there was a large drop in the loop voltage needed to sustain the plasma current. The data are consistent with simulations that indicate more stable plasmas having broader current profiles, higher temperatures, and lowered impurities with liquid lithium walls. As further evidence for reduced recycling with a liquid lithium limiter, the gas puffing had to be increased by up to a factor of eight for the same plasma density achieved with an empty toroidal tray limiter.

  19. Overview of the ALPS Program

    SciTech Connect (OSTI)

    Brooks, J.N. [Argonne National Laboratory (United States); Allain, J.P. [Argonne National Laboratory (United States); Bastasz, R. [Sandia National Laboratories (United States); Doerner, R. [University of California San Diego (United States); Evans, T. [General Atomics (United States); Hassanein, A. [Argonne National Laboratory (United States); Kaita, R. [Princeton Plasma Physics Laboratory (United States); Luckhardt, S. [University of California San Diego (United States); Maingi, R. [Oak Ridge National Laboratory (United States); Majeski, R. [Princeton Plasma Physics Laboratory (United States); Morley, N.B. [University of California Los Angeles (United States); Narula, M. [University of California Los Angeles (United States); Rognlien, T. [Lawrence Livermore National Laboratory (United States); Ruzic, D. [University of Illinois Urbana Champaign (United States); Stubbers, R. [University of Illinois Urbana Champaign (United States); Ulrickson, M. [Sandia National Laboratories (United States); Wong, C.P.C. [General Atomics (United States); Whyte, D. [University of California San Diego (United States); Ying, A. [University of California Los Angeles (United States)

    2005-04-15T23:59:59.000Z

    The US Advanced Limiter-divertor Plasma-facing Systems (ALPS) program is developing the science of liquid metal surface divertors for near and long term tokamaks. These systems may help solve the demanding heat removal, particle removal, and erosion issues of fusion plasma/surface interactions. ALPS combines tokamak experiments, lab experiments, and modeling. We are designing both static and flowing liquid lithium divertors for the National Spherical Torus Experiment (NSTX) at Princeton. We are also studying tin, gallium, and tin-lithium systems. Results to date are extensive and generally encouraging, e.g., showing: 1) good tokamak performance with a liquid Li limiter, 2) high D pumping in Li and non-zero He/Li pumping, 3) well-characterized temperature-dependent liquid metal surface composition and sputter yield data, 4) predicted stable low-recycle improved-plasma NSTX-Li performance, 5) high temperature capability Sn or Ga potential with reduced ELM and disruption response concerns. In the MHD area, analysis predicts good NSTX static Li performance, with dynamic systems being evaluated.

  20. Geodesics on the Torus and other Surfaces of Revolution Clarified Using Undergraduate Physics Tricks with Bonus: Nonrelativistic and Relativistic Kepler Problems

    E-Print Network [OSTI]

    Jantzen, Robert T

    2012-01-01T23:59:59.000Z

    In considering the mathematical problem of describing the geodesics on a torus or any other surface of revolution, there is a tremendous advantage in conceptual understanding that derives from taking the point of view of a physicist by interpreting parametrized geodesics as the paths traced out in time by the motion of a point in the surface, identifying the parameter with the time. Considering energy levels in an effective potential for the reduced motion then proves to be an extremely useful tool in studying the behavior and properties of the geodesics. The same approach can be easily tweaked to extend to both the nonrelativistic and relativistic Kepler problems. The spectrum of closed geodesics on the torus is analogous to the quantization of energy levels in models of atoms.

  1. Geodesics on the Torus and other Surfaces of Revolution Clarified Using Undergraduate Physics Tricks with Bonus: Nonrelativistic and Relativistic Kepler Problems

    E-Print Network [OSTI]

    Robert T. Jantzen

    2012-12-26T23:59:59.000Z

    In considering the mathematical problem of describing the geodesics on a torus or any other surface of revolution, there is a tremendous advantage in conceptual understanding that derives from taking the point of view of a physicist by interpreting parametrized geodesics as the paths traced out in time by the motion of a point in the surface, identifying the parameter with the time. Considering energy levels in an effective potential for the reduced motion then proves to be an extremely useful tool in studying the behavior and properties of the geodesics. The same approach can be easily tweaked to extend to both the nonrelativistic and relativistic Kepler problems. The spectrum of closed geodesics on the torus is analogous to the quantization of energy levels in models of atoms.

  2. SciDAC Center for Simulation of Wave-Plasma Interactions - Iterated Finite-Orbit Monte Carlo Simulations with Full-Wave Fields for Modeling Tokamak ICRF Wave Heating Experiments - Final Report

    SciTech Connect (OSTI)

    Choi, Myunghee [Retired] [Retired; Chan, Vincent S. [General Atomics] [General Atomics

    2014-02-28T23:59:59.000Z

    This final report describes the work performed under U.S. Department of Energy Cooperative Agreement DE-FC02-08ER54954 for the period April 1, 2011 through March 31, 2013. The goal of this project was to perform iterated finite-orbit Monte Carlo simulations with full-wall fields for modeling tokamak ICRF wave heating experiments. In year 1, the finite-orbit Monte-Carlo code ORBIT-RF and its iteration algorithms with the full-wave code AORSA were improved to enable systematical study of the factors responsible for the discrepancy in the simulated and the measured fast-ion FIDA signals in the DIII-D and NSTX ICRF fast-wave (FW) experiments. In year 2, ORBIT-RF was coupled to the TORIC full-wave code for a comparative study of ORBIT-RF/TORIC and ORBIT-RF/AORSA results in FW experiments.

  3. Results from deuterium-tritium tokamak confinement experiments

    SciTech Connect (OSTI)

    Hawryluk, R.J.

    1997-02-01T23:59:59.000Z

    Recent scientific and technical progress in magnetic fusion experiments has resulted in the achievement of plasma parameters (density and temperature) which enabled the production of significant bursts of fusion power from deuterium-tritium fuels and the first studies of the physics of burning plasmas. The key scientific issues in the reacting plasma core are plasma confinement, magnetohydrodynamic (MHD) stability, and the confinement and loss of energetic fusion products from the reacting fuel ions. Progress in the development of regimes of operation which have both good confinement and are MHD stable have enabled a broad study of burning plasma physics issues. A review of the technical and scientific results from the deuterium-tritium experiments on the Joint European Torus (JET) and the Tokamak Fusion Test Reactor (TFTR) is given with particular emphasis on alpha-particle physics issues.

  4. Liquid Lithium Wall Experiments in CDX-U

    SciTech Connect (OSTI)

    R. Doerner; R. Kaita; R. Majeski; S. Luckhardt; et al

    1999-10-01T23:59:59.000Z

    The concept of a flowing lithium first wall for a fusion reactor may lead to a significant advance in reactor design, since it could virtually eliminate the concerns with power density and erosion, tritium retention, and cooling associated with solid walls. Sputtering and erosion tests are currently underway in the PISCES device at the University of California at San Diego (UCSD). To complement this effort, plasma interaction questions in a toroidal plasma geometry will be addressed by a proposed new groundbreaking experiment in the Current Drive eXperiment-Upgrade (CDX-U) spherical torus (ST). The CDX-U plasma is intensely heated and well diagnosed, and an extensive liquid lithium plasma-facing surface will be used for the first time with a toroidal plasma. Since CDX-U is a small ST, only approximately1 liter or less of lithium is required to produce a toroidal liquid lithium limiter target, leading to a quick and cost-effective experiment.

  5. IRRADIATION EXPERIMENTS &

    E-Print Network [OSTI]

    McDonald, Kirk

    IRRADIATION EXPERIMENTS & FACILITIES AT BNL: BLIP & NSLS II Peter Wanderer Superconducting Magnet). Current user: LBNE ­ materials for Project X. · Long Baseline Neutrino Experiment ­ Abandoned gold mine

  6. Influence of plasma diagnostics and constraints on the quality of equilibrium reconstructions on Joint European Torus

    SciTech Connect (OSTI)

    Gelfusa, M.; Gaudio, P.; Peluso, E. [Associazione EURATOM-ENEA, University of Rome “Tor Vergata”, Roma (Italy)] [Associazione EURATOM-ENEA, University of Rome “Tor Vergata”, Roma (Italy); Murari, A.; Baruzzo, M. [Consorzio RFX-Associazione EURATOM ENEA per la Fusione, I-35127 Padova (Italy)] [Consorzio RFX-Associazione EURATOM ENEA per la Fusione, I-35127 Padova (Italy); Lupelli, I.; Hawkes, N.; Brix, M.; Drozdov, V.; Meigs, A.; Romanelli, M. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)] [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Craciunescu, T. [EURATOM-MEdC Association, NILPRP, Bucharest (Romania)] [EURATOM-MEdC Association, NILPRP, Bucharest (Romania); Schmuck, S.; Sieglin, B. [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, EURATOM Association, Wendelsteinstr.1, 17491 Greifswald (Germany)] [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, EURATOM Association, Wendelsteinstr.1, 17491 Greifswald (Germany); Collaboration: JET-EFDA Contributors

    2013-10-15T23:59:59.000Z

    One of the main approaches to thermonuclear fusion relies on confining high temperature plasmas with properly shaped magnetic fields. The determination of the magnetic topology is, therefore, essential for controlling the experiments and for achieving the required performance. In Tokamaks, the reconstruction of the fields is typically formulated as a free boundary equilibrium problem, described by the Grad-Shafranov equation in toroidal geometry and axisymmetric configurations. Unfortunately, this results in mathematically very ill posed problems and, therefore, the quality of the equilibrium reconstructions depends sensitively on the measurements used as inputs and on the imposed constraints. In this paper, it is shown how the different diagnostics (Magnetics Measurements, Polarimetry and Motional Stark Effect), together with the edge current density and plasma pressure constraints, can have a significant impact on the quality of the equilibrium on JET. Results show that both the Polarimetry and Motional Stark Effect internal diagnostics are crucial in order to obtain reasonable safety factor profiles. The impact of the edge current density constraint is significant when the plasma is in the H-mode of confinement. In this plasma scenario the strike point positions and the plasma last closed flux surface can change even by centimetres, depending on the edge constraints, with a significant impact on the remapping of the equilibrium-dependent diagnostics and of pedestal physics studies. On the other hand and quite counter intuitively, the pressure constraint can severely affect the quality of the magnetic reconstructions in the core. These trends have been verified with several JET discharges and consistent results have been found. An interpretation of these results, as interplay between degrees of freedom and available measurements, is provided. The systematic analysis described in the paper emphasizes the importance of having sufficient diagnostic inputs and of properly validating the results of the codes with independent measurements.

  7. Edge-Localized-Mode Suppression through Density-Profile Modification with Lithium-Wall Coatings in the National Spherical Torus Experiment

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    a pulsed power load that would limit the lifetime of plasma-facing components (PFCs) unless the energyEdge-Localized-Mode Suppression through Density-Profile Modification with Lithium-Wall Coatings to low-n peeling or ballooning modes, while broader pressure profiles stabilized the post-Li discharges

  8. Advances in neutral-beam-based diagnostics on the Madison Symmetric Torus reversed-field pinch (invited)

    SciTech Connect (OSTI)

    Den Hartog, D. J.; Craig, D.; Ennis, D. A.; Fiksel, G.; Gangadhara, S.; Holly, D. J.; Reardon, J. C.; Davydenko, V. I.; Ivanov, A. A.; Lizunov, A. A.; O'Mullane, M. G.; Summers, H. P. [Department of Physics, and Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation); University of Strathclyde, Glasgow, G1 1XQ Scotland (United Kingdom)

    2006-10-15T23:59:59.000Z

    Innovative charge-exchange recombination spectroscopy (CHERS), motional Stark effect (MSE), and Rutherford scattering diagnostics are now in operation on the Madison Symmetric Torus (MST) reversed-field pinch (RFP). The CHERS diagnostic measures impurity ion flow and temperature, localized to 2 cm with high time resolution ({approx}100 kHz). A spectral MSE diagnostic has been in use for five years, measuring |B| down to 0.2 T with high precision ({approx}2%) and good time resolution (10 kHz). The Rutherford scattering diagnostic has demonstrated the robustness of this technique for reliable measurement of majority (D) ion temperature, also with high time resolution. MST is a large RFP (R=1.5 m, a=0.52 m) operated at moderate current (I{sub p}{<=}600 kA), with n{sub e} typically (1-2)x10{sup 19} m{sup -3} and T{sub e}, T{sub i}{<=}2 keV. Two compact and reliable diagnostic neutral beams are installed on MST. These beams are short pulse, intense, monoenergetic, and low divergence. The first, a neutral H beam, is used in combination with ultraviolet and visible spectroscopy to make the CHERS and MSE measurements. For CHERS, the C VI line at 343.4 nm is collected by a custom high-throughput double grating spectrometer which simultaneously records both charge-exchange and background emissions. The spectrum is analyzed using a sophisticated model derived from the Atomic Database and Analysis Structure (ADAS) package. The MSE system records the entire H{alpha} Stark spectrum; |B| is derived from the measured splitting of the {pi}{sup +} and {pi}{sup -} manifolds. Measurement of |B| is critical to accurate equilibrium reconstruction in the RFP. The second diagnostic beam is a 20 keV neutral He beam and is used for the Rutherford scattering measurements. A pair of neutral particle analyzers is used to record the energy spectrum of the small-angle Rutherford scattered He atoms.

  9. TORUS: Theory of Reactions for Unstable iSotopes Annual Continuation and Progress Report Year-2: March 1, 2011 - February 29, 2012

    SciTech Connect (OSTI)

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

    2012-02-24T23:59:59.000Z

    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 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.

  10. Divertor options for NSTX and NSTX-Upgrade Rajesh Maingi,

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Program Advisory Committee Meeting Princeton, NJ Feb. 3-5, 2010 College W&M Colorado Sch Mines Columbia U power exhaust sharing may be required ­ Gas puffing for radiative/detached divertor would be used techniques ­ High flux expansion divertors ­ Gas puffing for extra radiation and partial detachment

  11. NSTX Program Overview andNSTX Program Overview and NSTX Upgrade Physics Design ProgressNSTX Upgrade Physics Design Progress

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    -B318, PPPL NSTXNSTX Supported by College W&M Colorado Sch Mines Columbia U CompX General Atomics INL in Upgrade 6. Develop normally-conducting radiation-tolerant magnets for ST applications · Desig

  12. NSTX Organization 2008 Heating Systems

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Erik Perry Central I&C Paul Sichta Power Systems John Lacenere Auxiliary Systems Bill Blanchard PPPL # University of Washington ## LLNL Topical Science Groups Theory Support J. Manickam Integrated Modeling Engineer Charles Neumeyer Physics Analysis and Simulation Stan Kaye Advanced Scenarios and Control David

  13. FACT SHEET NSTX-U

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField8,Dist. Category UC-l 1,EnergyExploringGamma-ray2

  14. Chaos in plasma simulation and experiment

    SciTech Connect (OSTI)

    Watts, C. [Texas Univ., Austin, TX (United States). Fusion Research Center; Newman, D.E. [Oak Ridge National Lab., TN (United States); Sprott, J.C. [Wisconsin Univ., Madison, WI (United States). Plasma Physics Research

    1993-09-01T23:59:59.000Z

    We investigate the possibility that chaos and simple determinism are governing the dynamics of reversed field pinch (RFP) plasmas using data from both numerical simulations and experiment. A large repertoire of nonlinear analysis techniques is used to identify low dimensional chaos. These tools include phase portraits and Poincard sections, correlation dimension, the spectrum of Lyapunov exponents and short term predictability. In addition, nonlinear noise reduction techniques are applied to the experimental data in an attempt to extract any underlying deterministic dynamics. Two model systems are used to simulate the plasma dynamics. These are -the DEBS code, which models global RFP dynamics, and the dissipative trapped electron mode (DTEM) model, which models drift wave turbulence. Data from both simulations show strong indications of low,dimensional chaos and simple determinism. Experimental data were obtained from the Madison Symmetric Torus RFP and consist of a wide array of both global and local diagnostic signals. None of the signals shows any indication of low dimensional chaos or other simple determinism. Moreover, most of the analysis tools indicate the experimental system is very high dimensional with properties similar to noise. Nonlinear noise reduction is unsuccessful at extracting an underlying deterministic system.

  15. Probes for measuring fluctuation-induced Maxwell and Reynolds stresses in the edge of the Madison Symmetric Torus reversed field pinch

    SciTech Connect (OSTI)

    Kuritsyn, A.; Fiksel, G.; Miller, M. C.; Almagri, A. F.; Reyfman, M.; Sarff, J. S. [Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas and Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2008-10-15T23:59:59.000Z

    Several probes have been constructed to measure fluctuation-induced Maxwell and Reynolds stresses in the edge of the Madison Symmetric Torus reversed field pinch (RFP). The magnetic probe is composed of six magnetic pickup coil triplets. The triplets are separated spatially, which allows for local measurements of the Maxwell stress. To measure the plasma flow components for evaluation of the Reynolds stress, we employ a combination of an optical probe [Kuritsyn et al., Rev. Sci. Indrum. 77, 10F112 (2006)] and a Mach probe. The optical probe measures the radial ion flow locally using Doppler spectroscopy. The Mach probe consists of four current collectors biased negatively with respect to a reference tip and allows for measurements of the poloidal and toroidal components of the bulk plasma flow. The stresses are observed to play an important role in the momentum balance in the RFP edge during internal reconnection events.

  16. experiment, collaboration

    E-Print Network [OSTI]

    -Departamento Energias Renovables, Plataforma Solar de Almeria, E-04080 Almeria, Spain Departamento de Lenguajes y ca. factor 10 less complex then imaging solar Cerenkov exp.:smaller cost, fewer systematic errors #12; 5 Rainer Plaga The GRAAL experiment, ECRS Lodz July 2000 Location of GRAAL " Plataforma Solar de

  17. Liquid Lithium Limiter Experiments in CDX-U

    SciTech Connect (OSTI)

    R. Majeski; S. Jardin; R. Kaita; T. Gray; P. Marfuta; J. Spaleta; J. Timberlake; L. Zakharov; G. Antar; R. Doerner; S. Luckhardt; R. Seraydarian; V. Soukhanovskii; R. Maingi; M. Finkenthal; D. Stutman; D. Rodgers

    2004-10-28T23:59:59.000Z

    Recent experiments in the Current Drive Experiment-Upgrade provide a first-ever test of large area liquid lithium surfaces as a tokamak first wall, to gain engineering experience with a liquid metal first wall, and to investigate whether very low recycling plasma regimes can be accessed with lithium walls. The CDX-U is a compact (R = 34 cm, a = 22 cm, B{sub toroidal} = 2 kG, I{sub P} = 100 kA, T{sub e}(0) = 100 eV, n{sub e}(0) {approx} 5 x 10{sup 19} m{sup -3}) spherical torus at the Princeton Plasma Physics Laboratory. A toroidal liquid lithium tray limiter with an area of 2000 cm{sup 2} (half the total plasma limiting surface) has been installed in CDX-U. Tokamak discharges which used the liquid lithium limiter required a fourfold lower loop voltage to sustain the plasma current, and a factor of 5-8 increase in gas fueling to achieve a comparable density, indicating that recycling is strongly reduced. Modeling of the discharges demonstrated that the lithium-limited discharges are consistent with Z{sub effective} < 1.2 (compared to 2.4 for the pre-lithium discharges), a broadened current channel, and a 25% increase in the core electron temperature. Spectroscopic measurements indicate that edge oxygen and carbon radiation are strongly reduced.

  18. First X-ray-Based Statistical Tests for Clumpy-Torus Models: Eclipse Events from 230 Years of Monitoring of Seyfert AGN

    E-Print Network [OSTI]

    Markowitz, Alex; Nikutta, Robert

    2014-01-01T23:59:59.000Z

    We present an analysis of multi-timescale variability in line-of-sight X-ray absorbing gas as a function of optical classification in a large sample of Seyfert AGN to derive the first X-ray statistical constraints for clumpy-torus models. We systematically search for discrete absorption events in the vast archive of RXTE monitoring of dozens of nearby type I and Compton-thin type II AGN. We are sensitive to discrete absorption events due to clouds of full-covering, neutral or mildly ionized gas with columns <~ 10^(22-25) cm^-2 transiting the line of sight. We detect 12 eclipse events in 8 objects, roughly tripling the number previously published from this archive. Peak column densities span ~ 4-26 x 10^22 cm^-2. Event durations span hours to months. The column density profile for an eclipsing cloud in NGC 3783 is doubly spiked, possibly indicating a cloud that is being tidally sheared. We infer the clouds' distances from the black hole to span ~0.3 -140 x 10^4 R_g. In seven objects, the clouds' distances a...

  19. IOP PUBLISHING and INTERNATIONAL ATOMIC ENERGY AGENCY NUCLEAR FUSION Nucl. Fusion 47 (2007) 14491457 doi:10.1088/0029-5515/47/11/006

    E-Print Network [OSTI]

    Callen, James D.

    -D; and electron heat diffusivities in non-tokamak experiments (NSTX/ST, MST/RFP, SSPX/spheromak). The radial

  20. On The Anomalous Fast Ion Energy Diffusion in Toroidal Plasmas Due to Cavity Modes

    SciTech Connect (OSTI)

    N.N. Gorelenkov, N.J. Fisch and E. Fredrickson

    2010-03-09T23:59:59.000Z

    An enormous wave-particle diffusion coefficient along paths suitable for alpha channeling had been deduced in mode converted ion Bernstein wave experiments on Tokamak Fusion Test Reactor (TFTR) the only plausible explanation advanced for such a large diffusion coefficient was the excitation of internal cavity modes which induce particle diffusion along identical diffusion paths, but at much higher rates. Although such a mode was conjectured, it was never observed. However, recent detailed observations of high frequency compressional Alfven eigenmodes (CAEs) on the National Spherical torus Experiment (NSTX) indirectly support the existence of the related conjectured modes on TFTR. The eigenmodes responsible for the high frequency magnetic activity can be identified as CAEs through the polarization of the observed magnetic field oscillations in NSTX and through a comparison with the theoretically derived freuency dispersion relation. Here, we show how these recent observations of high frequency CAEs lend support to this explanation of the long-standing puzzle of anomalous fast ion energy diffusion on TFTR. The support of the conjecure that these internal modes could have caused the remarkable ion energy diffusion on TFTR carries significant and favorable implications for the possibilities in achieving the alpha channeling effect with small injected power in a tokamak reactor.

  1. Recent Liquid Lithium Limiter Experiments in CDX-U

    SciTech Connect (OSTI)

    R. Majeski; S. Jardin; R. Kaita; T. Gray; P. Marfuta; J. Spaleta; J. Timberlake; L. Zakharov; G. Antar; R. Doerner; S. Luckhardt; R. Seraydarian; V. Soukhanovskii; R. Maingi; M. Finkenthal; D. Stutman; D. Rodgers; S. Angelini

    2005-05-03T23:59:59.000Z

    Recent experiments in the Current Drive eXperiment-Upgrade (CDX-U) provide a first-ever test of large area liquid lithium surfaces as a tokamak first wall, to gain engineering experience with a liquid metal first wall, and to investigate whether very low recycling plasma regimes can be accessed with lithium walls. The CDX-U is a compact (R=34 cm, a=22 cm, B{sub toroidal} = 2 kG, I{sub P} =100 kA, T{sub e}(0) {approx} 100 eV, n{sub e}(0) {approx} 5 x 10{sup 19} m{sup -3}) spherical torus at the Princeton Plasma Physics Laboratory. A toroidal liquid lithium pool limiter with an area of 2000 cm{sup 2} (half the total plasma limiting surface) has been installed in CDX-U. Tokamak discharges which used the liquid lithium pool limiter required a fourfold lower loop voltage to sustain the plasma current, and a factor of 5-8 increase in gas fueling to achieve a comparable density, indicating that recycling is strongly reduced. Modeling of the discharges demonstrated that the lithium limited discharges are consistent with Z{sub effective} < 1.2 (compared to 2.4 for the pre-lithium discharges), a broadened current channel, and a 25% increase in the core electron temperature. Spectroscopic measurements indicate that edge oxygen and carbon radiation are strongly reduced.

  2. Destabilization of Fast Magnetoacoustic Waves by Circulating Energetic Ions in Toroidal Plasmas

    SciTech Connect (OSTI)

    V.S. Belikov; Ya. I. Kolesnichenko; R. B. White

    2003-08-21T23:59:59.000Z

    An instability of fast magnetoacoustic waves (FMW) driven by circulating energetic ions in axisymmetric toroidal plasmas and characterized by the frequencies below the ion gyrofrequency is considered. An important role of the l=0 resonance (l is the number of a cyclotron harmonic) in the wave-particle interaction is revealed: It is shown that this resonance considerably extends an unstable region in the space of the pitch-angles of the energetic ions and the wave frequencies. The analysis is carried out for a ''slow'' instability, which has the growth rate less than the bounce frequency of the energetic ions. Specific examples relevant to the National Spherical Torus Experiment (NSTX) [J. Spitzer et al., Fusion Technol. 30 (1996) 1337], where instabilities of this kind were observed, are considered.

  3. Diabetes Experience Spring 2014 Interprofessional Diabetes Experience

    E-Print Network [OSTI]

    Thomas, David D.

    Diabetes Experience Spring 2014 Interprofessional Diabetes Experience Phar 6226/Nurs 5011 Spring the opportunity to learn in-depth knowledge of diabetes mellitus through active, hands-on learning experience of living with diabetes, in which they will give "insulin" injections and check blood glucoses

  4. Diagnostics for liquid lithium experiments in CDX-U

    SciTech Connect (OSTI)

    R. Kaita; P. Efthimion; D. Hoffman; B. Jones; H. Kugel; R. Majeski; T. Munsat; S. Raftopoulos; G. Taylor; J. Timberlake; V. Soukhanovskii; D. Stutman; M. Iovea; M. Finkenthal; R. Doerner; S. Luckhardt; R. Maingi; R. Causey

    2000-06-21T23:59:59.000Z

    A flowing liquid lithium first wall or diverter target could virtually eliminate the concerns with power density and erosion, tritium retention, and cooling associated with solid walls in fusion reactors. To investigate the interaction of a spherical torus plasma with liquid lithium limiters, large area diverter targets, and walls, discharges will be established in the Current Drive Experiment-Upgrade (CDX-U) where the plasma-wall interactions are dominated by liquid lithium surfaces. Among the unique CDX-U lithium diagnostics is a multi-layer mirror (MLM) array, which will monitor the 135 {angstrom} LiIII line for core lithium concentrations. Additional spectroscopic diagnostics include a grazing incidence XUV spectrometer (STRS) and a filterscope system to monitor D{sub {alpha}} and various impurity lines local to the lithium limiter. Profile data will be obtained with a multichannel tangential bolometer and a multipoint Thomson scattering system configured to give enhanced edge resolution. Coupons on th e inner wall of the CDX-U vacuum vessel will be used for surface analysis. A 10,000 frame per second fast visible camera and an IR camera will also be available.

  5. Diagnostics for liquid lithium experiments in CDX-U

    SciTech Connect (OSTI)

    Kaita, R.; Efthimion, P.; Hoffman, D.; Jones, B.; Kugel, H.; Majeski, R.; Munsat, T.; Raftopoulos, S.; Taylor, G.; Timberlake, J. (and others) [and others

    2001-01-01T23:59:59.000Z

    A flowing liquid lithium first wall or divertor target could virtually eliminate the concerns with power density and erosion, tritium retention, and cooling associated with solid walls in fusion reactors. To investigate the interaction of a spherical torus plasma with liquid lithium limiters, large area divertor targets, and walls, discharges will be established in the Current Drive Experiment-Upgrade (CDX-U) where the plasma--wall interactions are dominated by liquid lithium surfaces. Among the unique CDX-U lithium diagnostics is a multilayer mirror (MLM) array, which will monitor the 13.5 nm LiIII line for core lithium concentrations. Additional spectroscopic diagnostics include a grazing incidence extreme ultraviolet (XUV) spectrometer (STRS) and a filterscope system to monitor D{sub {alpha}} and various impurity lines local to the lithium limiter. Profile data will be obtained with a multichannel tangential bolometer and a multipoint Thomson scattering system configured to give enhanced edge resolution. Coupons on the inner wall of the CDX-U vacuum vessel will be used for surface analysis. A 10000 frame per second fast visible camera and an IR camera will also be available.

  6. NATIONAL SPHERICAL TORUS CENTER STACK

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    .................................. 2.4 Shear/Compression Tests ................................ INSULATION ELECTRICAL TESTS Conductor ............ 24 7.6 Winding Tension vs. Insulation Compression ......... 26 8.0 CONCLUSIONS SHEAR TESTS . . . 111 #12;INDEX OF TABLES 2-l 2-2 2-3 2-4 2-5 2-6 2-7 3-8 3-9 4-10 4-11 5-12 5-13 5-14 5

  7. Double beta decay experiments

    E-Print Network [OSTI]

    A. S. Barabash

    2006-02-22T23:59:59.000Z

    The present status of double beta decay experiments are reviewed. The results of the most sensitive experiments, NEMO-3 and CUORICINO, are discussed. Proposals for future double beta decay experiments are considered. In these experiments sensitivity for the effective neutrino mass will be on the level of (0.1-0.01) eV.

  8. PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76CH03073

    E-Print Network [OSTI]

    Fast Wave Heating Experiments on NSTX by J.R. Wilson, R. Bell, M. Bitter, P. Bonoli, M. Carter, D in Calendar Year 2000. The home page for PPPL Reports and Publications is: http://www.pppl.gov/pub_report/ DOE: http://www.ntis.gov/ordering.htm #12;High Harmonic Fast Wave Heating Experiments on NSTX J. R. Wilson 1

  9. PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76CH03073

    E-Print Network [OSTI]

    Harmonic Fast Wave Heating Experiments on NSTX by J.C. Hosea, R.E. Bell, M. Bitter, P. Bonoli, M. Carter, D in Calendar Year 2001. The home page for PPPL Reports and Publications is: http://www.pppl.gov/pub_report/ DOE: http://www.ntis.gov/ordering.htm #12;Results of High Harmonic Fast Wave Heating Experiments on NSTX* J

  10. PREPARED FORTHE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DEAC0276CH03073

    E-Print Network [OSTI]

    Fast Wave Heating Experiments NSTX Wilson, Bell, Bitter, Bonoli, Carter, Gates, J.C. Hosea, Le. The home PPPL Reports and Publications http://www.pppl.gov/pub_report/ DOE DOE Contractors obtain copies; High Harmonic Fast Wave Heating Experiments NSTX Wilson Bell Bitter Bonoli Carter Gates Hosea Le

  11. PREPARED FORTHE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DEAC0276CH03073

    E-Print Network [OSTI]

    Harmonic Fast Wave Heating Experiments NSTX J.C. Hosea, R.E. Bell, Bitter, Bonoli, Carter, Gates, B.P. Le Year 2001. The home PPPL Reports and Publications http://www.pppl.gov/pub_report/ DOE DOE Contractors://www.ntis.gov/ordering.htm #12; Results of High Harmonic Fast Wave Heating Experiments NSTX Hosea, 1 Bitter, 1 Bonoli, 2 Carter

  12. Portable controls experiments

    E-Print Network [OSTI]

    Larson, Richard Winston

    2012-01-01T23:59:59.000Z

    Experiments for controls classes like MIT's 2.004 require large lab setups and expensive equipment such as oscilloscopes and function generators. We developed a series of controls experiments based on National Instruments' ...

  13. Energetic Particle Physics In Fusion Research In Preparation For Burning Plasma Experiments

    SciTech Connect (OSTI)

    Gorelenkov, Nikolai N [PPPL

    2013-06-01T23:59:59.000Z

    The area of energetic particle (EP) physics of fusion research has been actively and extensively researched in recent decades. The progress achieved in advancing and understanding EP physics has been substantial since the last comprehensive review on this topic by W.W. Heidbrink and G.J. Sadler [1]. That review coincided with the start of deuterium-tritium (DT) experiments on Tokamak Fusion Test reactor (TFTR) and full scale fusion alphas physics studies. Fusion research in recent years has been influenced by EP physics in many ways including the limitations imposed by the "sea" of Alfven eigenmodes (AE) in particular by the toroidicityinduced AEs (TAE) modes and reversed shear Alfven (RSAE). In present paper we attempt a broad review of EP physics progress in tokamaks and spherical tori since the first DT experiments on TFTR and JET (Joint European Torus) including helical/stellarator devices. Introductory discussions on basic ingredients of EP physics, i.e. particle orbits in STs, fundamental diagnostic techniques of EPs and instabilities, wave particle resonances and others are given to help understanding the advanced topics of EP physics. At the end we cover important and interesting physics issues toward the burning plasma experiments such as ITER (International Thermonuclear Experimental Reactor).

  14. Double beta decay experiments

    E-Print Network [OSTI]

    A. S. Barabash

    2011-07-28T23:59:59.000Z

    The present status of double beta decay experiments is reviewed. The results of the most sensitive experiments are discussed. Proposals for future double beta decay experiments with a sensitivity to the $$ at the level of (0.01--0.1) eV are considered.

  15. Experiments: Preparation and Measurement

    E-Print Network [OSTI]

    Neumaier, Arnold

    the experimental set­up und the results of performing the experiment. Again, this is part of human cultureExperiments: Preparation and Measurement by Arnold Neumaier, Vienna March 1996 Abstract Introduction Experiments, properly arranged, provide information about a physical system by suitable

  16. Princeton Plasma Physics Laboratory Annual Site Environmental Report for Calendar Year 2000

    SciTech Connect (OSTI)

    Virginia L. Finley

    2002-04-22T23:59:59.000Z

    The results of the 2000 environmental surveillance and monitoring program for the Princeton Plasma Physics Laboratory (PPPL) are presented and discussed. The purpose of this report is to provide the U.S. Department of Energy and the public with information on the level of radioactive and nonradioactive pollutants (if any) that are added to the environment as a result of PPPL's operations. The report also summarizes environmental initiatives, assessments, and programs that were undertaken in 2000. The Princeton Plasma Physics Laboratory has engaged in fusion energy research since 1951. The long-range goal of the U.S. Magnetic Fusion Energy Research Program is to create innovations to make fusion power a practical reality -- an alternative energy source. The year 2000 marked the second year of National Spherical Torus Experiment (NSTX) operations and Tokamak Fusion Test Reactor (TFTR) dismantlement and deconstruction activities. A collaboration among fourteen national laboratories, universities, and research institutions, the NSTX is a major element in the U.S. Fusion Energy Sciences Program. It has been designed to test the physics principles of spherical torus (ST) plasmas. The ST concept could play an important role in the development of smaller, more economical fusion power plants. With its completion within budget and ahead of its target schedule, NSTX first plasma occurred on February 12, 1999. In 2000, PPPL's radiological environmental monitoring program measured tritium in the air at on-site and off-site sampling stations. PPPL is capable of detecting small changes in the ambient levels of tritium by using highly sensitive monitors. The operation of an in-stack monitor located on D-site is a requirement of the National Emission Standard for Hazardous Air Pollutants (NESHAPs) regulations with limits set by the Environmental Protection Agency (EPA). Also included in PPPL's radiological environmental monitoring program, are precipitation, surface, ground, a nd waste water monitoring. Groundwater investigations continued under a voluntary agreement with the New Jersey Department of Environmental Protection. PPPL monitored for the presence of nonradiological contaminants, mainly volatile organic compounds (components of degreasing solvents). Monitoring revealed the presence of low levels of volatile organic compounds in an area adjacent to PPPL. Also, PPPL's radiological monitoring program characterized the ambient, background levels of tritium in the environment and from the D-site stack; the data are presented in this report.

  17. Princeton Plasma Physics Laboratory Annual Site Environmental Report for Calendar Year 1999

    SciTech Connect (OSTI)

    Virginia Finley

    2001-04-20T23:59:59.000Z

    The results of the 1999 environmental surveillance and monitoring program for the Princeton Plasma Physics Laboratory (PPPL) are presented and discussed. The purpose of this report is to provide the U.S. Department of Energy and the public with information on the level of radioactive and non-radioactive pollutants (if any) that are added to the environment as a result of PPPL's operations. The report also summarizes environmental initiatives, assessments, and programs that were undertaken in 1999. The Princeton Plasma Physics Laboratory has engaged in fusion energy research since 1951. The long-range goal of the U.S. Magnetic Fusion Energy Research Program is to create innovations to make fusion power a practical reality--an alternative energy source. 1999 marked the first year of National Spherical Torus Experiment (NSTX) operations and Tokamak Fusion Test Reactor (TFTR) dismantlement and deconstruction activities. A collaboration among fourteen national laboratories, universities, and research institutions, the NSTX is a major element in the U.S. Fusion Energy Sciences Program. It has been designed to test the physics principles of spherical torus (ST) plasmas. The ST concept could play an important role in the development of smaller, more economical fusion reactors. With its completion within budget and ahead of its target schedule, NSTX first plasma occurred on February 12, 1999. The 1999 performance of the Princeton Plasma Physics Laboratory was rated ''outstanding'' by the U.S. Department of Energy in the Laboratory Appraisal report issued early in 2000. The report cited the Laboratory's consistently excellent scientific and technological achievements, its successful management practices, and included high marks in a host of other areas including environmental management, employee health and safety, human resources administration, science education, and communications. Groundwater investigations continued under a voluntary agreement with the New Jersey Department of Environmental Protection. PPPL monitored for the presence of non-radiological contaminants, mainly volatile organic compounds (components of degreasing solvents). Monitoring revealed the presence of low levels of volatile organic compounds in an area adjacent to PPPL. Also, PPPL's radiological monitoring program characterized the ambient, background levels of tritium in the environment and from the TFTR stack; the data are presented in this report.

  18. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    to 2.0 (e.g. reload 130652), SPA waveform from series 3 (1) Lower frequency of n=3 pulses if necessary of magnetically triggered ELMs in lithium conditioned discharges OP-XP-926 Revision: 0 Effective Date: 7: Characterization of magnetically triggered ELMs in lithium conditioned discharges DATE: 7/16/09 1. Overview

  19. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    × 2.0 ii) Reproduce 0.8MA (112546), 0.9 (112570), 1.0 (112581) and 1.2 MA (112596) iii) Document q will then be adjusted to try to reduce tearing and ELM activity in the discharge. Scans of TF and/or plasma current suffer from increased tearing activity in the flat-top and larger ELMs than obtained previously in lower

  20. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    at the target and wall. The observed ~ cm scale decay lengths at the midplane are the result of the competition strongly with Ip, with the width narrowing rapidly, indicating a reduction in cross-field transport

  1. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Division: Experimental Research Operations Chit Review Board (designated by Run Coordinator) MINOR others, that affects the divertor detachment threshold. Deuterium will be injected from the outer wall divertor is cold (Te

  2. P a g e | 1 NSTX Upgrade

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    24 MPa in the inner leg corners near the friction stir welded flags. Pending acceptable results from the friction stir welded flags. The global model load files are base

  3. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    (Days) Total Float Budgeted Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost: Period of Performance: $353 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work Description: Attachments: ECP# Implement Date Prior Budget New Budget Name Control Account Manager Kozub

  4. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    (Days) Total Float Budgeted Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost Float Budgeted Cost n n % PPCTe B Earned value cost (BCWP) m Bg o %CPlanned value cost (BCWS) FY: Period of Performance: $5,812 Control Account Manager: Revision #: Revision Date: July-11 Authorized Work

  5. Michael Bell for the NSTX Research Team

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    NSTXNSTX Supported by College W&M Colorado Sch Mines Columbia U CompX General Atomics INL Johns Hopkins U accumulation increases radiated power and Zeff H. Kugel, B. LeBlanc, R.E. Bell #12;M.G. Bell / PPPL Theory Dept

  6. Overview of the Initial NSTX Experimental Results

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    , Japan O. Mitarai, Kyushu Tokai Univ., Kumamoto, Japan M. Nagata, Himeji Inst. Technology, Okayama, Japan. Takase, ,H. Hayashiya, S. Shiraiwa, Univ. Tokyo, Tokyo, Japan N. Nishino, Hiroshima Univ., Hiroshima-sustaining by pressure driven current. Combination of highCombination of high TT, high, high , and high q(a) leads

  7. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    is to apply small oscillations in the plasma vertical position, in order to trigger ELMs. The vertical oscillations will be generated in one of two ways i) by requesting rapid variations in the plasma vertical position, or ii) explicitly adding a "kick" voltage to the PF-3 coil, and then allowing the vertical

  8. Martin Peng*, Charles Neumeyer NSTX National Team

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    30 Injector Voltage Toroidal Current Injector current SN 106488 kAkVmWbkAkA n = 1 oscillations n=1 oscillations related to reconnection mechanisms (U Wash, PPPL) (JHU) #12;Plasmas with Beam Heating Can Surpass · Moderate plasma current · High p ~ 1 · H-mode with Edge-Localized Modes · Induction voltage reduced to

  9. NSTX Upgrade Project Project Execution Plan

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Diagnostics 1.5 Power Systems 1.5.1 AC Power Systems 1.5.2 AC/DC Converters 1.5.3 DC Systems 1.5.4 Control and Protection System 1.5.5 General Power Systems and Integration 1.6 Central Instrumentation and Controls (I Integrated Model 1.1.1 Plasma Facing Components 1.1.2 Vacuum Vessel and Support Structure 1.1.3 Magnet

  10. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    AUG14 01AUG14 0 41 1,094,172.40 0.00 0.00 Design 24200020 PDR Prep PPL 26 17MAY10A 17MAY10A 22JUN10A.00 0.00 24200059 Peer Review 0 31MAR11 14APR11A -10 0.00 0.00 0.00 24200060 FDR Prep PPL 24* 17MAY11 16

  11. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    joint (flex bus assembly), the OH solenoid, the shaping coils, and the center stack casing. This WBS

  12. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    The inner poloidal/shaping coils subsystem consists of the new coils that will make up the poloidal field

  13. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    by month. 3- Original Work Authorization Form (WAF) OHMIC Heating Coil (OH) Magnet Systems 23 February 2009 The ohmic heating solenoid subsystem consists of the new coils that will make up the center solenoid advance procurement of the copper conductor and co-wound [glass/Kapton] insulation. Also includes

  14. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Author: G. Taylor Date ATI ­ ET Group Leader: G. Taylor Date RLM - Run Coordinator: E. Fredrickson Date-Driven 100% Non-Inductive H-Mode Plasma No. OP-XP-1010 AUTHORS: G. Taylor, D. Mueller, J.C. Hosea, S. Gerhardt, C. Kessel, B.P. LeBlanc, C.K. Phillips, S. Zweben, R. Maingi, P.M. Ryan, R. Maingi DATE: February

  15. Princeton Plasma Physics Laboratory NSTX Experimental Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Authors: P. Ryan Date 7/7/09 ATI ­ ET Group Leaders: G. Taylor Date 7/7/09 RLM - Run Coordinator: R. Raman. Hosea, R. Bell, B. LeBlanc, C.K. Phillips, G. Taylor, J. Wilgen, J.R. Wilson DATE: June 25, 2009 1. Theoretical/ empirical justification This XP addresses Research Milestone R(10-2) Characterize High

  16. NSTX Upgrade Armor Plate Backing Plate

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    available during this time period. Assumptions 1.) 2-D Opera Results uniformly expanded into 3-D as provided the calculation was not repeated. #12;Cognizant Engineer's printed name, signature, and date __________

  17. Princeton Plasma Physics Laboratory NSTX Machine Proposal

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    : Normal plasma ops requirements - Sources A, B, and C at ~90kV. #12;OP-XMP-60 4 / 6 5. Sign off at run): Off Phasing: Duration (s): CHI: Off Bank capacitance (mF): LITER: On or Off (either way) Either: List gaps, , , heating, fuelling, etc. as appropriate. Accurately label the ske

  18. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    01JUN10A 0 0.00 100 0.00 0.00 1000-0008 Fault, FMEA evaluation and analyses 21 03MAY10A 03MAY10A 0110A 25FEB11 18MAY11 -58 147 18,651.56 75 13,823.15 18,430.86 1000-0017 Fault, FMEA analyses (LOE) 220

  19. Work Authorization Document NSTX Upgrade Project

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    -NBI-Control & Instm 5 08JUN10A 08JUN10A 14JUN10A 14JUN10A 0 0.00 100 0.00 0.00 2475-0004 FMEA Analysis

  20. Princeton Plasma Physics Lab - NSTX-U

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible forPortsmouth/Paducah47,193.7 348,016.0 336,514.0laser-diagnostics Thenstx-u The National

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

    SciTech Connect (OSTI)

    Peng, Y-K.M.

    1999-11-14T23:59:59.000Z

    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.

  2. Double Beta Decay Experiments

    SciTech Connect (OSTI)

    Nanal, Vandana [Dept. of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai 400 005 (India)

    2011-11-23T23:59:59.000Z

    At present, neutrinoless double beta decay is perhaps the only experiment that can tell us whether the neutrino is a Dirac or a Majorana particle. Given the significance of the 0{nu}{beta}{beta}, there is a widespread interest for these rare event studies employing a variety of novel techniques. This paper describes the current status of DBD experiments. The Indian effort for an underground NDBD experiment at the upcoming INO laboratory is also presented.

  3. PREPARED FOR THE U.S. DEPARTMENT OF ENERGY, UNDER CONTRACT DE-AC02-76CH03073

    E-Print Network [OSTI]

    Experiment (NSTX) by means of thermocouples, an infrared (IR) camera, and a Faraday cup probe. The losses temperatures and high beta, auxiliary heating is needed, the simplest form being neutral beam (NB) heating. NB heating has been applied to NSTX, commencing in September 2000, and has resulted in toroidal beta values

  4. CSR SHIELDING EXPERIMENT

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

    triplets are essential elements of CSR shielding experiment beamline setup. e - e - e - BPMflag image HES image Dispersion function minimized in the dipole where shielding plates...

  5. Franklin: User Experiences

    SciTech Connect (OSTI)

    National Energy Research Supercomputing Center; He, Yun (Helen); Kramer, William T.C.; Carter, Jonathan; Cardo, Nicholas

    2008-05-07T23:59:59.000Z

    The newest workhorse of the National Energy Research Scientific Computing Center is a Cray XT4 with 9,736 dual core nodes. This paper summarizes Franklin user experiences from friendly early user period to production period. Selected successful user stories along with top issues affecting user experiences are presented.

  6. Undergraduate reactor control experiment

    SciTech Connect (OSTI)

    Edwards, R.M.; Power, M.A.; Bryan, M. (Pennsylvania State Univ., University Park (United States))

    1992-01-01T23:59:59.000Z

    A sequence of reactor and related experiments has been a central element of a senior-level laboratory course at Pennsylvania State University (Penn State) for more than 20 yr. A new experiment has been developed where the students program and operate a computer controller that manipulates the speed of a secondary control rod to regulate TRIGA reactor power. Elementary feedback control theory is introduced to explain the experiment, which emphasizes the nonlinear aspect of reactor control where power level changes are equivalent to a change in control loop gain. Digital control of nuclear reactors has become more visible at Penn State with the replacement of the original analog-based TRIGA reactor control console with a modern computer-based digital control console. Several TRIGA reactor dynamics experiments, which comprise half of the three-credit laboratory course, lead to the control experiment finale: (a) digital simulation, (b) control rod calibration, (c) reactor pulsing, (d) reactivity oscillator, and (e) reactor noise.

  7. Radiochemical solar neutrino experiments

    E-Print Network [OSTI]

    V. N. Gavrin; B. T. Cleveland

    2007-03-06T23:59:59.000Z

    Radiochemical experiments have been crucial to solar neutrino research. Even today, they provide the only direct measurement of the rate of the proton-proton fusion reaction, p + p --> d + e^+ + nu_e, which generates most of the Sun's energy. We first give a little history of radiochemical solar neutrino experiments with emphasis on the gallium experiment SAGE -- the only currently operating detector of this type. The combined result of all data from the Ga experiments is a capture rate of 67.6 +/- 3.7 SNU. For comparison to theory, we use the calculated flux at the Sun from a standard solar model, take into account neutrino propagation from the Sun to the Earth and the results of neutrino source experiments with Ga, and obtain 67.3 ^{+3.9}_{-3.5} SNU. Using the data from all solar neutrino experiments we calculate an electron neutrino pp flux at the earth of (3.41 ^{+0.76}_{-0.77}) x 10^{10}/(cm^2-s), which agrees well with the prediction from a detailed solar model of (3.30 ^{+0.13} _{-0.14}) x 10^{10}/(cm^2-s). Four tests of the Ga experiments have been carried out with very intense reactor-produced neutrino sources and the ratio of observed to calculated rates is 0.88 +/- 0.05. One explanation for this unexpectedly low result is that the cross section for neutrino capture by the two lowest-lying excited states in 71Ge has been overestimated. We end with consideration of possible time variation in the Ga experiments and an enumeration of other possible radiochemical experiments that might have been.

  8. Reactor Neutrino Experiments

    E-Print Network [OSTI]

    Jun Cao

    2007-12-06T23:59:59.000Z

    Precisely measuring $\\theta_{13}$ is one of the highest priority in neutrino oscillation study. Reactor experiments can cleanly determine $\\theta_{13}$. Past reactor neutrino experiments are reviewed and status of next precision $\\theta_{13}$ experiments are presented. Daya Bay is designed to measure $\\sin^22\\theta_{13}$ to better than 0.01 and Double Chooz and RENO are designed to measure it to 0.02-0.03. All are heading to full operation in 2010. Recent improvements in neutrino moment measurement are also briefed.

  9. ATLAS APPROVED EXPERIMENTS

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

    Experiment Title Days 433-9 Miller Ion Irradiations of Anisotropic High-Tc Superconductors: Probing Dynamics of Magnetic Vortices 2 651-2 Paul Accelerator-Mass-Spectrometry...

  10. General relativity and experiment

    E-Print Network [OSTI]

    T. Damour

    1994-12-08T23:59:59.000Z

    The confrontation between Einstein's theory of gravitation and experiment is summarized. Although all current experimental data are compatible with general relativity, the importance of pursuing the quest for possible deviations from Einstein's theory is emphasized.

  11. Simulated pion photoproduction experiments

    E-Print Network [OSTI]

    Howe, Ethan (Ethan Gabriel Grief)

    2005-01-01T23:59:59.000Z

    Introduction: In this paper, I will be assessing the capabilities of the Neutral Meson Spectrometer (NMS) detector in a planned experiment at the High Intensity Gamma Source at Duke University. I will review the relevant ...

  12. The MAJORANA Experiment

    E-Print Network [OSTI]

    The MAJORANA Collaboration

    2011-09-22T23:59:59.000Z

    The MAJORANA collaboration is actively pursuing research and development aimed at a tonne-scale 76Ge neutrinoless double-beta decay) experiment. The current, primary focus is the construction of the MAJORANA DEMONSTRATOR experiment, an R&D effort that will field approximately 40kg of germanium detectors with mixed enrichment levels. This article provides a status update on the construction of the DEMONSTRATOR.

  13. The Majorana Experiment

    SciTech Connect (OSTI)

    Aguayo, E.; Fast, J. E.; Hoppe, E. W.; Keillor, M. E.; Kephart, J. D.; Kouzes, R. T.; LaFerriere, B. D.; Merriman, J. H.; Orrell, J. L.; Overman, N. R. [Pacific Northwest National Laboratory, Richland, WA (United States); Avignone, F. T. III [Department of Physics and Astronomy, University of South Carolina, Columbia, SC (United States); Oak Ridge National Laboratory, Oak Ridge, TN (United States); Back, H. O. [Department of Physics, North Carolina State University, Raleigh, NC (United States); Triangle Universities Nuclear Laboratory, Durham, NC (United States); Barabash, A. S.; Konovalov, S. I.; Vanyushin, I.; Yumatov, V. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Bergevin, M.; Chan, Y.-D.; Detwiler, J. A.; Loach, J. C. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); and others

    2011-12-16T23:59:59.000Z

    The Majorana collaboration is actively pursuing research and development aimed at a tonne-scale {sup 76}Ge neutrinoless double-beta decay ({beta}{beta}(0{nu})-decay) experiment. The current, primary focus is the construction of the Majorana Demonstrator experiment, an R and D effort that will field approximately 40 kg of germanium detectors with mixed enrichment levels. This article provides a status update on the construction of the Demonstrator.

  14. The MAJORANA Experiment

    SciTech Connect (OSTI)

    Aguayo Navarrete, Estanislao; Avignone, F. T.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, Steven R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, Matthew P.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Phillips, D.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Sobolev, V.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, John; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.

    2011-10-01T23:59:59.000Z

    The Majorana collaboration is actively pursuing research and development aimed at a tonne-scale {sup 76}Ge neutrinoless double-beta decay ({beta}{beta}(0{nu})-decay) experiment. The current, primary focus is the construction of the Majorana Demonstrator experiment, an R and D effort that will field approximately 40 kg of germanium detectors with mixed enrichment levels. This article provides a status update on the construction of the Demonstrator.

  15. Dulye Leadership Experience The Ultimate Professional Development Experience

    E-Print Network [OSTI]

    Crowston, Kevin

    Experience Do YOU have what it takes to join the team? Find out more at dle.dulye.com Facebook: https://www.facebook.com/DulyeLeadershipExperience Twitter: DLE4SU #12;Dulye Leadership Experience Program Overview Dulye Leadership Experience The Dulye Leadership Experience (DLE) is a full scholarship, professional development program for Syracuse University

  16. Irish Potato Fertilizer Experiments.

    E-Print Network [OSTI]

    Hotchkiss, W.S.; Kyle, E. J. (Edwin Jackson)

    1908-01-01T23:59:59.000Z

    . Foliage dark and healthy. Plat 15. About same as Plat 10. Plat 16. No noticeable diflerence from Plat 14. 1 than oi IRISH POTATO EXPERIMENT, 1907. ..HARVEST RECORD. Plat 146 bu ....... 113.3 bu.. ...... I Gain Ma'ket- ab e Check Cotton Seed... Feed Inspector ....................... W. C. WELBORN.. .Vice Director and Agriculturist .............................................. M. FRANCIS. .Veterinarian .............................................. E. J. KYLE.. Horticulturist...

  17. Ganges valley aerosol experiment.

    SciTech Connect (OSTI)

    Kotamarthi, V.R.; Satheesh, S.K. (Environmental Science Division); (Indian Institute of Science, Bangalore, India)

    2011-08-01T23:59:59.000Z

    In June 2011, the Ganges Valley Aerosol Experiment (GVAX) began in the Ganges Valley region of India. The objective of this field campaign is to obtain measurements of clouds, precipitation, and complex aerosols to study their impact on cloud formation and monsoon activity in the region.

  18. The Majorana Experiment

    E-Print Network [OSTI]

    V. E. Guiseppe; for the Majorana Collaboration

    2010-12-30T23:59:59.000Z

    The Majorana Collaboration is assembling an array of HPGe detectors to search for neutrinoless double-beta decay in Ge-76. Initially, Majorana aims to construct a prototype module to demonstrate the potential of a future 1-tonne experiment. The design and potential reach of this prototype Demonstrator module are presented.

  19. The OLYMPUS Experiment

    E-Print Network [OSTI]

    R. Milner; D. K. Hasell; M. Kohl; U. Schneekloth; N. Akopov; R. Alarcon; V. A. Andreev; O. Ates; A. Avetisyan; D. Bayadilov; R. Beck; S. Belostotski; J. C. Bernauer; J. Bessuille; F. Brinker; B. Buck; J. R. Calarco; V. Carassiti; E. Cisbani; G. Ciullo; M. Contalbrigo; N. D'Ascenzo; R. De Leo; J. Diefenbach; T. W. Donnelly; K. Dow; G. Elbakian; D. Eversheim; S. Frullani; Ch. Funke; G. Gavrilov; B. Gläser; N. Görrissen; J. Hauschildt; B. S. Henderson; Ph. Hoffmeister; Y. Holler; L. D. Ice; A. Izotov; R. Kaiser; G. Karyan; J. Kelsey; D. Khaneft; P. Klassen; A. Kiselev; A. Krivshich; I. Lehmann; P. Lenisa; D. Lenz; S. Lumsden; Y. Ma; F. Maas; H. Marukyan; O. Miklukho; A. Movsisyan; M. Murray; Y. Naryshkin; C. O'Connor; R. Perez Benito; R. Perrino; R. P. Redwine; D. Rodríguez Piñeiro; G. Rosner; R. L. Russell; A. Schmidt; B. Seitz; M. Statera; A. Thiel; H. Vardanyan; D. Veretennikov; C. Vidal; A. Winnebeck; V. Yeganov

    2013-12-05T23:59:59.000Z

    The OLYMPUS experiment was designed to measure the ratio between the positron-proton and electron-proton elastic scattering cross sections, with the goal of determining the contribution of two-photon exchange to the elastic cross section. Two-photon exchange might resolve the discrepancy between measurements of the proton form factor ratio, $\\mu_p G^p_E/G^p_M$, made using polarization techniques and those made in unpolarized experiments. OLYMPUS operated on the DORIS storage ring at DESY, alternating between 2.01~GeV electron and positron beams incident on an internal hydrogen gas target. The experiment used a toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight detectors to measure rates for elastic scattering over the polar angular range of approximately $25^\\circ$--$75^\\circ$. Symmetric M{\\o}ller/Bhabha calorimeters at $1.29^\\circ$ and telescopes of GEM and MWPC detectors at $12^\\circ$ served as luminosity monitors. A total luminosity of approximately 4.5~fb$^{-1}$ was collected over two running periods in 2012. This paper provides details on the accelerator, target, detectors, and operation of the experiment.

  20. The MAJORANA Experiment

    SciTech Connect (OSTI)

    Guiseppe, V.E. [Univ S Dakota; Keller, C. [Univ S Dakota; Mei, D-M [Univ S Dakota; Perevozchikov, O. [Univ S Dakota; Perumpilly, G. [Univ S Dakota; Thomas, K. [Univ S Dakota; Xiang, W. [Univ S Dakota; Zhang, C. [Univ S Dakota; Aalseth, C.E. [Pacific NW Natl Lab Richland, WA; Aguayo, E. [Pacific NW Natl Lab Richland, WA; Ely, J. [Pacific NW Natl Lab Richland, WA; Fast, J.E. [Pacific NW Natl Lab Richland, WA; Hoppe, E.W. [Pacific NW Natl Lab Richland, WA; Hossbach, T.W. [Pacific NW Natl Lab Richland, WA; Keillor, M. [Pacific NW Natl Lab Richland, WA; Kephart, J.D. [Pacific NW Natl Lab Richland, WA; Kouzes, R. [Pacific NW Natl Lab Richland, WA; Miley, H.S. [Pacific NW Natl Lab Richland, WA; Mizouni, L. [Pacific NW Natl Lab Richland, WA; Myers, A.W. [Pacific NW Natl Lab Richland, WA; Reid, D. [Pacific NW Natl Lab Richland, WA; Amman, M. [Lawrence Berkeley National Laboratory (LBNL); Bergevin, M. [Lawrence Berkeley National Laboratory (LBNL); Chan, Y-D [Lawrence Berkeley National Laboratory (LBNL); Detwiler, J.A. [Lawrence Berkeley National Laboratory (LBNL); Loach, J.C. [Lawrence Berkeley National Laboratory (LBNL); Luke, P.N. [Lawrence Berkeley National Laboratory (LBNL); Martin, R.D. [Lawrence Berkeley National Laboratory (LBNL); Poon, A.W.P. [Lawrence Berkeley National Laboratory (LBNL); Prior, G. [Lawrence Berkeley National Laboratory (LBNL); Vetter, K. [Lawrence Berkeley National Laboratory (LBNL); Yaver, H. [Lawrence Berkeley National Laboratory (LBNL); Avignone, F.T. III [University of South Carolina; Creswick, R. [University of South Carolina; Farach, H. [University of South Carolina; Mizouni, L. [University of South Carolina; Avignone, Frank Titus [ORNL; Bertrand Jr, Fred E [ORNL; Capps, Gregory L [ORNL; Cooper, Reynold J [ORNL; Radford, David C [ORNL; Varner Jr, Robert L [ORNL; Wilkerson, John F [University of North Carolina, Chapel Hill; Yu, Chang-Hong [ORNL; Back, H.O. [University of North Carolina; Leviner, L. [North Carolina State University; Young, A.R. [North Carolina State University; Back (et al.), H.O. [Triangle Universities Nuclear Laboratory, Durham, NC; Bai, X. [South Dakota School of Mines and Technology; Hong, H. [South Dakota School of Mines and Technology; Howard, S. [South Dakota School of Mines and Technology; Medlin, D. [South Dakota School of Mines and Technology; Sobolev, V. [South Dakota School of Mines and Technology; Barabash, A.S. [Inst Theort & Expt Phys, Moscow, Russia; Konovalov, S.I. [Inst Theort & Expt Phys, Moscow, Russia; Vanyushin, I. [Inst Theort & Expt Phys, Moscow, Russia; Yumatov, V. [Inst Theort & Expt Phys, Moscow, Russia; Barbeau, P.S. [University of Chicago; Collar, J.I. [University of Chicago; Fields, N. [University of Chicago; Boswell (et al.), M. [Los Alamos National Laboratory (LANL); Brudanin, V. [Joint Institute for Nuclear Research, Dubna, Russia; Egorov, V. [Joint Institute for Nuclear Research, Dubna, Russia; Gusey, K. [Joint Institute for Nuclear Research, Dubna, Russia; Kochetov, O. [Joint Institute for Nuclear Research, Dubna, Russia; Shirchenko, M. [Joint Institute for Nuclear Research, Dubna, Russia; Timkin, V. [Joint Institute for Nuclear Research, Dubna, Russia; Yakushev, E. [Joint Institute for Nuclear Research, Dubna, Russia; Bugg, W. [University of Tennessee, Knoxville (UTK); Efremenko, M. [University of Tennessee, Knoxville (UTK); Burritt (et al.), T.H. [University of Washington, Ctr Expt Nucle Phys & Astrophys; Burritt (et al.), T.H. [University of Washington, Dept Phys, Seattle, WA; Busch, M. [Duke University; Esterline, J. [Duke University; Swift, G. [Duke University; Tornow, W. [Duke University/TUNL; Ejiri, H. [Osaka University; Hazama, R. [Osaka University; Nomachi, M. [Osaka University; Shima, T. [Osaka University; Finnerty (et al.), P. [University of North Carolina; et al.

    2011-01-01T23:59:59.000Z

    The Majorana Collaboration is assembling an array of HPGe detectors to search for neutrinoless double-beta decay in {sup 76}Ge. Initially, Majorana aims to construct a prototype module to demonstrate the potential of a future 1-tonne experiment. The design and potential reach of this prototype Demonstrator module are presented.

  1. The Majorana Experiment

    SciTech Connect (OSTI)

    Aalseth, Craig E.; Aguayo Navarrete, Estanislao; Amman, M.; Avignone, F. T.; Back, Henning O.; Bai, Xinhua; Barabash, Alexander S.; Barbeau, P. S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Bugg, William; Burritt, Tom H.; Busch, Matthew; Capps, Greg L.; Chan, Yuen-Dat; Collar, J. I.; Cooper, R. J.; Creswick, R.; Detwiler, Jason A.; Diaz, J.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Ely, James H.; Esterline, James H.; Farach, H. A.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, M.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Harper, Gregory; Hazama, R.; Henning, Reyco; Hime, Andrew; Hong, H.; Hoppe, Eric W.; Hossbach, Todd W.; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaRoque, B. H.; Leviner, L.; Loach, J. C.; Luke, P.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Medlin, D.; Mei, Dong-Ming; Miley, Harry S.; Miller, M. L.; Mizouni, Leila; Myers, Allan W.; Nomachi, Masaharu; Orrell, John L.; Peterson, David; Phillips, D.; Poon, Alan; Perevozchikov, O.; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Reid, Douglas J.; Rielage, Keith; Robertson, R. G. H.; Rodriguez, Larry; Ronquest, M. C.; Salazar, Harold; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Sobolev, V.; Steele, David; Strain, J.; Swift, Gary; Thomas, K.; Timkin, V.; Tornow, W.; Van Wechel, T. D.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Wolfe, B. A.; Xiang, W.; Yakushev, E.; Yaver, Harold; Young, A.; Yu, Chang-Hong; Yumatov, V.; Zhang, C.

    2011-08-01T23:59:59.000Z

    The Majorana Collaboration is assembling an array of HPGe detectors to search for neutrinoless double-beta decay in 76Ge. Initially, Majorana aims to construct a prototype module to demonstrate the potential of a future 1-tonne experiment. The design and potential reach of this prototype Demonstrator module are presented.

  2. NSTX Weekly Report (August 27, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    feedback phase and suitable gain settings for the RWM active control system in these low li target plasmas the programmed pulse length appear to be due to slow edge instabilities leading to edge cooling and loss progress was made in developing stable, reproducible Snowflake divertor configurations. In the afternoon we

  3. NSTX Weekly Report (July 16, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    , methodology, structure and implementation plan for the ITER Plasma Control System (PCS) and develop of a conceptual design for the ITER PCS. First, we were given up to date information on the progress on CODAC current-injection measurements indicated that the potential fault appears to be near the cooling water

  4. NSTX Weekly Report (Mar. 12, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    . Emergency-stop, safety interlock, and coil protection system testing is in progress, and pre internal gas cooling system were pressure tested to study #12;their qualifications for possible use on the Parking Stands in the South High Bay. - Preparations for loading LITER units F1 and K1 are in progress

  5. NSTX Weekly Report (Feb. 5, 2009) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    of the Integrated Systems Test Procedure (ISTP) now in progress. - The air cooling lines of the 4 plates of the LLD of the MPTS diagnostic. Systems have been configured for the upcoming vacuum- vessel bake, which will start upon the successful conclusion of the Liquid Lithium Divertor (LLD) system integrated testing now

  6. NSTX Weekly Report (June 11, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    modes. Radio frequency heating (wave-particle and edge interactions, and fast wave antenna loading heating, as well as dual probe lithium evaporation. The lithium (LITER) probe in the Bay F #12;position (H. Kugel) · Liquid Lithium Diver

  7. NSTX Weekly Report (Mar. 5, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    obtained by lowering the edge density with lithium wall conditioning. Lithium conditioning allowed of rf power. Visible and infrared camera images show that fast wave interactions can deposit Physics Operations (H. Kugel) · Liquid Lithium Divertor (LLD) Diagnostics - Filters for the Divertor Fast

  8. NSTX Weekly Report (May 7, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    at that bay. Also this week, tests of a prototype hot air-based heating system for one of the four Liquid-air heating of an LLD plate. · LLD Diagnostics - The fabrication of the fiber holder for the divertor week. The last of the remote mirror control mechanisms for the High-k turbulence diagnostic has been

  9. NSTX Weekly Report (August 6, 2010) FY 2010 NSTX plasma operations

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    and features that are required for divertor and PMI testing and also discussed PFC/PMI testing strategy in FNSF

  10. http://NSTX.pppl.gov/nstx/Software/IDL/ idl_intro.html#GOTCHAS

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    graphics get erased? When a window gets covered, then uncovered, someone has to keep a copy of the obscured be stopped using control-C. (Hold down the control key and hit the letter c). IDL can be aborted immediately using control-\\. (All variables are lost and the state of open files will be uncertain). Programs

  11. NSTX Upgrade Project Final Design Review June 22 -24, 2011 1 NSTX Supported by

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    ­ Bakeout ­ Gas Injection ­ Cooling Water · Requirements · Description of the Design · Previous Chits, 2011 Cooling Water Requirements · Upgrade 8 OH Flow Paths ­ Existing · Eight (8) OH flow paths @ 1 GPM to equalize temperature of coil conductors · Add local pressure monitoring gage · Add remote pressure

  12. Gross decontamination experiment report

    SciTech Connect (OSTI)

    Mason, R.; Kinney, K.; Dettorre, J.; Gilbert, V.

    1983-07-01T23:59:59.000Z

    A Gross Decontamination Experiment was conducted on various levels and surfaces of the TMI - Unit 2 reactor building in March 1982. The polar crane, D-rings, missile shields, refueling canals, refueling bridges, equipment, and elevations 305' and 347'-6'' were flushed with low pressure water. Additionally, floor surfaces on elevation 305' and floor surfaces and major pieces of equipment on elevation 347'-6'' were sprayed with high pressure water. Selective surfaces were decontaminated with a mechanical scrubber and chemicals. Strippable coating was tested and evaluated on equipment and floor surfaces. The effectiveness, efficiency, and safety of several decontamination techniques were established for the large, complex decontamination effort. Various decontamination equipment was evaluated and its effectiveness was documented. Decontamination training and procedures were documented and evaluated, as were the support system and organization for the experiment.

  13. A demonstration mobility experiment

    E-Print Network [OSTI]

    Martin, Howard Lawrence

    1961-01-01T23:59:59.000Z

    among under graduate physics students in the field of solid-stats physics. Ths Shocklsy Haynes mobility experiment, presented in this thesis, was selected because it is considered an excellent means of gaining these objectives by giving sn...& constructive criticism& and patience throughout the long period required to complete the experismntl Dr& J ~ R ~ haynes, of Bell Laboratories, for informat'on on exper- imental procedure and sm&ross of semiconductor samplssl Bill Closssr of' the Sandia...

  14. Hog Feeding Experiments.

    E-Print Network [OSTI]

    Burns, John C.

    1910-01-01T23:59:59.000Z

    ................................................................................. ~eriment,s Nos. 111 and IV 17 I ...................................................................................... ,,,,proved Hogs vs. Scrubs 19 I Corn vs. Rice Bran vs. Spanish Peanuts ........................................................... 22... Straight Corn Ration IV. Rice Bran and Spanish Peanuts for Fattening Hogs. Compared with Indian Corn for Pork Production. for 190 II ascc st1zj coll fatt nnr7 fe\\v dnc reg: was The experiments reported in this bulletin cover all of those...

  15. The OLYMPUS Experiment

    E-Print Network [OSTI]

    Milner, R; Kohl, M; Schneekloth, U; Akopov, N; Alarcon, R; Andreev, V A; Ates, O; Avetisyan, A; Bayadilov, D; Beck, R; Belostotski, S; Bernauer, J C; Bessuille, J; Brinker, F; Buck, B; Calarco, J R; Carassiti, V; Cisbani, E; Ciullo, G; Contalbrigo, M; D'Ascenzo, N; De Leo, R; Diefenbach, J; Donnelly, T W; Dow, K; Elbakian, G; Eversheim, D; Frullani, S; Funke, Ch; Gavrilov, G; Gläser, B; Görrissen, N; Hauschildt, J; Henderson, B S; Hoffmeister, Ph; Holler, Y; Ice, L D; Izotov, A; Kaiser, R; Karyan, G; Kelsey, J; Khaneft, D; Klassen, P; Kiselev, A; Krivshich, A; Lehmann, I; Lenisa, P; Lenz, D; Lumsden, S; Ma, Y; Maas, F; Marukyan, H; Miklukho, O; Movsisyan, A; Murray, M; Naryshkin, Y; O'Connor, C; Benito, R Perez; Perrino, R; Redwine, R P; Piñeiro, D Rodríguez; Rosner, G; Russell, R L; Schmidt, A; Seitz, B; Statera, M; Thiel, A; Vardanyan, H; Veretennikov, D; Vidal, C; Winnebeck, A; Yeganov, V

    2014-01-01T23:59:59.000Z

    The OLYMPUS experiment was designed to measure the ratio between the positron-proton and electron-proton elastic scattering cross sections, with the goal of determining the contribution of two-photon exchange to the elastic cross section. Two-photon exchange might resolve the discrepancy between measurements of the proton form factor ratio, $\\mu_p G^p_E/G^p_M$, made using polarization techniques and those made in unpolarized experiments. OLYMPUS operated on the DORIS storage ring at DESY, alternating between 2.01~GeV electron and positron beams incident on an internal hydrogen gas target. The experiment used a toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight detectors to measure rates for elastic scattering over the polar angular range of approximately $25^\\circ$--$75^\\circ$. Symmetric M{\\o}ller/Bhabha calorimeters at $1.29^\\circ$ and telescopes of GEM and MWPC detectors at $12^\\circ$ served as luminosity monitors. A total luminosity of approximately 4.5~fb$^{-1}$ was collect...

  16. 2169 steel waveform experiments.

    SciTech Connect (OSTI)

    Furnish, Michael David; Alexander, C. Scott; Reinhart, William Dodd; Brown, Justin L.

    2012-11-01T23:59:59.000Z

    In support of LLNL efforts to develop multiscale models of a variety of materials, we have performed a set of eight gas gun impact experiments on 2169 steel (21% Cr, 6% Ni, 9% Mn, balance predominantly Fe). These experiments provided carefully controlled shock, reshock and release velocimetry data, with initial shock stresses ranging from 10 to 50 GPa (particle velocities from 0.25 to 1.05 km/s). Both windowed and free-surface measurements were included in this experiment set to increase the utility of the data set, as were samples ranging in thickness from 1 to 5 mm. Target physical phenomena included the elastic/plastic transition (Hugoniot elastic limit), the Hugoniot, any phase transition phenomena, and the release path (windowed and free-surface). The Hugoniot was found to be nearly linear, with no indications of the Fe - phase transition. Releases were non-hysteretic, and relatively consistent between 3- and 5-mm-thick samples (the 3 mm samples giving slightly lower wavespeeds on release). Reshock tests with explosively welded impactors produced clean results; those with glue bonds showed transient releases prior to the arrival of the reshock, reducing their usefulness for deriving strength information. The free-surface samples, which were steps on a single piece of steel, showed lower wavespeeds for thin (1 mm) samples than for thicker (2 or 4 mm) samples. A configuration used for the last three shots allows release information to be determined from these free surface samples. The sample strength appears to increase with stress from ~1 GPa to ~ 3 GPa over this range, consistent with other recent work but about 40% above the Steinberg model.

  17. Fundamental experiments in velocimetry

    SciTech Connect (OSTI)

    Briggs, Matthew Ellsworth [Los Alamos National Laboratory; Hull, Larry [Los Alamos National Laboratory; Shinas, Michael [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    One can understand what velocimetry does and does not measure by understanding a few fundamental experiments. Photon Doppler Velocimetry (PDV) is an interferometer that will produce fringe shifts when the length of one of the legs changes, so we might expect the fringes to change whenever the distance from the probe to the target changes. However, by making PDV measurements of tilted moving surfaces, we have shown that fringe shifts from diffuse surfaces are actually measured only from the changes caused by the component of velocity along the beam. This is an important simplification in the interpretation of PDV results, arising because surface roughness randomizes the scattered phases.

  18. BooNE Experiment

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced Materials Find FindRewind Generator|December 5, 2011Experiment

  19. Fermilab | Tevatron | Experiments

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC) Environmental Assessments (EA)Budget » FYU.S.at500-mileFYGrowing| HowExperiments In

  20. The NEXT experiment

    E-Print Network [OSTI]

    Gomez-Cadenas, Juan Jose

    2014-01-01T23:59:59.000Z

    NEXT (Neutrino Experiment with a Xenon TPC) is an experiment to search neutrinoless double beta decay processes (bb0nu) in Xe136. The NEXT technology is based in the use of time projection chambers operating at a typical pressure of 15 bar and using electroluminescence to amplify the signal (HPXE). The main advantages of the experimental technique are: a) excellent energy resolution; b) the ability to reconstruct the trajectory of the two electrons emitted in the decays, which further contributes to the suppression of backgrounds; c) scalability to large masses; and d) the possibility to reduce the background to negligible levels thanks to the barium tagging technology (BATA). The NEXT roadmap was designed in four stages: i) Demonstration of the HPXE technology with prototypes deploying a mass of natural xenon in the range of 1 kg, using the NEXT-DEMO (IFIC) and NEXT-DBDM (Berkeley) prototypes; ii) Characterisation of the backgrounds to the bb0nu signal and measurement of the bb2nu signal with the NEW detecto...

  1. The majorana experiment

    SciTech Connect (OSTI)

    Rielage, Keith R [Los Alamos National Laboratory; Elliott, Steven R [Los Alamos National Laboratory; Boswell, Melissa [Los Alamos National Laboratory; Gehman, Victor M [Los Alamos National Laboratory; Hime, Andrew [Los Alamos National Laboratory; Kidd, Mary F [Los Alamos National Laboratory; La Roque, Benjamin H [Los Alamos National Laboratory; Rodriguez, Larry [Los Alamos National Laboratory; Ronquest, Michael C [Los Alamos National Laboratory; Salazar, Harry [Los Alamos National Laboratory; Steele, David [Los Alamos National Laboratory

    2010-12-13T23:59:59.000Z

    The MAJORANA Collaboration is assembling an array of HPGe detectors to search for neutrinoless double-beta decay in {sup 76}Ge. Initially, MAJORANA aims to construct a prototype module to demonstrate the potential of a future 1-tonne experiment. The design and potential reach of this prototype DEMONSTRATOR module are presented. Our proposed method uses the well-established technique of searching for neutrinoless double-beta decay in high purity Ge-diode radiation detectors that play both roles of source and detector. The use of P-PC Ge detectors present advances in background rejection and a Significantly lower energy threshold than conventional Ge detector technologies. The lower energy threshold opens up a broader and exciting physics program including searches for dark matter and axions concurrent with the double-beta decay search. The DEMONSTRATOR should establish that the backgrounds are low enough to justify scaling to tonne-scale experiment, probe the neutrino effective mass region above 100 meV, and search the low energy region with a sensitivity to dark matter. The DEMONSTRATOR will be sited at the 4850-ft level (4200 m.w.e) of the Sanford Underground Laboratory at Homestake and preparations for construction are currently underway.

  2. Experience Report for WOPR

    SciTech Connect (OSTI)

    Pope, G

    2010-04-06T23:59:59.000Z

    One of the purposes of the SQA effort at LLNL is to attempt to determine the 'goodness' of the research codes used for various scientific applications. Typically these are two and three dimensional multi-physics simulation and modeling codes. These legacy research codes are used for applciations such as atmospheric dispersion modeling and analysis and prediction of the performance of engineered systems. These codes are continually subjected to automated regression test suites consisting of verified and validated expected results. Code is managed in repositories. Experience level of developers is high in the knowledge domain, platforms, and languages used. Code size of the multi-physics code used in this study was 578,242 lines excluding comment and blank lines or 5538.7 function points. Languages were 70% C++, 20% C, and 10% Fortran. The code has 130 users and a development team of 14 and an embedded SQE. The code has achieved 100% prime feature test coverage, 73.6% functional test coverage, and 71.5% statement test coverage. The average cyclomatic complexity of the code was 6.25. The codes have evolved over 10 years. Research codes are challenging because there is a desire to balance agility with discipline as well as compliance with DOE standards. Agility is important to allow experimentation with new algorithms and addition of the latest physics features. Discipline is important to increase the quality of the codes. Automation of processes and defect prevention/detection are deployed throughout the software development process. Since resarch codes are a small segment of the software industry, not much information exists in terms of reliability studies on these types of codes. This paper describes attempts to determine the goodness of these research codes. Goodness defined as both correctness of the codes and their fault densities. Correctness is determined by user interviews, peer review; feature based automated testing, and coverage measurement. This paper focuses on the fault density aspect of goodness and reliability of the codes in particular. The approach taken was to use multiple fault density prediction methods and compare results to actual experimentation and other industry studies on fault density. As a result of the predictions and experiments our confidence in the prediction methods was increased and our confidence in the goodness of the code from a fault density perspective was given more context. A large unintended benefit of these experiments was to find defects hidden for years in the codes when using the Monte Carlo reliability testing results to develop heuristic based bug driven tests.

  3. Experience with capture cavity II

    SciTech Connect (OSTI)

    Koeth, T.; /Fermilab /Rutgers U., Piscataway; Branlard, J.; Edwards, H.; Fliller, R.; Harms, E.; Hocker, A.; McGee, M.; Pischalnikov, Y.; Prieto, P.; Reid, J.; /Fermilab

    2007-06-01T23:59:59.000Z

    Valuable experience in operating and maintaining superconducting RF cavities in a horizontal test module has been gained with Capture Cavity II. We report on all facets of our experience to date.

  4. The T2K Experiment

    E-Print Network [OSTI]

    Abgrall, N; Ajima, Y; Albert, J B; Allan, D; Amaudruz, P -A; Andreopoulos, C; Andrieu, B; Anerella, M D; Angelsen, C; Aoki, S; Araoka, O; Argyriades, J; Ariga, A; Ariga, T; Assylbekov, S; de André, J P A M; Autiero, D; Badertscher, A; Ballester, O; Barbi, M; Barker, G J; Baron, P; Barr, G; Bartoszek, L; Batkiewicz, M; Bay, F; Bentham, S; Berardi, V; Berger, B E; Berns, H; Bertram, I; Besnier, M; Beucher, J; Beznosko, D; Bhadra, S; Birney, P; Bishop, D; Blackmore, E; Blaszczyk, F d M; Blocki, J; Blondel, A; Bodek, A; Bojechko, C; Bouchez, J; Boussuge, T; Boyd, S B; Boyer, M; Braam, N; Bradford, R; Bravar, A; Briggs, K; Brinson, J D; Bronner, C; Brook-Roberge, D G; Bryant, M; Buchanan, N; Budd, H; Cadabeschi, M; Calland, R G; Calvet, D; Rodríguez, J Caravaca; Carroll, J; Cartwright, S L; Carver, A; Castillo, R; Catanesi, M G; Cavata, C; Cazes, A; Cervera, A; Charrier, J P; Chavez, C; Choi, S; Chollet, S; Christodoulou, G; Colas, P; Coleman, J; Coleman, W; Collazuol, G; Connolly, K; Cooke, P; Curioni, A; Dabrowska, A; Danko, I; Das, R; Davies, G S; Davis, S; Day, M; De La Broise, X; de Perio, P; De Rosa, G; Dealtry, T; Debraine, A; Delagnes, E; Delbart, A; Densham, C; Di Lodovico, F; Di Luise, S; Tran, P Dinh; Dobson, J; Doornbos, J; Dore, U; Drapier, O; Druillole, F; Dufour, F; Dumarchez, J; Durkin, T; Dytman, S; Dziewiecki, M; Dziomba, M; Ellison, B; Emery, S; Ereditato, A; Escallier, J E; Escudero, L; Esposito, L S; Faszer, W; Fechner, M; Ferrero, A; Finch, A; Fisher, C; Fitton, M; Flight, R; Forbush, D; Frank, E; Fransham, K; Fujii, Y; Fukuda, Y; Gallop, M; Galymov, V; Ganetis, G L; Gannaway, F C; Gaudin, A; Gaweda, J; Gendotti, A; George, M; Giffin, S; Giganti, C; Gilje, K; Giomataris, I; Giraud, J; Ghosh, A K; Golan, T; Goldhaber, M; Gomez-Cadenas, J J; Gomi, S; Gonin, M; Goyette, M; Grant, A; Grant, N; Grañena, F; Greenwood, S; Gumplinger, P; Guzowski, P; Haigh, M D; Hamano, K; Hansen, C; Hara, T; Harrison, P F; Hartfiel, B; Hartz, M; Haruyama, T; Hasanen, R; Hasegawa, T; Hastings, N C; Hastings, S; Hatzikoutelis, A; Hayashi, K; Hayato, Y; Haycock, T D J; Hearty, C; Helmer, R L; Henderson, R; Herlant, S; Higashi, N; Hignight, J; Hiraide, K; Hirose, E; Holeczek, J; Honkanen, N; Horikawa, S; Hyndman, A; Ichikawa, A K; Ieki, K; Ieva, M; Iida, M; Ikeda, M; Ilic, J; Imber, J; Ishida, T; Ishihara, C; Ishii, T; Ives, S J; Iwasaki, M; Iyogi, K; Izmaylov, A; Jamieson, B; Johnson, R A; Joo, K K; Jover-Manas, G; Jung, C K; Kaji, H; Kajita, T; Kakuno, H; Kameda, J; Kaneyuki, K; Karlen, D; Kasami, K; Kasey, V; Kato, I; Kawamuko, H; Kearns, E; Kellet, L; Khabibullin, M; Khaleeq, M; Khan, N; Khotjantsev, A; Kielczewska, D; Kikawa, T; Kim, J Y; Kim, S -B; Kimura, N; Kirby, B; Kisiel, J; Kitching, P; Kobayashi, T; Kogan, G; Koike, S; Komorowski, T; Konaka, A; Kormos, L L; Korzenev, A; Koseki, K; Koshio, Y; Kouzuma, Y; Kowalik, K; Kravtsov, V; Kreslo, I; Kropp, W; Kubo, H; Kubota, J; Kudenko, Y; Kulkarni, N; Kurchaninov, L; Kurimoto, Y; Kurjata, R; Kurosawa, Y; Kutter, T; Lagoda, J; Laihem, K; Langstaf, R; Laveder, M; Lawson, T B; Le, P T; Coguie, A Le; Ross, M Le; Lee, K P; Lenckowski, M; Licciardi, C; Lim, I T; Lindner, T; Litchfield, R P; Longhin, A; Lopez, G D; Lu, P; Ludovici, L; Lux, T; Macaire, M; Magaletti, L; Mahn, K; Makida, Y; Malafis, C J; Malek, M; Manly, S; Marchionni, A; Mark, C; Marino, A D; Marone, A J; Marteau, J; Martin, J F; Maruyama, T; Maryon, T; Marzec, J; Masliah, P; Mathie, E L; Matsumura, C; Matsuoka, K; Matveev, V; Mavrokoridis, K; Mazzucato, E; McCauley, N; McFarland, K S; McGrew, C; McLachlan, T; Mercer, I; Messina, M; Metcalf, W; Metelko, C; Mezzetto, M; Mijakowski, P; Miller, C A; Minamino, A; Mineev, O; Mine, S; Minvielle, R E; Mituka, G; Miura, M; Mizouchi, K; Mols, J -P; Monfregola, L; Monmarthe, E; Moreau, F; Morgan, B; Moriyama, S; Morris, D; Muir, A; Murakami, A; Muratore, J F; Murdoch, M; Murphy, S; Myslik, J; Nagashima, G; Nakadaira, T; Nakahata, M; Nakamoto, T; Nakamura, K; Nakayama, S; Nakaya, T; Naples, D; Nelson, B; Nicholls, T C; Nishikawa, K; Nishino, H; Nitta, K; Nizery, F; Nowak, J A; Noy, M; Obayashi, Y; Ogitsu, T; Ohhata, H; Okamura, T; Okumura, K; Okusawa, T; Ohlmann, C; Olchanski, K; Openshaw, R; Oser, S M; Otani, M; Owen, R A; Oyama, Y; Ozaki, T; Pac, M Y; Palladino, V; Paolone, V; Paul, P; Payne, D; Pearce, G F; Pearson, C; Perkin, J D; Pfleger, M; Pierre, F; Pierrepont, D; Plonski, P; Poffenberger, P; Poplawska, E; Popov, B; Posiadala, M; Poutissou, J -M; Poutissou, R; Preece, R; Przewlocki, P; Qian, W; Raaf, J L; Radicioni, E; Ramos, K; Ratoff, P; Raufer, T M; Ravonel, M; Raymond, M; Retiere, F; Richards, D; Ritou, J -L; Robert, A; Rodrigues, P A; Rondio, E; Roney, M; Rooney, M; Ross, D; Rossi, B; Roth, S; Rubbia, A; Ruterbories, D; Sacco, R; Sadler, S; Sakashita, K; Sanchez, F; Sarrat, A; Sasaki, K; Schaack, P; Schmidt, J; Scholberg, K; Schwehr, J; Scott, M

    2011-01-01T23:59:59.000Z

    The T2K experiment is a long-baseline neutrino oscillation experiment. Its main goal is to measure the last unknown lepton sector mixing angle {\\theta}_{13} by observing {\

  5. Understanding Human Experience Henry Kautz

    E-Print Network [OSTI]

    Kautz, Henry

    Understanding Human Experience Henry Kautz One of the earliest goals of research in artificial intelligence was to create systems that can interpret and understand day to day human experience. Early work on the goal of building systems that understand human experience. Each of the previous barriers is weakened

  6. Princeton Plasma Physics Laboratory Annual Site Environmental Report for Calendar Year 2001

    SciTech Connect (OSTI)

    Virginia L. Finley

    2004-04-07T23:59:59.000Z

    The purpose of this report is to provide the U.S. Department of Energy (DOE) and the public with information on the level of radioactive and nonradioactive pollutants (if any) that are added to the environment as a result of the Princeton Plasma Physics Laboratory's (PPPL) operations. The results of the 2001 environmental surveillance and monitoring program for PPPL are presented and discussed. The report also summarizes environmental initiatives, assessments, and programs that were undertaken in 2001. PPPL has engaged in fusion energy research since 1951. The vision of the Laboratory is to create innovations to make fusion power a practical reality--a clean, alternative energy source. The Year 2001 marked the third year of National Spherical Torus Experiment (NSTX) operations and Tokamak Fusion Test Reactor (TFTR) dismantlement and deconstruction activities. A collaboration among fourteen national laboratories, universities, and research institutions, the NSTX is a major element in the U.S. Fusion Energy Sciences Program. It has been designed to test the physics principles of spherical torus (ST) plasmas. The ST concept could play an important role in the development of smaller, more economical fusion reactors. In 2001, PPPL's radiological environmental monitoring program measured tritium in the air at on- and off-site sampling stations. PPPL is capable of detecting small changes in the ambient levels of tritium by using highly sensitive monitors. The operation of an in-stack monitor located on D-site is a requirement of the National Emission Standard for Hazardous Air Pollutants (NESHAPs) regulations; also included in PPPL's radiological environmental monitoring program, are water monitoring--precipitation, ground-, surface-, and waste-waters. PPPL's radiological monitoring program characterized the ambient, background levels of tritium in the environment and from the D-site stack; the data are presented in this report. Groundwater monitoring continue d under a voluntary agreement with the New Jersey Department of Environmental Protection. PPPL monitored for the presence of nonradiological contaminants, mainly volatile organic compounds (components of degreasing solvents). Monitoring revealed the low levels of volatile organic compounds in an area adjacent to PPPL. In 2001, PPPL was in compliance with its permit limits for surface and sanitary discharges and had no reportable releases. Additionally, as part of DOE's program for the purchase of recycled content and other environmentally preferred products, PPPL has ranked in the excellent category of 80 to 90% of the goal.

  7. Ultrafast gas switching experiments

    SciTech Connect (OSTI)

    Frost, C.A.; Martin, T.H.; Patterson, P.E.; Rinehart, L.F.; Rohwein, G.J.; Roose, L.D.; Aurand, J.F.; Buttram, M.T.

    1996-11-01T23:59:59.000Z

    We describe recent experiments which studied the physics of ultrafast gas breakdown under the extreme overvoltages which occur when a high pressure gas switch is pulse charged to hundreds of kV in 1 ns or less. The highly overvolted peaking gaps produce powerful electromagnetic pulses with risetimes < 100 ps which can be used for ultrawideband radar systems, particle accelerators, laser drivers, bioelectromagnetic studies, electromagnetic effects testing, and for basic studies of gas breakdown physics. We have produced and accurately measured pulses with 50 to 100 ps risetimes to peak levels of 75 to 160 kV at pulse repetition frequencies (PRF) to I kHz. A unique gas switch was developed to hold off hundreds of kV with parasitic inductance less than I nH. An advanced diagnostic system using Fourier compensation was developed to measure single-shot risetimes below 35 ps. The complete apparatus is described and wave forms are presented. The measured data are compared with a theoretical model which predicts key features including dependence on gas species and pressure. We have applied this technology to practical systems driving ultrawideband radiating antennas and bounded wave simulators. For example, we have developed a thyristor/pulse transformer based system using a highly overvolted cable switch. This pulser driving a Sandia- designed TEM cell, provides an ultra wideband impulse with < 200 ps risetime to the test object at a PRF > 1 kHz at > 100 kV/m E field.

  8. ADVANCES IN DUST DETECTION AND REMOVAL FOR TOKAMAKS

    SciTech Connect (OSTI)

    Campos, A.; Skinner, C.H.

    2009-01-01T23:59:59.000Z

    Dust diagnostics and removal techniques are vital for the safe operation of next step fusion devices such as ITER. In the tokamak environment, large particles or fi bers can fall on the electrostatic detector potentially causing a permanent short. An electrostatic dust detector developed in the laboratory is being applied to the National Spherical Torus Experiment (NSTX). We report on the development of a gas puff system that uses helium to clear such particles from the detector. Experiments at atmospheric pressure with varying nozzle designs, backing pressures, puff durations and exit fl ow orientations have given an optimal confi guration that effectively removes particles from a 25 cm² area. Similar removal effi ciencies were observed under a vacuum base pressure of 1 mTorr. Dust removal from next step tokamaks will be required to meet regulatory dust limits. A tri-polar grid of fi ne interdigitated traces has been designed that generates an electrostatic traveling wave for conveying dust particles to a “drain.” First trials with only two working electrodes have shown particle motion in optical microscope images.

  9. Coupled-channel scattering on a torus

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

    Guo, Peng [JLAB; Dudek, Jozef Jon [Old Dominion U., JLAB; Edwards, Robert G. [JLAB; Szczepaniak, Adam Pawel [Indiana U.

    2013-07-01T23:59:59.000Z

    Based on the Hamiltonian formalism approach, a generalized Luscher's formula for two particle scattering in both the elastic and coupled-channel cases in moving frames is derived from a relativistic Lippmann-Schwinger equation. Some strategies for extracting scattering amplitudes for a coupled-channel system from the discrete finite-volume spectrum are discussed and illustrated with a toy model of two-channel resonant scattering. This formalism will, in the near future, be used to extract information about hadron scattering from lattice QCD computations.

  10. Zone routing in a torus network

    DOE Patents [OSTI]

    Chen, Dong; Heidelberger, Philip; Kumar, Sameer

    2013-01-29T23:59:59.000Z

    A system for routing data in a network comprising a network logic device at a sending node for determining a path between the sending node and a receiving node, wherein the network logic device sets one or more selection bits and one or more hint bits within the data packet, a control register for storing one or more masks, wherein the network logic device uses the one or more selection bits to select a mask from the control register and the network logic device applies the selected mask to the hint bits to restrict routing of the data packet to one or more routing directions for the data packet within the network and selects one of the restricted routing directions from the one or more routing directions and sends the data packet along a link in the selected routing direction toward the receiving node.

  11. Evaluation of the DHCE Experiment

    SciTech Connect (OSTI)

    Greenwood, Lawrence R.; Baldwin, David L.; Hollenberg, Glenn W.; Kurtz, Richard J.

    2002-03-31T23:59:59.000Z

    The Dynamic Helium Charging Experiment (DHCE) experiment was conducted in the Fast Flux Test Facility (FFTF) during cycle 12, which was completed in 1992. The purpose of the experiment was to enhance helium generation in vanadium alloys to simulate fusion reactor helium-to-dpa ratios with a target goal of 4-5 appm He/dpa. The Fusion Materials Science Program is considering mounting another experiment in hopes of gathering additional data on the effect of helium on the mechanical and physical properties of vanadium structural materials. Pacific Northwest National Laboratory was assigned the task of evaluating the feasibility of conducting another DHCE experiment by carefully evaluating the results obtained of the first DHCE experiment. This report summarizes the results of our evaluation and presents recommendations for consideration by the Materials Science Coordinators Organization.

  12. Short Baseline Neutrino Oscillation Experiments

    E-Print Network [OSTI]

    Katori, Teppei

    2014-01-01T23:59:59.000Z

    Series of short baseline neutrino oscillation experiments provided unexpected results, and now they are called short baseline anomalies, and all indicates an existence of sterile neutrinos with a mass scale around 1~eV. The signals of short baseline anomalies are reported from 4 different classes of experiments. However, at this moment, there is no convincing theoretical model to explain such sterile neutrinos, and a single experiment to confirm 1~eV sterile neutrinos may be challenging. In this short note, we describe classes of short baseline neutrino oscillation experiments and their goals.

  13. Early strong interaction counter experiments

    SciTech Connect (OSTI)

    Terwilliger, K.M.

    1980-06-01T23:59:59.000Z

    The 17 /sup 0/ beam and some ..pi..-p two body scattering experiments run in the beginning years of the ZGS are discussed. (AIP)

  14. LANL | Physics | Dynamic Plutonium Experiments

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

    Dynamic plutonium experiments Since the end of nuclear testing the nation has had to rely on sophisticated computer models to ensure the safety and reliability of the nuclear...

  15. Work Experience Guidance for Managers

    E-Print Network [OSTI]

    Work Experience Guidance for Managers When approached with a request for work experience, managers. Any queries regarding CRB checks should be directed to your designated HR Manager. When a work any work, paid or unpaid: Before 7am or after 7pm For more than two hours on a school day or Sunday

  16. DHS Research Experience Summary

    SciTech Connect (OSTI)

    Venkatachalam, V

    2008-10-24T23:59:59.000Z

    I learned a great deal during my summer internship at Lawrence Livermore National Laboratory (LLNL). I plan to continue a career in research, and I feel that my experience at LLNL has been formative. I was exposed to a new area of research, as part of the Single Particle Aerosol Mass Spectrometry (SPAMS) group, and I had the opportunity to work on projects that I would not have been able to work on anywhere else. The projects both involved the use of a novel mass spectrometer that was developed at LLNL, so I would not have been able to do this research at any other facility. The first project that Zachary and I worked on involved using SPAMS to detect pesticides. The ability to rapidly detect pesticides in a variety of matrices is applicable to many fields including public health, homeland security, and environmental protection. Real-time, or near real-time, detection of potentially harmful or toxic chemical agents can offer significant advantages in the protection of public health from accidental or intentional releases of harmful pesticides, and can help to monitor the environmental effects of controlled releases of pesticides for pest control purposes. The use of organophosphate neurotoxins by terrorists is a possibility that has been described; this is a legitimate threat, considering the ease of access, toxicity, and relatively low cost of these substances. Single Particle Aerosol Mass Spectrometry (SPAMS) has successfully been used to identify a wide array of chemical compounds, including drugs, high explosives, biological materials, and chemical warfare agent simulants. Much of this groundbreaking work was carried out by our group at LLNL. In our work, we had the chance to show that SPAMS fulfills a demonstrated need for a method of carrying out real-time pesticide detection with minimal sample preparation. We did this by using a single particle aerosol mass spectrometer to obtain spectra of five different pesticides. Pesticide samples were chosen to represent four common classes of pesticides that are currently used in the US. Permethrin (a pyrethrin insecticide), dichlorvos and malathion (organophosphates), imidacloprid (a chloronicotinyl pesticide), and carbaryl (a carbamate) were selected for analysis. Samples were aerosolized either in water (using a plastic nebulizer) or in ethanol (using a glass nebulizer), and the particles entered the SPAMS instrument through a focusing lens stack. The particles then passed through a stage with three tracking lasers that were used to determine each particle's velocity. This velocity was used to calculate when to fire a desorption/ionization (D/I) laser in order to fragment the particle for analysis in a dual polarity time of flight mass spectrometer. Signals were digitized, and then analyzed using LLNL-developed software. We obtained chemical mass spectral signatures for each pesticide, and assigned peaks to the mass spectra based on our knowledge of the pesticides chemical structures. We then proved the robustness of our detection method by identifying the presence of pesticides in two real-world matrices: Raid{trademark} Ant Spray and a flea collar. To sample these, we simply needed to direct aerosolized particles into the SPAMS instrument. The minimal sample preparation required makes SPAMS very attractive as a detector. Essentially, we were able to show that SPAMS is a reliable and effective method for detecting pesticides at extremely low concentrations in a variety of matrices and physical states. The other project that I had the opportunity to be a part of did not involve data collection in the lab; it consisted of analyzing a large amount of data that had already been collected. We got to look at data collected over the course of about two months, when the SPAMS instrument was deployed to a public place. The machine sampled the air and collected spectra for over two months, storing all the spectra and associated data; we then looked at an approximately two-month subset of this data to search for patterns in the types of particles being detected. Essentially, we we

  17. Flexible corrugated cryotransferlines, long term experience at JET and the experience with supercritical helium flow conditions

    E-Print Network [OSTI]

    Obert, W

    1996-01-01T23:59:59.000Z

    Flexible corrugated cryotransferlines, long term experience at JET and the experience with supercritical helium flow conditions

  18. New Safety and Technical Challenges and Operational Experience on the JET First Trace Tritium Experiment

    E-Print Network [OSTI]

    New Safety and Technical Challenges and Operational Experience on the JET First Trace Tritium Experiment

  19. Flexible Corrugated Cryotransferlines, Long Term Experience at JET and the Experience with Supercritical Helium Flow Conditions

    E-Print Network [OSTI]

    Flexible Corrugated Cryotransferlines, Long Term Experience at JET and the Experience with Supercritical Helium Flow Conditions

  20. Essays in macroeconomics and experiments

    E-Print Network [OSTI]

    Shurchkov, Olga

    2008-01-01T23:59:59.000Z

    This dissertation consists of four chapters on empirical and experimental macroeconomics and other experimental topics. Chapter 1 uses a laboratory experiment to test the predictions of a dynamic global game designed to ...

  1. Progress in Compact Toroid Experiments

    SciTech Connect (OSTI)

    Dolan, Thomas James

    2002-09-01T23:59:59.000Z

    The term "compact toroids" as used here means spherical tokamaks, spheromaks, and field reversed configurations, but not reversed field pinches. There are about 17 compact toroid experiments under construction or operating, with approximate parameters listed in Table 1.

  2. DOE Corporate Operating Experience Program

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2011-04-08T23:59:59.000Z

    The Order institutes a DOE wide program for the management of operating experience to prevent adverse operating incidents and facilitate the sharing of good work practices among DOE sites. Cancels DOE O 210.2.

  3. ADVANCE! Leadership Experience Project Guidelines

    E-Print Network [OSTI]

    Hone, James

    ADVANCE! Leadership Experience Project Guidelines Fieldwork Practicum Description: The fieldwork component of the ADVANCE! leadership program offers students the opportunity to integrate theory exposure to that industry. Together, they design a leadership project in which the student takes an active

  4. Experiment Report Instructions General Instructions

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

    and the full name of their institutions. * Experiment report: Text and graphics must fit on the two page form. The level of detail to be provided is outlined in the following...

  5. Logo of the ALICE Experiment

    E-Print Network [OSTI]

    Hadre, Julie

    2011-01-01T23:59:59.000Z

    Logo of the ALICE Experiment. For dark background the 'ALICE' label is white. The ALICE label cannot be deleted. For further details about the ALICE graphic charter, contact: alice.image@cern.ch

  6. The MINERvA Experiment

    SciTech Connect (OSTI)

    Harris, Deborah A.; Kopp, Sacha; /Fermilab

    2011-03-18T23:59:59.000Z

    The MINERvA experiment is a dedicated cross-section experiment whose aim is to measure neutrino cross sections for inclusive and exclusive final states on several nuclei. The detector is fully commissioned and began running in March 2010. As a dedicated cross-section experiment, MINERvA has a particular need to know the incident neutrino flux: both the absolute level and the energy dependence. In these proceedings we describe the MINERvA detector, give an update on the experimental status, and discuss the means to determine the neutrino flux. The MINERvA experiment is now running and has completed 25% of its full Low Energy run. There are various techniques planned for understanding the flux, including taking neutrino data at several different beam configurations. The experiment has gotten a first glimpse of two of the six configurations, and completed four horn current scans. Because of its exclusive final state reconstruction capabilities MINERvA can provide the much needed input for current and future oscillation experiments. The inclusive final state measurements and comparisons of nuclear effects across as many states as possible will provide new insights into neutrino-nucleus scattering.

  7. Southern Ocean Iron Experiment (SOFex)

    SciTech Connect (OSTI)

    Coale, Kenneth H.

    2005-07-28T23:59:59.000Z

    The Southern Ocean Iron Experiment (SOFeX) was an experiment decades in the planning. It's implementation was among the most complex ship operations that SIO has been involved in. The SOFeX field expedition was successful in creating and tracking two experimentally enriched areas of the Southern Ocean, one characterized by low silicic acid, one characterized by high silicic acid. Both experimental sites were replete with abundant nitrate. About 100 scientists were involved overall. The major findings of this study were significant in several ways: (1) The productivity of the southern ocean is limited by iron availability. (2) Carbon uptake and flux is therefore controlled by iron availability (3) In spite of low silicic acid, iron promotes non-silicious phytoplankton growth and the uptake of carbon dioxide. (4) The transport of fixed carbon from the surface layers proceeds with a C:N ratio that would indicate differential remineralization of nitrogen at shallow depths. (5) These finding have major implications for modeling of carbon export based on nitrate utilization. (6) The general results of the experiment indicate that, beyond other southern ocean enrichment experiments, iron inputs have a much wider impact of productivity and carbon cycling than previously demonstrated. Scientific presentations: Coale, K., Johnson, K, Buesseler, K., 2002. The SOFeX Group. Eos. Trans. AGU 83(47) OS11A-0199. Coale, K., Johnson, K. Buesseler, K., 2002. SOFeX: Southern Ocean Iron Experiments. Overview and Experimental Design. Eos. Trans. AGU 83 (47) OS22D-01. Buesseler, K.,et al. 2002. Does Iron Fertilization Enhance Carbon Sequestration? Particle flux results from the Southern Ocean Iron Experiment. Eos. Trans. AGU 83 (47), OS22D-09. Johnson, K. et al. 2002. Open Ocean Iron Fertilization Experiments From IronEx-I through SOFeX: What We Know and What We Still Need to Understand. Eos. Trans. AGU 83 (47), OS22D-12. Coale, K. H., 2003. Carbon and Nutrient Cycling During the Southern Ocean Iron Enrichment Experiments. Seattle, WA. Geological Society of America. Coale, K., 2003. Open Ocean Iron Enrichment Experiments: What they have told us, what they have not. American Society for Limnology and Oceanography and The Oceanography Society, Honolulu, February 2004. Coale, K., 2004. Recent Research from the Southern Ocean Iron Experiment (SOFeX), in Taking the Heat: What is the impact of ocean fertilization on climate and ocean ecology? Science of earth and sky. AAAS, February 12-16, Seattle, WA

  8. Results from D-T Experiments on TFTR and Implications for Achieving an Ignited Plasma

    E-Print Network [OSTI]

    of fusion energy from deuterium-tritium plasmas in the Tokamak Fusion Test Reactor (TFTR) and the Joint-like temperatures and densities and, through the use of deuterium-tritium (D-T) fuel on the Joint European Torus defined, even power producing reactors, for control reasons, will most likely be operating "near

  9. Experiment

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField8,Dist. Category UC-l 1,Energy Consumers | Department ofaExpedited

  10. Experiences

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC) Environmental Assessments (EA) /EmailMolecular Solids |5Expanded Pending

  11. Optimizing New Dark Energy Experiments

    SciTech Connect (OSTI)

    Tyson, J. Anthony [University of California, Davis

    2013-08-26T23:59:59.000Z

    Next generation “Stage IV” dark energy experiments under design during this grant, and now under construction, will enable the determination of the properties of dark energy and dark matter to unprecedented precision using multiple complementary probes. The most pressing challenge in these experiments is the characterization and understanding of the systematic errors present within any given experimental configuration and the resulting impact on the accuracy of our constraints on dark energy physics. The DETF and the P5 panel in their reports recommended “Expanded support for ancillary measurements required for the long-term program and for projects that will improve our understanding and reduction of the dominant systematic measurement errors.” Looking forward to the next generation Stage IV experiments we have developed a program to address the most important potential systematic errors within these experiments. Using data from current facilities it has been feasible and timely to undertake a detailed investigation of the systematic errors. In this DOE grant we studied of the source and impact of the dominant systematic effects in dark energy measurements, and developed new analysis tools and techniques to minimize their impact. Progress under this grant is briefly reviewed in this technical report. This work was a necessary precursor to the coming generations of wide-deep probes of the nature of dark energy and dark matter. The research has already had an impact on improving the efficiencies of all Stage III and IV dark energy experiments.

  12. From HumanFrom Human--Subject Experiments ToSubject Experiments To ComputationalComputational--Agent ExperimentsAgent Experiments

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    1 From HumanFrom Human--Subject Experiments ToSubject Experiments To Computational: ACE Electricity Market ACE Human-Subject (HS) Experiments Proof-of-Concept Proposal (GMUComputational--Agent ExperimentsAgent Experiments (And Everything In Between)(And Everything In Between) New Directions, IESA

  13. Neutrinoless Double Beta Decay Experiments

    E-Print Network [OSTI]

    Garfagnini, Alberto

    2014-01-01T23:59:59.000Z

    Neutrinoless double beta decay is the only process known so far able to test the neutrino intrinsic nature: its experimental observation would imply that the lepton number is violated by two units and prove that neutrinos have a Majorana mass components, being their own anti-particle. While several experiments searching for such a rare decay have been performed in the past, a new generation of experiments using different isotopes and techniques have recently released their results or are taking data and will provide new limits, should no signal be observed, in the next few years to come. The present contribution reviews the latest public results on double beta decay searches and gives an overview on the expected sensitivities of the experiments in construction which will be able to set stronger limits in the near future.

  14. Neutrinoless Double Beta Decay Experiments

    E-Print Network [OSTI]

    Alberto Garfagnini

    2014-08-11T23:59:59.000Z

    Neutrinoless double beta decay is the only process known so far able to test the neutrino intrinsic nature: its experimental observation would imply that the lepton number is violated by two units and prove that neutrinos have a Majorana mass components, being their own anti-particle. While several experiments searching for such a rare decay have been performed in the past, a new generation of experiments using different isotopes and techniques have recently released their results or are taking data and will provide new limits, should no signal be observed, in the next few years to come. The present contribution reviews the latest public results on double beta decay searches and gives an overview on the expected sensitivities of the experiments in construction which will be able to set stronger limits in the near future.

  15. The PICASSO Dark Matter Experiment

    SciTech Connect (OSTI)

    Wichoski, Ubi [Department of Physics, Laurentian University, Sudbury, ON, P3E 2C6 (Canada); Collaboration: PICASSO Collaboration

    2011-12-16T23:59:59.000Z

    The PICASSO experiment searches for cold dark matter through the direct detection of weakly interacting massive particles (WIMPs) via their spin-dependent interactions with fluorine at SNOLAB, Sudbury--ON, Canada since 2002. The detection principle is based on the superheated droplet technique; the detectors consist of a gel matrix with millions of liquid droplets of superheated fluorocarbon (C4F10) dispersed in it. Recently, a new setup has been built and installed in the Ladder Lab area at SNOLAB. In the present phase of the experiment the Collaboration is running 4.5-litre detector modules with approximately 85 g of active mass per module. Here, we give an overview of the experiment and discuss the progress in background mitigation, in particular background discrimination in the PICASSO detectors.

  16. The Lead Radius Experiment PREX

    SciTech Connect (OSTI)

    Robert Michaels

    2006-10-02T23:59:59.000Z

    The proposed PREX experiment at Jefferson Lab will measure the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons at an energy of 850 MeV and a scattering angle of 6 degrees. Since the Z0 boson couples mainly to neutrons, this asymmetry provides a clean measurement of R{sub n} with a projected experimental precision of 1 %. In addition to being a fundamental test of nuclear theory, a precise measurement of R{sub n} pins down the density dependence of the symmetry energy of neutron rich nuclear matter which has impacts on neutron star structure, heavy ion collisions, and atomic parity violation experiments.

  17. University Housing! First Year Experience

    E-Print Network [OSTI]

    community -Committed faculty member for academic success -Group Work focused -Learning Community Assistant for academic success -Group Work focused -Learning Community Assistant (LCA) Living Learning Communities (LLCs) + + The choice is yours! First Year Experience Thematic First Year Student Housing focused around development

  18. DOE Corporate Operating Experience Program

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2006-06-12T23:59:59.000Z

    The Order establishes a DOE wide program for management of operating experience to prevent adverse operating incidents and to expand the sharing of good work practices among DOE sites. Canceled by DOE O 210.2A. Does not cancel other directives.

  19. Hydrogen Piping Experience in Chevron

    E-Print Network [OSTI]

    Hydrogen Piping Experience in Chevron Refining Ned Niccolls Materials Engineer Chevron Energy Technology Company Hydrogen Pipeline Working Group Workshop August 30-31, 2005 #12;Outline 2 Overall perspectives from long term use of hydrogen piping in refining. Piping specifications and practices. The (few

  20. Soliton molecules: Experiments and optimization

    SciTech Connect (OSTI)

    Mitschke, Fedor [Universität Rostock, Institut für Physik, Universitätsplatz 3, 18051 Rostock (Germany)

    2014-10-06T23:59:59.000Z

    Stable compound states of several fiber-optic solitons have recently been demonstrated. In the first experiment their shape was approximated, for want of a better description, by a sum of Gaussians. Here we discuss an optimization strategy which helps to find preferable shapes so that the generation of radiative background is reduced.

  1. ID-69 Sodium drain experiments

    SciTech Connect (OSTI)

    Johnston, D.C.

    1996-09-19T23:59:59.000Z

    This paper describes experiments to determine the sodium retention and drainage from the two key areas of an ID-69. This information is then used as the initiation point for guidelines of how to proceed with washing an ID-69 in the IEM Cell Sodium Removal System.

  2. Maintenance FUSION IGNITION RESEARCH EXPERIMENT

    E-Print Network [OSTI]

    Insulation Enclosure Remote Maintenance Module FUSION IGNITION RESEARCH EXPERIMENT SYSTEM coils. The magnets are liquid nitrogen cooled and the entire device is surrounded by a thermal enclosure. The double wall vacuum vessel integrates cooling and shielding in a shape that maximizes shielding of ex

  3. Fusion Ignition Research Experiment Highlights

    E-Print Network [OSTI]

    of the FIRE pre-conceptual design study is to define a low-cost (~$1B) burning plasma experiment to attain to the burning plasma step because of the progress made in fusion science and fusion technology. Progress toward design and fabrication of FIRE, and that there is confidence that FIRE will achieve burning plasma

  4. Organic Photovoltaics Experiments Showcase 'Superfacility' Research

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

    Organic Photovoltaics Experiments Showcase 'Superfacility' Concept Organic Photovoltaics Experiments Showcase 'Superfacility' Concept Collaboration Key to Enabling On-The-Fly HPC...

  5. Former Workers Medical Facilities with Experience Evaluating...

    Office of Environmental Management (EM)

    Workers Medical Facilities with Experience Evaluating Chronic Beryllium Disease Former Workers Medical Facilities with Experience Evaluating Chronic Beryllium Disease April 2011...

  6. Documentation Requirements for Pressurized Experiment Equipment

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

    Documentation Requirements for Pressurized Experiment Apparatus PSSC NOTE01 15-Jan-2013 When bringing a piece of apparatus to the APS for an experiment that will involve pressure,...

  7. NSTX Run Statistics and Update Friday November 16, 2001

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    ->MDSplus direct Electron Bernstein Wave EB X ECH Electron Cyclotron Heating EC X NPA Neutral Particle FIReTIP Far Infrared Tang Interferom. FT X PC & PLC for control Filtered Visible (Filter scopes) FV X (old) PC broke Coaxial Helicity Injection (CHI) HI X X EPICS Interim CHERS IC X PC FTP Infrared Cameras

  8. Edge Physics Studies on the NSTX Spherical Tokamak

    SciTech Connect (OSTI)

    Boedo, J.

    2013-01-29T23:59:59.000Z

    In this funding period, activities were focused on processing data for publication, writing code to facilitate processing of data in the future as programmatic needs arise, and closing down grant activities.

  9. Status of the NSTX control Presented by D. A. Gates

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    - 2005 #12;Hardware standards ease development Merlin 9422 16-bit Digitizer w/ FPDP 0.5Gbit/s-3µsec · Graphical user interface · Shot "construction" from multiple archived shots · Interface to EFIT database

  10. NSTX-U PRINCETON PLASMA D-NSTXU-??-??-???

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    Requirements designated by RLM LABWIDE: Work Planning Form #_______(ENG-032) Lockout/Tagout (ESH-016) Confined

  11. NSTX Upgrade: ST research to accelerate fusion development

    E-Print Network [OSTI]

    parameter regimes to advance predictive capability - for ITER and beyond · Develop ST as fusion energy. Radiation-tolerant magnets, design (backup) 4 Culham (UK) UT Austin ORNLPPPL Example ST-FNSF concepts #12-up/ramp-up strategy Time Fast wave EC/EBW · 1 3MW 28GHz (with 2nd NBI) world-leading start-up/ramp-up for ST

  12. Objective Criteria for Assessing Safe NSTX-U Startup

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    ) and Failure Modes and Effects Analysis (FMEA) reviews. SAD/FMEA Author and Activity Certification Committee-U facility and systems adequately described in the SAD? 1. Review SAD Chapter 3 and associated FMEAs FMEAs, and review SAD Chapter 4. Consider follow up interviews with cognizant systems engineers, SAD

  13. Meson Photoproduction Experiments with CLAS

    SciTech Connect (OSTI)

    Eugene Pasyuk

    2012-12-01T23:59:59.000Z

    A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to light baryon spectroscopy. Meson photoprodcution experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams and frozen spin polarized targets provide unique conditions for this type of experiments. This combination of experimental tools gives a remarkable opportunity to measure double polarization observables for different pseudo-scalar meson photoproduction processes. For the first time, a complete or nearly complete measurement became possible and will facilitate model independent extraction of the reaction amplitude. An overview of the experimental program and its current status together with recent results on double polarization measurements in ?{sup +} photoproduction are presented.

  14. The Super-Kamiokande Experiment

    E-Print Network [OSTI]

    C. W. Walter

    2008-02-07T23:59:59.000Z

    Super-Kamiokande is a 50 kiloton water Cherenkov detector located at the Kamioka Observatory of the Institute for Cosmic Ray Research, University of Tokyo. It was designed to study neutrino oscillations and carry out searches for the decay of the nucleon. The Super-Kamiokande experiment began in 1996 and in the ensuing decade of running has produced extremely important results in the fields of atmospheric and solar neutrino oscillations, along with setting stringent limits on the decay of the nucleon and the existence of dark matter and astrophysical sources of neutrinos. Perhaps most crucially, Super-Kamiokande for the first time definitively showed that neutrinos have mass and undergo flavor oscillations. This chapter will summarize the published scientific output of the experiment with a particular emphasis on the atmospheric neutrino results.

  15. The Suli Experience | The Ames Laboratory

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

    The Suli Experience Students and mentors talk about the Science Undergraduate Laboratory Internship (SULI) program...

  16. From HumanFrom Human--Subject Experiments ToSubject Experiments To ComputationalComputational--Agent ExperimentsAgent Experiments

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    1 From HumanFrom Human--Subject Experiments ToSubject Experiments To Computational Experiments - 100% human 100% computational agents What is Agent-based Comp Econ (ACE)? - 100% computational://www.econ.iastate.edu/tesfatsi/aexper.htm #12;3 Spectrum of Possible Experiments 100% human Humans with computer access Human

  17. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION APOLLO EXPERIMENTS

    E-Print Network [OSTI]

    Rathbun, Julie A.

    .·... .. ..·.·.·.::::::::::::::::::::::: :::::::::::::::::::::::·.·.·.·.·.·.·.·.·.·.·.·::::::::::::::::::::::: :·:·:·:·:·:·:·:·:·:·:·: ·:·:·:·:·:·:·:·:·:·:·:· NATIONAL AERONAUTICS AND SPACE ADMINISTRATION APOLLO EXPERIMENTS PROGRAM REVIEW LUNAR SURFACE EXPERIMENTS;9:30 10:00 12:00 AGENDA APOLLO EXPERIMENTS PROGRAM REVIEW FEBRUARY 17 - 18, 1972 MSC, BLDG. 2, ROOM 602 THURSDAY, FEBRUARY 17, 1972 LUNAR SURFACE EXPERIMENTS - 10:00 A. MISSION ANOMALIES - 11:30 B. APOLLO 16, 17

  18. My PhD Experience Rosta Farzan

    E-Print Network [OSTI]

    Brusilovsky, Peter

    10/25/09 1 My PhD Experience Rosta Farzan (rfarzan@cs.cmu.edu) Oct 19, 2009 My PhD Experience... #12;10/25/09 2 My PhD Experience... SharifUniversityofTechnology Bachelor'sofScienceinComputerEngineering My PhD Experience... So;wareengineer@aso;warecompany Ebusinesssystemsfordialoguesbetweenpeers #12

  19. Nodalization study for BETHSY experiment

    SciTech Connect (OSTI)

    Petelin, S.; Mavko, B.; Ravnikar, I. [Univ. of Ljubljana (Slovenia); Cebull, P.; Hassan, Y.A. [Texas A and M Univ., College Station, TX (United States). Dept. of Nuclear Engineering

    1996-08-01T23:59:59.000Z

    The BETHSY experiment 9.1.b was used to assess different versions of the RELAP5 computer code using three various detailed nodalizations. This experimental transient scenario involved a scaled 2 inch cold leg break without high pressure safety injection and with delayed operator action for a secondary system depressurization. In order to optimize details of nodalization regard to satisfactory accuracy a detailed study of different RELAP5 codes and nodalizations was performed. Qualitative evolution of RELAP5 code was also analyzed.

  20. Final Report: Levitated Dipole Experiment

    SciTech Connect (OSTI)

    Kesner, Jay [Massachusetts Institute of Technology; Mauel, Michael [Columbia University

    2013-03-10T23:59:59.000Z

    Since the very first experiments with the LDX, research progress was rapid and significant. Initial experiments were conducted with the high-field superconducting coil suspended by three thin rods. These experiments produced long-pulse, quasi-steady-state microwave discharges, lasting more than 10 s, having peak beta values of 20% [Garnier et al., Physics of Plasmas, 13 (2006) 056111]. High- beta, near steady-state discharges have been maintained in LDX for more than 20 seconds, and this capability made LDX the longest pulse fusion confinement experiment operating in the U.S. fusion program. A significant measure of progress in the LDX research program was the routine investigation of plasma confinement with a magnetically-levitated dipole and the resulting observations of confinement improvement. In both supported and levitated configurations, detailed measurements were made of discharge evolution, plasma dynamics and instability, and the roles of gas fueling, microwave power deposition profiles, and plasma boundary shape. High-temperature plasma was created by multi frequency electron cyclotron resonance heating at 2.45 GHz, 6.4 GHz, 10.5 GHz and 28 GHz allowing control of heating profiles. Depending upon neutral fueling rates, the LDX discharges contain a fraction of energetic electrons, with mean energies above 50 keV. Depending on whether or not the superconducting dipole was levitated or supported, the peak thermal electron temperature was estimated to exceed 500 eV and peak densities to approach 1e18 m?3. We have found that levitation causes a strong inwards density pinch [Boxer et al., Nature Physics, 6 (2010) 207] and we have observed the central plasma density increase dramatically indicating a significant improvement in the confinement of a thermal plasma species.

  1. Plasma Wakefield Experiments at FACET

    SciTech Connect (OSTI)

    Hogan, M.J.; England, R.J.; Frederico, J.; Hast, C.; Li, S.Z.; Litos, M.; Walz, D.; /SLAC; An, W.; Clayton, C.E.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.; Tochitsky, S.; /UCLA; Muggli, P.; Pinkerton, S.; Shi, Y.; /Southern California U.

    2011-08-19T23:59:59.000Z

    FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration beginning in summer 2011. The nominal FACET parameters are 23GeV, 3nC electron bunches compressed to {approx}20{micro}m long and focused to {approx}10{micro}m wide. The intense fields of the FACET bunches will be used to field ionize neutral lithium or cesium vapor produced in a heat pipe oven. Previous experiments at the SLAC FFTB facility demonstrated 50GeV/m gradients in an 85cm field ionized lithium plasma where the interaction distance was limited by head erosion. Simulations indicate the lower ionization potential of cesium will decrease the rate of head erosion and increase single stage performance. The initial experimental program will compare the performance of lithium and cesium plasma sources with single and double bunches. Later experiments will investigate improved performance with a pre-ionized cesium plasma. The status of the experiments and expected performance are reviewed. The FACET Facility is being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The facility will begin commissioning in summer 2011 and conduct an experimental program over the coming five years to study electron and positron beam driven plasma acceleration with strong wake loading in the non-linear regime. The FACET experiments aim to demonstrate high-gradient acceleration of electron and positron beams with high efficiency and negligible emittance growth.

  2. Damaged Fuel Experiment DF-1

    SciTech Connect (OSTI)

    Gasser, R.D.; Fryer, C.P.; Gauntt, R.O.; Marshall, A.C.; Reil, K.O.; Stalker, K.T.

    1990-01-01T23:59:59.000Z

    A series of in-pile experiments addressing LWR severe fuel damage phenomena has been conducted in the Annular Core Research Reactor (ACRR) at Sandia National Laboratories. The ACRR Debris Formation and Relocation (DF) experiments are quasi-separate effects tests that provide a data base for the development and verification of models for LWR severe core damage accidents. The first experiment in this series, DF-1, was performed on March 15, 1984, and the results are presented in this report. The DF-1 experiment examined the effects of low initial clad oxidation conditions on fuel damage and relocation processes. The DF-1 test assembly consisted of a nine-rod square-matrix bundle that employed PWR-type fuel rods with a 0.5-m fissile length. The fuel rods were composed of 10% enriched UO{sub 2} pellets within a zircaloy-4 cladding. Steam flowed through the test bundle at flow rates varying between 0.5 and 3 g/s, and the ACRR maintained a peak power level of 1.5 MW during the high temperature oxidation phase of the test inducing {approximately}8.5 kW fission power and {approximately}20 kW peak oxidation power in the assembly. Visual observation showed early clad relocation and partial blockage formation at the grid spacer location accompanied by production of a dense aerosol. Posttest cross sections show liquefaction losses of fuel in excess of 10 volume percent, as well as large fractional losses of cladding material from the upper two-thirds of the bundle. The quantity of hydrogen measured during the test was consistent with the observed magnitude of cladding oxidation. Oxidation driven heating rates of 25 K/s and peak temperatures in excess of 2525 K were observed. The analyses, interpretation, and application of these results to severe fuel damage accidents are discussed. 27 refs., 118 figs., 23 tabs.

  3. Attosecond Double-Slit Experiment

    SciTech Connect (OSTI)

    Lindner, F.; Schaetzel, M.G.; Baltuska, A.; Goulielmakis, E. [Max-Planck-Institut fuer Quantenoptik, 85748 Garching (Germany); Walther, H. [Max-Planck-Institut fuer Quantenoptik, 85748 Garching (Germany); Ludwig-Maximilians-Universitaet Muenchen, 85748 Garching (Germany); Krausz, F. [Max-Planck-Institut fuer Quantenoptik, 85748 Garching (Germany); Ludwig-Maximilians-Universitaet Muenchen, 85748 Garching (Germany); Institut fuer Photonik, Technische Universitaet Wien, Gusshausstr. 27, A-1040 Vienna (Austria); Milosevic, D.B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Bauer, D. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Becker, W. [Max-Born-Institut, Max-Born-Str. 2a, 12489 Berlin (Germany); Paulus, G.G. [Max-Planck-Institut fuer Quantenoptik, 85748 Garching (Germany); Ludwig-Maximilians-Universitaet Muenchen, 85748 Garching (Germany); Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States)

    2005-07-22T23:59:59.000Z

    A new scheme for a double-slit experiment in the time domain is presented. Phase-stabilized few-cycle laser pulses open one to two windows (slits) of attosecond duration for photoionization. Fringes in the angle-resolved energy spectrum of varying visibility depending on the degree of which-way information are measured. A situation in which one and the same electron encounters a single and a double slit at the same time is observed. The investigation of the fringes makes possible interferometry on the attosecond time scale. From the number of visible fringes, for example, one derives that the slits are extended over about 500 as.

  4. A Class Experiment in Imagery

    E-Print Network [OSTI]

    Hanger, James Howard

    1911-01-01T23:59:59.000Z

    '. Various arguments we~>e introduced as evidence. This is a good example*-"Wot all my motor tendencies depend upon past motor experiences. It is possible for me to imagine' myself falling through space from an airship or any high point. I have never... when looking for the first time from a considerable height is,no doubt,the basis for his imagined feeling in connedtion with the thought^of falling from an airship. But in this sensation, it is safe to say that the rush of air as one approaches...

  5. Commissioning of the ATLAS Experiment

    E-Print Network [OSTI]

    Juergen Thomas; for the ATLAS Collaboration at CERN

    2008-08-07T23:59:59.000Z

    The status of the commissioning of the ATLAS experiment as of May 2008 is presented. The sub-detector integration in recent milestone weeks is described. Cosmic commissioning in milestone week M6 included simultaneous data-taking and combined track analysis of the muon detector and inner detector, as well as combined analysis of muon detector and muon trigger. The calorimeters have achieved near-full operation, and are integrated with the calorimeter trigger. The high-level-trigger infrastructure is being installed and algorithms tested in technical runs.

  6. Physics with the ALICE experiment

    SciTech Connect (OSTI)

    Kharlov, Yu. V. [Institute for High Energy Physics (Russian Federation)

    2013-12-15T23:59:59.000Z

    ALICE experiment at LHC collects data in pp collisions at 1497-1 = 0.9, 2.76, and 7 TeV and in PbPb collisions at 2.76 TeV. Highlights of the detector performance and an overview of experimental results measured with ALICE in pp and AA collisions are presented in this paper. Physics with protonproton collisions is focused on hadron spectroscopy at low and moderate p{sub t}. Measurements with lead-lead collisions are shown in comparison with those in pp collisions, and the properties of hot quark matter are discussed.

  7. Neutrinoless double beta decay experiments

    E-Print Network [OSTI]

    K. Zuber

    2006-10-04T23:59:59.000Z

    The study of neutrinoless double beta decay is of outmost importance for neutrino physics. It is considered to be the gold plated channel to probe the fundamental character of neutrinos and to determine the neutrino mass. From the experimental point about nine different isotopes are explored for the search. After a general introduction follows a short discussion on nuclear matrix element calculations and supportive measurements. The current experimental status of double beta searches is presented followed by a short discussion of the ideas and proposals for large scale experiments.

  8. Experiment Design and Analysis Guide - Neutronics & Physics

    SciTech Connect (OSTI)

    Misti A Lillo

    2014-06-01T23:59:59.000Z

    The purpose of this guide is to provide a consistent, standardized approach to performing neutronics/physics analysis for experiments inserted into the Advanced Test Reactor (ATR). This document provides neutronics/physics analysis guidance to support experiment design and analysis needs for experiments irradiated in the ATR. This guide addresses neutronics/physics analysis in support of experiment design, experiment safety, and experiment program objectives and goals. The intent of this guide is to provide a standardized approach for performing typical neutronics/physics analyses. Deviation from this guide is allowed provided that neutronics/physics analysis details are properly documented in an analysis report.

  9. Stack Monitor Operating Experience Review

    SciTech Connect (OSTI)

    L. C. Cadwallader; S. A. Bruyere

    2009-05-01T23:59:59.000Z

    Stack monitors are used to sense radioactive particulates and gases in effluent air being vented from rooms of nuclear facilities. These monitors record the levels and types of effluents to the environment. This paper presents the results of a stack monitor operating experience review of the U.S. Department of Energy (DOE) Occurrence Reporting and Processing System (ORPS) database records from the past 18 years. Regulations regarding these monitors are briefly described. Operating experiences reported by the U.S. DOE and in engineering literature sources were reviewed to determine the strengths and weaknesses of these monitors. Electrical faults, radiation instrumentation faults, and human errors are the three leading causes of failures. A representative “all modes” failure rate is 1E-04/hr. Repair time estimates vary from an average repair time of 17.5 hours (with spare parts on hand) to 160 hours (without spare parts on hand). These data should support the use of stack monitors in any nuclear facility, including the National Ignition Facility and the international ITER project.

  10. Final Report: Levitated Dipole Experiment

    SciTech Connect (OSTI)

    Kesner, Jay; Mauel, Michael

    2013-03-10T23:59:59.000Z

    Since the very first experiments with the LDX, research progress was rapid and significant. Initial experiments were conducted with the high-field superconducting coil suspended by three thin rods. These experiments produced long-pulse, quasi-steady-state microwave discharges, lasting more than 10 s, having peak beta values of 20% [Garnier, Phys. Plasmas, v13, p. 056111, 2006]. High-beta, near steady-state discharges have been maintained in LDX for more than 20 seconds, and this capability makes LDX the longest pulse fusion confinement experiment now operating in the U.S. fusion program. In both supported and levitated configurations, detailed measurements are made of discharge evolution, plasma dynamics and instability, and the roles of gas fueling, microwave power deposition profiles, and plasma boundary shape. High-temperature plasma is created by multifrequency electron cyclotron resonance heating allowing control of heating profiles. Depending upon neutral fueling rates, the LDX discharges contain a fraction of energetic electrons, with mean energies above 50 keV. Depending on whether or not the superconducting dipole is levitated or supported, the peak thermal electron temperature is estimated to exceed 500 eV and peak densities reach 1.0E18 (1/m3). Several significant discoveries resulted from the routine investigation of plasma confinement with a magnetically-levitated dipole. For the first time, toroidal plasma with pressure approaching the pressure of the confining magnetic field was well-confined in steady-state without a toroidal magnetic field. Magnetic levitation proved to be reliable and is now routine. The dipole's cryostat allows up to three hours of "float time" between re-cooling with liquid helium and providing scientists unprecedented access to the physics of magnetizd plasma. Levitation eliminates field-aligned particle sources and sinks and results in a toroidal, magnetically-confined plasma where profiles are determined by cross-field transport. We find levitation causes the central plasma density to increase dramatically and to significantly improve the confinement of thermal plasma [Boxer, Nature-Physics, v8, p. 949, 2010]. Several diagnostic systems have been used to measure plasma fluctuations, and these appear to represent low-frequency convection that may lead to adiabatic heating and strongly peaked pressure profiles. These experiments are remarkable, and the motivate wide-ranging studies of plasma found in space and confined for fusion energy. In the following report, we describe: (i) observations of the centrally-peaked density profile that appears naturally as a consequence of a strong turbulent pinch, (ii) observations of overall density and pressure increases that suggest large improvements to the thermal electron confinement time result occur during levitation, and (iii) the remarkable properties of low-frequency plasma fluctuations that cause magnetized plasma to "self-organize" into well-confined, centrally-peaked profiles that are relative to fusion and to space.

  11. HERS experiment cause for confidence.

    SciTech Connect (OSTI)

    Cavallo, J. D.; Energy Systems

    1999-09-01T23:59:59.000Z

    At last April's Affordable Comfort conference, I conducted a small HERS (home energy ratings) experiment to examine the relative variability of ratings in new and older homes. The experiment grew out of discussions with Oak Ridge National Laboratory Senior Researcher Mark Ternes and EPA Energy Specialist Mia South about how good the HERS tools currently employed in the new homes market are at identifying cost-effective conservation measures in existing homes. Older homes present challenges for raters that may not generally exist in new construction. These include the absence of blueprints, the inability to interview the builder, the difficulty of identifying the operating efficiency of installed equipment, and different envelope characteristics within the home caused by partial remodels over the years. For precisely these reasons, the need for accurate ratings of older homes is acute. The efficacy of ratings in existing homes hinges on two questions: How accurate are the ratings in existing homes? and, How much does accuracy matter to the selection of conservation measures? A small experiment was organized to test the variability of ratings. Two homes were chosen to represent the very broad spectra that raters can find in the new-construction and existing-home housing stock. The new home in Park Ridge, Illinois, is typical in size and layout of the homes being built in the suburbs around Chicago. This four-bedroom, two-story house with finished basement measures slightly more than 4,000 ft{sup 2}, including the basement. The older home is located in Elgin, Illinois, and was built before 1940, probably sometime in the '20s or '30s. This two-bedroom house has a basement in which the furnace, water heater, clothes washer, and dryer are located. The raters disagreed as to whether the basement should be considered part of the conditioned space. Excluding the basement area, the house measurement approximately 1,000 ft{sup 2}. The rating process included a site visit to measure the homes features, inspection of the blueprints for the new home (none existed for the Elgin home), and a blower door test. After the raters completed their analysis, I examined the effect that the variability of ratings for the Elgin home had on choices for energy conservation measures. Although the sample was small, the results of this experiment are valuable. They may be summarized as follows: First, the ratings that different analysts estimated varied more widely for the older home than they did for the new home. Second, for the older home, the identification of cost-effective energy conservation measures was insensitive to the variation in ratings. Clearly, these findings need to be verified in further experiments. But it is noteworthy that the separate ratings of the new home were in such good agreement, and that cost-effective efficiency recommendations can be arrived at even when divergences exist in the absolute rating value. These findings also suggest that it is appropriate to have confidence in ratings as a tool for identifying cost-effective energy measures in older housing stock.

  12. Experiences of Women Leaders in México 

    E-Print Network [OSTI]

    Moreno, Ana

    2012-10-19T23:59:59.000Z

    This qualitative study sought to understand better the experiences of women leaders in México, a predominantly male-dominated culture. Seven women leaders were interviewed. They shared personal experiences, reflections, ...

  13. The MINOS Experiment: Results and Prospects

    SciTech Connect (OSTI)

    Evans, Justin [University of Manchester] (ORCID:0000000346973337)

    2013-01-01T23:59:59.000Z

    The Minos experiment has used the world's most powerful neutrino beam to make precision neutrino oscillation experiments. By observing the disappearance of muon neutrinos, MINOS has made the world's most precise measurement of the larger neutrino mass splitting....

  14. Proposal for PLASMA LENS EXPERIMENT AT

    E-Print Network [OSTI]

    Proposal for PLASMA LENS EXPERIMENT AT THE FINAL FOCUS TEST BEAM April 1, 1997 THE PLASMA LENS.....................................................................................3 1.1 Plasma Focusing ......................................................................3 1.2 Previous Plasma Lens Experiments.................................................4 1.3 Plasma Lens

  15. Interactive portraiture : designing intimate interactive experiences

    E-Print Network [OSTI]

    Zuckerman, Orit

    2006-01-01T23:59:59.000Z

    In this thesis I present a set of interactive portrait experiences that strive to create an intimate connection between the viewer and the portrayed subject; an emotional experience, one of personal reflection. My interactive ...

  16. Infusing Real World Experiences into ENGINEERING

    E-Print Network [OSTI]

    Napier, Terrence

    Infusing Real World Experiences into ENGINEERING EDUCATION #12;This project is a collaboration with the authors and NAE. #12;Infusing Real World Experiences into Engineering Education 2012 #12;2 Preface The aim

  17. Hanbury Brown-Twiss Experiment with Coherent

    E-Print Network [OSTI]

    39 Chapter 2 Hanbury Brown-Twiss Experiment with Coherent Light This chapter was previously a theory that allows us #12;40 Hanbury Brown-Twiss Experiment with Coherent Light to construct processes

  18. Status of the MAJORANA DEMONSTRATOR experiment

    SciTech Connect (OSTI)

    Martin, R. D. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA and Department of Physics, University of South Dakota, Vermillion, SD (United States); Abgrall, N.; Chan, Y-D.; Hegai, A.; Mertens, S.; Poon, A. W. P.; Vetter, K. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Aguayo, E.; Fast, J. E.; Hoppe, E. W.; Kouzes, R. T.; LaFerriere, B. D.; Orrell, J. L.; Overman, N. R.; Soin, A. [Pacific Northwest National Laboratory, Richland, WA (United States); Avignone III, F. T. [Department of Physics and Astronomy, University of South Carolina, Columbia, SC, USA and Oak Ridge National Laboratory, Oak Ridge, TN (United States); Barabash, A. S.; Konovalov, S. I.; Yumatov, V. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Bertrand, F. E. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); and others

    2014-06-24T23:59:59.000Z

    The MAJORANA DEMONSTRATOR neutrinoless double beta-decay experiment is currently under construction at the Sanford Underground Research Facility in South Dakota, USA. An overview and status of the experiment are given.

  19. Overview of Fusion Nuclear Technology in the US

    SciTech Connect (OSTI)

    Morley, Neil B.; Abdou, Mohamed A.; Anderson, Mark; Calderoni, P.; Kurtz, Richard J.; Nygren, R N.; Raffray, R; Sawan, M.; Sharpe, Peter J.; Smolentsev, S.; Willms, Scott; Ying, A Y.

    2006-02-01T23:59:59.000Z

    Fusion Nuclear Technology (FNT) research in the United States encompasses many activities and requires expertise and capabilities in many different disciplines. The US Enabling Technology program is divided into several task areas, with aspects of fusion nuclear technology being addressed mainly in the Plasma Chamber, Neutronics, Safety, Materials, Tritium and Plasma Facing Component Programs. These various programs work together to address key FNT topics, including support for the ITER basic machine and the ITER Test Blanket Module, support for domestic plasma experiments, and development of DEMO relevant material and technological systems for blankets, shields, and plasma facing components. While it is difficult to describe all these activities in adequate detail, this paper gives an overview of critical FNT activities. With the recent return of the US to the ITER collaboration, several activities in support of the ITER machine have been initiated, including development of the first wall shielding blanket baffle module (module 18), testing of plasma facing components, ITER tokamak exhaust tritium processing system development, and 3-D neutronics and activation code advances. The ITER test blanket module development activity has also been restarted in the US, and critical R&D is proceeding on ceramic breeder thermomechanical systems and lead-lithium breeder systems utilizing SiC composite flow channel inserts for thermal and MHD electrical insulation. Novel research on free surface liquid metal divertors is also continuing, with the goal of fielding a lithium free surface divertor in the National Spherical Torus eXperimental device (NSTX) and aiding the development of the Lithium Tokamak Experiment at Princeton. Materials research in the long term is focused on coupled computational materials science and carefully designed experiments to determine the underlying mechanisms that control the mechanical and physical behavior of advanced body-centered cubic metals and ceramic composites in the harsh fusion environment. In addition, two inertial fusion energy (IFE) research programs conducting FNT-related research for IFE are also described.

  20. Bimetric Relativity and the Opera Neutrino Experiment

    E-Print Network [OSTI]

    Moffat, J W

    2011-01-01T23:59:59.000Z

    We investigate the possibility of explaining the propagation of neutrinos measured by the OPERA experiment with $\\delta v_\