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Sample records for advanced physics tokamak

  1. Advanced tokamak physics experiments on DIII-D

    SciTech Connect

    Taylor, T.S.

    1998-12-01

    Significant reductions in the size and cost of a fusion power plant core can be realized if simultaneous improvements in the energy confinement time ({tau}{sub E}) and the plasma pressure (or beta {beta}{sub T} = 2 {mu}{sub 0} < p > /B{sub T}{sup 2}) can be achieved in steady-state conditions with high self driven bootstrap current fraction. In addition, effective power exhaust and impurity and particle control is required. Significant progress has been made in experimentally achieving regimes having the required performance in all of these aspects as well as in developing a theoretical understanding of the underlying physics. The authors have extended the duration of high performance ELMing H-mode plasmas with {beta}{sub N} H{sub iop} {approximately} 10 for 5 {tau}{sub E} ({approximately}1 s) and have demonstrated that core transport barriers can be sustained for the entire 5-s neutral beam duration in L-mode plasmas. Recent DIII-D work has advanced the understanding of improved confinement and internal transport barriers in terms of E x B shear stabilization of micro turbulence. With the aim of current profile control in discharges with negative central magnetic shear, they have demonstrated off-axis electron cyclotron current drive for the first time in a tokamak, finding an efficiency above theoretical expectations. MHD stability has been improved through shape optimization, wall stabilization, and modification of the pressure and current density profiles. Heat flux reduction and improved impurity and particle control have been realized through edge/divertor radiation and understanding and utilization of forced scrape off layer flow and divertor baffling.

  2. Physics basis for an advanced physics and advanced technology tokamak power plant configuration: ARIES-ACT1

    SciTech Connect

    Kessel, C. E.; Poli, F. M.; Ghantous, K.; Gorelenkov, N. N.; Rensink, M. E.; Rognlien, T. D.; Snyder, P. B.; St. John, H.; Turnbull, A. D.

    2015-01-01

    Here, the advanced physics and advanced technology tokamak power plant ARIES-ACT1 has a major radius of 6.25 m at an aspect ratio of 4.0, toroidal field of 6.0 T, strong shaping with elongation of 2.2, and triangularity of 0.63. The broadest pressure cases reached wall-stabilized βN ~ 5.75, limited by n = 3 external kink mode requiring a conducting shell at b/a = 0.3, requiring plasma rotation, feedback, and/or kinetic stabilization. The medium pressure peaking case reaches βN = 5.28 with BT = 6.75, while the peaked pressure case reaches βN < 5.15. Fast particle magnetohydrodynamic stability shows that the alpha particles are unstable, but this leads to redistribution to larger minor radius rather than loss from the plasma. Edge and divertor plasma modeling shows that 75% of the power to the divertor can be radiated with an ITER-like divertor geometry, while >95% can be radiated in a stable detached mode with an orthogonal target and wide slot geometry. The bootstrap current fraction is 91% with a q95 of 4.5, requiring ~1.1 MA of external current drive. This current is supplied with 5 MW of ion cyclotron radio frequency/fast wave and 40 MW of lower hybrid current drive. Electron cyclotron is most effective for safety factor control over ρ~0.2 to 0.6 with 20 MW. The pedestal density is ~0.9×1020/m3, and the temperature is ~4.4 keV. The H98 factor is 1.65, n/nGr = 1.0, and the ratio of net power to threshold power is 2.8 to 3.0 in the flattop.

  3. Physics basis for an advanced physics and advanced technology tokamak power plant configuration: ARIES-ACT1

    DOE PAGESBeta

    Kessel, C. E.; Poli, F. M.; Ghantous, K.; Gorelenkov, N. N.; Rensink, M. E.; Rognlien, T. D.; Snyder, P. B.; St. John, H.; Turnbull, A. D.

    2015-01-01

    Here, the advanced physics and advanced technology tokamak power plant ARIES-ACT1 has a major radius of 6.25 m at an aspect ratio of 4.0, toroidal field of 6.0 T, strong shaping with elongation of 2.2, and triangularity of 0.63. The broadest pressure cases reached wall-stabilized βN ~ 5.75, limited by n = 3 external kink mode requiring a conducting shell at b/a = 0.3, requiring plasma rotation, feedback, and/or kinetic stabilization. The medium pressure peaking case reaches βN = 5.28 with BT = 6.75, while the peaked pressure case reaches βN < 5.15. Fast particle magnetohydrodynamic stability shows that themore » alpha particles are unstable, but this leads to redistribution to larger minor radius rather than loss from the plasma. Edge and divertor plasma modeling shows that 75% of the power to the divertor can be radiated with an ITER-like divertor geometry, while >95% can be radiated in a stable detached mode with an orthogonal target and wide slot geometry. The bootstrap current fraction is 91% with a q95 of 4.5, requiring ~1.1 MA of external current drive. This current is supplied with 5 MW of ion cyclotron radio frequency/fast wave and 40 MW of lower hybrid current drive. Electron cyclotron is most effective for safety factor control over ρ~0.2 to 0.6 with 20 MW. The pedestal density is ~0.9×1020/m3, and the temperature is ~4.4 keV. The H98 factor is 1.65, n/nGr = 1.0, and the ratio of net power to threshold power is 2.8 to 3.0 in the flattop.« less

  4. The Physics Basis For An Advanced Physics And Advanced Technology Tokamak Power Plant Configuration, ARIES-ACT1

    SciTech Connect

    Charles Kessel, et al

    2014-03-05

    The advanced physics and advanced technology tokamak power plant ARIES-ACT1 has a major radius of 6.25 m at aspect ratio of 4.0, toroidal field of 6.0 T, strong shaping with elongation of 2.2 and triangularity of 0.63. The broadest pressure cases reached wall stabilized βN ~ 5.75, limited by n=3 external kink mode requiring a conducting shell at b/a = 0.3, and requiring plasma rotation, feedback, and or kinetic stabilization. The medium pressure peaking case reached βN = 5.28 with BT = 6.75, while the peaked pressure case reaches βN < 5.15. Fast particle MHD stability shows that the alpha particles are unstable, but this leads to redistribution to larger minor radius rather than loss from the plasma. Edge and divertor plasma modeling show that about 75% of the power to the divertor can be radiated with an ITER-like divertor geometry, while over 95% can be radiated in a stable detached mode with an orthogonal target and wide slot geometry. The bootstrap current fraction is 91% with a q95 of 4.5, requiring about ~ 1.1 MA of external current drive. This current is supplied with 5 MW of ICRF/FW and 40 MW of LHCD. EC was examined and is most effective for safety factor control over ρ ~ 0.2-0.6 with 20 MW. The pedestal density is ~ 0.9x1020 /m3 and the temperature is ~ 4.4 keV. The H98 factor is 1.65, n/nGr = 1.0, and the net power to LH threshold power is 2.8- 3.0 in the flattop.

  5. Physics design requirements for the Tokamak Physics Experiment (TPX)

    SciTech Connect

    Neilson, G.H.; Goldston, R.J.; Jardin, S.C.; Reiersen, W.T.; Nevins, W.M.; Porkolab, M.; Ulrickson, M.

    1993-11-01

    The design of TPX is driven by physics requirements that follow from its mission. The tokamak and heating systems provide the performance and profile controls needed to study advanced steady state tokamak operating modes. The magnetic control systems provide substantial flexibility for the study of regimes with high beta and bootstrap current. The divertor is designed for high steady state power and particle exhaust.

  6. Physics Basis for the Advanced Tokamak Fusion Power Plant ARIES-AT

    SciTech Connect

    S.C. Jardin; C.E. Kessel; T.K. Mau; R.L. Miller; F. Najmabadi; V.S. Chan; M.S. Chu; R. LaHaye; L.L. Lao; T.W. Petrie; P. Politzer; H.E. St. John; P. Snyder; G.M. Staebler; A.D. Turnbull; W.P. West

    2003-10-07

    The advanced tokamak is considered as the basis for a fusion power plant. The ARIES-AT design has an aspect ratio of A always equal to R/a = 4.0, an elongation and triangularity of kappa = 2.20, delta = 0.90 (evaluated at the separatrix surface), a toroidal beta of beta = 9.1% (normalized to the vacuum toroidal field at the plasma center), which corresponds to a normalized beta of bN * 100 x b/(I(sub)P(MA)/a(m)B(T)) = 5.4. These beta values are chosen to be 10% below the ideal-MHD stability limit. The bootstrap-current fraction is fBS * I(sub)BS/I(sub)P = 0.91. This leads to a design with total plasma current I(sub)P = 12.8 MA, and toroidal field of 11.1 T (at the coil edge) and 5.8 T (at the plasma center). The major and minor radii are 5.2 and 1.3 m, respectively. The effects of H-mode edge gradients and the stability of this configuration to non-ideal modes is analyzed. The current-drive system consists of ICRF/FW for on-axis current drive and a lower-hybrid system for off-axis. Tran sport projections are presented using the drift-wave based GLF23 model. The approach to power and particle exhaust using both plasma core and scrape-off-layer radiation is presented.

  7. Advanced tokamak research on the DIII-D tokamak

    SciTech Connect

    Chan, V.S.

    1994-01-01

    The objective of the planned research in advanced tokamak development on DIII-D at General Atomics, San Diego, USA. is to establish improved tokamak operation through significant improvements in the stability factor, confinement quality, and bootstrap current fraction using localized radio frequency (rf) current profile control, rf and neutral beam heating for pressure profile control, as well as control of plasma rotation and optimization of the plasma boundary conditions. Recent research results in H-mode confinement, modifications of current profiles to achieve higher confinement and higher {beta}, a new regime of improved confinement (VH-mode), and rf noninductive current drive are encouraging. In this talk, arguments will be presented supporting the need for improved performance in tokamak reactors. Experimentally observed advanced performance regimes on DIII-D will be discussed. Confinement improvement up to H = 4, where H is the ratio of energy confinement time to the ITER89-P scaling H{triple_bond} {Tau}{sub E}/{Tau}{sub E-ITER89-P}, has been achieved. In other discharges {beta}{sub N} = {beta}/(I/aB),[%-m{center_dot}{Tau}/MA] {approx_gt} 6 has been obtained. These values have so far been achieved transiently and independently. Techniques, will be described which can extend the high performance to quasi-steady-state and sustain the high H and {beta}{sub N} values simultaneously. Two high performance regimes, one in first stable regime and the other in second stable regime, have been simulated br self-consistently evolving a magnetohydrodynamic (MHD) equilibrium-transport code. Finally, experimental program plans and outstanding important physics issues will be discussed.

  8. Progress in physics and control of the resistive wall mode in advanced tokamaks

    SciTech Connect

    Liu Yueqiang; Chapman, I. T.; Gimblett, C. G.; Hastie, R. J.; Hender, T. C.; Reimerdes, H.; Villone, F.; Ambrosino, G.; Pironti, A.; Portone, A.

    2009-05-15

    Self-consistent computations are carried out to study the stability of the resistive wall mode (RWM) in DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] plasmas with slow plasma rotation, using the hybrid kinetic-magnetohydrodynamic code MARS-K[Y. Q. Liu et al., Phys. Plasmas 15, 112503 (2008)]. Based on kinetic resonances between the mode and the thermal particle toroidal precession drifts, the self-consistent modeling predicts less stabilization of the mode compared to perturbative approaches, and with the DIII-D experiments. A simple analytic model is proposed to explain the MARS-K results, which also gives a qualitative interpretation of the recent experimental results observed in JT-60U [S. Takeji et al., Nucl. Fusion 42, 5 (2002)]. Our present analysis does not include the kinetic contribution from hot ions, which may give additional damping on the mode. The effect of particle collision is not included either. Using the CARMA code [R. Albanese et al., IEEE Trans. Magn. 44, 1654 (2008)], a stability and control analysis is performed for the RWM in ITER [R. Aymar et al., Plasma Phys. Controlled Fusion 44, 519 (2002)] steady state advanced plasmas, taking into account the influence of three-dimensional conducting structures.

  9. ADX - Advanced Divertor and RF Tokamak Experiment

    NASA Astrophysics Data System (ADS)

    Greenwald, Martin; Labombard, Brian; Bonoli, Paul; Irby, Jim; Terry, Jim; Wallace, Greg; Vieira, Rui; Whyte, Dennis; Wolfe, Steve; Wukitch, Steve; Marmar, Earl

    2015-11-01

    The Advanced Divertor and RF Tokamak Experiment (ADX) is a design concept for a compact high-field tokamak that would address boundary plasma and plasma-material interaction physics challenges whose solution is critical for the viability of magnetic fusion energy. This device would have two crucial missions. First, it would serve as a Divertor Test Tokamak, developing divertor geometries, materials and operational scenarios that could meet the stringent requirements imposed in a fusion power plant. By operating at high field, ADX would address this problem at a level of power loading and other plasma conditions that are essentially identical to those expected in a future reactor. Secondly, ADX would investigate the physics and engineering of high-field-side launch of RF waves for current drive and heating. Efficient current drive is an essential element for achieving steady-state in a practical, power producing fusion device and high-field launch offers the prospect of higher efficiency, better control of the current profile and survivability of the launching structures. ADX would carry out this research in integrated scenarios that simultaneously demonstrate the required boundary regimes consistent with efficient current drive and core performance.

  10. Tokamak Physics Experiment (TPX) power supply design and development

    SciTech Connect

    Neumeyer, C.; Bronner, G.; Lu, E.; Ramakrishnan, S.

    1995-04-01

    The Tokamak Physics Experiment (TPX) is an advanced tokamak project aimed at the production of quasi-steady state plasmas with advanced shape, heating, and particle control. TPX is to be built at the Princeton Plasma Physics Laboratory (PPPL) using many of the facilities from the Tokamak Fusion Test Reactor (TFTR). TPX will be the first tokamak to utilize superconducting (SC) magnets in both the toroidal field (TF) and poloidal field (PF) systems. This new feature requires a departure from the traditional tokamak power supply schemes. This paper describes the plan for the adaptation of the PPPL/FTR power system facilities to supply TPX. Five major areas are addressed, namely the AC power system, the TF, PF and Fast Plasma Position Control (FPPC) power supplies, and quench protection for the TF and PF systems. Special emphasis is placed on the development of new power supply and protection schemes.

  11. Power supplies and quench protection for the Tokamak Physics Experiment

    SciTech Connect

    Neumeyer, C.L.

    1994-07-01

    The Tokamak Physics Experiment (TPX) is an advanced tokamak project aimed at the production of quasi-steady state plasmas with advanced shape, heating, and particle control. TPX is to be built at the Princeton Plasma Physics Laboratory (PPPL) using many of the facilities from the Tokamak Fusion Test Reactor (TFTR). First plasma is scheduled for the year 2000. TPX will be the first tokamak to utilize superconducting (SC) magnets in both the toroidal field (TF) and poloidal field (PF) systems. This is a new feature which requires not only a departure from the traditional tokamak power supply schemes but also that ultra-reliable quench protection devices be used to rapidly discharge the stored energy from the magnets in the event of a quench. This paper describes the plan and basis for the adaptation and augmentation of the PPPL/TFTR power system facilities to supply TPX. Following a description of the basic operational requirements, four major areas are addressed, namely the AC power system, the TF power supply, the PF power supply, and quench protection for the TF and PF systems.

  12. Basic Physics of Tokamak Transport Final Technical Report.

    SciTech Connect

    Sen, Amiya K.

    2014-05-12

    The goal of this grant has been to study the basic physics of various sources of anomalous transport in tokamaks. Anomalous transport in tokamaks continues to be one of the major problems in magnetic fusion research. As a tokamak is not a physics device by design, direct experimental observation and identification of the instabilities responsible for transport, as well as physics studies of the transport in tokamaks, have been difficult and of limited value. It is noted that direct experimental observation, identification and physics study of microinstabilities including ITG, ETG, and trapped electron/ion modes in tokamaks has been very difficult and nearly impossible. The primary reasons are co-existence of many instabilities, their broadband fluctuation spectra, lack of flexibility for parameter scans and absence of good local diagnostics. This has motivated us to study the suspected tokamak instabilities and their transport consequences in a simpler, steady state Columbia Linear Machine (CLM) with collisionless plasma and the flexibility of wide parameter variations. Earlier work as part of this grant was focused on both ITG turbulence, widely believed to be a primary source of ion thermal transport in tokamaks, and the effects of isotope scaling on transport levels. Prior work from our research team has produced and definitively identified both the slab and toroidal branches of this instability and determined the physics criteria for their existence. All the experimentally observed linear physics corroborate well with theoretical predictions. However, one of the large areas of research dealt with turbulent transport results that indicate some significant differences between our experimental results and most theoretical predictions. Latter years of this proposal were focused on anomalous electron transport with a special focus on ETG. There are several advanced tokamak scenarios with internal transport barriers (ITB), when the ion transport is reduced to

  13. INTEGRATED PLASMA CONTROL FOR ADVANCED TOKAMAKS

    SciTech Connect

    HUMPHREYS,D.A; FERRON,J.R; JOHNSON,R.D; LEUER,J.A; PENAFLOR,B.G; WALKER,M.L; WELANDER,A.S; KHAYRUTDINOV,R.R; DOKOUKA,V; EDGELL,D.H; FRANSSON,C.M

    2003-10-01

    OAK-B135 Advanced tokamaks (AT) are distinguished from conventional tokamaks by their high degree of shaping, achievement of profiles optimized for high confinement and stability characteristics, and active stabilization of MHD instabilities to attain high values of normalized beta and confinement. These high performance fusion devices thus require accurate regulation of the plasma boundary, internal profiles, pumping, fueling, and heating, as well as simultaneous and well-coordinated MHD control action to stabilize such instabilities as tearing modes and resistive wall modes. Satisfying the simultaneous demands on control accuracy, reliability, and performance for all of these subsystems requires a high degree of integration in both design and operation of the plasma control system in an advanced tokamak. The present work describes the approach, benefits, and progress made in integrated plasma control with application examples drawn from the DIII-D tokamak. The approach includes construction of plasma and system response models, validation of models against operating experiments, design of integrated controllers which operate in concert with one another as well as with supervisory modules, simulation of control action against off-line and actual machine control platforms, and iteration of the design-test loop to optimize performance.

  14. LIDAR Thomson scattering for advanced tokamaks. Final report

    SciTech Connect

    Molvik, A.W.; Lerche, R.A.; Nilson, D.G.

    1996-03-18

    The LIDAR Thomson Scattering for Advanced Tokamaks project made a valuable contribution by combining LLNL expertise from the MFE Program: tokamak design and diagnostics, and the ICF Program and Physics Dept.: short-pulse lasers and fast streak cameras. This multidisciplinary group evaluated issues involved in achieving a factor of 20 higher high spatial resolution (to as small as 2-3 mm) from the present state of the art in LIDAR Thomson scattering, and developed conceptual designs to apply LIDAR Thomson scattering to three tokamaks: Upgraded divertor measurements in the existing DIII-D tokamak; Both core and divertor LIDAR Thomson scattering in the proposed (now cancelled) TPX; and core, edge, and divertor LIDAR Thomson scattering on the presently planned International Tokamak Experimental Reactor, ITER. Other issues were evaluated in addition to the time response required for a few millimeter spatial resolution. These include the optimum wavelength, 100 Hz operation of the laser and detectors, minimizing stray light - always the Achilles heel of Thomson scattering, and time dispersion in optics that could prevent good spatial resolution. Innovative features of our work included: custom short pulsed laser concepts to meet specific requirements, use of a prism spectrometer to maintain a constant optical path length for high temporal and spatial resolution, the concept of a laser focus outside the plasma to ionize gas and form an external fiducial to use in locating the plasma edge as well as to spread the laser energy over a large enough area of the inner wall to avoid laser ablation of wall material, an improved concept for cleaning windows between shots by means of laser ablation, and the identification of a new physics issue - nonlinear effects near a laser focus which could perturb the plasma density and temperature that are to be measured.

  15. Plasma Physics Regimes in Tokamaks with Li Walls

    SciTech Connect

    L.E. Zakharo; N.N. Gorelenkov; R.B. White; S.I. Krasheninnikov; G.V. Pereverzev

    2003-08-21

    Low recycling regimes with a plasma limited by a lithium wall surface suggest enhanced stability and energy confinement, both necessary for tokamak reactors. These regimes could make ignition feasible in compact tokamaks. Ignited Spherical Tokamaks (IST), self-sufficient in the bootstrap current, are introduced as a necessary step for development of the physics and technology of power reactors.

  16. DIII-D Advanced Tokamak Research Overview

    SciTech Connect

    V.S. Chan; C.M. Greenfield; L.L. Lao; T.C. Luce; C.C. Petty; G.M. Staebler

    1999-12-01

    This paper reviews recent progress in the development of long-pulse, high performance discharges on the DIII-D tokamak. It is highlighted by a discharge achieving simultaneously {beta}{sub N}H of 9, bootstrap current fraction of 0.5, noninductive current fraction of 0.75, and sustained for 16 energy confinement times. The physics challenge has changed in the long-pulse regime. Non-ideal MHD modes are limiting the stability, fast ion driven modes may play a role in fast ion transport which limits the stored energy and plasma edge behavior can affect the global performance. New control tools are being developed to address these issues.

  17. Tokamak physics experiment: Diagnostic windows study

    SciTech Connect

    Merrigan, M.; Wurden, G.A.

    1995-11-01

    We detail the study of diagnostic windows and window thermal stress remediation in the long-pulse, high-power Tokamak Physics Experiment (TPX) operation. The operating environment of the TPX diagnostic windows is reviewed, thermal loads on the windows estimated, and cooling requirements for the windows considered. Applicable window-cooling technology from other fields is reviewed and its application to the TPX windows considered. Methods for TPX window thermal conditioning are recommended, with some discussion of potential implementation problems provided. Recommendations for further research and development work to ensure performance of windows in the TPX system are presented.

  18. The design of the Tokamak Physics Experiment (TPX)

    NASA Astrophysics Data System (ADS)

    Schmidt, J. A.; Thomassen, K. I.; Goldston, R. J.; Neilson, G. H.; Nevins, W. M.; Sinnis, J. C.; Andersen, P.; Bair, W.; Barr, W. L.; Batchelor, D. B.; Baxi, C.; Berg, G.; Bernabei, S.; Bialek, J. M.; Bonoli, P. T.; Boozer, A.; Bowers, D.; Bronner, G.; Brooks, J. N.; Brown, T. G.; Bulmer, R.; Butner, D.; Campbell, R.; Casper, T.; Chaniotakis, E.; Chaplin, M.; Chen, S. J.; Chin, E.; Chrzanowski, J.; Citrolo, J.; Cole, M. J.; Dahlgren, F.; Davis, F. C.; Davis, J.; Davis, S.; Diatchenko, N.; Dinkevich, S.; Feldshteyn, Y.; Felker, B.; Feng, T.; Fenstermacher, M. E.; Fleming, R.; Fogarty, P. J.; Fragetta, W.; Fredd, E.; Gabler, M.; Galambos, J.; Gohar, Y.; Goranson, P. L.; Greenough, N.; Grisham, L. R.; Haines, J.; Haney, S.; Hassenzahl, W.; Heim, J.; Heitzenroeder, P. J.; Hill, D. N.; Hodapp, T.; Houlberg, W. A.; Hubbard, A.; Hyatt, A.; Jackson, M.; Jaeger, E. F.; Jardin, S. C.; Johnson, J.; Jones, G. H.; Juliano, D. R.; Junge, R.; Kalish, M.; Kessel, C. E.; Knutson, D.; LaHaye, R. J.; Lang, D. D.; Langley, R. A.; Liew, S.-L.; Lu, E.; Mantz, H.; Manickam, J.; Mau, T. K.; Medley, S.; Mikkelsen, D. R.; Miller, R.; Monticello, D.; Morgan, D.; Moroz, P.; Motloch, C.; Mueller, J.; Myatt, L.; Nelson, B. E.; Neumeyer, C. L.; Nilson, D.; O'Conner, T.; Pearlstein, L. D.; Peebles, W. A.; Pelovitz, M.; Perkins, F. W.; Perkins, L. J.; Petersen, D.; Pillsbury, R.; Politzer, P. A.; Pomphrey, N.; Porkolab, M.; Posey, A.; Radovinsky, A.; Raftopoulis, S.; Ramakrishnan, S.; Ramos, J.; Rauch, W.; Ravenscroft, D.; Redler, K.; Reiersen, W. T.; Reiman, A.; Reis, E.; Rewoldt, G.; Richards, D. J.; Rocco, R.; Rognlien, T. D.; Ruzic, D.; Sabbagh, S.; Sapp, J.; Sayer, R. O.; Scharer, J. E.; Schmitz, L.; Schnitz, J.; Sevier, L.; Shipley, S. E.; Simmons, R. T.; Slack, D.; Smith, G. R.; Stambaugh, R.; Steill, G.; Stevenson, T.; Stoenescu, S.; Onge, K. T. St.; Stotler, D. P.; Strait, T.; Strickler, D. J.; Swain, D. W.; Tang, W.; Tuszewski, M.; Ulrickson, M. A.; VonHalle, A.; Walker, M. S.; Wang, C.; Wang, P.; Warren, J.; Werley, K. A.; West, W. P.; Williams, F.; Wong, R.; Wright, K.; Wurden, G. A.; Yugo, J. J.; Zakharov, L.; Zbasnik, J.

    1993-09-01

    The Tokamak Physics Experiment is designed to develop the scientific basis for a compact and continuously operating tokamak fusion reactor. It is based on an emerging class of tokamak operating modes, characterized by beta limits well in excess of the Troyon limit, confinement scaling well in excess of H-mode, and bootstrap current fractions approaching unity. Such modes are attainable through the use of advanced, steady state plasma controls including strong shaping, current profile control, and active particle recycling control. Key design features of the TPX are superconducting toroidal and poloidal field coils; actively-cooled plasma-facing components; a flexible heating and current drive system; and a spacious divertor for flexibility. Substantial deuterium plasma operation is made possible with an in-vessel remote maintenance system, a lowactivation titanium vacuum vessel, and shielding of ex-vessel components. The facility will be constructed as a national project with substantial participation by U.S. industry. Operation will begin with first plasma in the year 2000.

  19. Physics evaluation of compact tokamak ignition experiments

    SciTech Connect

    Uckan, N.A.; Houlberg, W.A.; Sheffield, J.

    1985-01-01

    At present, several approaches for compact, high-field tokamak ignition experiments are being considered. A comprehensive method for analyzing the potential physics operating regimes and plasma performance characteristics of such ignition experiments with O-D (analytic) and 1-1/2-D (WHIST) transport models is presented. The results from both calculations are in agreement and show that there are regimes in parameter space in which a class of small (R/sub o/ approx. 1-2 m), high-field (B/sub o/ approx. 8-13 T) tokamaks with aB/sub o/S/q/sub */ approx. 25 +- 5 and kappa = b/a approx. 1.6-2.0 appears ignitable for a reasonable range of transport assumptions. Considering both the density and beta limits, an evaluation of the performance is presented for various forms of chi/sub e/ and chi/sub i/, including degradation at high power and sawtooth activity. The prospects of ohmic ignition are also examined. 16 refs., 13 figs.

  20. Development of a free-boundary tokamak equilibrium solver for advanced study of tokamak equilibria

    NASA Astrophysics Data System (ADS)

    Jeon, Young Mu

    2015-09-01

    A free-boundary Tokamak equilibrium solver (TES), developed for advanced study of tokamak equilibra, is described with two distinctive features. One is a generalized method to resolve the intrinsic axisymmetric instability, which is encountered in all equilibrium calculations with a freeboundary condition. The other is an extension to deal with a new divertor geometry such as snowflake or X divertors. For validations, the uniqueness of a solution is confirmed by the independence of variations in the computational domain, the mathematical correctness and accuracy of equilibrium profiles are checked by using a direct comparison with an analytic equilibrium known as a generalized Solov'ev equilibrium, and the governing force balance relation is tested by examining the intrinsic axisymmetric instabilities. As an application of an advanced equilibrium study, a snow-flake divertor configuration that requires a second-order zero of the poloidal magnetic flux is discussed in the circumstance of the Korea superconducting tokamak advanced research (KSTAR) coil system.

  1. Advanced ICRF antenna design for R-TOKAMAK

    NASA Astrophysics Data System (ADS)

    Kako, E.; Ando, R.; Ichimura, M.; Ogawa, Y.; Amano, T.; Watari, T.

    1986-01-01

    The advanced ICRF antennas designed for the R-TOKAMAK (a proposal in the Institute of Plasma Physics, Nagoya University) are described. They are a standard loop antenna and a panel heater antenna for fast wave heating, and a waveguide antenna for ion Bernstein wave heating. The standard loop antenna is made of Al-alloy and has a simple structure to install because of radioactivation by D-T neutrons. For high power heating, a new type antenna called Panel heater antenna is proposed. It has a wide radiation area and is able to select a parallel wave number k. The field pattern of the panel heater antenna is measured. The feasibility of the waveguide antenna is discussed for ion Bernstein wave heating. The radiation from the aperture of the double ridge waveguide is experimentally estimated with a load simulating the plasma.

  2. Physics of compact ignition tokamak designs

    SciTech Connect

    Singer, C.E.; Ku, L.P.; Bateman, G.; Seidl, F.; Sugihara, M.

    1986-03-01

    Models for predicting plasma performance in compact ignition experiments are constructed on the basis of theoretical and empirical constraints and data from tokamak experiments. Emphasis is placed on finding transport and confinement models which reproduce results of both ohmically and auxiliary heated tokamak data. Illustrations of the application of the models to compact ignition designs are given.

  3. Designing a tokamak fusion reactor—How does plasma physics fit in?

    NASA Astrophysics Data System (ADS)

    Freidberg, J. P.; Mangiarotti, F. J.; Minervini, J.

    2015-07-01

    This paper attempts to bridge the gap between tokamak reactor design and plasma physics. The analysis demonstrates that the overall design of a tokamak fusion reactor is determined almost entirely by the constraints imposed by nuclear physics and fusion engineering. Virtually, no plasma physics is required to determine the main design parameters of a reactor: a , R 0 , B 0 , T i , T e , p , n , τ E , I . The one exception is the value of the toroidal current I , which depends upon a combination of engineering and plasma physics. This exception, however, ultimately has a major impact on the feasibility of an attractive tokamak reactor. The analysis shows that the engineering/nuclear physics design makes demands on the plasma physics that must be satisfied in order to generate power. These demands are substituted into the well-known operational constraints arising in tokamak physics: the Troyon limit, Greenwald limit, kink stability limit, and bootstrap fraction limit. Unfortunately, a tokamak reactor designed on the basis of standard engineering and nuclear physics constraints does not scale to a reactor. Too much current is required to achieve the necessary confinement time for ignition. The combination of achievable bootstrap current plus current drive is not sufficient to generate the current demanded by the engineering design. Several possible solutions are discussed in detail involving advances in plasma physics or engineering. The main contribution of the present work is to demonstrate that the basic reactor design and its plasma physics consequences can be determined simply and analytically. The analysis thus provides a crisp, compact, logical framework that will hopefully lead to improved physical intuition for connecting plasma physic to tokamak reactor design.

  4. Divertor design for the Tokamak Physics Experiment

    SciTech Connect

    Hill, D.N.; Braams, B.; Brooks, J.N.

    1994-05-01

    In this paper we discuss the present divertor design for the planned TPX tokamak, which will explore the physics and technology of steady-state (1000s pulses) heat and particle removal in high confinement (2--4{times} L-mode), high beta ({beta}{sub N} {ge} 3) divertor plasmas sustained by non-inductive current drive. The TPX device will operate in the double-null divertor configuration, with actively cooled graphite targets forming a deep (0.5 m) slot at the outer strike point. The peak heat flux on, the highly tilted (74{degrees} from normal) re-entrant (to recycle ions back toward the separatrix) will be in the range of 4--6 MW/m{sup 2} with 18 MW of neutral beams and RF heating power. The combination of active pumping and gas puffing (deuterium plus impurities), along with higher heating power (45 MW maximum) will allow testing of radiative divertor concepts at ITER-like power densities.

  5. Physics aspects of the Compact Ignition Tokamak

    SciTech Connect

    Post, D.; Bateman, G.; Houlberg, W.; Bromberg, L.; Cohn, D.; Colestock, P.; Hughes, M.; Ignat, D.; Izzo, R.; Jardin, S.

    1986-11-01

    The Compact Ignition Tokamak (CIT) is a proposed modest-size ignition experiment designed to study the physics of alpha-particle heating. The basic concept is to achieve ignition in a modest-size minimum cost experiment by using a high plasma density to achieve the condition of ntau/sub E/ approx. 2 x 10/sup 20/ sec m/sup -3/ required for ignition. The high density requires a high toroidal field (10 T). The high toroidal field allows a large plasma current (10 MA) which improves the energy confinement, and provides a high level of ohmic heating. The present CIT design also has a gigh degree of elongation (k approx. 1.8) to aid in producing the large plasma current. A double null poloidal divertor and a pellet injector are part of the design to provide impurity and particle control, improve the confinement, and provide flexibility for impurity and particle control, improve the confinement, and provide flexibility for improving the plasma profiles. Since auxiliary heating is expected to be necessary to achieve ignition, 10 to 20 MW of Ion Cyclotron Radio Frequency (ICRF) is to be provided.

  6. The ARIES Advanced And Conservative Tokamak (ACT) Power Plant Study

    SciTech Connect

    Kessel, C. E.; Poli, F. M.; Ghantous, K.; Gorelenkov, N.; Tillack, M. S.; Najmabadi, F.; Wang, X. R.; Navaei, D.; Toudeshki, H. H.; Koehly, C.; El-Guebaly, L.; Blanchard, J. P.; Martin, C. J.; Mynsburge, L.; Humrickhouse, P.; Rensink, M. E.; Rognlien, T. D.; Yoda, M.; Abdel-Khalik, S. I.; Hageman, M. D.; Mills, B. H.; Radar, J. D.; Sadowski, D. L.; Snyder, P. B.; St. John, H.; Turnbull, A. D.; Waganer, L. M.; Malang, S.; Rowcliffe, A. F.

    2014-03-05

    Tokamak power plants are studied with advanced and conservative design philosophies in order to identify the impacts on the resulting designs and to provide guidance to critical research needs. Incorporating updated physics understanding, and using more sophisticated engineering and physics analysis, the tokamak configurations have developed a more credible basis compared to older studies. The advanced configuration assumes a self-cooled lead lithium (SCLL) blanket concept with SiC composite structural material with 58% thermal conversion efficiency. This plasma has a major radius of 6.25 m, a toroidal field of 6.0 T, a q95 of 4.5, a {beta}N{sup total} of 5.75, H{sub 98} of 1.65, n/nGr of 1.0, and peak divertor heat flux of 13.7 MW/m{sup 2}. The conservative configuration assumes a dual coolant lead lithium (DCLL) blanket concept with ferritic steel structural material and helium coolant, achieving a thermal conversion efficiency of 45%. The plasma major radius is 9.75 m, a toroidal field of 8.75 T, a q95 of 8.0, a {beta}N{sup total} of 2.5, H{sub 98} of 1.25, n/n{sub Gr} of 1.3, and peak divertor heat flux of 10 MW/m{sup 2}. The divertor heat flux treatment with a narrow power scrape-off width has driven the plasmas to larger major radius. Edge and divertor plasma simulations are targeting a basis for high radiated power fraction in the divertor, which is necessary for solutions to keep the peak heat flux in the range of 10-15 MW/m{sup 2}. Combinations of the advanced and conservative approaches show intermediate sizes. A new systems code using a database approach has been used and shows that the operating point is really an operating zone with some range of plasma and engineering parameters and very similar costs of electricity. Papers in this issue provide more detailed discussion of the work summarized here.

  7. The ARIES Advanced and Conservative Tokamak Power Plant Study

    SciTech Connect

    Kessel, C. E; Tillak, M. S; Najmabadi, F.; Poli, F. M.; Ghantous, K.; Gorelenkov, N.; Wang, X. R.; Navaei, D.; Toudeshki, H. H.; Koehly, C.; EL-Guebaly, L.; Blanchard, J. P.; Martin, C. J.; Mynsburge, L.; Humrickhouse, P.; Rensink, M. E.; Rognlien, T. D.; Yoda, M.; Abdel-Khalik, S. I.; Hageman, M. D.; Mills, B. H.; Rader, J. D.; Sadowski, D. L.; Snyder, P. B.; St. John, H.; Turnbull, A. D.; Waganer, L. M.; Malang, S.; Rowcliffe, A. F.

    2015-12-22

    Tokamak power plants are studied with advanced and conservative design philosophies to identify the impacts on the resulting designs and to provide guidance to critical research needs. Incorporating updated physics understanding and using more sophisticated engineering and physics analysis, the tokamak configurations have developed a more credible basis compared with older studies. The advanced configuration assumes a self-cooled lead lithium blanket concept with SiC composite structural material with 58% thermal conversion efficiency. This plasma has a major radius of 6.25 m, a toroidal field of 6.0 T, a q₉₅ of 4.5, aᵦtotal N of 5.75, an H98 of 1.65, an n/nGr of 1.0, and a peak divertor heat flux of 13.7 MW/m² . The conservative configuration assumes a dual-coolant lead lithium blanket concept with reduced activation ferritic martensitic steel structural material and helium coolant, achieving a thermal conversion efficiency of 45%. The plasma has a major radius of 9.75 m, a toroidal field of 8.75 T, a q₉₅ of 8.0, aᵦtotalN of 2.5, an H₉₈ of 1.25, an n/nGr of 1.3, and a peak divertor heat flux of 10 MW/m² . The divertor heat flux treatment with a narrow power scrape off width has driven the plasmas to larger major radius. Edge and divertor plasma simulations are targeting a basis for high radiated power fraction in the divertor, which is necessary for solutions to keep the peak heat flux in the range 10 to 15 MW/m² . Combinations of the advanced and conservative approaches show intermediate sizes. A new systems code using a database approach has been used and shows that the operating point is really an operating zone with some range of plasma and engineering parameters and very similar costs of electricity. Other papers in this issue provide more detailed discussion of the work summarized here.

  8. The ARIES Advanced and Conservative Tokamak Power Plant Study

    DOE PAGESBeta

    Kessel, C. E; Tillak, M. S; Najmabadi, F.; Poli, F. M.; Ghantous, K.; Gorelenkov, N.; Wang, X. R.; Navaei, D.; Toudeshki, H. H.; Koehly, C.; et al

    2015-12-22

    Tokamak power plants are studied with advanced and conservative design philosophies to identify the impacts on the resulting designs and to provide guidance to critical research needs. Incorporating updated physics understanding and using more sophisticated engineering and physics analysis, the tokamak configurations have developed a more credible basis compared with older studies. The advanced configuration assumes a self-cooled lead lithium blanket concept with SiC composite structural material with 58% thermal conversion efficiency. This plasma has a major radius of 6.25 m, a toroidal field of 6.0 T, a q₉₅ of 4.5, aᵦtotal N of 5.75, an H98 of 1.65, anmore » n/nGr of 1.0, and a peak divertor heat flux of 13.7 MW/m² . The conservative configuration assumes a dual-coolant lead lithium blanket concept with reduced activation ferritic martensitic steel structural material and helium coolant, achieving a thermal conversion efficiency of 45%. The plasma has a major radius of 9.75 m, a toroidal field of 8.75 T, a q₉₅ of 8.0, aᵦtotalN of 2.5, an H₉₈ of 1.25, an n/nGr of 1.3, and a peak divertor heat flux of 10 MW/m² . The divertor heat flux treatment with a narrow power scrape off width has driven the plasmas to larger major radius. Edge and divertor plasma simulations are targeting a basis for high radiated power fraction in the divertor, which is necessary for solutions to keep the peak heat flux in the range 10 to 15 MW/m² . Combinations of the advanced and conservative approaches show intermediate sizes. A new systems code using a database approach has been used and shows that the operating point is really an operating zone with some range of plasma and engineering parameters and very similar costs of electricity. Other papers in this issue provide more detailed discussion of the work summarized here.« less

  9. The role of spherical torus in clarifying tokamak physics

    SciTech Connect

    Morris, A. W.; Peng, Yueng Kay Martin

    1999-01-01

    The spherical tokamak (ST) provides a unique environment in which to perform complementary and exacting tests of the tokamak physics required for a burning plasma experiment of any aspect ratio, while also having the potential for long-term fusion applications in its own right. New experiments are coming on-line in the UK (MAST), USA (NSTX, Pegasus), Russia (Globus-M), Brazil (ETE) and elsewhere, and the status of these devices will be reported, along with newly-analysed data from START. Those physics issues where the ST provides an opportunity to remove degeneracy in the databases or clarify one s understanding will be emphasized.

  10. The Physics of Tokamak Start-up

    SciTech Connect

    D. Mueller

    2012-11-13

    Tokamak start-up on present-day devices usually relies on inductively induced voltage from a central solenoid. In some cases inductive startup is assisted with auxiliary power from electron cyclotron radio frequency heating. ITER, the National Spherical Torus eXperiment Upgrade and JT60, now under construction, will make use of the understanding gained from present-day devices to ensure successful start-up. Design of a spherical tokamak (ST) with DT capability for nuclear component testing would require an alternative to a central solenoid because the small central column in an ST has insufficient space to provide shielding for the insulators in the solenoid. Alternative start-up techniques such as induction using outer poloidal field coils, electron Bernstein wave start-up, coaxial helicity injection and point source helicity injection have been used with success, but require demonstration of scaling to higher plasma current.

  11. The physics of tokamak start-up

    SciTech Connect

    Mueller, D.

    2013-05-15

    Tokamak start-up on present-day devices usually relies on inductively induced voltage from a central solenoid. In some cases, inductive startup is assisted with auxiliary power from electron cyclotron radio frequency heating. International Thermonuclear Experimental Reactor, the National Spherical Torus Experiment Upgrade and JT60, now under construction, will make use of the understanding gained from present-day devices to ensure successful start-up. Design of a spherical tokamak (ST) with DT capability for nuclear component testing would require an alternative to a central solenoid because the small central column in an ST has insufficient space to provide shielding for the insulators in the solenoid. Alternative start-up techniques such as induction using outer poloidal field coils, electron Bernstein wave start-up, coaxial helicity injection, and point source helicity injection have been used with success, but require demonstration of scaling to higher plasma current.

  12. The physics of tokamak start-upa)

    NASA Astrophysics Data System (ADS)

    Mueller, D.

    2013-05-01

    Tokamak start-up on present-day devices usually relies on inductively induced voltage from a central solenoid. In some cases, inductive startup is assisted with auxiliary power from electron cyclotron radio frequency heating. International Thermonuclear Experimental Reactor, the National Spherical Torus Experiment Upgrade and JT60, now under construction, will make use of the understanding gained from present-day devices to ensure successful start-up. Design of a spherical tokamak (ST) with DT capability for nuclear component testing would require an alternative to a central solenoid because the small central column in an ST has insufficient space to provide shielding for the insulators in the solenoid. Alternative start-up techniques such as induction using outer poloidal field coils, electron Bernstein wave start-up, coaxial helicity injection, and point source helicity injection have been used with success, but require demonstration of scaling to higher plasma current.

  13. Advanced Tokamak Plasmas in the Fusion Ignition Research Experiment

    SciTech Connect

    C.E. Kessel; D. Meade; D.W. Swain; P. Titus; M.A. Ulrickson

    2003-10-13

    The Advanced Tokamak (AT) capability of the Fusion Ignition Research Experiment (FIRE) burning plasma experiment is examined with 0-D systems analysis, equilibrium and ideal-MHD stability, radio-frequency current-drive analysis, and full discharge dynamic simulations. These analyses have identified the required parameters for attractive burning AT plasmas, and indicate that these are feasible within the engineering constraints of the device.

  14. LONG PULSE ADVANCED TOKAMAK DISCHARGES IN THE DIII-D TOKAMAK

    SciTech Connect

    P.I. PETERSEN

    2002-06-01

    One of the main goals for the DIII-D research program is to establish an advanced tokamak plasma with high bootstrap current fraction that can be sustained in-principle steady-state. Substantial progress has been made in several areas during the last year. The resistive wall mode stabilization has been done with spinning plasmas in which the plasma pressure has been extended well above the no-wall beta limit. The 3/2 neoclassical tearing mode has been stabilized by the injection of ECH into the magnetic islands, which drives current to substitute the missing bootstrap current. In these experiments either the plasma was moved or the toroidal field was changed to overlap the ECCD resonance with the location of the NTMs. Effective disruption mitigation has been obtained by massive noble gas injection into shots where disruptions were deliberately triggered. The massive gas puff causes a fast and clean current quench with essentially all the plasma energy radiated fairly uniformly to the vessel walls. The run-away electrons that are normally seen accompanying disruptions are suppressed by the large density of electrons still bound on the impurity nuclei. Major elements required to establish integrated, long-pulse, advanced tokamak operations have been achieved in DIII-D: {beta}{sub T} = 4.2%, {beta}{sub p} = 2, f{sub BS} = 65%, and {beta}{sub N}H{sub 89} = 10 for 600 ms ({approx} 4{tau}{sub E}). The next challenge is to integrate the different elements, which will be the goal for the next five years when additional control will be available. Twelve resistive wall mode coils are scheduled to be installed in DIII-D during the summer of 2003. The future plans include upgrading the tokamak pulse length capability and increasing the ECH power, to control the current profile evolution.

  15. The Tokamak Fusion Test Reactor decontamination and decommissioning project and the Tokamak Physics Experiment at the Princeton Plasma Physics Laboratory. Environmental Assessment

    SciTech Connect

    1994-05-27

    If the US is to meet the energy needs of the future, it is essential that new technologies emerge to compensate for dwindling supplies of fossil fuels and the eventual depletion of fissionable uranium used in present-day nuclear reactors. Fusion energy has the potential to become a major source of energy for the future. Power from fusion energy would provide a substantially reduced environmental impact as compared with other forms of energy generation. Since fusion utilizes no fossil fuels, there would be no release of chemical combustion products to the atmosphere. Additionally, there are no fission products formed to present handling and disposal problems, and runaway fuel reactions are impossible due to the small amounts of deuterium and tritium present. The purpose of the TPX Project is to support the development of the physics and technology to extend tokamak operation into the continuously operating (steady-state) regime, and to demonstrate advances in fundamental tokamak performance. The purpose of TFTR D&D is to ensure compliance with DOE Order 5820.2A ``Radioactive Waste Management`` and to remove environmental and health hazards posed by the TFTR in a non-operational mode. There are two proposed actions evaluated in this environmental assessment (EA). The actions are related because one must take place before the other can proceed. The proposed actions assessed in this EA are: the decontamination and decommissioning (D&D) of the Tokamak Fusion Test Reactor (TFTR); to be followed by the construction and operation of the Tokamak Physics Experiment (TPX). Both of these proposed actions would take place primarily within the TFTR Test Cell Complex at the Princeton Plasma Physics Laboratory (PPPL). The TFTR is located on ``D-site`` at the James Forrestal Campus of Princeton University in Plainsboro Township, Middlesex County, New Jersey, and is operated by PPPL under contract with the United States Department of Energy (DOE).

  16. Halo current diagnostic system of experimental advanced superconducting tokamak.

    PubMed

    Chen, D L; Shen, B; Granetz, R S; Sun, Y; Qian, J P; Wang, Y; Xiao, B J

    2015-10-01

    The design, calibration, and installation of disruption halo current sensors for the Experimental Advanced Superconducting Tokamak are described in this article. All the sensors are Rogowski coils that surround conducting structures, and all the signals are analog integrated. Coils with two different cross-section sizes have been fabricated, and their mutual inductances are calibrated. Sensors have been installed to measure halo currents in several different parts of both the upper divertor (tungsten) and lower divertor (graphite) at several toroidal locations. Initial measurements from disruptions show that the halo current diagnostics are working well. PMID:26520954

  17. Halo current diagnostic system of experimental advanced superconducting tokamak

    SciTech Connect

    Chen, D. L.; Shen, B.; Sun, Y.; Qian, J. P. Wang, Y.; Xiao, B. J.; Granetz, R. S.

    2015-10-15

    The design, calibration, and installation of disruption halo current sensors for the Experimental Advanced Superconducting Tokamak are described in this article. All the sensors are Rogowski coils that surround conducting structures, and all the signals are analog integrated. Coils with two different cross-section sizes have been fabricated, and their mutual inductances are calibrated. Sensors have been installed to measure halo currents in several different parts of both the upper divertor (tungsten) and lower divertor (graphite) at several toroidal locations. Initial measurements from disruptions show that the halo current diagnostics are working well.

  18. The Numerical Tokamak Project (NTP) simulation of turbulent transport in the core plasma: A grand challenge in plasma physics

    SciTech Connect

    Not Available

    1993-12-01

    The long-range goal of the Numerical Tokamak Project (NTP) is the reliable prediction of tokamak performance using physics-based numerical tools describing tokamak physics. The NTP is accomplishing the development of the most advanced particle and extended fluid model`s on massively parallel processing (MPP) environments as part of a multi-institutional, multi-disciplinary numerical study of tokamak core fluctuations. The NTP is a continuing focus of the Office of Fusion Energy`s theory and computation program. Near-term HPCC work concentrates on developing a predictive numerical description of the core plasma transport in tokamaks driven by low-frequency collective fluctuations. This work addresses one of the greatest intellectual challenges to our understanding of the physics of tokamak performance and needs the most advanced computational resources to progress. We are conducting detailed comparisons of kinetic and fluid numerical models of tokamak turbulence. These comparisons are stimulating the improvement of each and the development of hybrid models which embody aspects of both. The combination of emerging massively parallel processing hardware and algorithmic improvements will result in an estimated 10**2--10**6 performance increase. Development of information processing and visualization tools is accelerating our comparison of computational models to one another, to experimental data, and to analytical theory, providing a bootstrap effect in our understanding of the target physics. The measure of success is the degree to which the experimentally observed scaling of fluctuation-driven transport may be predicted numerically. The NTP is advancing the HPCC Initiative through its state-of-the-art computational work. We are pushing the capability of high performance computing through our efforts which are strongly leveraged by OFE support.

  19. Development of frequency modulation reflectometer for Korea Superconducting Tokamak Advanced Research tokamak

    SciTech Connect

    Seo, Seong-Heon; Wi, H. M.; Lee, W. R.; Kim, H. S.; Lee, T. G.; Kim, Y. S.; Park, Jinhyung; Kang, Jin-Seob; Bog, M. G.; Yokota, Y.; Mase, A.

    2013-08-15

    Frequency modulation reflectometer has been developed to measure the plasma density profile of the Korea Superconducting Tokamak Advanced Research tokamak. Three reflectometers are operating in extraordinary polarization mode in the frequency range of Q band (33.6–54 GHz), V band (48–72 GHz), and W band (72–108 GHz) to measure the density up to 7 × 10{sup 19} m{sup −3} when the toroidal magnetic field is 2 T on axis. The antenna is installed inside of the vacuum vessel. A new vacuum window is developed by using 50 μm thick mica film and 0.1 mm thick gold gasket. The filter bank of low pass filter, notch filter, and Faraday isolator is used to reject the electron cyclotron heating high power at attenuation of 60 dB. The full frequency band is swept in 20 μs. The mixer output is directly digitized with sampling rate of 100 MSamples/s. The phase is obtained by using wavelet transform. The whole hardware and software system is described in detail and the measured density profile is presented as a result.

  20. Modeling of ICRF Internal Transport Barrier Control for Advanced Tokamaks

    NASA Astrophysics Data System (ADS)

    Sund, R. S.; Scharer, J. E.

    1998-11-01

    We present an analysis of TFTR ICRF current drive experiments carried out by Majeski et al.(R. Majeski, J. Rodgers, G. Schilling, C. Phillips, J. Hosea and the TFTR Group, private communication.) The influence of deuterium, tritium, minority specie, electron and alpha concentrations, temperatures and beam fractions are considered for the two-ion mode conversion current drive experiments. Direct comparison with experimental data is carried out by means of a nonlocal large gyroradius ICRF code(O. Sauter, Ph.D. thesis, Ecole Polytechnique de Lausanne, Switzerland (1992).) which incorporates 1-D plasma profiles. It is found that substantial beam and alpha particle absorption can occur for some cases. Application of ion cyclotron range of frequencies internal transport barrier control requires further examination of fast wave mode conversion and the interaction of ion Bernstein waves with plasmas in advanced tokamaks. The effects of perpendicular and parallel magnetic gradients on the ion, electron, and alpha particle absorption are examined. A viable internal transport barrier control scheme for a reactor grade advanced tokamak will be discussed.

  1. Design of core and edge Thomson scattering systems for Korea Superconducting Tokamak Advanced Research tokamak

    SciTech Connect

    Lee, H.G.; Lee, J.H.; Johnson, D.; Ellis, R.; Feder, R.; Park, H.

    2004-10-01

    The core and edge Thomson systems on Korea Superconducting Tokamak Advanced Research employ two different sets of lens collection optics. Their collection systems are positioned in the front end of a long reentrant cassette for optimum viewing coverage and optical throughput. Both systems collect the scattered light from a single tangential beam of multiple 50-Hz Nd:YAG lasers and image the scattering volume from core to edge with 40 spatial points. In order to obtain a higher resolution of 5 mm, the edge system has more spatial channels than the core system. Pressure-free heat shield windows, which will absorb the radiation heat flux, are mounted in front of large vacuum windows to protect them from the radiation heat load during long-pulse discharges.

  2. Development on JET of advanced tokamak operations for ITER

    NASA Astrophysics Data System (ADS)

    Tuccillo, A. A.; Crisanti, F.; Litaudon, X.; Baranov, Yu. F.; Becoulet, A.; Becoulet, M.; Bertalot, L.; Castaldo, C.; Challis, C. D.; Cesario, R.; DeBaar, M. R.; de Vries, P. C.; Esposito, B.; Frigione, D.; Garzotti, L.; Giovannozzi, E.; Giroud, C.; Gorini, G.; Gormezano, C.; Hawkes, N. C.; Hobirk, J.; Imbeaux, F.; Joffrin, E.; Lomas, P. J.; Mailloux, J.; Mantica, P.; Mantsinen, M. J.; Mazon, D.; Moreau, D.; Murari, A.; Pericoli-Ridolfini, V.; Rimini, F.; Sips, A. C. C.; Sozzi, C.; Tudisco, O.; Van Eester, D.; Zastrow, K.-D.; work-programme contributors, JET-EFDA

    2006-02-01

    Recent research on advanced tokamak in JET has focused on scenarios with both monotonic and reversed shear q-profiles having plasma parameters as relevant as possible for extrapolation to ITER. Wide internal transport barriers (ITBs), r/a ~ 0.7, are formed at ITER relevant triangularity δ ~ 0.45 and moderate plasma current, IP = 1.5-2.5 MA, with ne/nG ~ 60% when ELMs are moderated by Ne injection. At higher current (IP <= 3.5 MA, δ ~ 0.25) wide ITBs sitting at r/a >= 0.5, in the positive shear region, have been developed. Generally MHD events terminate these barriers otherwise limited in strength by power availability. ITBs with core density close to Greenwald value, Te ~ Ti and low toroidal rotation (4 times lower than standard ITBs) are obtained in plasma target preformed by opportune timing of lower hybrid current drive (LHCD), pellet injection and a small amount of NBI power. Wide ITBs, r/a ~ 0.6, of moderate strength, can be sustained without impurities accumulation for a time close to neoclassical resistive time in 3 T/1.8 MA discharges that exhibit reversed magnetic shear profiles and type-III ELMy edge. These discharges have been extended to the maximum duration allowed by JET subsystems (20 s) bringing to the record of injected energy in a JET discharge: E ~ 330 MJ. Portability of ITB physics has been addressed through dedicated similarity experiments. The ITB is identified as a layer of reduced diffusivity studying the propagation of the heat wave generated by modulating the ICRF mode conversion (MC) electron heating. Impressive results, QDT ~ 0.25, are obtained in these deuterium discharges with 3He minority when the MC layer is located in the core. The ion behaviour has been investigated in pure LHCD electron ITBs optimizing the 3He minority concentration for direct ion heating. Preliminary results of particle transport, studied via injection of a trace of tritium and an Ar-Ne mixture, will be presented.

  3. Development of precision measurement network of experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Yu, Liandong; Zhao, Huining; Zhang, Wei; Li, Weishi; Deng, Huaxia; Song, Yuntao; Gu, Yongqi

    2014-12-01

    In order to obtain accurate position of the inner key components in the experimental advanced superconducting tokamak (EAST), a combined optical measurement method which is comprised of a laser tracker (LT) and articulated coordinate measuring machine (CMM) has been brought forward. LT, which is an optical measurement instrument and has a large measurement range and high accuracy, is employed for establishing the precision measurement network of EAST, and the articulated CMM is also employed for measuring the inner key components of EAST. The measurement uncertainty analyzed by the Unified Spatial Metrology Network (USMN) is 0.20 mm at a confidence probability of 95.44%. The proposed technology is appropriate for the inspection of the reconstruction of the EAST.

  4. Microwave Doppler reflectometer system in the Experimental Advanced Superconducting Tokamak.

    PubMed

    Zhou, C; Liu, A D; Zhang, X H; Hu, J Q; Wang, M Y; Li, H; Lan, T; Xie, J L; Sun, X; Ding, W X; Liu, W D; Yu, C X

    2013-10-01

    A Doppler reflectometer system has recently been installed in the Experimental Advanced Superconducting (EAST) Tokamak. It includes two separated systems, one for Q-band (33-50 GHz) and the other for V-band (50-75 GHz). The optical system consists of a flat mirror and a parabolic mirror which are optimized to improve the spectral resolution. A synthesizer is used as the source and a 20 MHz single band frequency modulator is used to get a differential frequency for heterodyne detection. Ray tracing simulations are used to calculate the scattering location and the perpendicular wave number. In EAST last experimental campaign, the Doppler shifted signals have been obtained and the radial profiles of the perpendicular propagation velocity during L-mode and H-mode are calculated. PMID:24182112

  5. A flowing liquid lithium limiter for the Experimental Advanced Superconducting Tokamak.

    PubMed

    Ren, J; Zuo, G Z; Hu, J S; Sun, Z; Yang, Q X; Li, J G; Zakharov, L E; Xie, H; Chen, Z X

    2015-02-01

    A program involving the extensive and systematic use of lithium (Li) as a "first," or plasma-facing, surface in Tokamak fusion research devices located at Institute of Plasma Physics, Chinese Academy of Sciences, was started in 2009. Many remarkable results have been obtained by the application of Li coatings in Experimental Advanced Superconducting Tokamak (EAST) and liquid Li limiters in the HT-7 Tokamak-both located at the institute. In furtherance of the lithium program, a flowing liquid lithium (FLiLi) limiter system has been designed and manufactured for EAST. The design of the FLiLi limiter is based on the concept of a thin flowing film which was previously tested in HT-7. Exploiting the capabilities of the existing material and plasma evaluation system on EAST, the limiter will be pre-wetted with Li and mechanically translated to the edge of EAST during plasma discharges. The limiter will employ a novel electro-magnetic pump which is designed to drive liquid Li flow from a collector at the bottom of limiter into a distributor at its top, and thus supply a continuously flowing liquid Li film to the wetted plasma-facing surface. This paper focuses on the major design elements of the FLiLi limiter. In addition, a simulation of incoming heat flux has shown that the distribution of heat flux on the limiter surface is acceptable for a future test of power extraction on EAST. PMID:25725839

  6. Alpha Particle Physics Experiments in the Tokamak Fusion Test Reactor

    SciTech Connect

    Budny, R.V.; Darrow, D.S.; Medley, S.S.; Nazikian, R.; Zweben, S.J.; et al.

    1998-12-14

    Alpha particle physics experiments were done on the Tokamak Fusion Test Reactor (TFTR) during its deuterium-tritium (DT) run from 1993-1997. These experiments utilized several new alpha particle diagnostics and hundreds of DT discharges to characterize the alpha particle confinement and wave-particle interactions. In general, the results from the alpha particle diagnostics agreed with the classical single-particle confinement model in magnetohydrodynamic (MHD) quiescent discharges. Also, the observed alpha particle interactions with sawteeth, toroidal Alfvén eigenmodes (TAE), and ion cyclotron resonant frequency (ICRF) waves were roughly consistent with theoretical modeling. This paper reviews what was learned and identifies what remains to be understood.

  7. Preliminary Safety Analysis Report for the Tokamak Physics Experiment

    SciTech Connect

    Motloch, C.G.; Bonney, R.F.; Levine, J.D.; McKenzie-Carter, M.A.; Masson, L.S.; Commander, J.C.

    1995-04-01

    This Preliminary Safety Analysis Report (PSAR), includes an indication of the magnitude of facility hazards, complexity of facility operations, and the stage of the facility life-cycle. It presents the results of safety analyses, safety assurance programs, identified vulnerabilities, compensatory measures, and, in general, the rationale describing why the Tokamak Physics Experiment (TPX) can be safely operated. It discusses application of the graded approach to the TPX safety analysis, including the basis for using Department of Energy (DOE) Order 5480.23 and DOE-STD-3009-94 in the development of the PSAR.

  8. OVERVIEW OF RECENT EXPERIMENTAL RESULTS FROM THE DIII-D ADVANCED TOKAMAK PROGRAM

    SciTech Connect

    BURRELL,HK

    2002-11-01

    OAK A271 OVERVIEW OF RECENT EXPERIMENTAL RESULTS FROM THE DIII-D ADVANCED TOKAMAK PROGRAM. The DIII-D research program is developing the scientific basis for advanced tokamak (AT) modes of operation in order to enhance the attractiveness of the tokamak as an energy producing system. Since the last International Atomic Energy Agency (IAEA) meeting, they have made significant progress in developing the building blocks needed for AT operation: (1) they have doubled the magnetohydrodynamic (MHD) stable tokamak operating space through rotational stabilization of the resistive wall mode; (2) using this rotational stabilization, they have achieved {beta}{sub N}H{sub 89} {ge} 10 for 4 {tau}{sub E} limited by the neoclassical tearing mode; (3) using real-time feedback of the electron cyclotron current drive (ECCD) location, they have stabilized the (m,n) = (3,2) neoclassical tearing mode and then increased {beta}{sub T} by 60%; (4) they have produced ECCD stabilization of the (2,1) neoclassical tearing mode in initial experiments; (5) they have made the first integrated AT demonstration discharges with current profile control using ECCD; (6) ECCD and electron cyclotron heating (ECH) have been used to control the pressure profile in high performance plasmas; and (7) they have demonstrated stationary tokamak operation for 6.5 s (36 {tau}{sub E}) at the same fusion gain parameter of {beta}{sub N}H{sub 89}/q{sub 95}{sup 2} {approx} 0.4 as ITER but at much higher q{sub 95} = 4.2. The authors have developed general improvements applicable to conventional and advanced tokamak operating modes: (1) they have an existence proof of a mode of tokamak operation, quiescent H-mode, which has no pulsed, ELM heat load to the divertor and which can run for long periods of time (3.8 s or 25 {tau}{sub E}) with constant density and constant radiated power; (2) they have demonstrated real-time disruption detection and mitigation for vertical disruption events using high pressure gas jet

  9. Overview of recent experimental results from the DIII-D advanced tokamak program.

    SciTech Connect

    Burrell, K. H.

    2003-12-01

    The DIII-D research program is developing the scientific basis for advanced tokamak (AT) modes of operation in order to enhance the attractiveness of the tokamak as an energy producing system. Since the last international atomic energy agency (IAEA) meeting, we have made significant progress in developing the building blocks needed for AT operation: (1) we have doubled the magnetohydrodynamic (MHD) stable tokamak operating space through rotational stabilization of the resistive wall mode; (2) using this rotational stabilization, we have achieved {beta}{sub N}H{sub 89} {ge} 10 for 4{tau}{sub E} limited by the neoclassical tearing mode (NTM); (3) using real-time feedback of the electron cyclotron current drive (ECCD) location, we have stabilized the (m, n) = (3, 2) NTM and then increased {beta}{sub T} by 60%; (4) we have produced ECCD stabilization of the (2, 1) NTM in initial experiments; (5) we have made the first integrated AT demonstration discharges with current profile control using ECCD; (6) ECCD and electron cyclotron heating (ECH) have been used to control the pressure profile in high performance plasmas; and (7) we have demonstrated stationary tokamak operation for 6.5 s (36{tau}{sub E}) at the same fusion gain parameter of {beta}{sub N}H{sub 89}/q{sub 95}{sup 2} {approx_equal} as ITER but at much higher q{sub 95} = 4.2. We have developed general improvements applicable to conventional and AT operating modes: (1) we have an existence proof of a mode of tokamak operation, quiescent H-mode, which has no pulsed, edge localized modes (ELM) heat load to the divertor and which can run for long periods of time (3.8 s or 25{tau}{sub E}) with constant density and constant radiated power; (2) we have demonstrated real-time disruption detection and mitigation for vertical disruption events using high pressure gas jet injection of noble gases; (3) we have found that the heat and particle fluxes to the inner strike points of balanced, double-null divertors are much

  10. Development of an integrated energetic neutral particle measurement system on experimental advanced full superconducting tokamak

    SciTech Connect

    Zhu, Y. B. Liu, D.; Heidbrink, W. W.; Zhang, J. Z.; Qi, M. Z.; Xia, S. B.; Wan, B. N.; Li, J. G.

    2014-11-15

    Full function integrated, compact silicon photodiode based solid state neutral particle analyzers (ssNPA) have been developed for energetic particle (EP) relevant studies on the Experimental Advanced Superconducting Tokamak (EAST). The ssNPAs will be mostly operated in advanced current mode with a few channels to be operated in conventional pulse-counting mode, aiming to simultaneously achieve individually proved ultra-fast temporal, spatial, and spectral resolution capabilities. The design details together with considerations on EAST specific engineering realities and physics requirements are presented. The system, including a group of single detectors on two vertical ports and two 16-channel arrays on a horizontal port, can provide both active and passive charge exchange measurements. ssNPA detectors, with variable thickness of ultra thin tungsten dominated foils directly deposited on the front surface, are specially fabricated and utilized to achieve about 22 keV energy resolution for deuterium particle detection.

  11. ADVANCED TOKAMAK OPERATION USING THE DIII-D PLASMA CONTROL SYSTEM

    SciTech Connect

    HUMPHREYS,DA; FERRON,JR; GAROFALO,AM; HYATT,AW; JERNIGAN,TC; JOHNSON,RD; LAHAYE,RJ; LEUER,JA; OKABAYASHI,M; PENAFLOR,BG; SCOVILLE,JT; STRAIT,EJ; WALKER,ML; WHYTE,DG

    2002-10-01

    A271 ADVANCED TOKAMAK OPERATION USING THE DIII-D PLASMA CONTROL SYSTEM. The principal focus of experimental operations in the DIII-D tokamak is the advanced tokamak (AT) regime to achieve, which requires highly integrated and flexible plasma control. In a high performance advanced tokamak, accurate regulation of the plasma boundary, internal profiles, pumping, fueling, and heating must be well coordinated with MHD control action to stabilize such instabilities as tearing modes and resistive wall modes. Sophisticated monitors of the operational regime must provide detection of off-normal conditions and trigger appropriate safety responses with acceptable levels of reliability. Many of these capabilities are presently implemented in the DIII-D plasma control system (PCS), and are now in frequent or routine operational use. The present work describes recent development, implementation, and operational experience with AT regime control elements for equilibrium control, MHD suppression, and off-normal event detection and response.

  12. Hollow current profile scenarios for advanced tokamak reactor operations

    SciTech Connect

    Gourdain, P.-A.; Leboeuf, J.-N.

    2009-11-15

    Advanced tokamak scenarios are a possible approach to boosting reactor performances. Such schemes usually trigger current holes, a particular magnetohydrodynamics equilibrium where no current or pressure gradients exist in the core of the plasma. While such equilibria have large bootstrap fractions, flat pressure profiles in the plasma core may not be optimal for a reactor. However, moderate modifications of the equilibrium current profile can lead to diamagnetism where most of the pressure gradient is now balanced by poloidal currents and the toroidal magnetic field. In this paper, we consider the properties of diamagnetic current holes, also called ''dual equilibria,'' and demonstrate that fusion throughput can be significantly increased in such scenarios. Their stability is investigated using the DCON code. Plasmas with a beta peak of 30% and an average beta of 6% are found stable to both fixed and free-boundary modes with toroidal mode numbers n=1-4, as well as Mercier and high-n ballooning modes. This is not surprising as these scenarios have a normal beta close to 3.

  13. Radial and poloidal correlation reflectometry on Experimental Advanced Superconducting Tokamak.

    PubMed

    Qu, Hao; Zhang, Tao; Han, Xiang; Wen, Fei; Zhang, Shoubiao; Kong, Defeng; Wang, Yumin; Gao, Yu; Huang, Canbin; Cai, Jianqing; Gao, Xiang

    2015-08-01

    An X-mode polarized V band (50 GHz-75 GHz) radial and poloidal correlation reflectometry is designed and installed on Experimental Advanced Superconducting Tokamak (EAST). Two frequency synthesizers (12 GHz-19 GHz) are used as sources. Signals from the sources are up-converted to V band using active quadruplers and then coupled together for launching through one single pyramidal antenna. Two poloidally separated antennae are installed to receive the reflected waves from plasma. This reflectometry system can be used for radial and poloidal correlation measurement of the electron density fluctuation. In ohmically heated plasma, the radial correlation length is about 1.5 cm measured by the system. The poloidal correlation analysis provides a means to estimate the fluctuation velocity perpendicular to the main magnetic field. In the present paper, the distance between two poloidal probing points is calculated with ray-tracing code and the propagation time is deduced from cross-phase spectrum. Fluctuation velocity perpendicular to the main magnetic field in the core of ohmically heated plasma is about from -1 km/s to -3 km/s. PMID:26329188

  14. Radial and poloidal correlation reflectometry on Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Qu, Hao; Zhang, Tao; Han, Xiang; Wen, Fei; Zhang, Shoubiao; Kong, Defeng; Wang, Yumin; Gao, Yu; Huang, Canbin; Cai, Jianqing; Gao, Xiang

    2015-08-15

    An X-mode polarized V band (50 GHz–75 GHz) radial and poloidal correlation reflectometry is designed and installed on Experimental Advanced Superconducting Tokamak (EAST). Two frequency synthesizers (12 GHz–19 GHz) are used as sources. Signals from the sources are up-converted to V band using active quadruplers and then coupled together for launching through one single pyramidal antenna. Two poloidally separated antennae are installed to receive the reflected waves from plasma. This reflectometry system can be used for radial and poloidal correlation measurement of the electron density fluctuation. In ohmically heated plasma, the radial correlation length is about 1.5 cm measured by the system. The poloidal correlation analysis provides a means to estimate the fluctuation velocity perpendicular to the main magnetic field. In the present paper, the distance between two poloidal probing points is calculated with ray-tracing code and the propagation time is deduced from cross-phase spectrum. Fluctuation velocity perpendicular to the main magnetic field in the core of ohmically heated plasma is about from −1 km/s to −3 km/s.

  15. ADVANCES IN COMPREHENSIVE GYROKINETIC SIMULATIONS OF TRANSPORT IN TOKAMAKS

    SciTech Connect

    WALTZ RE; CANDY J; HINTON FL; ESTRADA-MILA C; KINSEY JE

    2004-10-01

    A continuum global gyrokinetic code GYRO has been developed to comprehensively simulate core turbulent transport in actual experimental profiles and enable direct quantitative comparisons to the experimental transport flows. GYRO not only treats the now standard ion temperature gradient (ITG) mode turbulence, but also treats trapped and passing electrons with collisions and finite {beta}, equilibrium ExB shear stabilization, and all in real tokamak geometry. Most importantly the code operates at finite relative gyroradius ({rho}{sub *}) so as to treat the profile shear stabilization and nonlocal effects which can break gyroBohm scaling. The code operates in either a cyclic flux-tube limit (which allows only gyroBohm scaling) or a globally with physical profile variation. Rohm scaling of DIII-D L-mode has been simulated with power flows matching experiment within error bars on the ion temperature gradient. Mechanisms for broken gyroBohm scaling, neoclassical ion flows embedded in turbulence, turbulent dynamos and profile corrugations, plasma pinches and impurity flow, and simulations at fixed flow rather than fixed gradient are illustrated and discussed.

  16. ADVANCES IN COMPREHENSIVE GYROKINETIC SIMULATIONS OF TRANSPORT IN TOKAMAKS

    SciTech Connect

    WALTZ,R.E; CANDY,J; HINTON,F.L; ESTRADA-MILA,C; KINSEY,J.E

    2004-10-01

    A continuum global gyrokinetic code GYRO has been developed to comprehensively simulate core turbulent transport in actual experimental profiles and enable direct quantitative comparisons to the experimental transport flows. GYRO not only treats the now standard ion temperature gradient (ITG) mode turbulence, but also treats trapped and passing electrons with collisions and finite {beta}, equilibrium ExB shear stabilization, and all in real tokamak geometry. Most importantly the code operates at finite relative gyroradius ({rho}{sub *}) so as to treat the profile shear stabilization and nonlocal effects which can break gyroBohm scaling. The code operates in either a cyclic flux-tube limit (which allows only gyroBohm scaling) or globally with physical profile variation. Bohm scaling of DIII-D L-mode has been simulated with power flows matching experiment within error bars on the ion temperature gradient. Mechanisms for broken gyroBohm scaling, neoclassical ion flows embedded in turbulence, turbulent dynamos and profile corrugations, are illustrated.

  17. Recent advances in long-pulse high-confinement plasma operations in Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Guo, H. Y.; Li, J.; Wan, B. N. Gong, X. Z.; Xu, G. S.; Zhang, X. D.; Ding, S. Y.; Gan, K. F.; Hu, J. S.; Hu, L. Q.; Liu, S. C.; Qian, J. P.; Sun, Y. W.; Wang, H. Q.; Wang, L.; Xia, T. Y.; Xiao, B. J.; Zeng, L.; Zhao, Y. P.; and others

    2014-05-15

    A long-pulse high confinement plasma regime known as H-mode is achieved in the Experimental Advanced Superconducting Tokamak (EAST) with a record duration over 30 s, sustained by Lower Hybrid wave Current Drive (LHCD) with advanced lithium wall conditioning and divertor pumping. This long-pulse H-mode plasma regime is characterized by the co-existence of a small Magneto-Hydrodynamic (MHD) instability, i.e., Edge Localized Modes (ELMs) and a continuous quasi-coherent MHD mode at the edge. We find that LHCD provides an intrinsic boundary control for ELMs, leading to a dramatic reduction in the transient power load on the vessel wall, compared to the standard Type I ELMs. LHCD also induces edge plasma ergodization, broadening heat deposition footprints, and the heat transport caused by ergodization can be actively controlled by regulating edge plasma conditions, thus providing a new means for stationary heat flux control. In addition, advanced tokamak scenarios have been newly developed for high-performance long-pulse plasma operations in the next EAST experimental campaign.

  18. First results on fast wave current drive in advanced tokamak discharges in DIII-D

    SciTech Connect

    Prater, R.; Cary, W.P.; Baity, F.W.

    1995-07-01

    Initial experiments have been performed on the DIII-D tokamak on coupling, direct electron heating, and current drive by fast waves in advanced tokamak discharges. These experiments showed efficient central heating and current drive in agreement with theory in magnitude and profile. Extrapolating these results to temperature characteristic of a power plant (25 keV) gives current drive efficiency of about 0.3 MA/m{sup 2}.

  19. The superconducting magnet system for the Tokamak Physics Experiment

    SciTech Connect

    Lang, D.D.; Bulmer, R.J.; Chaplin, M.R.

    1994-06-18

    The superconducting magnet system for the Tokamak Physics experiment (TPX) will be the first all superconducting magnet system for a Tokamak, where the poloidal field coils, in addition to the toroidal field coils are superconducting. The magnet system is designed to operate in a steady state mode, and to initiate the plasma discharge ohmically. The toroidal field system provides a peak field of 4.0 Tesla on the plasma axis at a plasma major radius of 2.25 m. The peak field on the niobium 3-tin, cable-in-conduit (CIC) conductor is 8.4 Tesla for the 16 toroidal field coils. The toroidal field coils must absorb approximately 5 kW due to nuclear heating, eddy currents, and other sources. The poloidal field system provides a total of 18 volt seconds to initiate the plasma and drive a plasma current up to 2 MA. The poloidal field system consists of 14 individual coils which are arranged symmetrically above and below the horizontal mid plane. Four pairs of coils make up the central solenoid, and three paris of poloidal ring coils complete the system. The poloidal field coils all use a cable-in-conduit conductor, using either niobium 3-tin (NB{sub 3}Sn) or niobium titanium (NbTi) superconducting strands depending on the operating conditions for that coil. All of the coils are cooled by flowing supercritical helium, with inlet and outlet connections made on each double pancake. The superconducting magnet system has gone through a conceptual design review, and is in preliminary design started by the LLNL/MIT/PPPL collaboration. A number of changes have been made in the design since the conceptual design review, and are described in this paper.

  20. ADX: a high field, high power density, advanced divertor and RF tokamak

    NASA Astrophysics Data System (ADS)

    LaBombard, B.; Marmar, E.; Irby, J.; Terry, J. L.; Vieira, R.; Wallace, G.; Whyte, D. G.; Wolfe, S.; Wukitch, S.; Baek, S.; Beck, W.; Bonoli, P.; Brunner, D.; Doody, J.; Ellis, R.; Ernst, D.; Fiore, C.; Freidberg, J. P.; Golfinopoulos, T.; Granetz, R.; Greenwald, M.; Hartwig, Z. S.; Hubbard, A.; Hughes, J. W.; Hutchinson, I. H.; Kessel, C.; Kotschenreuther, M.; Leccacorvi, R.; Lin, Y.; Lipschultz, B.; Mahajan, S.; Minervini, J.; Mumgaard, R.; Nygren, R.; Parker, R.; Poli, F.; Porkolab, M.; Reinke, M. L.; Rice, J.; Rognlien, T.; Rowan, W.; Shiraiwa, S.; Terry, D.; Theiler, C.; Titus, P.; Umansky, M.; Valanju, P.; Walk, J.; White, A.; Wilson, J. R.; Wright, G.; Zweben, S. J.

    2015-05-01

    The MIT Plasma Science and Fusion Center and collaborators are proposing a high-performance Advanced Divertor and RF tokamak eXperiment (ADX)—a tokamak specifically designed to address critical gaps in the world fusion research programme on the pathway to next-step devices: fusion nuclear science facility (FNSF), fusion pilot plant (FPP) and/or demonstration power plant (DEMO). This high-field (⩾6.5 T, 1.5 MA), high power density facility (P/S ˜ 1.5 MW m-2) will test innovative divertor ideas, including an ‘X-point target divertor’ concept, at the required performance parameters—reactor-level boundary plasma pressures, magnetic field strengths and parallel heat flux densities entering into the divertor region—while simultaneously producing high-performance core plasma conditions that are prototypical of a reactor: equilibrated and strongly coupled electrons and ions, regimes with low or no torque, and no fuelling from external heating and current drive systems. Equally important, the experimental platform will test innovative concepts for lower hybrid current drive and ion cyclotron range of frequency actuators with the unprecedented ability to deploy launch structures both on the low-magnetic-field side and the high-magnetic-field side—the latter being a location where energetic plasma-material interactions can be controlled and favourable RF wave physics leads to efficient current drive, current profile control, heating and flow drive. This triple combination—advanced divertors, advanced RF actuators, reactor-prototypical core plasma conditions—will enable ADX to explore enhanced core confinement physics, such as made possible by reversed central shear, using only the types of external drive systems that are considered viable for a fusion power plant. Such an integrated demonstration of high-performance core-divertor operation with steady-state sustainment would pave the way towards an attractive pilot plant, as envisioned in the ARC concept

  1. A flowing liquid lithium limiter for the Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Ren, J.; Zuo, G. Z.; Hu, J. S.; Sun, Z.; Yang, Q. X.; Li, J. G.; Xie, H.; Chen, Z. X.; Zakharov, L. E.

    2015-02-15

    A program involving the extensive and systematic use of lithium (Li) as a “first,” or plasma-facing, surface in Tokamak fusion research devices located at Institute of Plasma Physics, Chinese Academy of Sciences, was started in 2009. Many remarkable results have been obtained by the application of Li coatings in Experimental Advanced Superconducting Tokamak (EAST) and liquid Li limiters in the HT-7 Tokamak—both located at the institute. In furtherance of the lithium program, a flowing liquid lithium (FLiLi) limiter system has been designed and manufactured for EAST. The design of the FLiLi limiter is based on the concept of a thin flowing film which was previously tested in HT-7. Exploiting the capabilities of the existing material and plasma evaluation system on EAST, the limiter will be pre-wetted with Li and mechanically translated to the edge of EAST during plasma discharges. The limiter will employ a novel electro-magnetic pump which is designed to drive liquid Li flow from a collector at the bottom of limiter into a distributor at its top, and thus supply a continuously flowing liquid Li film to the wetted plasma-facing surface. This paper focuses on the major design elements of the FLiLi limiter. In addition, a simulation of incoming heat flux has shown that the distribution of heat flux on the limiter surface is acceptable for a future test of power extraction on EAST.

  2. A flowing liquid lithium limiter for the Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Ren, J.; Zuo, G. Z.; Hu, J. S.; Sun, Z.; Yang, Q. X.; Li, J. G.; Zakharov, L. E.; Xie, H.; Chen, Z. X.

    2015-02-01

    A program involving the extensive and systematic use of lithium (Li) as a "first," or plasma-facing, surface in Tokamak fusion research devices located at Institute of Plasma Physics, Chinese Academy of Sciences, was started in 2009. Many remarkable results have been obtained by the application of Li coatings in Experimental Advanced Superconducting Tokamak (EAST) and liquid Li limiters in the HT-7 Tokamak—both located at the institute. In furtherance of the lithium program, a flowing liquid lithium (FLiLi) limiter system has been designed and manufactured for EAST. The design of the FLiLi limiter is based on the concept of a thin flowing film which was previously tested in HT-7. Exploiting the capabilities of the existing material and plasma evaluation system on EAST, the limiter will be pre-wetted with Li and mechanically translated to the edge of EAST during plasma discharges. The limiter will employ a novel electro-magnetic pump which is designed to drive liquid Li flow from a collector at the bottom of limiter into a distributor at its top, and thus supply a continuously flowing liquid Li film to the wetted plasma-facing surface. This paper focuses on the major design elements of the FLiLi limiter. In addition, a simulation of incoming heat flux has shown that the distribution of heat flux on the limiter surface is acceptable for a future test of power extraction on EAST.

  3. Improving Advanced High School Physics

    NASA Astrophysics Data System (ADS)

    Spital, Robin David

    2003-04-01

    A National Research Council study committee recently commissioned a "Physics Panel" to evaluate and make recommendations for improving advanced physics education in American high schools [1]. The Physics Panel recommends the creation of a nationally standardized Newtonian Mechanics Unit that would form the foundation of all advanced physics programs. In a one-year program, the Panel recommends that advanced physics students study at most one other major area of physics, so that sufficient time is available to develop the deep conceptual understanding that is the primary goal of advanced study. The Panel emphasizes that final assessments must be improved to focus on depth of understanding, rather than technical problem-solving skill. The Physics Panel strongly endorses the inclusion of meaningful real-world experiences in advanced physics programs, but believes that traditional "cook-book" laboratory exercises are not worth the enormous amount of time and effort spent on them. The Physics Panel believes that the talent and preparation of teachers are the most important ingredients in effective physics instruction; it therefore calls for a concerted effort by all parts of the physics community to remedy the desperate shortage of highly qualified teachers. [1] Jerry P. Gollub and Robin Spital, "Advanced Physics in the High Schools", Physics Today, May 2002.

  4. Development of Burning Plasma and Advanced Scenarios in the DIII-D Tokamak

    SciTech Connect

    Luce, T C

    2004-10-18

    Significant progress in the development of burning plasma scenarios, steady-state scenarios at high fusion performance, and basic tokamak physics has been made by the DIII-D Team. Discharges similar to the ITER baseline scenario have demonstrated normalized fusion performance nearly 50% higher than required for Q = 10 in ITER, under stationary conditions. Discharges that extrapolate to Q {approx} 10 for longer than one hour in ITER at reduced current have also been demonstrated in DIII-D under stationary conditions. Proof of high fusion performance with full noninductive operation has been obtained. Underlying this work are studies validating approaches to confinement extrapolation, disruption avoidance and mitigation, tritium retention, ELM avoidance, and operation above the no-wall pressure limit. In addition, the unique capabilities of the DIII-D facility have advanced studies of the sawtooth instability with unprecedented time and space resolution, threshold behavior in the electron heat transport, and rotation in plasmas in the absence of external torque.

  5. Development of Burning Plasma and Advanced Scenarios in the DIII-D Tokamak

    SciTech Connect

    Luce, T C

    2004-12-01

    Significant progress in the development of burning plasma scenarios, steady-state scenarios at high fusion performance, and basic tokamak physics has been made by the DIII-D Team. Discharges similar to the ITER baseline scenario have demonstrated normalized fusion performance nearly 50% higher than required for Q = 10 in ITER, under stationary conditions. Discharges that extrapolate to Q {approx} 10 for longer than one hour in ITER at reduced current have also been demonstrated in DIII-D under stationary conditions. Proof of high fusion performance with full noninductive operation has been obtained. Underlying this work are studies validating approaches to confinement extrapolation, disruption avoidance and mitigation, tritium retention, ELM avoidance, and operation above the no-wall pressure limit. In addition, the unique capabilities of the DIII-D facility have advanced studies of the sawtooth instability with unprecedented time and space resolution, threshold behavior in the electron heat transport, and rotation in plasmas in the absence of external torque.

  6. The ignition physics study group supports the compact ignition tokamak and engineering test reactor programs

    SciTech Connect

    Sheffield, J.

    1987-01-01

    This report presents a collection of Vugraphs dealing with the Compact Ignition Tokamak (CIT) and the Engineering Test Reactor (ETR). The role of the Ignition Physics Study Group is defined. Several design goals are presented. (JDH)

  7. Proposals for an influential role of small tokamaks in mainstream fusion physics and technology research

    NASA Astrophysics Data System (ADS)

    Van Oost, G.; Del Bosco, E.; Gryaznevich, M. P.; Malaquias, A.; Mank, G.

    2006-12-01

    Small tokamaks may significantly contribute to the better understanding of phenomena in a wide range of fields such as plasma confinement and energy transport; plasma stability in different magnetic configurations; plasma turbulence and its impact on local and global plasma parameters; processes at the plasma edge and plasma-wall interaction; scenarios of additional heating and non-inductive current drive; new methods of plasma profile and parameter control; development of novel plasma diagnostics; benchmarking of new numerical codes and so on. Furthermore, due to the compactness, flexibility, low operation costs and high skill of their personnel small tokamaks are very convenient to develop and test new materials and technologies, which because of the risky nature cannot be done in large machines without preliminary studies. Small tokamaks are suitable and important for broad international cooperation, providing the necessary environment and manpower to conduct dedicated joint research programmes. In addition, the experimental work on small tokamaks is very appropriate for the education of students, scientific activities of post-graduate students and for the training of personnel for large tokamaks. All these tasks are well recognised and reflected in documents and understood by the large tokamak teams. Recent experimental results will be presented of contributions to mainstream fusion physics and technology research on small tokamaks involved in the IAEA Coordinated Research Project "Joint Research using small tokamaks", started in 2004.

  8. Lower hybrid system design for the Tokamak physics experiment

    SciTech Connect

    Goranson, P.L.; Conner, D.L.; Swain, D.W.; Yugo, J.J.; Bernabei, S.; Greenough, N.

    1995-12-31

    The lower hybrid (LH) launcher configuration has been redesigned to integrate the functions of the vertical four-way power splitter and the front waveguide array (front array). This permits 256 waveguide channels to be fed by only 64 waveguides at the vacuum window interface. The resulting configuration is a more compact coupler, which incorporates the simplicity of a multijunction coupler while preserving the spectral flexibility of a conventional lower hybrid launcher. Other spin-offs of the redesign are reduction in thermal incompatibility between the front array and vacuum windows, improved maintainability, in situ vacuum window replacement, a reduced number of radio frequency (rf) connections, and a weight reduction of 7300 kg. There should be a significant cost reduction as well. Issues associated with the launcher design and fabrication have been addressed by a research and development program that includes brazing of the front array and testing of the power splitter configuration to confirm that phase errors due to reflections in the shorted splitter legs will not significantly impact the rf spectrum. The Conceptual Design Review requires that radiation levels at the torus radial port mounting flange and outer surface of the toroidal field coils should be sufficiently low to permit hands-on maintenance. Low activation materials and neutron shielding are incorporated in the launcher design to meet these requirements. The launcher is configured to couple 3 MW of steady state LH heating/LH current drive power at 3.7 GHz to the Tokamak Physics Experiment plasma.

  9. Advances in atomic physics

    PubMed Central

    El-Sherbini, Tharwat M.

    2013-01-01

    In this review article, important developments in the field of atomic physics are highlighted and linked to research works the author was involved in himself as a leader of the Cairo University – Atomic Physics Group. Starting from the late 1960s – when the author first engaged in research – an overview is provided of the milestones in the fascinating landscape of atomic physics. PMID:26425356

  10. Tokamak physics studies using x-ray diagnostic methods

    SciTech Connect

    Hill, K.W.; Bitter, M.; von Goeler, S.; Beiersdorfer, P.; Fredrickson, E.; Hsuan, H.; McGuire, K.; Sauthoff, N.R.; Sesnic, S.; Stevens, J.E.

    1987-03-01

    X-ray diagnostic measurements have been used in a number of experiments to improve our understanding of important tokamak physics issues. The impurity content in TFTR plasmas, its sources and control have been clarified through soft x-ray pulse-height analysis (PHA) measurements. The dependence of intrinsic impurity concentrations and Z/sub eff/ on electron density, plasma current, limiter material and conditioning, and neutral-beam power have shown that the limiter is an important source of metal impurities. Neoclassical-like impurity peaking following hydrogen pellet injection into Alcator C and a strong effect of impurities on sawtooth behavior were demonstrated by x-ray imaging (XIS) measurements. Rapid inward motion of impurities and continuation of m = 1 activity following an internal disruption were demonstrated with XIS measurements on PLT using injected aluminum to enhance the signals. Ion temperatures up to 12 keV and a toroidal plasma rotation velocity up to 6 x 10/sup 5/ m/s have been measured by an x-ray crystal spectrometer (XCS) with up to 13 MW of 85-keV neutral-beam injection in TFTR. Precise wavelengths and relative intensities of x-ray lines in several helium-like ions and neon-like ions of silver have been measured in TFTR and PLT by the XCS. The data help to identify the important excitation processes predicted in atomic physics. Wavelengths of n = 3 to 2 silver lines of interest for x-ray lasers were measured, and precise instrument calibration techniques were developed. Electron thermal conductivity and sawtooth dynamics have been studied through XIS measurements on TFTR of heat-pulse propagation and compound sawteeth. A non-Maxwellian electron distribution function has been measured, and evidence of the Parail-Pogutse instability identified by hard x-ray PHA measurements on PLT during lower-hybrid current-drive experiments.

  11. Probe diagnostics in the far scrape-off layer plasma of Korea Superconducting Tokamak Advanced Research tokamak using a sideband harmonic method

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Hwan; Hong, Suk-Ho; Park, Il-Seo; Lee, Hyo-Chang; Kang, Hyun-Ju; Chung, Chin-Wook

    2015-12-01

    Plasma characteristics in the far scrape-off layer region of tokamak play a crucial role in the stable plasma operation and its sustainability. Due to the huge facility, electrical diagnostic systems to measure plasma properties have extremely long cable length resulting in large stray current. To overcome this problem, a sideband harmonic method was applied to the Korea Superconducting Tokamak Advanced Research tokamak plasma. The sideband method allows the measurement of the electron temperature and the plasma density without the effect of the stray current. The measured plasma densities are compared with those from the interferometer, and the results show reliability of the method.

  12. Probe diagnostics in the far scrape-off layer plasma of Korea Superconducting Tokamak Advanced Research tokamak using a sideband harmonic method.

    PubMed

    Kim, Dong-Hwan; Hong, Suk-Ho; Park, Il-Seo; Lee, Hyo-Chang; Kang, Hyun-Ju; Chung, Chin-Wook

    2015-12-01

    Plasma characteristics in the far scrape-off layer region of tokamak play a crucial role in the stable plasma operation and its sustainability. Due to the huge facility, electrical diagnostic systems to measure plasma properties have extremely long cable length resulting in large stray current. To overcome this problem, a sideband harmonic method was applied to the Korea Superconducting Tokamak Advanced Research tokamak plasma. The sideband method allows the measurement of the electron temperature and the plasma density without the effect of the stray current. The measured plasma densities are compared with those from the interferometer, and the results show reliability of the method. PMID:26724028

  13. Probe diagnostics in the far scrape-off layer plasma of Korea Superconducting Tokamak Advanced Research tokamak using a sideband harmonic method

    SciTech Connect

    Kim, Dong-Hwan; Hong, Suk-Ho; Park, Il-Seo; Lee, Hyo-Chang; Kang, Hyun-Ju; Chung, Chin-Wook

    2015-12-15

    Plasma characteristics in the far scrape-off layer region of tokamak play a crucial role in the stable plasma operation and its sustainability. Due to the huge facility, electrical diagnostic systems to measure plasma properties have extremely long cable length resulting in large stray current. To overcome this problem, a sideband harmonic method was applied to the Korea Superconducting Tokamak Advanced Research tokamak plasma. The sideband method allows the measurement of the electron temperature and the plasma density without the effect of the stray current. The measured plasma densities are compared with those from the interferometer, and the results show reliability of the method.

  14. Advances in Dust Detection and Removal for Tokamaks

    NASA Astrophysics Data System (ADS)

    Campos, A.; Skinner, C. H.; Roquemore, A. L.; Leisure, J. O. V.; Wagner, S.

    2008-11-01

    Dust diagnostics and removal techniques are vital for the safe operation of next step fusion devices such as ITER. An electrostatic dust detector[1] developed in the laboratory is being applied to NSTX. In the tokamak environment, large particles or fibres can fall on the grid potentially causing a permanent short. We report on the development of a gas puff system that uses helium to clear such particles from the detector. Experiments with varying nozzle designs, backing pressures, puff durations, and exit flow orientations have obtained an optimal configuration that effectively removes particles from a 25 cm^2 area. Dust removal from next step tokamaks will be required to meet regulatory dust limits. A tripolar grid of fine interdigitated traces has been designed that generates an electrostatic travelling wave for conveying dust particles to a ``drain.'' First trials have shown particle motion in optical microscope images. [1] C. H. Skinner et al., J. Nucl. Mater., 376 (2008) 29.

  15. Advances in antihydrogen physics.

    PubMed

    Charlton, Mike; Van der Werf, Dirk Peter

    2015-01-01

    The creation of cold antihydrogen atoms by the controlled combination of positrons and antiprotons has opened up a new window on fundamental physics. More recently, techniques have been developed that allow some antihydrogen atoms to be created at low enough kinetic energies that they can be held inside magnetic minimum neutral atom traps. With confinement times of many minutes possible, it has become feasible to perform experiments to probe the properties of the antiatom for the first time. We review the experimental progress in this area, outline some of the motivation for studying basic aspects of antimatter physics and provide an outlook of where we might expect this field to go in the coming years. PMID:25942774

  16. Advanced Fuels Reactor using Aneutronic Rodless Ultra Low Aspect Ratio Tokamak Hydrogenic Plasmas

    NASA Astrophysics Data System (ADS)

    Ribeiro, Celso

    2015-11-01

    The use of advanced fuels for fusion reactor is conventionally envisaged for field reversed configuration (FRC) devices. It is proposed here a preliminary study about the use of these fuels but on an aneutronic Rodless Ultra Low Aspect Ratio (RULART) hydrogenic plasmas. The idea is to inject micro-size boron pellets vertically at the inboard side (HFS, where TF is very high and the tokamak electron temperature is relatively low because of profile), synchronised with a proton NBI pointed to this region. Therefore, p-B reactions should occur and alpha particles produced. These pellets will act as an edge-like disturbance only (cp. killer pellet, although the vertical HFS should make this less critical, since the unablated part should appear in the bottom of the device). The boron cloud will appear at midplance, possibly as a MARFE-look like. Scaling of the p-B reactions by varying the NBI energy should be compared with the predictions of nuclear physics. This could be an alternative to the FRC approach, without the difficulties of the optimization of the FRC low confinement time. Instead, a robust good tokamak confinement with high local HFS TF (enhanced due to the ultra low aspect ratio and low pitch angle) is used. The plasma central post makes the RULART concept attractive because of the proximity of NBI path and also because a fraction of born alphas will cross the plasma post and dragged into it in the direction of the central plasma post current, escaping vertically into a hole in the bias plate and reaching the direct electricity converter, such as in the FRC concept.

  17. Numerical study of Alfvén eigenmodes in the Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Hu, Youjun; Li, Guoqiang; Yang, Wenjun; Zhou, Deng; Ren, Qilong; Gorelenkov, N. N.; Cai, Huishan

    2014-05-15

    Alfvén eigenmodes in up-down asymmetric tokamak equilibria are studied by a new magnetohydrodynamic eigenvalue code. The code is verified with the NOVA code for the Solovév equilibrium and then is used to study Alfvén eigenmodes in a up-down asymmetric equilibrium of the Experimental Advanced Superconducting Tokamak. The frequency and mode structure of toroidicity-induced Alfvén eigenmodes are calculated. It is demonstrated numerically that up-down asymmetry induces phase variation in the eigenfunction across the major radius on the midplane.

  18. An Advanced Tokamak Fusion Nuclear Science Facility (FNSF-AT)

    NASA Astrophysics Data System (ADS)

    Chan, V. S.; Garofalo, A. M.; Stambaugh, R. D.

    2010-11-01

    A Fusion Development Facility (FDF) is a candidate for FNSF-AT. It is a compact steady-state machine of moderate gain that uses AT physics to provide the neutron fluence required for fusion nuclear science development. FDF is conceived as a double-null plasma with high elongation and triangularity, predicted to allow good confinement of high plasma pressure. Steady-state is achieved with high bootstrap current and radio frequency current drive. Neutral beam injection and 3D non-resonant magnetic field can provide edge plasma rotation for stabilization of MHD and access to Quiescent H-mode. The estimated power exhaust is somewhat lower than that of ITER because of higher core radiation and stronger tilting of the divertor plates. FDF is capable of further developing all elements of AT physics, qualifying them for an advanced performance DEMO. The latest concept has accounted for realistic neutron shielding and divertor implementation. Self-consistent evolution of the transport profiles and equilibrium will quantify the stability and confinement required to meet the FNS mission.

  19. ATOMIC PHYSICS PROCESSES IMPORTANT TO THE UNDERSTANDING OF THE SCRAPE-OFF LAYER OF TOKAMAKS

    SciTech Connect

    WEST, W.P.; GOLDSMITH,; B. EVANS,T.E.; OLSON, R.J.

    2002-05-01

    The region between the well-confined plasma and the vessel walls of a magnetic confinement fusion research device, the scrape-off layer (SOL), is typically rich in atomic and molecular physics processes. The most advanced magnetic confinement device, the magnetically diverted tokamak, uses a magnetic separatrix to isolate the confinement zone (closed flux surfaces) from the edge plasma (open field lines). Over most of their length the open field lines run parallel to the separatrix, forming a thin magnetic barrier with the nearby vessel walls. In a poloidally-localized region, the open field lines are directed away from the separatrix and into the divertor, a region spatially separated from the separatrix where intense plasma wall interaction can occur relatively safely. Recent data from several tokamaks indicate that particle transport across the field lines of the SOL can be somewhat faster than previously thought. In these cases, the rate at which particles reach the vessel wall is comparable to the rate to the divertor from parallel transport. The SOL can be thin enough that the recycling neutrals and sputtered impurities from the wall may refuel or contaminate the confinement zone more efficiently than divertor plasma wall interaction. Just inside the SOL is a confinement barrier that produces a sharp pedestal in plasma density and temperature. Understanding neutral transport through the SOL and into the pedestal is key to understanding particle balance and particle and impurity exhaust. The SOL plasma is sufficiently hot and dense to excite and ionize neutrals. Ion and neutral temperatures are high enough that charge exchange between the neutrals and fuel and impurity ions is fast. Excitation of neutrals can be fast enough to lead to nonlinear behavior in charge exchange and ionization processes. In this paper the detailed atomic physics important to the understanding of the neutral transport through the SOL will be discussed.

  20. The impact of improved physics on commercial tokamak reactors

    SciTech Connect

    Galambos, J.D.; Perkins, L.J.; Haney, S.; Mandrekas, J.

    1994-01-01

    Improvements in the confinement and beta capability of tokamak devices have long been a goal of the fusion program. We examine the impact of improvements in present day confinement and beta capabilities on commercial tokamak reactors. We characterize confinement with the achievable enhancement factor (H) over the ITER89 Power scaling confinement time, and beta by the Troyon coefficient g. A surprisingly narrow range of plasma confinement and beta are found to be useful in minimizing the cost of electricity for a tokamak reactor. Improvements in only one of these quantities is not useful beyond some point, without accompanying improvements in the other. For the plasma beta limited by a Troyon coefficient (g) near 4.3 (%mT/MA), confinement levels characterized by H factor enhancements of only 2 are useful for our nominal steady-state driven tokamak. These confinement levels are similar to those observed in present day experiments. If the permissible Troyon beta coefficient is near 6, the useful H factor confinement range increases to 2.5, still close to present day confinement levels. Inductively driven, pulsed reactors have somewhat increased useful ranges of confinement, relative to the steady-state cases. For a Troyon beta limit coefficient g near 4.3, H factors up to 2.5 are useful, and for g near 6, H factors up to 3 are useful.

  1. ADVANCES IN DUST DETECTION AND REMOVAL FOR TOKAMAKS

    SciTech Connect

    Campos, A.; Skinner, C.H.

    2009-01-01

    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.

  2. Review Committee report on the conceptual design of the Tokamak Physics Experiment

    SciTech Connect

    Not Available

    1993-04-01

    This report discusses the following topics on the conceptual design of the Tokamak Physics Experiment: Role and mission of TPX; overview of design; physics design assessment; engineering design assessment; evaluation of cost, schedule, and management plans; and, environment safety and health.

  3. Preface: Advances in solar physics

    NASA Astrophysics Data System (ADS)

    Georgoulis, Manolis K.; Nakariakov, Valery M.

    2015-12-01

    The idea for this special issue of Advances in Space Research (ASR) was formulated during the 14th European Solar Physics Meeting (ESPM-14) that took place in Dublin, Ireland in September 2014. Since ASR does not publish conference proceedings, it was decided to extend a general call to the international solar-physics community for manuscripts pertinent to the following thematic areas: New and upcoming heliospheric observational and data assimilation facilities.

  4. OVERVIEW OF RECENT EXPERIMENTAL RESULTS FROM THE DIII-D ADVANCED TOKAMAK PROGRAM

    SciTech Connect

    BURRELL,KH

    2002-11-01

    OAK A271 OVERVIEW OF RECENT EXPERIMENTAL RESULTS FROM THE DIII-D ADVANCED TOKAMAK PROGRAM. The DIII-D research program is developing the scientific basis for advanced tokamak (AT) modes of operation in order to enhance the attractiveness of the tokamak as an energy producing system. Since the last International Atomic Energy Agency (IAEA) meeting, the authors have made significant progress in developing the building blocks needed for AT operation: (1) the authors have doubled the magnetohydrodynamic (MHD) stable tokamak operating space through rotational stabilization of the resistive wall mode; (2) using this rotational stabilization, they have achieved {beta}{sub N}H{sub 89} {le} 10 for 4 {tau}{sub E} limited by the neoclassical tearing mode; (3) using real-time feedback of the electron cyclotron current drive (ECCD) location, they have stabilized the (m,n) = (3,2) neoclassical tearing mode and then increased {beta}{sub T} by 60%; (4) they have produced ECCD stabilization of the (2,1) neoclassical tearing mode in initial experiments; (5) they have made the first integrated AT demonstration discharges with current profile control using ECCD; (6) ECCD and electron cyclotron heating (ECH) have been used to control the pressure profile in high performance plasmas; and (7) they have demonstrated stationary tokamak operation for 6.5 s (36 {tau}{sub E}) at the same fusion gain parameter of {beta}{sub N}H{sub 89}/q{sub 95}{sup 2} {approx} 0.4 as ITER but at much higher q{sub 95} = 4.2. They have developed general improvements applicable to conventional and advanced tokamak operating modes: (1) they have an existence proof of a mode of tokamak operation, quiescent H-mode, which has no pulsed, ELM heat load to the divertor and which can run for long periods of time (3.8 s or 25 {tau}{sub E}) with constant density and constant radiation power; (2) they have demonstrated real-time disruption detection and mitigation for vertical disruption events using high pressure gas jet

  5. Profile control of advanced tokamak plasmas in view of continuous operation

    NASA Astrophysics Data System (ADS)

    Mazon, D.

    2015-07-01

    The concept of the tokamak is a very good candidate to lead to a fusion reactor. In fact, certain regimes of functioning allow today the tokamaks to attain performances close to those requested by a reactor. Among the various scenarios of functioning nowadays considered for the reactor option, certain named 'advanced scenarios' are characterized by an improvement of the stability and confinement in the plasma core, as well as by a modification of the current profile, notably thank to an auto-generated 'bootstrap' current. The general frame of this paper treats the perspective of a real-time control of advanced regimes. Concrete examples will underline the impact of diagnostics on the identification of plasma models, from which the control algorithms are constructed. Several preliminary attempts will be described.

  6. Absolute intensity calibration of the 32-channel heterodyne radiometer on experimental advanced superconducting tokamak

    SciTech Connect

    Liu, X.; Zhao, H. L.; Liu, Y. Li, E. Z.; Han, X.; Ti, A.; Hu, L. Q.; Zhang, X. D.; Domier, C. W.; Luhmann, N. C.

    2014-09-15

    This paper presents the results of the in situ absolute intensity calibration for the 32-channel heterodyne radiometer on the experimental advanced superconducting tokamak. The hot/cold load method is adopted, and the coherent averaging technique is employed to improve the signal to noise ratio. Measured spectra and electron temperature profiles are compared with those from an independent calibrated Michelson interferometer, and there is a relatively good agreement between the results from the two different systems.

  7. Absolute intensity calibration of the 32-channel heterodyne radiometer on experimental advanced superconducting tokamak.

    PubMed

    Liu, X; Zhao, H L; Liu, Y; Li, E Z; Han, X; Domier, C W; Luhmann, N C; Ti, A; Hu, L Q; Zhang, X D

    2014-09-01

    This paper presents the results of the in situ absolute intensity calibration for the 32-channel heterodyne radiometer on the experimental advanced superconducting tokamak. The hot/cold load method is adopted, and the coherent averaging technique is employed to improve the signal to noise ratio. Measured spectra and electron temperature profiles are compared with those from an independent calibrated Michelson interferometer, and there is a relatively good agreement between the results from the two different systems. PMID:25273727

  8. Advanced Tokamak Regimes in Alcator C-Mod with Lower Hybrid Current Drive

    NASA Astrophysics Data System (ADS)

    Parker, R.; Bonoli, P.; Gwinn, D.; Hutchinson, I.; Porkolab, M.; Ramos, J.; Bernabei, S.; Hosea, J.; Wilson, R.

    1999-11-01

    Alcator C-Mod has been proposed as a test-bed for developing advanced tokamak scenarios owing to its strong shaping, relatively long pulse length capability at moderate field, e.g. t ~ L/R at B = 5T and T_eo ~ 7keV, and the availability of strong ICRF heating. We plan to exploit this capability by installing up to 4 MW RF power at 4.6 GHz for efficient off-axis current drive by lower hybrid waves. By launching LH waves with a grill whose n_xx spectrum can be dynamically controlled over the range 2 < n_xx < 3.5, the driven current profile can be modified so that, when combined with bootstrap current in high ɛβ_pol regimes, q_min > 2. Such reversed or nearly zero shear regimes have already been proposed as the basis of an advanced tokamak burning-plasma experiment-ATBX (M. Porkolab et al, IAEA-CN-69/FTP/13, IAEA,Yokohama 1998.), and could provide the basis for a demonstration power reactor. Theoretical and experimental basis for this advanced tokamak research program on C-Mod, including design of the lower hybrid coupler, its spectrum and current drive capabilities will be presented.

  9. The ARIES tokamak reactor study

    SciTech Connect

    Not Available

    1989-10-01

    The ARIES study is a community effort to develop several visions of tokamaks as fusion power reactors. The aims are to determine the potential economics, safety, and environmental features of a range of possible tokamak reactors, and to identify physics and technology areas with the highest leverage for achieving the best tokamak reactor. Three ARIES visions are planned, each having a different degree of extrapolation from the present data base in physics and technology. The ARIES-I design assumes a minimum extrapolation from current tokamak physics (e.g., 1st stability) and incorporates technological advances that can be available in the next 20 to 30 years. ARIES-II is a DT-burning tokamak which would operate at a higher beta in the 2nd MHD stability regime. It employs both potential advances in the physics and expected advances in technology and engineering. ARIES-II will examine the potential of the tokamak and the D{sup 3}He fuel cycle. This report is a collection of 14 papers on the results of the ARIES study which were presented at the IEEE 13th Symposium on Fusion Engineering (October 2-6, 1989, Knoxville, TN). This collection describes the ARIES research effort, with emphasis on the ARIES-I design, summarizing the major results, the key technical issues, and the central conclusions.

  10. Observation of Energetic Particle Driven Modes Relevant to Advanced Tokamak Regimes

    SciTech Connect

    R. Nazikian; B. Alper; H.L. Berk; D. Borba; C. Boswell; R.V. Budny; K.H. Burrell; C.Z. Cheng; E.J. Doyle; E. Edlund; R.J. Fonck; A. Fukuyama; N.N. Gorelenkov; C.M. Greenfield; D.J. Gupta; M. Ishikawa; R.J. Jayakumar; G.J. Kramer; Y. Kusama; R.J. La Haye; G.R. McKee; W.A. Peebles; S.D. Pinches; M. Porkolab; J. Rapp; T.L. Rhodes; S.E. Sharapov; K. Shinohara; J.A. Snipes; W.M. Solomon; E.J. Strait; M. Takechi; M.A. Van Zeeland; W.P. West; K.L. Wong; S. Wukitch; L. Zeng

    2004-10-21

    Measurements of high-frequency oscillations in JET [Joint European Torus], JT-60U, Alcator C-Mod, DIII-D, and TFTR [Tokamak Fusion Test Reactor] plasmas are contributing to a new understanding of fast ion-driven instabilities relevant to Advanced Tokamak (AT) regimes. A model based on the transition from a cylindrical-like frequency-chirping mode to the Toroidal Alfven Eigenmode (TAE) has successfully encompassed many of the characteristics seen in experiments. In a surprising development, the use of internal density fluctuation diagnostics has revealed many more modes than has been detected on edge magnetic probes. A corollary discovery is the observation of modes excited by fast particles traveling well below the Alfven velocity. These observations open up new opportunities for investigating a ''sea of Alfven Eigenmodes'' in present-scale experiments, and highlight the need for core fluctuation and fast ion measurements in a future burning-plasma experiment.

  11. Integrated magnetic and kinetic control of advanced tokamak plasmas on DIII-D based on data-driven models

    NASA Astrophysics Data System (ADS)

    Moreau, D.; Walker, M. L.; Ferron, J. R.; Liu, F.; Schuster, E.; Barton, J. E.; Boyer, M. D.; Burrell, K. H.; Flanagan, S. M.; Gohil, P.; Groebner, R. J.; Holcomb, C. T.; Humphreys, D. A.; Hyatt, A. W.; Johnson, R. D.; La Haye, R. J.; Lohr, J.; Luce, T. C.; Park, J. M.; Penaflor, B. G.; Shi, W.; Turco, F.; Wehner, W.; the ITPA-IOS Group members; experts

    2013-06-01

    The first real-time profile control experiments integrating magnetic and kinetic variables were performed on DIII-D in view of regulating and extrapolating advanced tokamak scenarios to steady-state devices and burning plasma experiments. Device-specific, control-oriented models were obtained from experimental data using a generic two-time-scale method that was validated on JET, JT-60U and DIII-D under the framework of the International Tokamak Physics Activity for Integrated Operation Scenarios (Moreau et al 2011 Nucl. Fusion 51 063009). On DIII-D, these data-driven models were used to synthesize integrated magnetic and kinetic profile controllers. The neutral beam injection (NBI), electron cyclotron current drive (ECCD) systems and ohmic coil provided the heating and current drive (H&CD) sources. The first control actuator was the plasma surface loop voltage (i.e. the ohmic coil), and the available beamlines and gyrotrons were grouped to form five additional H&CD actuators: co-current on-axis NBI, co-current off-axis NBI, counter-current NBI, balanced NBI and total ECCD power from all gyrotrons (with off-axis current deposition). Successful closed-loop experiments showing the control of (a) the poloidal flux profile, Ψ(x), (b) the poloidal flux profile together with the normalized pressure parameter, βN, and (c) the inverse of the safety factor profile, \\bar{\\iota}(x)=1/q(x) , are described.

  12. ELMy H-mode linear simulation with 3-field model on experimental advanced superconducting tokamak using BOUT++

    SciTech Connect

    Liu, Z. X.; Gao, X.; Liu, S. C.; Ding, S. Y.; Li, J. G.; Xia, T. Y.; Xu, X. Q.; Hughes, J. W.

    2012-10-15

    H-mode plasmas with ELM (edge localized mode) have been realized on experimental advanced superconducting tokamak (EAST) with 2.45 GHz low hybrid wave at P{sub LHW}{approx}1 MW in 2010. Data from EAST experiments including magnetic geometry, measured pressure profiles, and calculated current profiles are used to investigate the physics of ELM utilizing the BOUT++ code. Results from linear simulations show that the ELMs in EAST are dominated by resistive ballooning modes. When the Lundquist number (dimensionless ratio of the resistive diffusion time to the Alfven time) is equal to or less than 10{sup 7}, the resistive ballooning modes are found to become unstable in the ELMy H-mode plasma. For a fixed pedestal pressure profile, increasing plasma current generates more activities of low-n ELMs.

  13. Physical meaning of one-machine and multimachine tokamak scalings

    SciTech Connect

    Dnestrovskij, Yu. N. Danilov, A. V.; Dnestrovskij, A. Yu.; Lysenko, S. E.; Ongena, J.

    2013-04-15

    Specific features of energy confinement scalings constructed using different experimental databases for tokamak plasmas are considered. In the multimachine database, some pairs of engineering variables are collinear; e.g., the current I and the input power P both increase with increasing minor radius a. As a result, scalings derived from this database are reliable only for discharges in which such ratios as I/a{sup 2} or P/a{sup 2} are close to their values averaged over the database. The collinearity of variables allows one to exclude the normalized Debye radius d* from the scaling expressed in a nondimensional form. In one-machine databases, the dimensionless variables are functionally dependent, which allow one to cast a scaling without d*. In a database combined from two devices, the collinearity may be absent, so the Debye radius cannot generally be excluded from the scaling. It is shown that the experiments performed in support of the absence of d* in the two-machine scaling are unconvincing. Transformation expressions are given that allow one to compare experiments for the determination of scaling in any set of independent variables.

  14. Superconducting magnet system for the TPX Tokamak

    SciTech Connect

    Hassenzahl, W.V.; Chaplin, M.R.; Heim, J.R.

    1993-09-15

    The Tokamak Physics Experiment (TPX) will be the first Tokamak using superconducting magnets for both the poloidal and toroidal field. It is designed for advanced Tokamak physics experiments in steady-state and long-pulse operation. The TPX superconducting magnets use an advanced cable-in-conduit conductor (CICC) design similar to that developed in support of the International Thermonuclear Experimental Reactor (ITER). The toroidal field magnets provide 4.0 T at 2.25 m with a stored energy of 1.05 GJ. The poloidal field magnets provide 18.0 V-s to ohmically start and control long burns of a 2.0 MA plasma.

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

    SciTech Connect

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

    1986-06-01

    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.

  16. Conceptual design of a fast-ion D-alpha diagnostic on experimental advanced superconducting tokamak

    SciTech Connect

    Huang, J. Wan, B.; Hu, L.; Hu, C.; Heidbrink, W. W.; Zhu, Y.; Hellermann, M. G. von; Gao, W.; Wu, C.; Li, Y.; Fu, J.; Lyu, B.; Yu, Y.; Ye, M.; Shi, Y.

    2014-11-15

    To investigate the fast ion behavior, a fast ion D-alpha (FIDA) diagnostic system has been planned and is presently under development on Experimental Advanced Superconducting Tokamak. The greatest challenges for the design of a FIDA diagnostic are its extremely low intensity levels, which are usually significantly below the continuum radiation level and several orders of magnitude below the bulk-ion thermal charge-exchange feature. Moreover, an overlaying Motional Stark Effect (MSE) feature in exactly the same wavelength range can interfere. The simulation of spectra code is used here to guide the design and evaluate the diagnostic performance. The details for the parameters of design and hardware are presented.

  17. Impact of E × B flow shear on turbulence and resulting power fall-off width in H-mode plasmas in experimental advanced superconducting tokamak

    SciTech Connect

    Yang, Q. Q. Zhong, F. C. E-mail: fczhong@dhu.edu.cn; Jia, M. N.; Xu, G. S. E-mail: fczhong@dhu.edu.cn; Wang, L.; Wang, H. Q.; Chen, R.; Yan, N.; Liu, S. C.; Chen, L.; Li, Y. L.; Liu, J. B.

    2015-06-15

    The power fall-off width in the H-mode scrape-off layer (SOL) in tokamaks shows a strong inverse dependence on the plasma current, which was noticed by both previous multi-machine scaling work [T. Eich et al., Nucl. Fusion 53, 093031 (2013)] and more recent work [L. Wang et al., Nucl. Fusion 54, 114002 (2014)] on the Experimental Advanced Superconducting Tokamak. To understand the underlying physics, probe measurements of three H-mode discharges with different plasma currents have been studied in this work. The results suggest that a higher plasma current is accompanied by a stronger E×B shear and a shorter radial correlation length of turbulence in the SOL, thus resulting in a narrower power fall-off width. A simple model has also been applied to demonstrate the suppression effect of E×B shear on turbulence in the SOL and shows relatively good agreement with the experimental observations.

  18. Health physics measurement of Princeton Tokamaks, 1977-1987.

    PubMed

    Stencel, J R; Gilbert, J D; Couch, J G; Griesbach, O A; Fennimore, J J; Greco, J M

    1989-06-01

    The Princeton Plasma Physics Laboratory (PPPL) began fusion experiments in 1951. In the early years, the major health physics concerns were associated with x radiation produced by energetic electrons in the plasma. Within the past year, neutron and 3H production from 2H-2H (represented hereafter as D-D) reactions has increased significantly on the larger fusion devices. Tritium retention noted in graphite tiles underscores the significance of material selection in present and future 3H-fueled fusion devices. This paper reports on operational health physics radiation measurements made on various PPPL machines over the past 10 y. PMID:2722515

  19. Spectroscopy and atomic physics of highly ionized Cr, Fe, and Ni for tokamak plasmas

    NASA Technical Reports Server (NTRS)

    Feldman, U.; Doschek, G. A.; Cheng, C.-C.; Bhatia, A. K.

    1980-01-01

    The paper considers the spectroscopy and atomic physics for some highly ionized Cr, Fe, and Ni ions produced in tokamak plasmas. Forbidden and intersystem wavelengths for Cr and Ni ions are extrapolated and interpolated using the known wavelengths for Fe lines identified in solar-flare plasmas. Tables of transition probabilities for the B I, C I, N I, O I, and F I isoelectronic sequences are presented, and collision strengths and transition probabilities for Cr, Fe, and Ni ions of the Be I sequence are given. Similarities of tokamak and solar spectra are discussed, and it is shown how the atomic data presented may be used to determine ion abundances and electron densities in low-density plasmas.

  20. A long-pulse high-confinement plasma regime in the Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Li, J.; Guo, H. Y.; Wan, B. N.; Gong, X. Z.; Liang, Y. F.; Xu, G. S.; Gan, K. F.; Hu, J. S.; Wang, H. Q.; Wang, L.; Zeng, L.; Zhao, Y. P.; Denner, P.; Jackson, G. L.; Loarte, A.; Maingi, R.; Menard, J. E.; Rack, M.; Zou, X. L.

    2013-12-01

    High-performance and long-pulse operation is a crucial goal of current magnetic fusion research. Here, we demonstrate a high-confinement plasma regime known as an H-mode with a record pulse length of over 30s in the Experimental Advanced Superconducting Tokamak sustained by lower hybrid wave current drive (LHCD) with advanced lithium wall conditioning. We find that LHCD provides a flexible boundary control for a ubiquitous edge instability in H-mode plasmas known as an edge-localized mode, which leads to a marked reduction in the heat load on the vessel wall compared with standard edge-localized modes. LHCD also induces edge plasma ergodization that broadens the heat deposition footprint. The heat transport caused by this ergodization can be actively controlled by regulating the edge plasma conditions. This potentially offers a new means for heat-flux control, which is a key issue for next-step fusion development.

  1. First plasma of megawatt high current ion source for neutral beam injector of the experimental advanced superconducting tokamak on the test bed

    SciTech Connect

    Hu Chundong; Xie Yahong; Liu Sheng; Xie Yuanlai; Jiang Caichao; Song Shihua; Li Jun; Liu Zhimin

    2011-02-15

    High current ion source is the key part of the neutral beam injector. In order to develop the project of 4 MW neutral beam injection for the experimental advanced superconducting tokamak (EAST) on schedule, the megawatt high current ion source is prestudied in the Institute of Plasma Physics in China. In this paper, the megawatt high current ion source test bed and the first plasma are presented. The high current discharge of 900 A at 2 s and long pulse discharge of 5 s at 680 A are achieved. The arc discharge characteristic of high current ion source is analyzed primarily.

  2. Overview of JT-60U results towards the establishment of advanced tokamak operation

    NASA Astrophysics Data System (ADS)

    Oyama, N.; JT-60 Team

    2009-10-01

    Recent JT-60U experimental results towards the establishment of advanced tokamak (AT) operation are reviewed. We focused on the further expansion of the operational regime of AT plasmas towards higher βN regime with wall stabilization. After the installation of ferritic steel tiles in 2005, the high power heating in a large plasma cross-section in which the wall stabilization is expected has been possible. In 2007, the modification of power supply of NBIs improved the flexibility of the heating profile in long-pulse plasmas. The investigation of key physics issues for the establishment of steady-state AT operation is also in progress using new diagnostics and improved heating systems. In weak magnetic shear plasma, high βN ~ 3 exceeding the ideal MHD limit without a conducting wall ( \\beta_N^{{\\scriptsize{\\mbox{no-wall}}}} ) is sustained for ~5 s (~3τR) with RWM stabilization by a toroidal rotation at the q = 2 surface. External current drivers of negative-ion based NB and lower-hybrid waves together with a large bootstrap current fraction (fBS) of 0.5 can sustain the whole plasma current of 0.8 MA for 2 s (1.5τR). In reversed magnetic shear plasma, high βN ~ 2.7 (βp ~ 2.3) exceeding \\beta_N^{{\\scriptsize{\\mbox{no-wall}}}} with qmin ~ 2.4 (q95 ~ 5.3), HH98(y,2) ~ 1.7 and fBS ~ 0.9 is obtained with wall stabilization. These plasma parameters almost satisfy the requirement of ITER steady-state scenario. In long-pulse plasmas with positive magnetic shear, a high βNHH98(y,2) of 2.6 with βN ~ 2.6 and HH98(y,2) ~ 1 is sustained for 25 s, significantly longer than the current diffusion time (~14τR) without neoclassical tearing modes (NTMs). A high G-factor, \\beta_NH_{89P}/q_{95}^{2} (a major of fusion gain), of 0.54 and a large fBS > 0.43 are suitable for ITER hybrid operation scenario. Based on the plasma for ITER hybrid operation scenario, the high βN of 2.1 with good thermal plasma confinement of HH98(y,2) > 0.85 is sustained for longer than 12 s at

  3. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research.

    PubMed

    Lampert, M; Anda, G; Czopf, A; Erdei, G; Guszejnov, D; Kovácsik, Á; Pokol, G I; Réfy, D; Nam, Y U; Zoletnik, S

    2015-07-01

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera's measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties. PMID:26233377

  4. Fishbone activity in experimental advanced superconducting tokamak neutral beam injection plasma

    SciTech Connect

    Xu, Liqing; Zhang, Jizong; Chen, Kaiyun E-mail: lqhu@ipp.cas.cn; Hu, Liqun E-mail: lqhu@ipp.cas.cn; Li, Erzhong; Lin, Shiyao; Shi, Tonghui; Duan, Yanmin; Zhu, Yubao

    2015-12-15

    Repetitive fishbones near the trapped ion procession frequency were observed for the first time in the neutral beam injection high confinement plasmas in Experimental Advanced Superconducting Tokamak (EAST) tokamak, and diagnosed using a solid-state neutral particle analyzer based on a compact silicon photodiode together with an upgraded high spatial-temporal-resolution multi-arrays soft X-ray (SX) system. This 1/1 typical internal kink mode propagates in the ion-diamagnetism direction with a rotation speed faster than the bulk plasma in the plasma frame. From the SX measurements, this mode frequency is typical of chirping down and the energetic particle effect related to the twisting mode structure. This ion fishbone was found able to trigger a multiple core sawtooth crashes with edge-2/1 sideband modes, as well as to lead to a transition from fishbone to long lived saturated kink mode to fishbone. Furthermore, using SX tomography, a correlation between mode amplitude and mode frequency was found. Finally, a phenomenological prey–predator model was found to reproduce the fishbone nonlinear process well.

  5. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research

    SciTech Connect

    Lampert, M.; Anda, G.; Réfy, D.; Zoletnik, S.; Czopf, A.; Erdei, G.; Guszejnov, D.; Kovácsik, Á.; Pokol, G. I.; Nam, Y. U.

    2015-07-15

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera’s measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties.

  6. The study of heat flux for disruption on experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Yang, Zhendong; Fang, Jianan; Gong, Xianzu; Gan, Kaifu; Luo, Jiarong; Zhao, Hailin; Cui, Zhixue; Zhang, Bin; Chen, Meiwen

    2016-05-01

    Disruption of the plasma is one of the most dangerous instabilities in tokamak. During the disruption, most of the plasma thermal energy is lost, which causes damages to the plasma facing components. Infrared (IR) camera is an effective tool to detect the temperature distribution on the first wall, and the energy deposited on the first wall can be calculated from the surface temperature profile measured by the IR camera. This paper concentrates on the characteristics of heat flux distribution onto the first wall under different disruptions, including the minor disruption and the vertical displacement events (VDE) disruption. Several minor disruptions have been observed before the major disruption under the high plasma density in experimental advanced superconducting tokamak. During the minor disruption, the heat fluxes are mainly deposited on the upper/lower divertors. The magnetic configuration prior to the minor disruption is a lower single null with the radial distance between the two separatrices in the outer midplane dRsep = -2 cm, while it changes to upper single null (dRsep = 1.4 cm) during the minor disruption. As for the VDE disruption, the spatial distribution of heat flux exhibits strong toroidal and radial nonuniformity, and the maximum heat flux received on the dome plate can be up to 11 MW/m2.

  7. CONTROL OF MHD STABILITY IN DIII-D ADVANCED TOKAMAK DISCHARGES

    SciTech Connect

    STRAIT,EJ; BIALEK,J; CHANCE,MS; CHU,MS; EDGELL,DH; FERRON,JR; GREENFIELD,CM; GAROFALO,AM; HUMPHREYS,DA; JACKSON,GL; JAYAKUMAR,RJ; JERNIGAN,TC; KIM,JS; LA HAYE,RJ; LAO,LL; LUCE,TC; MAKOWSKI,MA; MURAKAMI,M; NAVRATIL,GA; OKABAYASHI,M; PETTY,CC; REIMERDES,H; SCOVILLE,JT; TURNBULL,AD; WADE,MR; WALKER,ML; WHYTE,DG; DIII-D TEAM

    2003-06-01

    OAK-B135 Advanced tokamak research in DIII-D seeks to optimize the tokamak approach for fusion energy production, leading to a compact, steady state power source. High power density implies operation at high toroidal beta, {beta}{sub T}=

    2{micro}{sub 0}/B{sub T}{sup 2}, since fusion power density increases roughly as the square of the plasma pressure. Steady-state operation with low recirculating power for current drive implies operation at high poloidal beta, {beta}{sub P} =

    2{micro}{sub 0}/{sup 2}, in order to maximize the fraction of self-generated bootstrap current. Together, these lead to a requirement of operation at high normalized beta, {beta}{sub N} = {beta}{sub T}(aB/I), since {beta}{sub P}{beta}{sub T} {approx} 25[(1+{kappa}{sup 2})/2] ({beta}{sub N}/100){sup 2}. Plasmas with high normalized beta are likely to operate near one or more stability limits, so control of MHD stability in such plasmas is crucial.

  8. New dual gas puff imaging system with up-down symmetry on experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Liu, S. C.; Shao, L. M.; Zweben, S. J.; Xu, G. S.; Guo, H. Y.; Cao, B.; Wang, H. Q.; Wang, L.; Yan, N.; Xia, S. B.; Zhang, W.; Chen, R.; Chen, L.; Ding, S. Y.; Xiong, H.; Zhao, Y.; Wan, B. N.; Gong, X. Z.; Gao, X.

    2012-12-01

    Gas puff imaging (GPI) offers a direct and effective diagnostic to measure the edge turbulence structure and velocity in the edge plasma, which closely relates to edge transport and instability in tokamaks. A dual GPI diagnostic system has been installed on the low field side on experimental advanced superconducting tokamak (EAST). The two views are up-down symmetric about the midplane and separated by a toroidal angle of 66.6°. A linear manifold with 16 holes apart by 10 mm is used to form helium gas cloud at the 130×130 mm (radial versus poloidal) objective plane. A fast camera is used to capture the light emission from the image plane with a speed up to 390 804 frames/s with 64×64 pixels and an exposure time of 2.156 μs. The spatial resolution of the system is 2 mm at the objective plane. A total amount of 200 Pa.L helium gas is puffed into the plasma edge for each GPI viewing region for about 250 ms. The new GPI diagnostic has been applied on EAST for the first time during the recent experimental campaign under various plasma conditions, including ohmic, L-mode, and type-I, and type-III ELMy H-modes. Some of these initial experimental results are also presented.

  9. Physics Basis for a Spherical Tokamak Power Plant

    NASA Astrophysics Data System (ADS)

    Jardin, S. C.; Kessel, C. E.; Menard, J.; Mau, T. K.; Lin-Liu, Y. R.; Miller, R. L.; Stambaugh, R. D.; Turnbull, A. D.

    1998-11-01

    We present the results of physics optimization studies done as part of the ARIES-ST power plant study. The baseline configuration has the following parameters: β = 54%, β N = 7.5, elongation κ = 3.4, triangularity δ = .65, Aspect Ratio A = 1.6. Calculations using the PEST-II, GATO, BALLOON, and BALOO codes show this is stable to ballooning and kink modes up to n=6 with an ideally conducting wall with a separation of 0.165 a. Neutral beams (40 MW at 120 kV) will provide 5% of the plasma current and the rotation needed to stabilize the resistive-wall mode. We also address the vertical control and plasma initiation issues. Vertical stability is provided by a vertically stabilizing wall segment behind the breeding blanket, but within a separation of 0.45 minor radii from the plasma boundary. Plasma startup is facilitated by a combination of bootstrap current and external heating and current drive. Requirements on heating and current-drive systems and the timescales for current rampup are discussed.

  10. Design of a magnetic shielding system for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Cui, Z. Q.; Chen, Z. J.; Xie, X. F.; Peng, X. Y.; Hu, Z. M.; Du, T. F.; Ge, L. J.; Zhang, X.; Yuan, X.; Fan, T. S.; Chen, J. X.; Li, X. Q. E-mail: guohuizhang@pku.edu.cn; Zhang, G. H. E-mail: guohuizhang@pku.edu.cn; Xia, Z. W.; Hu, L. Q.; Zhong, G. Q.; Lin, S. Y.; Wan, B. N.

    2014-11-15

    The novel neutron spectrometer TOFED (Time of Flight Enhanced Diagnostics), comprising 90 individual photomultiplier tubes coupled with 85 plastic scintillation detectors through light guides, has been constructed and installed at Experimental Advanced Superconducting Tokamak. A dedicated magnetic shielding system has been constructed for TOFED, and is designed to guarantee the normal operation of photomultiplier tubes in the stray magnetic field leaking from the tokamak device. Experimental measurements and numerical simulations carried out employing the finite element method are combined to optimize the design of the magnetic shielding system. The system allows detectors to work properly in an external magnetic field of 200 G.

  11. Design of a magnetic shielding system for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak.

    PubMed

    Cui, Z Q; Chen, Z J; Xie, X F; Peng, X Y; Hu, Z M; Du, T F; Ge, L J; Zhang, X; Yuan, X; Xia, Z W; Hu, L Q; Zhong, G Q; Lin, S Y; Wan, B N; Fan, T S; Chen, J X; Li, X Q; Zhang, G H

    2014-11-01

    The novel neutron spectrometer TOFED (Time of Flight Enhanced Diagnostics), comprising 90 individual photomultiplier tubes coupled with 85 plastic scintillation detectors through light guides, has been constructed and installed at Experimental Advanced Superconducting Tokamak. A dedicated magnetic shielding system has been constructed for TOFED, and is designed to guarantee the normal operation of photomultiplier tubes in the stray magnetic field leaking from the tokamak device. Experimental measurements and numerical simulations carried out employing the finite element method are combined to optimize the design of the magnetic shielding system. The system allows detectors to work properly in an external magnetic field of 200 G. PMID:25430242

  12. Design of a magnetic shielding system for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Cui, Z. Q.; Chen, Z. J.; Xie, X. F.; Peng, X. Y.; Hu, Z. M.; Du, T. F.; Ge, L. J.; Zhang, X.; Yuan, X.; Xia, Z. W.; Hu, L. Q.; Zhong, G. Q.; Lin, S. Y.; Wan, B. N.; Fan, T. S.; Chen, J. X.; Li, X. Q.; Zhang, G. H.

    2014-11-01

    The novel neutron spectrometer TOFED (Time of Flight Enhanced Diagnostics), comprising 90 individual photomultiplier tubes coupled with 85 plastic scintillation detectors through light guides, has been constructed and installed at Experimental Advanced Superconducting Tokamak. A dedicated magnetic shielding system has been constructed for TOFED, and is designed to guarantee the normal operation of photomultiplier tubes in the stray magnetic field leaking from the tokamak device. Experimental measurements and numerical simulations carried out employing the finite element method are combined to optimize the design of the magnetic shielding system. The system allows detectors to work properly in an external magnetic field of 200 G.

  13. Physics Studies of a Proposed Small Aspect Ratio Torsatron-Tokamak Hybrid

    NASA Astrophysics Data System (ADS)

    Valanju, P. M.; Gentle, K. W.; McCool, S.; Miner, W. H., Jr.; Ross, D. W.; Wiley, J. C.; Wootton, A. J.

    1996-11-01

    Physics studies of a proposed small aspect ratio torsatron-tokamak hybrid (SMARTH) are presented. This small aspect ratio configuration attempts to remedy a major drawback of conventional stellarator reactors, viz. the large volume resulting from the large aspect ratio. Considering a small aspect ratio machine with 8 field periods (m=8) and with 8 or 16 modular coils, we investigate vacuum configurations and MHD equilibria to determine the optimum configuration which produces large rotational transform, large plasma volume, large beta, and small field ripple. Implications for particle confinement will also be discussed. Effects of radial electric fields on orbit losses and confinement will also be explored.

  14. Vacuum photodiode detectors for broadband vacuum ultraviolet detection in the Saha Institute of Nuclear Physics Tokamak

    NASA Astrophysics Data System (ADS)

    Rao, C. V. S.; Shankara Joisa, Y.; Hansalia, C. J.; Hui, Amit K.; Paul, Ratan; Ranjan, Prabhat

    1997-02-01

    We report on the application of the vacuum photodiode to detect vacuum ultraviolet (VUV) radiation emitted from the Saha Institute of Nuclear Physics (SINP) Tokamak. It is simple to fabricate and provides broadband spectral response in the VUV and ultrasoft x ray (10 eV-1 keV). In our design, a stainless steel photocathode is used, which has a response identical to tungsten in the wavelength range 100-1200 Å. Its surface is passivated, to minimize contamination and monolayer deposition, by electropolishing it. Some representative experimental results illustrating the range of applicability are presented with special emphasis on its performance in disruptive shots.

  15. Inward particle transport at high collisionality in the Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Wang, G. Q.; Ma, J.; Weiland, J.; Zang, Q.

    2013-10-01

    We have made the first drift wave study of particle transport in the Experimental Advanced Superconducting Tokamak (Wan et al., Nucl. Fusion 49, 104011 (2009)). The results reveal that collisions make the particle flux more inward in the high collisionality regime. This can be traced back to effects that are quadratic in the collision frequency. The particle pinch is due to electron trapping which is not very efficient in the high collisionality regime so the approach to equilibrium is slow. We have included also the electron temperature gradient (ETG) mode to give the right electron temperature gradient, since the Trapped Electron Mode (TE mode) is weak in this regime. However, at the ETG mode number ions are Boltzmann distributed so the ETG mode does not give particle transport.

  16. Development of an alternating integrator for magnetic measurements for experimental advanced superconducting tokamak

    SciTech Connect

    Liu, D. M. Zhao, W. Z.; He, Y. G.; Chen, B.; Wan, B. N.; Shen, B.; Huang, J.; Liu, H. Q.

    2014-11-15

    A high-performance integrator is one of the key electronic devices for reliably controlling plasma in the experimental advanced superconducting tokamak for long pulse operation. We once designed an integrator system of real-time drift compensation, which has a low integration drift. However, it is not feasible for really continuous operations due to capacitive leakage error and nonlinearity error. To solve the above-mentioned problems, this paper presents a new alternating integrator. In the new integrator, the integrator system of real-time drift compensation is adopted as one integral cell while two such integral cells work alternately. To achieve the alternate function, a Field Programmable Gate Array built in the digitizer is utilized. The performance test shows that the developed integrator with the integration time constant of 20 ms has a low integration drift (<15 mV) for 1000 s.

  17. Application of visible bremsstrahlung to Z(eff) measurement on the Experimental Advanced Superconducting Tokamak.

    PubMed

    Chen, Yingjie; Wu, Zhenwei; Gao, Wei; Ti, Ang; Zhang, Ling; Jie, Yinxian; Zhang, Jizong; Huang, Juan; Xu, Zong; Zhao, Junyu

    2015-02-01

    The multi-channel visible bremsstrahlung measurement system has been developed on Experimental Advanced Superconducting Tokamak (EAST). In addition to providing effective ion charge Zeff as a routine diagnostic, this diagnostic can also be used to estimate other parameters. With the assumption that Zeff can be seen as constant across the radius and does not change significantly during steady state discharges, central electron temperature, averaged electron density, electron density profile, and plasma current density profile have been obtained based on the scaling of Zeff with electron density and the relations between Zeff and these parameters. The estimated results are in good coincidence with measured values, providing an effective and convenient method to estimate other plasma parameters. PMID:25725844

  18. Development of an alternating integrator for magnetic measurements for experimental advanced superconducting tokamak.

    PubMed

    Liu, D M; Wan, B N; Zhao, W Z; Shen, B; He, Y G; Chen, B; Huang, J; Liu, H Q

    2014-11-01

    A high-performance integrator is one of the key electronic devices for reliably controlling plasma in the experimental advanced superconducting tokamak for long pulse operation. We once designed an integrator system of real-time drift compensation, which has a low integration drift. However, it is not feasible for really continuous operations due to capacitive leakage error and nonlinearity error. To solve the above-mentioned problems, this paper presents a new alternating integrator. In the new integrator, the integrator system of real-time drift compensation is adopted as one integral cell while two such integral cells work alternately. To achieve the alternate function, a Field Programmable Gate Array built in the digitizer is utilized. The performance test shows that the developed integrator with the integration time constant of 20 ms has a low integration drift (<15 mV) for 1000 s. PMID:25430391

  19. Conceptual design of a fast-ion D-alpha diagnostic on experimental advanced superconducting tokamak.

    PubMed

    Huang, J; Heidbrink, W W; Wan, B; von Hellermann, M G; Zhu, Y; Gao, W; Wu, C; Li, Y; Fu, J; Lyu, B; Yu, Y; Shi, Y; Ye, M; Hu, L; Hu, C

    2014-11-01

    To investigate the fast ion behavior, a fast ion D-alpha (FIDA) diagnostic system has been planned and is presently under development on Experimental Advanced Superconducting Tokamak. The greatest challenges for the design of a FIDA diagnostic are its extremely low intensity levels, which are usually significantly below the continuum radiation level and several orders of magnitude below the bulk-ion thermal charge-exchange feature. Moreover, an overlaying Motional Stark Effect (MSE) feature in exactly the same wavelength range can interfere. The simulation of spectra code is used here to guide the design and evaluate the diagnostic performance. The details for the parameters of design and hardware are presented. PMID:25430314

  20. Application of visible bremsstrahlung to Z{sub eff} measurement on the Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Chen, Yingjie; Wu, Zhenwei; Gao, Wei; Ti, Ang; Zhang, Ling; Jie, Yinxian; Zhang, Jizong; Huang, Juan; Xu, Zong; Zhao, Junyu

    2015-02-15

    The multi-channel visible bremsstrahlung measurement system has been developed on Experimental Advanced Superconducting Tokamak (EAST). In addition to providing effective ion charge Z{sub eff} as a routine diagnostic, this diagnostic can also be used to estimate other parameters. With the assumption that Z{sub eff} can be seen as constant across the radius and does not change significantly during steady state discharges, central electron temperature, averaged electron density, electron density profile, and plasma current density profile have been obtained based on the scaling of Z{sub eff} with electron density and the relations between Z{sub eff} and these parameters. The estimated results are in good coincidence with measured values, providing an effective and convenient method to estimate other plasma parameters.

  1. Analog integrator for the Korea superconducting tokamak advanced research magnetic diagnostics

    NASA Astrophysics Data System (ADS)

    Bak, J. G.; Lee, S. G.; Son, D.; Ga, E. M.

    2007-04-01

    An analog integrator, which automatically compensates an integrating drift, has been developed for the magnetic diagnostics in the Korea superconducting tokamak advanced research (KSTAR). The compensation of the drift is done by the analog to digital converter-register-digital to analog converter in the integrator. The integrator will be used in the equilibrium magnetic field measurements by using inductive magnetic sensors during a plasma discharge in the KSTAR machine. Two differential amplifiers are added to the signal path between each magnetic sensor and the integrator in order to improve the performance of the integrator because a long signal cable of 100 m will be used for the measurement in the KSTAR machine. In this work, the characteristics of the integrator with two differential amplifiers are experimentally investigated.

  2. Recent Advances in Neutron Physics

    ERIC Educational Resources Information Center

    Feshbach, Herman; Sheldon, Eric

    1977-01-01

    Discusses new studies in neutron physics within the last decade, such as ultracold neutrons, neutron bottles, resonance behavior, subthreshold fission, doubly radiative capture, and neutron stars. (MLH)

  3. ADX: A high Power Density, Advanced RF-Driven Divertor Test Tokamak for PMI studies

    NASA Astrophysics Data System (ADS)

    Whyte, Dennis; ADX Team

    2015-11-01

    The MIT PSFC and collaborators are proposing an advanced divertor experiment, ADX; a divertor test tokamak dedicated to address critical gaps in plasma-material interactions (PMI) science, and the world fusion research program, on the pathway to FNSF/DEMO. Basic ADX design features are motivated and discussed. In order to assess the widest range of advanced divertor concepts, a large fraction (>50%) of the toroidal field volume is purpose-built with innovative magnetic topology control and flexibility for assessing different surfaces, including liquids. ADX features high B-field (>6 Tesla) and high global power density (P/S ~ 1.5 MW/m2) in order to access the full range of parallel heat flux and divertor plasma pressures foreseen for reactors, while simultaneously assessing the effect of highly dissipative divertors on core plasma/pedestal. Various options for efficiently achieving high field are being assessed including the use of Alcator technology (cryogenic cooled copper) and high-temperature superconductors. The experimental platform would also explore advanced lower hybrid current drive and ion-cyclotron range of frequency actuators located at the high-field side; a location which is predicted to greatly reduce the PMI effects on the launcher while minimally perturbing the core plasma. The synergistic effects of high-field launchers with high total B on current and flow drive can thus be studied in reactor-relevant boundary plasmas.

  4. Physics of Radiation-driven Islands Near the Tokamak Density Limit

    SciTech Connect

    D.A. Gates, L. Delgado-Apricio and R.B. White

    2013-01-10

    In previous work [1], the onset criterion for radiation driven islands [2] in combination with a simple cylindrical model of tokamak current channel behavior was shown to be consistent with the empirical scaling of the tokamak density limit [3]. A number of the unexplained phenomena at the density limit are consistent with this novel physics mechanism. In this work, a more formal theoretical underpinning, consistent with cylindrical tearing mode theory, is developed for the onset criteria of these modes. The appropriate derivation of the radiation-driven addition to the modified Rutherford equation is discussed. Additionally, the ordering of the terms in the MRE is examined in a regime near the density limit. It is hoped that given the apparent success of this simple model in explaining the observed global scalings will lead to a more comprehensive analysis of the possibility that radiation driven islands are the physics mechanism responsible for the density limit. In particular, with modern diagnostic capabilities detailed measurements of current densities, electron densities and impurity concentrations at rational surfaces should be possible, enabling verification of the concepts described above.

  5. The National Spherical Tokamak Experiment at the Princeton Plasma Physics Laboratory

    SciTech Connect

    1995-12-01

    The Department of Energy (DOE) has prepared an Environmental Assessment (EA), DOE/EA-1108, evaluating the environmental effects of the proposed construction and operation of the National Spherical Tokamak Experiment (NSTX) within the existing C-Stellarator (CS) Building at the Princeton Plasma Physics Laboratory, Princeton, New Jersey. The purpose of the NSTX is to investigate the physics of spherically shaped plasmas as an alternative path to conventional tokamaks for development of fusion energy. Fusion energy has the potential to help compensate for dwindling supplies of fossil fuels and the eventual depletion of fissionable uranium used in present-day nuclear reactors. Construction of the NSTX in the CS Building would require the dismantling and removal of the existing unused Princeton Large Torus (PLT) device, part of which would be reused to construct the NSTX. Based on the analyses in the EA, the DOE has determined that the proposed action does not constitute a major federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969, 42 U.S.C. 4,321 et seq. The preparation of an Environmental Impact Statement is not required. Thus, the DOE is issuing a FONSI pursuant to the Council on Environmental Quality regulations implementing NEPA (40 CFR Parts 1500--1508) and the DOE NEPA implementing regulations (10 CFR Part 1021).

  6. Status of Advanced Tokamak Scenario Modeling with Off-Axis Electron Cyclotron Current Drive in DIII-D

    SciTech Connect

    M. Murakami; H.E. St.John; T.A. Casper; M.S. Chu; J.C. DeBoo; C.M. Greenfield; J.E. Kinsey; L.L. Lao; R.J. La Haye; Y.R. Lin-Liu; T.C. Luce; P.A. Politzer; B.W. Rice; G.M. Staebler; T.S. Taylor; M.R. Wade

    1999-12-01

    The status of modeling work focused on developing the advanced tokamak scenarios in DIII-D is discussed. The objectives of the work are two-fold: (1) to develop AT scenarios with ECCD using time-dependent transport simulations, coupled with heating and current drive models, consistent with MHD equilibrium and stability; and (2) to use time-dependent simulations to help plan experiments and to understand the key physics involved. Time-dependent simulations based on transport coefficients derived from experimentally achieved target discharges are used to perform AT scenario modeling. The modeling indicates off-axis ECCD with approximately 3 MW absorbed power can maintain high-performance discharges with q{sub min} > 1 for 5 to 10 s. The resultant equilibria are calculated to be stable to n = 1 pressure driven modes. The plasma is well into the second stability regime for high-n ballooning modes over a large part of the plasma volume. The role of continuous localized ECCD is studied for stabilizing m/n = 2/1 tearing modes. The progress towards validating current drive and transport models, consistent with experimental results, and developing self-consistent, integrated high performance AT scenarios is discussed.

  7. Advanced Physics Lab at TCU

    NASA Astrophysics Data System (ADS)

    Quarles, C. A.

    2009-04-01

    The one semester, one credit hour Modern Physics Lab is viewed as a transition between the structured Physics 1 and 2 labs and junior/senior research. The labs focus on a variety of experiments built around a multichannel analyzer, various alpha, beta and gamma ray detectors and weak radioactive sources. Experiments include radiation safety and detection with a Geiger counter and NaI detector, gamma ray spectroscopy with a germanium detector, beta spectrum, alpha energy loss, gamma ray absorption, Compton effect, nuclear and positron annihilation lifetime, speed of gamma rays. Other experiments include using the analog oscilloscope, x-ray diffraction of diamond and using an SEM/EDX. Error analysis is emphasized throughout. The semester ends with an individual project, often an extension of one of the earlier experiments, and students present their results as a paper and an APS style presentation to the department.

  8. Investigation of relativistic runaway electrons in electron cyclotron resonance heating discharges on Korea Superconducting Tokamak Advanced Research

    SciTech Connect

    Kang, C. S.; Lee, S. G.

    2014-07-15

    The behavior of relativistic runaway electrons during Electron Cyclotron Resonance Heating (ECRH) discharges is investigated in the Korea Superconducting Tokamak Advanced Research device. The effect of the ECRH on the runaway electron population is discussed. Observations on the generation of superthermal electrons during ECRH will be reported, which will be shown to be consistent with existing theory for the development of a superthermal electron avalanche during ECRH [A. Lazaros, Phys. Plasmas 8, 1263 (2001)].

  9. Advanced analysis methods in particle physics

    SciTech Connect

    Bhat, Pushpalatha C.; /Fermilab

    2010-10-01

    Each generation of high energy physics experiments is grander in scale than the previous - more powerful, more complex and more demanding in terms of data handling and analysis. The spectacular performance of the Tevatron and the beginning of operations of the Large Hadron Collider, have placed us at the threshold of a new era in particle physics. The discovery of the Higgs boson or another agent of electroweak symmetry breaking and evidence of new physics may be just around the corner. The greatest challenge in these pursuits is to extract the extremely rare signals, if any, from huge backgrounds arising from known physics processes. The use of advanced analysis techniques is crucial in achieving this goal. In this review, I discuss the concepts of optimal analysis, some important advanced analysis methods and a few examples. The judicious use of these advanced methods should enable new discoveries and produce results with better precision, robustness and clarity.

  10. Simultaneous measurements of plasma parameters in the Saha Institute of Nuclear Physics Tokamak using a new low cost optoisolator

    NASA Astrophysics Data System (ADS)

    Ghosh, J.; Chattopadhyay, P. K.; Pal, R.; Bal, B.; Bhattacharya, P. S.

    2000-09-01

    In the Saha Institute of Nuclear Physics Tokamak (SINP-TOKAMAK), simultaneous measurement of signals from some diagnostics, like, electrostatic probes, etc., is not possible because pickup noises due to the formation of ground and other loops affect them quite severely. To avoid these loops and also to isolate some diagnostics from the ground, we developed a new type of optical isolator using a very low cost optical isolator chip (MC2TE made by Motorola) in a novel configuration. We continuously kept the light emitting diode on and used a feedback arrangement at the receiving side of the photoemitted signal for achieving good isolation for very low signals with reasonably high frequency response and good linearity. The method is highly cost effective in low budget tokamak experiments.

  11. Selected highlights of ECH/ECCD physics studies in the TCV tokamak

    NASA Astrophysics Data System (ADS)

    Goodman, T. P.; Coda, S.; Duval, B. P.; Kim, D.; Sauter, O.; Felici, F.; Decker, J.

    2015-03-01

    The Tokamak a Configuration Variable, TCV, has used Electron Cyclotron Heating and Current Drive as its only auxiliary heating system for nearly two decades. In addition to basic plasma heating and current profiling, ECH and ECCD under either feedforward or real-time (feedback) control allows control of plasma parameters and MHD behaviour to aid in physics studies and measurements. This paper describes four such studies in which EC control has proved crucial - increased resolution Thomson Scattering measurements in the plasma edge, time-resolved plasma rotation modification during the sawtooth cycle, robust neoclassical tearing mode (NTM) suppression, and double pass transmission measurements of EC waves for scattering and polarization studies. The relative merits of feedforward and feedback methods for recent TCV experiments are discussed.

  12. Edge multi-energy soft x-ray diagnostic in Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Li, Y. L.; Xu, G. S.; Tritz, K.; Zhu, Y. B.; Wan, B. N.; Lan, H.; Liu, Y. L.; Wei, J.; Zhang, W.; Hu, G. H.; Wang, H. Q.; Duan, Y. M.; Zhao, J. L.; Wang, L.; Liu, S. C.; Ye, Y.; Li, J.; Lin, X.; Li, X. L.

    2015-12-01

    A multi-energy soft x-ray (ME-SXR) diagnostic has been built for electron temperature profile in the edge plasma region in Experimental Advanced Superconducting Tokamak (EAST) after two rounds of campaigns. Originally, five preamplifiers were mounted inside the EAST vacuum vessel chamber attached to five vertically stacked compact diode arrays. A custom mechanical structure was designed to protect the detectors and electronics under constraints of the tangential field of view for plasma edge and the allocation of space. In the next experiment, the mechanical structure was redesigned with a barrel structure to absolutely isolate it from the vacuum vessel. Multiple shielding structures were mounted at the pinhole head to protect the metal foils from lithium coating. The pre-amplifiers were moved to the outside of the vacuum chamber to avoid introducing interference. Twisted copper cooling tube was embedded into the back-shell near the diode to limit the temperature of the preamplifiers and diode arrays during vacuum vessel baking when the temperature reached 150 °C. Electron temperature profiles were reconstructed from ME-SXR measurements using neural networks.

  13. The circuit of polychromator for Experimental Advanced Superconducting Tokamak edge Thomson scattering diagnostic.

    PubMed

    Zang, Qing; Hsieh, C L; Zhao, Junyu; Chen, Hui; Li, Fengjuan

    2013-09-01

    The detector circuit is the core component of filter polychromator which is used for scattering light analysis in Thomson scattering diagnostic, and is responsible for the precision and stability of a system. High signal-to-noise and stability are primary requirements for the diagnostic. Recently, an upgraded detector circuit for weak light detecting in Experimental Advanced Superconducting Tokamak (EAST) edge Thomson scattering system has been designed, which can be used for the measurement of large electron temperature (T(e)) gradient and low electron density (n(e)). In this new circuit, a thermoelectric-cooled avalanche photodiode with the aid circuit is involved for increasing stability and enhancing signal-to-noise ratio (SNR), especially the circuit will never be influenced by ambient temperature. These features are expected to improve the accuracy of EAST Thomson diagnostic dramatically. Related mechanical construction of the circuit is redesigned as well for heat-sinking and installation. All parameters are optimized, and SNR is dramatically improved. The number of minimum detectable photons is only 10. PMID:24089826

  14. New steady-state quiescent high-confinement plasma in an experimental advanced superconducting tokamak.

    PubMed

    Hu, J S; Sun, Z; Guo, H Y; Li, J G; Wan, B N; Wang, H Q; Ding, S Y; Xu, G S; Liang, Y F; Mansfield, D K; Maingi, R; Zou, X L; Wang, L; Ren, J; Zuo, G Z; Zhang, L; Duan, Y M; Shi, T H; Hu, L Q

    2015-02-01

    A critical challenge facing the basic long-pulse high-confinement operation scenario (H mode) for ITER is to control a magnetohydrodynamic (MHD) instability, known as the edge localized mode (ELM), which leads to cyclical high peak heat and particle fluxes at the plasma facing components. A breakthrough is made in the Experimental Advanced Superconducting Tokamak in achieving a new steady-state H mode without the presence of ELMs for a duration exceeding hundreds of energy confinement times, by using a novel technique of continuous real-time injection of a lithium (Li) aerosol into the edge plasma. The steady-state ELM-free H mode is accompanied by a strong edge coherent MHD mode (ECM) at a frequency of 35-40 kHz with a poloidal wavelength of 10.2 cm in the ion diamagnetic drift direction, providing continuous heat and particle exhaust, thus preventing the transient heat deposition on plasma facing components and impurity accumulation in the confined plasma. It is truly remarkable that Li injection appears to promote the growth of the ECM, owing to the increase in Li concentration and hence collisionality at the edge, as predicted by GYRO simulations. This new steady-state ELM-free H-mode regime, enabled by real-time Li injection, may open a new avenue for next-step fusion development. PMID:25699449

  15. Edge multi-energy soft x-ray diagnostic in Experimental Advanced Superconducting Tokamak.

    PubMed

    Li, Y L; Xu, G S; Tritz, K; Zhu, Y B; Wan, B N; Lan, H; Liu, Y L; Wei, J; Zhang, W; Hu, G H; Wang, H Q; Duan, Y M; Zhao, J L; Wang, L; Liu, S C; Ye, Y; Li, J; Lin, X; Li, X L

    2015-12-01

    A multi-energy soft x-ray (ME-SXR) diagnostic has been built for electron temperature profile in the edge plasma region in Experimental Advanced Superconducting Tokamak (EAST) after two rounds of campaigns. Originally, five preamplifiers were mounted inside the EAST vacuum vessel chamber attached to five vertically stacked compact diode arrays. A custom mechanical structure was designed to protect the detectors and electronics under constraints of the tangential field of view for plasma edge and the allocation of space. In the next experiment, the mechanical structure was redesigned with a barrel structure to absolutely isolate it from the vacuum vessel. Multiple shielding structures were mounted at the pinhole head to protect the metal foils from lithium coating. The pre-amplifiers were moved to the outside of the vacuum chamber to avoid introducing interference. Twisted copper cooling tube was embedded into the back-shell near the diode to limit the temperature of the preamplifiers and diode arrays during vacuum vessel baking when the temperature reached 150 °C. Electron temperature profiles were reconstructed from ME-SXR measurements using neural networks. PMID:26724032

  16. Edge multi-energy soft x-ray diagnostic in Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Li, Y. L.; Xu, G. S.; Wan, B. N.; Lan, H.; Liu, Y. L.; Wei, J.; Zhang, W.; Hu, G. H.; Wang, H. Q.; Duan, Y. M.; Zhao, J. L.; Wang, L.; Liu, S. C.; Ye, Y.; Li, J.; Lin, X.; Li, X. L.; Tritz, K.; Zhu, Y. B.

    2015-12-15

    A multi-energy soft x-ray (ME-SXR) diagnostic has been built for electron temperature profile in the edge plasma region in Experimental Advanced Superconducting Tokamak (EAST) after two rounds of campaigns. Originally, five preamplifiers were mounted inside the EAST vacuum vessel chamber attached to five vertically stacked compact diode arrays. A custom mechanical structure was designed to protect the detectors and electronics under constraints of the tangential field of view for plasma edge and the allocation of space. In the next experiment, the mechanical structure was redesigned with a barrel structure to absolutely isolate it from the vacuum vessel. Multiple shielding structures were mounted at the pinhole head to protect the metal foils from lithium coating. The pre-amplifiers were moved to the outside of the vacuum chamber to avoid introducing interference. Twisted copper cooling tube was embedded into the back-shell near the diode to limit the temperature of the preamplifiers and diode arrays during vacuum vessel baking when the temperature reached 150 °C. Electron temperature profiles were reconstructed from ME-SXR measurements using neural networks.

  17. The circuit of polychromator for Experimental Advanced Superconducting Tokamak edge Thomson scattering diagnostic

    SciTech Connect

    Zang, Qing; Zhao, Junyu; Chen, Hui; Li, Fengjuan; Hsieh, C. L.

    2013-09-15

    The detector circuit is the core component of filter polychromator which is used for scattering light analysis in Thomson scattering diagnostic, and is responsible for the precision and stability of a system. High signal-to-noise and stability are primary requirements for the diagnostic. Recently, an upgraded detector circuit for weak light detecting in Experimental Advanced Superconducting Tokamak (EAST) edge Thomson scattering system has been designed, which can be used for the measurement of large electron temperature (T{sub e}) gradient and low electron density (n{sub e}). In this new circuit, a thermoelectric-cooled avalanche photodiode with the aid circuit is involved for increasing stability and enhancing signal-to-noise ratio (SNR), especially the circuit will never be influenced by ambient temperature. These features are expected to improve the accuracy of EAST Thomson diagnostic dramatically. Related mechanical construction of the circuit is redesigned as well for heat-sinking and installation. All parameters are optimized, and SNR is dramatically improved. The number of minimum detectable photons is only 10.

  18. Analysis of pedestal gradient characteristic on the Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Wang, Teng Fei; Han, Xiao Feng; Zang, Qing; Xiao, Shu Mei; Tian, Bao Gang; Hu, Ai Lan; Zhao, Jun Yu

    2016-05-01

    A pedestal database was built based on type I edge localized mode H-modes in the Experimental Advanced Superconducting Tokamak. The most common functional form hyperbolic tangent function (tanh) method is used to analyze pedestal characteristics. The pedestal gradient scales linearly with its pedestal top and the normalized pedestal pressure gradient α shows a strong correlation with electron collisionality. The connection among pedestal top value, gradient, and width is established with the normalized pedestal pressure gradient. In the core region of the plasma, the nature of the electron temperature stiffness reflects a proportionality between core and pedestal temperature while the increase proportion is lower than that expected in the high temperature region. However, temperature profile stiffness is limited or even disappears at the edge of the plasma, while the gradient length ratio ( ηe ) on the pedestal is important. The range of ηe is from 0.5 to 2, varying with the plasma parameters. The pedestal temperature brings a more significant impact on ηe than pedestal density.

  19. First results on disruption mitigation by massive gas injection in Korea Superconducting Tokamak Advanced Research

    SciTech Connect

    Yu Yaowei; Kim, Young-Ok; Kim, Hak-Kun; Kim, Hong-Tack; Kim, Woong-Chae; Kim, Kwang-Pyo; Son, Soo-Hyun; Bang, Eun-Nam; Hong, Suk-Ho; Yoon, Si-Woo; Zhuang Huidong; Chen Zhongyong

    2012-12-15

    Massive gas injection (MGI) system was developed on Korea Superconducting Tokamak Advanced Research (KSTAR) in 2011 campaign for disruption studies. The MGI valve has a volume of 80 ml and maximum injection pressure of 50 bar, the diameter of valve orifice to vacuum vessel is 18.4 mm, the distance between MGI valve and plasma edge is {approx}3.4 m. The MGI power supply employs a large capacitor of 1 mF with the maximum voltage of 3 kV, the valve can be opened in less than 0.1 ms, and the amount of MGI can be controlled by the imposed voltage. During KSTAR 2011 campaign, MGI disruptions are carried out by triggering MGI during the flat top of circular and limiter discharges with plasma current 400 kA and magnetic field 2-3.5 T, deuterium injection pressure 39.7 bar, and imposed voltage 1.1-1.4 kV. The results show that MGI could mitigate the heat load and prevent runaway electrons with proper MGI amount, and MGI penetration is deeper under higher amount of MGI or lower magnetic field. However, plasma start-up is difficult after some of D{sub 2} MGI disruptions due to the high deuterium retention and consequently strong outgassing of deuterium in next shot, special effort should be made to get successful plasma start-up after deuterium MGI under the graphite first wall.

  20. Plasma Profile and Shape Optimization for the Advanced Tokamak Power Plant, ARIES-AT

    SciTech Connect

    C.E. Kessel; T.K. Mau; S.C. Jardin; and F. Najmabadi

    2001-06-05

    An advanced tokamak plasma configuration is developed based on equilibrium, ideal-MHD stability, bootstrap current analysis, vertical stability and control, and poloidal-field coil analysis. The plasma boundaries used in the analysis are forced to coincide with the 99% flux surface from the free-boundary equilibrium. Using an accurate bootstrap current model and external current-drive profiles from ray-tracing calculations in combination with optimized pressure profiles, beta(subscript N) values above 7.0 have been obtained. The minimum current drive requirement is found to lie at a lower beta(subscript N) of 5.4. The external kink mode is stabilized by a tungsten shell located at 0.33 times the minor radius and a feedback system. Plasma shape optimization has led to an elongation of 2.2 and triangularity of 0.9 at the separatrix. Vertical stability could be achieved by a combination of tungsten shells located at 0.33 times the minor radius and feedback control coils located behind the shield. The poloidal-field coils were optimized in location and current, providing a maximum coil current of 8.6 MA. These developments have led to a simultaneous reduction in the power plant major radius and toroidal field.

  1. Modelling of radiative divertor operation towards detachment in experimental advanced superconducting tokamak

    SciTech Connect

    Chen Yiping; Wang, F. Q.; Hu, L. Q.; Guo, H. Y.; Wu, Z. W.; Zhang, X. D.; Wan, B. N.; Li, J. G.; Zha, X. J.

    2013-02-15

    In order to actively control power load on the divertor target plates and study the effect of radiative divertor on plasma parameters in divertor plasmas and heat fluxes to the targets, dedicated experiments with Ar impurity seeding have been performed on experimental advanced superconducting tokamak in typical L-mode discharge with single null divertor configuration, ohmic heating power of 0.5 MW, and lower hybrid wave heating power of 1.0 MW. Ar is puffed into the divertor plasma at the outer target plate near the separatrix strike point with the puffing rate 1.26 Multiplication-Sign 10{sup 20} s{sup -1}. The radiative divertor is formed during the Ar puffing. The SOL/divertor plasma in the L-mode discharge with radiative divertor has been modelled by using SOLPS5.2 code package [V. Rozhansky et al., Nucl. Fusion 49, 025007 (2009)]. The modelling shows the cooling of the divertor plasma due to Ar seeding and is compared with the experimental measurement. The changes of peak electron temperature and heat fluxes at the targets with the shot time from the modelling results are similar to the experimental measurement before and during the Ar impurity seeding, but there is a major difference in time scales when Ar affects the plasma in between experiment and modelling.

  2. Advanced Propulsion Physics Lab: Eagleworks Investigations

    NASA Technical Reports Server (NTRS)

    Scogin, Tyler

    2014-01-01

    Eagleworks Laboratory is an advanced propulsions physics laboratory with two primary investigations currently underway. The first is a Quantum Vacuum Plasma Thruster (QVPT or Q-thrusters), an advanced electric propulsion technology in the development and demonstration phase. The second investigation is in Warp Field Interferometry (WFI). This is an investigation of Dr. Harold "Sonny" White's theoretical physics models for warp field equations using optical experiments in the Electro Optical laboratory (EOL) at Johnson Space Center. These investigations are pursuing technology necessary to enable human exploration of the solar system and beyond.

  3. Evidence for a resonant cyclotron interaction between runaway electrons and MHD modes in the experimental advanced superconducting tokamak

    SciTech Connect

    Li Erzhong; Zhou Ruijie; Hu Liqun

    2011-09-15

    In the past, the resonant cyclotron interaction between runaway electrons and lower hybrid waves via anomalous Doppler broadening was experimentally investigated, and it was shown to be able to create a barrier to the energy that could be reached by the runaway electrons [E. Li et al., Nucl. Instrum. Methods Phys. Res. A 621, 566 (2010)]. In this paper, to our knowledge for the first time, experimental evidence will be provided for a resonant cyclotron interaction between runaway electrons and magnetohydrodynamics modes in a stochastic magnetic field in the experimental advanced superconducting tokamak (EAST), which has been theoretically proposed as a mechanism able to limit the maximum attainable energy by runaway electrons in tokamak plasmas [J. R. Martin-Solis and R. Sanchez, Phys. Plasmas 15, 112505 (2008)].

  4. Physics challenges for advanced fuel cycle assessment

    SciTech Connect

    Giuseppe Palmiotti; Massimo Salvatores; Gerardo Aliberti

    2014-06-01

    Advanced fuel cycles and associated optimized reactor designs will require substantial improvements in key research area to meet new and more challenging requirements. The present paper reviews challenges and issues in the field of reactor and fuel cycle physics. Typical examples are discussed with, in some cases, original results.

  5. Advanced Analysis Methods in High Energy Physics

    SciTech Connect

    Pushpalatha C. Bhat

    2001-10-03

    During the coming decade, high energy physics experiments at the Fermilab Tevatron and around the globe will use very sophisticated equipment to record unprecedented amounts of data in the hope of making major discoveries that may unravel some of Nature's deepest mysteries. The discovery of the Higgs boson and signals of new physics may be around the corner. The use of advanced analysis techniques will be crucial in achieving these goals. The author discusses some of the novel methods of analysis that could prove to be particularly valuable for finding evidence of any new physics, for improving precision measurements and for exploring parameter spaces of theoretical models.

  6. Advances in tokamak control: from multi-actuator MHD control to model-based current profile tailoring

    NASA Astrophysics Data System (ADS)

    Felici, Federico

    2012-10-01

    Recent experiments on TCV have demonstrated integrated control of the sawtooth and Neoclassical Tearing Mode (NTM) instabilities in a combined preemption-suppression strategy. This strategy is enabled by new sawtooth control methods (sawtooth pacing) in which modulation of sawtooth-stabilizing electron cyclotron power during the sawtooth cycle stimulates the advent of the crash. Rather than controlling the average sawtooth period, the precise timing of each individual crash can now be prescribed. Using this knowledge, efficient preemptive stabilization of NTMs becomes possible by applying power on the rational surface only at the instant of the crash-generating seed island. TCV experiments demonstrate that this approach, reinforced by NTM stabilization as a backup strategy, is effectively failsafe. This opens the road to inductive H-mode scenarios with long sawteeth providing longer inter-crash periods of high density and temperature. Also Edge Localized Modes are susceptible to EC modulation and it is shown that individual ELM events can be controlled using similar techniques. For advanced tokamak scenarios, MHD control is to be combined with optimization and control of the plasma kinetic and magnetic profile evolution in time. Real-time simulation of a physical model (RAPTOR) of current transport, including bootstrap current, neoclassical conductivity and auxiliary current drive, yields complete knowledge of the relevant profiles at any given time. The pilot implementation on TCV shows that these calculations can indeed be done in real-time and the resulting profiles have been included in feedback control schemes. Integration of this model with time-varying equilibria and internal current profile diagnostics provides a new framework for real-time interpretation of diagnostic data for plasma prediction, scenario monitoring, disruption prevention and feedback control.

  7. Summary of the IEA Workshop on Alpha Physics and Tritium Issues in Large Tokamaks

    SciTech Connect

    Cheng, C.Z.; Stratton, B.; Zweben, S.J.; Pitcher, C.S.

    1993-11-01

    A brief summary is presented of the talks given during this meeting, which was held at PPPL and sponsored by the IEA (International Energy Agency) as part of the Large Tokamak collaboration. These talks are summarized into four sessions: tritium issues in large tokamaks, alpha particle simulation experiments, alpha particle theory, and alpha particle diagnostics.

  8. High heat flux testing of CFC composites for the tokamak physics experiment

    NASA Astrophysics Data System (ADS)

    Valentine, P. G.; Nygren, R. E.; Burns, R. W.; Rocket, P. D.; Colleraine, A. P.; Lederich, R. J.; Bradley, J. T.

    1996-10-01

    High heat flux (HHF) testing of carbon fiber reinforced carbon composites (CFC's) was conducted under the General Atomics program to develop plasma-facing components (PFC's) for Princeton Plasma Physics Laboratory's tokamak physics experiment (TPX). As part of the process of selecting TPX CFC materials, a series of HHF tests were conducted with the 30 kW electron beam test system (EBTS) facility at Sandia National Laboratories, and with the plasma disruption simulator I (PLADIS-I) facility at the University of New Mexico. The purpose of the tests was to make assessments of the thermal performance and erosion behavior of CFC materials. Tests were conducted with 42 different CFC materials. In general, the CFC materials withstood the rapid thermal pulse environments without fracturing, delaminating, or degrading in a non-uniform manner; significant differences in thermal performance, erosion behavior, vapor evolution, etc. were observed and preliminary findings are presented below. The CFC's exposed to the hydrogen plasma pulses in PLADIS-I exhibited greater erosion rates than the CFC materials exposed to the electron-beam pulses in EBTS. The results obtained support the continued consideration of a variety of CFC composites for TPX PFC components.

  9. Angular-divergence calculation for Experimental Advanced Superconducting Tokamak neutral beam injection ion source based on spectroscopic measurements

    SciTech Connect

    Chi, Yuan; Hu, Chundong; Zhuang, Ge

    2014-02-15

    Calorimetric method has been primarily applied for several experimental campaigns to determine the angular divergence of high-current ion source for the neutral beam injection system on the Experimental Advanced Superconducting Tokamak (EAST). A Doppler shift spectroscopy has been developed to provide the secondary measurement of the angular divergence to improve the divergence measurement accuracy and for real-time and non-perturbing measurement. The modified calculation model based on the W7AS neutral beam injectors is adopted to accommodate the slot-type accelerating grids used in the EAST's ion source. Preliminary spectroscopic experimental results are presented comparable to the calorimetrically determined value of theoretical calculation.

  10. Tomographic inversion techniques incorporating physical constraints for line integrated spectroscopy in stellarators and tokamaks

    SciTech Connect

    Pablant, N. A.; Bell, R. E.; Bitter, M.; Delgado-Aparicio, L.; Hill, K. W.; Lazerson, S.; Morita, S.

    2014-11-15

    Accurate tomographic inversion is important for diagnostic systems on stellarators and tokamaks which rely on measurements of line integrated emission spectra. A tomographic inversion technique based on spline optimization with enforcement of constraints is described that can produce unique and physically relevant inversions even in situations with noisy or incomplete input data. This inversion technique is routinely used in the analysis of data from the x-ray imaging crystal spectrometer (XICS) installed at the Large Helical Device. The XICS diagnostic records a 1D image of line integrated emission spectra from impurities in the plasma. Through the use of Doppler spectroscopy and tomographic inversion, XICS can provide profile measurements of the local emissivity, temperature, and plasma flow. Tomographic inversion requires the assumption that these measured quantities are flux surface functions, and that a known plasma equilibrium reconstruction is available. In the case of low signal levels or partial spatial coverage of the plasma cross-section, standard inversion techniques utilizing matrix inversion and linear-regularization often cannot produce unique and physically relevant solutions. The addition of physical constraints, such as parameter ranges, derivative directions, and boundary conditions, allow for unique solutions to be reliably found. The constrained inversion technique described here utilizes a modified Levenberg-Marquardt optimization scheme, which introduces a condition avoidance mechanism by selective reduction of search directions. The constrained inversion technique also allows for the addition of more complicated parameter dependencies, for example, geometrical dependence of the emissivity due to asymmetries in the plasma density arising from fast rotation. The accuracy of this constrained inversion technique is discussed, with an emphasis on its applicability to systems with limited plasma coverage.

  11. Magnetic confinement experiment. I: Tokamaks

    SciTech Connect

    Goldston, R.J.

    1995-08-01

    Reports were presented at this conference of important advances in all the key areas of experimental tokamak physics: Core Plasma Physics, Divertor and Edge Physics, Heating and Current Drive, and Tokamak Concept Optimization. In the area of Core Plasma Physics, the biggest news was certainly the production of 9.2 MW of fusion power in the Tokamak Fusion Test Reactor, and the observation of unexpectedly favorable performance in DT plasmas. There were also very important advances in the performance of ELM-free H- (and VH-) mode plasmas and in quasi-steady-state ELM`y operation in JT-60U, JET, and DIII-D. In all three devices ELM-free H-modes achieved nT{tau}`s {approximately} 2.5x greater than ELM`ing H-modes, but had not been sustained in quasi-steady-state. Important progress has been made on the understanding of the physical mechanism of the H-mode in DIII-D, and on the operating range in density for the H-mode in Compass and other devices.

  12. The Physics of Basis For A Conservative Physics And Conservative Technology Tokamak Power Plant, ARIES-ACT2

    SciTech Connect

    Kessel, C. E.

    2014-03-04

    The conservative physics and conservative technology tokamak power plant ARIES-ACT2 has a major radius of 9.75 m at aspect ratio of 4.0, strong shaping with elongation of 2.2 and triangularity of 0.63. The no wall {beta}N reaches {approximately} 2.4, limited by n=1 external kink mode, and can be extended to 3.2 with a stabilizing shell behind the ring structure shield. The bootstrap current fraction is 77% with a q95 of 8.0, requiring about {approximately} 4.0 MA of external current drive. This current is supplied with 30 MW of ICRF/FW and 80 MW of negative ion NB. Up to 1.0 MA can be driven with LH with no wall, and 1.5 or more MA can be driven with a stabilizing shell. EC was examined and is most effective for safety factor control over {rho} {approximately} 0.2-0.6 with 20 MW. The pedestal density is {approximately} 0.65x10{sup 20}/m{sup 3} and the temperature is {approximately} 9.0 keV. The H98 factor is 1.25, n/n{sub Gr} = 1.3, and the net power to LH threshold power is 1.3-1.4 in the flattop. Due to the high toroidal field and high central temperature the cyclotron radiation loss was found to be high depending on the first wall reflectivity.

  13. Prospects for Tokamak Fusion Reactors

    SciTech Connect

    Sheffield, J.; Galambos, J.

    1995-04-01

    This paper first reviews briefly the status and plans for research in magnetic fusion energy and discusses the prospects for the tokamak magnetic configuration to be the basis for a fusion power plant. Good progress has been made in achieving fusion reactor-level, deuterium-tritium (D-T) plasmas with the production of significant fusion power in the Joint European Torus (up to 2 MW) and the Tokamak Fusion Test Reactor (up to 10 MW) tokamaks. Advances on the technologies of heating, fueling, diagnostics, and materials supported these achievements. The successes have led to the initiation of the design phases of two tokamaks, the International Thermonuclear Experimental Reactor (ITER) and the US Toroidal Physics Experiment (TPX). ITER will demonstrate the controlled ignition and extended bum of D-T plasmas with steady state as an ultimate goal. ITER will further demonstrate technologies essential to a power plant in an integrated system and perform integrated testing of the high heat flux and nuclear components required to use fusion energy for practical purposes. TPX will complement ITER by testing advanced modes of steady-state plasma operation that, coupled with the developments in ITER, will lead to an optimized demonstration power plant.

  14. ICPP: Physics and Design Interplay Phenomena in a Long Pulse Tokamak: Tore Supra

    NASA Astrophysics Data System (ADS)

    Chatelier, Michel

    2000-10-01

    The Tore Supra Tokamak has been built with the aim of running steady state powerful long pulse discharges. It has been equipped with relevant technology such as a superconducting magnet, high frequency additional heating systems with long pulse capability, to heat up the plasma and drive the current, and actively cooled plasma facing components to remove steadily the large power flow at the plasma boundary. Due to this configuration, a number of physics processes differ from the conventional situation with inertially cooled plasma facing components that have to be carefully analysed, since they can have consequences on the design and the availability of future devices. Three examples are listed below. - Intense beams of well confined multi-MeV runaway electrons are formed when plasma discharge recovers after a current disruption, which eventually penetrate deep inside the wall and can drill holes in the water pipes. - Suprathermal electrons are generated by lower hybrid frequency waves, used for non inductive current drive in the plasma bulk. These electrons can be transported to the edge without having been slowed down. They impact on very localised areas where the heat deposition is so large that the metal layer between CFC and water can be melted. - Carbon blooms are generally not observed in Tore Supra, because the wall is maintained at low temperature in normal operating conditions. When local destruction of CFC-copper bond occurs, the surface temperature rises, but on a too small area for any significant impurity source to be generated. Bond destruction protects the water circuit from being melted. The excursion in surface temperature to very high values triggers a new heat flow equilibrium to the wall which depends also on the local electron temperature.

  15. MHD stability of tokamak plasmas

    SciTech Connect

    Chance, M.S. Sun, Y.C.; Jardin, S.C.; Kessel, C.E.; Okabayashi, M.

    1992-08-01

    This paper will give an overview of the some of the methods which are used to simulate the ideal MHD properties of tokamak plasmas. A great deal of the research in this field is necessarily numerical and the substantial progress made during the past several years has roughly paralleled the continuing availability of more advanced supercomputers. These have become essential to accurately model the complex configurations necessary for achieving MHD stable reactor grade conditions. Appropriate tokamak MHD equilibria will be described. Then the stability properties is discussed in some detail, emphasizing the difficulties of obtaining stable high {beta} discharges in plasmas in which the current is mainly ohmically driven and thus demonstrating the need for tailoring the current and pressure profiles of the plasma away from the ohmic state. The outline of this paper will roughly follow the physics development to attain the second region of stability in the PBX-M device at The Princeton Plasmas Physics Laboratory.

  16. Physics and Advanced Technologies 2001 Annual Report

    SciTech Connect

    Jacobs, R

    2002-05-09

    The Physics and Advanced Technologies (PAT) Directorate was created in July 2000 by Bruce Tarter, Director of Lawrence Livermore National Laboratory (LLNL). The Director called for the new organization to execute and support programs that apply cutting-edge physics and advanced technology to develop integrated solutions to problems in national security, fusion energy, information science, health care, and other national grand challenges. When I was appointed a year later as the PAT Directorate's first Associate Director, I initiated a strategic planning project to develop a vision, mission, and long-term goals for the Directorate. We adopted the goal of becoming a leader in frontier physics and technology for twenty-first-century national security missions: Stockpile Stewardship, homeland security, energy independence, and the exploration of space. Our mission is to: (1) Help ensure the scientific excellence and vitality of the major LLNL programs through its leadership role in performing basic and applied multidisciplinary research and development with programmatic impact, and by recruiting and retaining science and technology leaders; (2) Create future opportunities and directions for LLNL and its major programs by growing new program areas and cutting-edge capabilities that are synergistic with, and supportive of, its national security mission; (3) Provide a direct conduit to the academic and high-tech industrial sectors for LLNL and its national security programs, through which the Laboratory gains access to frontier science and technology, and can impact the science and technology communities; (4) Leverage unique Laboratory capabilities, to advance the state universe. This inaugural PAT Annual Report begins a series that will chronicle our progress towards fulfilling this mission. I believe the report demonstrates that the PAT Directorate has a strong base of capabilities and accomplishments on which to build in meeting its goals. Some of the highlights

  17. Development of high-speed and wide-angle visible observation diagnostics on Experimental Advanced Superconducting Tokamak using catadioptric optics.

    PubMed

    Yang, J H; Yang, X F; Hu, L Q; Zang, Q; Han, X F; Shao, C Q; Sun, T F; Chen, H; Wang, T F; Li, F J; Hu, A L

    2013-08-01

    A new wide-angle endoscope for visible light observation on the Experimental Advanced Superconducting Tokamak (EAST) has been recently developed. The head section of the optical system is based on a mirror reflection design that is similar to the International Thermonuclear Experimental Reactor-like wide-angle observation diagnostic on the Joint European Torus. However, the optical system design has been simplified and improved. As a result, the global transmittance of the system is as high as 79.6% in the wavelength range from 380 to 780 nm, and the spatial resolution is <5 mm for the full depth of field (4000 mm). The optical system also has a large relative aperture (1:2.4) and can be applied in high-speed camera diagnostics. As an important diagnostic tool, the optical system has been installed on the HT-7 (Hefei Tokamak-7) for its final experimental campaign, and the experiments confirmed that it can be applied to the investigation of transient processes in plasma, such as ELMy eruptions in H-mode, on EAST. PMID:24007102

  18. Development of high-speed and wide-angle visible observation diagnostics on Experimental Advanced Superconducting Tokamak using catadioptric optics

    SciTech Connect

    Yang, J. H.; Hu, L. Q.; Zang, Q.; Han, X. F.; Shao, C. Q.; Sun, T. F.; Chen, H.; Wang, T. F.; Li, F. J.; Hu, A. L.; Yang, X. F.

    2013-08-15

    A new wide-angle endoscope for visible light observation on the Experimental Advanced Superconducting Tokamak (EAST) has been recently developed. The head section of the optical system is based on a mirror reflection design that is similar to the International Thermonuclear Experimental Reactor-like wide-angle observation diagnostic on the Joint European Torus. However, the optical system design has been simplified and improved. As a result, the global transmittance of the system is as high as 79.6% in the wavelength range from 380 to 780 nm, and the spatial resolution is <5 mm for the full depth of field (4000 mm). The optical system also has a large relative aperture (1:2.4) and can be applied in high-speed camera diagnostics. As an important diagnostic tool, the optical system has been installed on the HT-7 (Hefei Tokamak-7) for its final experimental campaign, and the experiments confirmed that it can be applied to the investigation of transient processes in plasma, such as ELMy eruptions in H-mode, on EAST.

  19. Optical layout and mechanical structure of polarimeter-interferometer system for Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Zou, Z. Y.; Liu, H. Q. Jie, Y. X.; Wang, Z. X.; Shen, J. S.; An, Z. H.; Yang, Y.; Zeng, L.; Wei, X. C.; Li, G. S.; Zhu, X.; Ding, W. X.; Brower, D. L.; Lan, T.

    2014-11-15

    A Far-InfaRed (FIR) three-wave POlarimeter-INTerferometer (POINT) system for measurement current density profile and electron density profile is under development for the EAST tokamak. The FIR beams are transmitted from the laser room to the optical tower adjacent to EAST via ∼20 m overmoded dielectric waveguide and then divided into 5 horizontal chords. The optical arrangement was designed using ZEMAX, which provides information on the beam spot size and energy distribution throughout the optical system. ZEMAX calculations used to optimize the optical layout design are combined with the mechanical design from CATIA, providing a 3D visualization of the entire POINT system.

  20. Eagleworks Laboratories: Advanced Propulsion Physics Research

    NASA Technical Reports Server (NTRS)

    White, Harold; March, Paul; Williams, Nehemiah; ONeill, William

    2011-01-01

    NASA/JSC is implementing an advanced propulsion physics laboratory, informally known as "Eagleworks", to pursue propulsion technologies necessary to enable human exploration of the solar system over the next 50 years, and enabling interstellar spaceflight by the end of the century. This work directly supports the "Breakthrough Propulsion" objectives detailed in the NASA OCT TA02 In-space Propulsion Roadmap, and aligns with the #10 Top Technical Challenge identified in the report. Since the work being pursued by this laboratory is applied scientific research in the areas of the quantum vacuum, gravitation, nature of space-time, and other fundamental physical phenomenon, high fidelity testing facilities are needed. The lab will first implement a low-thrust torsion pendulum (<1 uN), and commission the facility with an existing Quantum Vacuum Plasma Thruster. To date, the QVPT line of research has produced data suggesting very high specific impulse coupled with high specific force. If the physics and engineering models can be explored and understood in the lab to allow scaling to power levels pertinent for human spaceflight, 400kW SEP human missions to Mars may become a possibility, and at power levels of 2MW, 1-year transit to Neptune may also be possible. Additionally, the lab is implementing a warp field interferometer that will be able to measure spacetime disturbances down to 150nm. Recent work published by White [1] [2] [3] suggests that it may be possible to engineer spacetime creating conditions similar to what drives the expansion of the cosmos. Although the expected magnitude of the effect would be tiny, it may be a "Chicago pile" moment for this area of physics.

  1. Fast valve based on double-layer eddy-current repulsion for disruption mitigation in Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Zhuang, H. D.; Zhang, X. D.

    2015-05-01

    A fast valve based on the double-layer eddy-current repulsion mechanism has been developed on Experimental Advanced Superconducting Tokamak (EAST). In addition to a double-layer eddy-current coil, a preload system was added to improve the security of the valve, whereby the valve opens more quickly and the open-valve time becomes shorter, making it much safer than before. In this contribution, testing platforms, open-valve characteristics, and throughput of the fast valve are discussed. Tests revealed that by choosing appropriate parameters the valve opened within 0.15 ms, and open-valve times were no longer than 2 ms. By adjusting working parameter values, the maximum number of particles injected during this open-valve time was estimated at 7 × 1022. The fast valve will become a useful tool to further explore disruption mitigation experiments on EAST in 2015.

  2. Design and characterization of a 32-channel heterodyne radiometer for electron cyclotron emission measurements on experimental advanced superconducting tokamak

    SciTech Connect

    Han, X.; Liu, X.; Liu, Y. Li, E. Z.; Hu, L. Q.; Gao, X.; Domier, C. W.; Luhmann, N. C.

    2014-07-15

    A 32-channel heterodyne radiometer has been developed for the measurement of electron cyclotron emission (ECE) on the experimental advanced superconducting tokamak (EAST). This system collects X-mode ECE radiation spanning a frequency range of 104–168 GHz, where the frequency coverage corresponds to a full radial coverage for the case with a toroidal magnetic field of 2.3 T. The frequency range is equally spaced every 2 GHz from 105.1 to 167.1 GHz with an RF bandwidth of ∼500 MHz and the video bandwidth can be switched among 50, 100, 200, and 400 kHz. Design objectives and characterization of the system are presented in this paper. Preliminary results for plasma operation are also presented.

  3. High power continuous wave microwave test bench at 4.6 GHz for experimental advanced superconducting tokamak.

    PubMed

    Ma, Wendong; Hu, Huaichuan; Shan, Jiafang; Xu, Handong; Wang, Mao; Wu, Zege; Zhu, Liang

    2013-01-01

    The lower hybrid current drive (LHCD) is an effective approach for auxiliary heating and non-inductive current drive in the experimental advanced superconducting tokamak. The 6 MW/4.6 GHz LHCD system is being designed and installed with twenty-four 250 KW/4.6 GHz high power klystron amplifiers. The test bench operating at 250 KW/4.6 GHz in continuous wave mode has been set up, which can test and train microwave components for the 6 MW/4.6 GHz LHCD system. In this paper, the system architecture and software of the microwave test bench are presented. Moreover, the test results of these klystrons and microwave units are described here in detail. The long term operation of the test bench and improved performance of all microwave component samples indicated that the related technologies on test bench can be applied in the large scale LHCD systems. PMID:23387646

  4. First results obtained from the soft x-ray pulse height analyzer on experimental advanced superconducting tokamak

    SciTech Connect

    Xu, P.; Lin, S. Y.; Hu, L. Q.; Duan, Y. M.; Zhang, J. Z.; Chen, K. Y.; Zhong, G. Q.

    2010-06-15

    An assembly of soft x-ray pulse height analyzer system, based on silicon drift detector (SDD), has been successfully established on the experimental advanced superconducting tokamak (EAST) to measure the spectrum of soft x-ray emission (E=1-20 keV). The system, including one 15-channel SDD linear array, is installed on EAST horizontal port C. The time-resolved radial profiles of electron temperature and K{sub {alpha}} intensities of metallic impurities have been obtained with a spatial resolution of around 7 cm during a single discharge. It was found that the electron temperatures derived from the system are in good agreement with the values from Thomson scattering measurements. The system can also be applied to the measurement of the long pulse discharge for EAST. The diagnostic system is introduced and some typical experimental results obtained from the system are also presented.

  5. Observations of compound sawteeth in ion cyclotron resonant heating plasma using ECE imaging on experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Hussain, Azam; Zhao, Zhenling; Xie, Jinlin; Zhu, Ping; Liu, Wandong; Ti, Ang

    2016-04-01

    The spatial and temporal evolutions of compound sawteeth were directly observed using 2D electron cyclotron emission imaging on experimental advanced superconducting tokamak. The compound sawtooth consists of partial and full collapses. After partial collapse, the hot core survives as only a small amount of heat disperses outwards, whereas in the following full collapse a large amount of heat is released and the hot core dissipates. The presence of two q = 1 surfaces was not observed. Instead, the compound sawtooth occurs mainly at the beginning of an ion cyclotron resonant frequency heating pulse and during the L-H transition phase, which may be related to heat transport suppression caused by a decrease in electron heat diffusivity.

  6. Effect of gas puffing from different side on lower hybrid wave-plasma coupling in experimental advanced superconductive tokamak

    SciTech Connect

    Ding, B. J.; Kong, E. H.; Li, M. H.; Zhang, L.; Wei, W.; Li, Y. C.; Wu, J. H.; Xu, G. S.; Wang, M.; Gong, X. Z.; Shan, J. F.; Liu, F. K.; Zhang, T.; Ekedahl, A.; Zhao, H. L.; Collaboration: EAST Team

    2013-10-15

    Effect of gas puffing from electron-side and ion-side on lower hybrid wave (LHW)-plasma is investigated in experimental advanced superconductive tokamak for the first time. Experimental results with different gas flow rates show that electron density at the grill is higher in the case of gas puffing from electron-side; consequently, a lower reflection coefficient is observed, suggesting better effect of puffing from electron-side on LHW-plasma. The difference in edge density between electron- and ion-side cases suggests that local ionization of puffed gas plays a dominant role in affecting the density at the grill due to different movement direction of ionized electrons and that part of gas has been locally ionized near the gas pipe before diffusing into the grill region. Such difference could be enlarged and important in ITER due to the improvement of plasma parameters and LHW power.

  7. Design of a collective scattering system for small scale turbulence study in Korea Superconducting Tokamak Advanced Research

    NASA Astrophysics Data System (ADS)

    Lee, W.; Park, H. K.; Lee, D. J.; Nam, Y. U.; Leem, J.; Kim, T. K.

    2016-04-01

    The design characteristics of a multi-channel collective (or coherent) scattering system for small scale turbulence study in Korea Superconducting Tokamak Advanced Research (KSTAR), which is planned to be installed in 2017, are given in this paper. A few critical issues are discussed in depth such as the Faraday and Cotton-Mouton effects on the beam polarization, radial spatial resolution, probe beam frequency, polarization, and power. A proper and feasible optics with the 300 GHz probe beam, which was designed based on these issues, provides a simultaneous measurement of electron density fluctuations at four discrete poloidal wavenumbers up to 24 cm-1. The upper limit corresponds to the normalized wavenumber kθρe of ˜0.15 in nominal KSTAR plasmas. To detect the scattered beam power and extract phase information, a quadrature detection system consisting of four-channel antenna/detector array and electronics will be employed.

  8. Observation of pedestal turbulence in edge localized mode-free H-mode on experimental advanced superconducting tokamak

    SciTech Connect

    Han, X. Zhang, T.; Zhang, S. B.; Wang, Y. M.; Shi, T. H.; Liu, Z. X.; Kong, D. F.; Qu, H.; Gao, X.

    2014-10-15

    Two different pedestal turbulence structures have been observed in edge localized mode-free phase of H-mode heated by lower hybrid wave and RF wave in ion cyclotron range of frequencies (ICRF) on experimental advanced superconducting tokamak. When the fraction of ICRF power P{sub ICRF}/P{sub total} exceeds 0.7, coherent mode is observed. The mode is identified as an electromagnetic mode, rotating in electron diamagnetic direction with a frequency around 50 kHz and toroidal mode number n = −3. Whereas when P{sub ICRF}/P{sub total} is less than 0.7, harmonic mode with frequency f = 40–300 kHz appears instead. The characteristics of these two modes are demonstrated preliminarily. The threshold value of heating power and also the plasma parameters are distinct.

  9. Design and characterization of a 32-channel heterodyne radiometer for electron cyclotron emission measurements on experimental advanced superconducting tokamak.

    PubMed

    Han, X; Liu, X; Liu, Y; Domier, C W; Luhmann, N C; Li, E Z; Hu, L Q; Gao, X

    2014-07-01

    A 32-channel heterodyne radiometer has been developed for the measurement of electron cyclotron emission (ECE) on the experimental advanced superconducting tokamak (EAST). This system collects X-mode ECE radiation spanning a frequency range of 104-168 GHz, where the frequency coverage corresponds to a full radial coverage for the case with a toroidal magnetic field of 2.3 T. The frequency range is equally spaced every 2 GHz from 105.1 to 167.1 GHz with an RF bandwidth of ~500 MHz and the video bandwidth can be switched among 50, 100, 200, and 400 kHz. Design objectives and characterization of the system are presented in this paper. Preliminary results for plasma operation are also presented. PMID:25085139

  10. Design of a collective scattering system for small scale turbulence study in Korea Superconducting Tokamak Advanced Research.

    PubMed

    Lee, W; Park, H K; Lee, D J; Nam, Y U; Leem, J; Kim, T K

    2016-04-01

    The design characteristics of a multi-channel collective (or coherent) scattering system for small scale turbulence study in Korea Superconducting Tokamak Advanced Research (KSTAR), which is planned to be installed in 2017, are given in this paper. A few critical issues are discussed in depth such as the Faraday and Cotton-Mouton effects on the beam polarization, radial spatial resolution, probe beam frequency, polarization, and power. A proper and feasible optics with the 300 GHz probe beam, which was designed based on these issues, provides a simultaneous measurement of electron density fluctuations at four discrete poloidal wavenumbers up to 24 cm(-1). The upper limit corresponds to the normalized wavenumber kθρe of ∼0.15 in nominal KSTAR plasmas. To detect the scattered beam power and extract phase information, a quadrature detection system consisting of four-channel antenna/detector array and electronics will be employed. PMID:27131668

  11. Fast valve based on double-layer eddy-current repulsion for disruption mitigation in Experimental Advanced Superconducting Tokamak.

    PubMed

    Zhuang, H D; Zhang, X D

    2015-05-01

    A fast valve based on the double-layer eddy-current repulsion mechanism has been developed on Experimental Advanced Superconducting Tokamak (EAST). In addition to a double-layer eddy-current coil, a preload system was added to improve the security of the valve, whereby the valve opens more quickly and the open-valve time becomes shorter, making it much safer than before. In this contribution, testing platforms, open-valve characteristics, and throughput of the fast valve are discussed. Tests revealed that by choosing appropriate parameters the valve opened within 0.15 ms, and open-valve times were no longer than 2 ms. By adjusting working parameter values, the maximum number of particles injected during this open-valve time was estimated at 7 × 10(22). The fast valve will become a useful tool to further explore disruption mitigation experiments on EAST in 2015. PMID:26026520

  12. An Assessment of the Penetrations in the First Wall Required for Plasma Measurments for Control of an Advanced Tokamak Plasma Demo

    SciTech Connect

    Kenneth M. Young

    2010-02-22

    A Demonstration tokamak (Demo) is an essential next step toward a magnetic-fusion based reactor. One based on advanced-tokamak (AT) plasmas is especially appealing because of its relative compactness. However, it will require many plasma measurements to provide the necessary signals to feed to ancillary systems to protect the device and control the plasma. This note addresses the question of how much intrusion into the blanket system will be required to allow the measurements needed to provide the information required for plasma control. All diagnostics will require, at least, the same shielding designs as planned for ITER, while having the capability to maintain their calibration through very long pulses. Much work is required to define better the measurement needs and the quantity and quality of the measurements that will have to be made, and how they can be integrated into the other tokamak structures.

  13. Simulations of the L-H transition on experimental advanced superconducting Tokamak

    SciTech Connect

    Weiland, Jan

    2014-12-15

    We have simulated the L-H transition on the EAST tokamak [Baonian Wan, EAST and HT-7 Teams, and International Collaborators, “Recent experiments in the EAST and HT-7 superconducting tokamaks,” Nucl. Fusion 49, 104011 (2009)] using a predictive transport code where ion and electron temperatures, electron density, and poloidal and toroidal momenta are simulated self consistently. This is, as far as we know, the first theory based simulation of an L-H transition including the whole radius and not making any assumptions about where the barrier should be formed. Another remarkable feature is that we get H-mode gradients in agreement with the α – α{sub d} diagram of Rogers et al. [Phys. Rev. Lett. 81, 4396 (1998)]. Then, the feedback loop emerging from the simulations means that the L-H power threshold increases with the temperature at the separatrix. This is a main feature of the C-mod experiments [Hubbard et al., Phys. Plasmas 14, 056109 (2007)]. This is also why the power threshold depends on the direction of the grad B drift in the scrape off layer and also why the power threshold increases with the magnetic field. A further significant general H-mode feature is that the density is much flatter in H-mode than in L-mode.

  14. Main Physical Factors Limiting the Accuracy of Polarimetric Measurements in Tokamak Plasma

    NASA Astrophysics Data System (ADS)

    Bieg, Bohdan; Chrzanowski, Janusz; Kravtsov, Yury A.; Orsitto, Francesco

    The paper reviews and discusses the main factors, limiting the accuracy of polarimetric measurements in tokamak plasma. Theoretical methods, describing evolution of polarimetry state in tokamak plasma, are demonstrated not to contribute noticeably to inaccuracy at sufficiently short beam wavelengths. Based on the literature data as well as on our preliminary estimates it is possible to conclude that the following factors dominate: i) calibration procedure; ii) refraction in the inhomogeneous plasma; iii) influence of weak relativistic effects on plasma dielectric permittivity. The contribution of these factors to is within the range of several per cent. Other causes of measurement inaccuracies (absorption in plasma, diffraction of sounding beam, ray torsion, nonstationary processes in plasma) seem to be less significant.

  15. Alternative approaches to fusion. [reactor design and reactor physics for Tokamak fusion reactors

    NASA Technical Reports Server (NTRS)

    Roth, R. J.

    1976-01-01

    The limitations of the Tokamak fusion reactor concept are discussed and various other fusion reactor concepts are considered that employ the containment of thermonuclear plasmas by magnetic fields (i.e., stellarators). Progress made in the containment of plasmas in toroidal devices is reported. Reactor design concepts are illustrated. The possibility of using fusion reactors as a power source in interplanetary space travel and electric power plants is briefly examined.

  16. Advances in multi-megawatt lower hybrid technology in support of steady-state tokamak operation

    NASA Astrophysics Data System (ADS)

    Delpech, L.; Achard, J.; Armitano, A.; Artaud, J. F.; Bae, Y. S.; Belo, J. H.; Berger-By, G.; Bouquey, F.; Cho, M. H.; Corbel, E.; Decker, J.; Do, H.; Dumont, R.; Ekedahl, A.; Garibaldi, P.; Goniche, M.; Guilhem, D.; Hillairet, J.; Hoang, G. T.; Kim, H. S.; Kim, J. H.; Kim, H.; Kwak, J. G.; Magne, R.; Mollard, P.; Na, Y. S.; Namkung, W.; Oh, Y. K.; Park, S.; Park, H.; Peysson, Y.; Poli, S.; Prou, M.; Samaille, F.; Yang, H. L.; The Tore Supra Team

    2014-10-01

    It has been demonstrated that lower hybrid current drive (LHCD) systems play a crucial role for steady-state tokamak operation, owing to their high current drive (CD) efficiency and hence their capability to reduce flux consumption. This paper describes the extensive technology programmes developed for the Tore Supra (France) and the KSTAR (Korea) tokamaks in order to bring continuous wave (CW) LHCD systems into operation. The Tore Supra LHCD generator at 3.7 GHz is fully CW compatible, with RF power PRF = 9.2 MW available at the generator to feed two actively water-cooled launchers. On Tore Supra, the most recent and novel passive active multijunction (PAM) launcher has sustained 2.7 MW (corresponding to its design value of 25 MW m-2 at the launcher mouth) for a 78 s flat-top discharge, with low reflected power even at large plasma-launcher gaps. The fully active multijunction (FAM) launcher has reached 3.8 MW of coupled power (24 MW m-2 at the launcher mouth) with the new TH2103C klystrons. By combining both the PAM and FAM launchers, 950 MJ of energy, using 5.2 MW of LHCD and 1 MW of ICRH (ion cyclotron resonance heating), was injected for 160 s in 2011. The 3.7 GHz CW LHCD system will be a key element within the W (for tungsten) environment in steady-state Tokamak (WEST) project, where the aim is to test ITER technologies for high heat flux components in relevant heat flux density and particle fluence conditions. On KSTAR, a 2 MW LHCD system operating at 5 GHz is under development. Recently the 5 GHz prototype klystron has reached 500 kW/600 s on a matched load, and studies are ongoing to design a PAM launcher. In addition to the studies of technology, a combination of ray-tracing and Fokker-Planck calculations have been performed to evaluate the driven current and the power deposition due to LH waves, and to optimize the N∥ spectrum for the future launcher design. Furthermore, an LHCD system at 5 GHz is being considered for a future upgrade of the ITER

  17. Advanced methods in global gyrokinetic full f particle simulation of tokamak transport

    SciTech Connect

    Ogando, F.; Heikkinen, J. A.; Henriksson, S.; Janhunen, S. J.; Kiviniemi, T. P.; Leerink, S.

    2006-11-30

    A new full f nonlinear gyrokinetic simulation code, named ELMFIRE, has been developed for simulating transport phenomena in tokamak plasmas. The code is based on a gyrokinetic particle-in-cell algorithm, which can consider electrons and ions jointly or separately, as well as arbitrary impurities. The implicit treatment of the ion polarization drift and the use of full f methods allow for simulations of strongly perturbed plasmas including wide orbit effects, steep gradients and rapid dynamic changes. This article presents in more detail the algorithms incorporated into ELMFIRE, as well as benchmarking comparisons to both neoclassical theory and other codes.Code ELMFIRE calculates plasma dynamics by following the evolution of a number of sample particles. Because of using an stochastic algorithm its results are influenced by statistical noise. The effect of noise on relevant magnitudes is analyzed.Turbulence spectra of FT-2 plasma has been calculated with ELMFIRE, obtaining results consistent with experimental data.

  18. Integrated particle simulation of neoclassical and turbulence physics in the tokamak pedestal/edge region using XGC

    SciTech Connect

    Chang, C S; Ku, Seung-Hoe; Adams, Mark; D'Azevedo, Eduardo; Chen, Yang; Cummings, Julian; Ethier, Stephane; Greengard, Leslie; Hahm, Taik Soo; Hinton, Fred; Keyes, David E; Klasky, Scott A; Lee, Wei-Li; Lin, Zhihong; Nishimura, Yasutaro; Parker, Scott; Samtaney, Ravi; Stotler, D.; Weitzner, Harold; Worley, Patrick H; Zorin, Denis

    2007-01-01

    An integrated gyrokinetic particle simulation with turbulence and neoclassical physics in a diverted tokamak edge plasma has been performed. Neoclassical equilibrium gyrokinetic solutions in the whole edge plasma have been separated from the turbulence activities for the first time, using the massively parallel Jaguar XT3 computer at Oak Ridge National Laboratory. The equilibrium solutions in an H-mode-like edge plasma condition show strongly sheared global ExB and parallel flows in the entire edge plasma including the pedestal and scrape-off regions. In an L-mode-like edge plasma condition, the sheared flows in the pedestal layer are much weaker, supporting the conjecture that the neoclassical flow-shear may play a significant role in the H-mode physics.

  19. Upgrade of Langmuir probe diagnostic in ITER-like tungsten mono-block divertor on experimental advanced superconducting tokamak.

    PubMed

    Xu, J C; Wang, L; Xu, G S; Luo, G N; Yao, D M; Li, Q; Cao, L; Chen, L; Zhang, W; Liu, S C; Wang, H Q; Jia, M N; Feng, W; Deng, G Z; Hu, L Q; Wan, B N; Li, J; Sun, Y W; Guo, H Y

    2016-08-01

    In order to withstand rapid increase in particle and power impact onto the divertor and demonstrate the feasibility of the ITER design under long pulse operation, the upper divertor of the EAST tokamak has been upgraded to actively water-cooled, ITER-like tungsten mono-block structure since the 2014 campaign, which is the first attempt for ITER on the tokamak devices. Therefore, a new divertor Langmuir probe diagnostic system (DivLP) was designed and successfully upgraded on the tungsten divertor to obtain the plasma parameters in the divertor region such as electron temperature, electron density, particle and heat fluxes. More specifically, two identical triple probe arrays have been installed at two ports of different toroidal positions (112.5-deg separated toroidally), which can provide fundamental data to study the toroidal asymmetry of divertor power deposition and related 3-dimension (3D) physics, as induced by resonant magnetic perturbations, lower hybrid wave, and so on. The shape of graphite tip and fixed structure of the probe are designed according to the structure of the upper tungsten divertor. The ceramic support, small graphite tip, and proper connector installed make it possible to be successfully installed in the very narrow interval between the cassette body and tungsten mono-block, i.e., 13.5 mm. It was demonstrated during the 2014 and 2015 commissioning campaigns that the newly upgraded divertor Langmuir probe diagnostic system is successful. Representative experimental data are given and discussed for the DivLP measurements, then proving its availability and reliability. PMID:27587120

  20. Upgrade of Langmuir probe diagnostic in ITER-like tungsten mono-block divertor on experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Xu, J. C.; Wang, L.; Xu, G. S.; Luo, G. N.; Yao, D. M.; Li, Q.; Cao, L.; Chen, L.; Zhang, W.; Liu, S. C.; Wang, H. Q.; Jia, M. N.; Feng, W.; Deng, G. Z.; Hu, L. Q.; Wan, B. N.; Li, J.; Sun, Y. W.; Guo, H. Y.

    2016-08-01

    In order to withstand rapid increase in particle and power impact onto the divertor and demonstrate the feasibility of the ITER design under long pulse operation, the upper divertor of the EAST tokamak has been upgraded to actively water-cooled, ITER-like tungsten mono-block structure since the 2014 campaign, which is the first attempt for ITER on the tokamak devices. Therefore, a new divertor Langmuir probe diagnostic system (DivLP) was designed and successfully upgraded on the tungsten divertor to obtain the plasma parameters in the divertor region such as electron temperature, electron density, particle and heat fluxes. More specifically, two identical triple probe arrays have been installed at two ports of different toroidal positions (112.5-deg separated toroidally), which can provide fundamental data to study the toroidal asymmetry of divertor power deposition and related 3-dimension (3D) physics, as induced by resonant magnetic perturbations, lower hybrid wave, and so on. The shape of graphite tip and fixed structure of the probe are designed according to the structure of the upper tungsten divertor. The ceramic support, small graphite tip, and proper connector installed make it possible to be successfully installed in the very narrow interval between the cassette body and tungsten mono-block, i.e., 13.5 mm. It was demonstrated during the 2014 and 2015 commissioning campaigns that the newly upgraded divertor Langmuir probe diagnostic system is successful. Representative experimental data are given and discussed for the DivLP measurements, then proving its availability and reliability.

  1. Advanced Dark Energy Physics Telescope (ADEPT)

    SciTech Connect

    Charles L. Bennett

    2009-03-26

    In 2006, we proposed to NASA a detailed concept study of ADEPT (the Advanced Dark Energy Physics Telescope), a potential space mission to reliably measure the time-evolution of dark energy by conducting the largest effective volume survey of the universe ever done. A peer-review panel of scientific, management, and technical experts reported back the highest possible 'excellent' rating for ADEPT. We have since made substantial advances in the scientific and technical maturity of the mission design. With this Department of Energy (DOE) award we were granted supplemental funding to support specific extended research items that were not included in the NASA proposal, many of which were intended to broadly advance future dark energy research, as laid out by the Dark Energy Task Force (DETF). The proposed work had three targets: (1) the adaptation of large-format infrared arrays to a 2 micron cut-off; (2) analytical research to improve the understanding of the dark energy figure-of- merit; and (3) extended studies of baryon acoustic oscillation systematic uncertainties. Since the actual award was only for {approx}10% of the proposed amount item (1) was dropped and item (2) work was severely restricted, consistent with the referee reviews of the proposal, although there was considerable contradictions between reviewer comments and several comments that displayed a lack of familiarity with the research. None the less, item (3) was the focus of the work. To characterize the nature of the dark energy, ADEPT is designed to observe baryon acoustic oscillations (BAO) in a large galaxy redshift survey and to obtain substantial numbers of high-redshift Type Ia supernovae (SNe Ia). The 2003 Wilkinson Microwave Anisotropy Probe (WMAP) made a precise determination of the BAO 'standard ruler' scale, as it was imprinted on the cosmic microwave background (CMB) at z {approx} 1090. The standard ruler was also imprinted on the pattern of galaxies, and was first detected in 2005 in Sloan

  2. Physics and Advanced Technologies 2003 Annual Report

    SciTech Connect

    Hazi, A; Sketchley, J

    2005-01-20

    The Physics and Advanced Technologies (PAT) Directorate overcame significant challenges in 2003 to deliver a wealth of scientific and programmatic milestones, and move toward closer alignment with programs at Lawrence Livermore National Laboratory. We acted aggressively in enabling the PAT Directorate to contribute to future, growing Lawrence Livermore missions in homeland security and at the National Ignition Facility (NIF). We made heavy investments to bring new capabilities to the Laboratory, to initiate collaborations with major Laboratory programs, and to align with future Laboratory directions. Consistent with our mission, we sought to ensure that Livermore programs have access to the best science and technology, today and tomorrow. For example, in a move aimed at revitalizing the Laboratory's expertise in nuclear and radiation detection, we brought the talented Measurement Sciences Group to Livermore from Lawrence Berkeley National Laboratory, after its mission there had diminished. The transfer to our I Division entailed significant investment by PAT in equipment and infrastructure required by the group. In addition, the move occurred at a time when homeland security funding was expected, but not yet available. By the end of the year, though, the group was making crucial contributions to the radiation detection program at Livermore, and nearly every member was fully engaged in programmatic activities. Our V Division made a move of a different sort, relocating en masse from Building 121 to the NIF complex. This move was designed to enhance interaction and collaboration among high-energy-density experimental scientists at the Laboratory, a goal that is essential to the effective use of NIF in the future. Since then, V Division has become increasingly integrated with NIF activities. Division scientists are heavily involved in diagnostic development and fielding and are poised to perform equation-of-state and high-temperature hohlraum experiments in 2004 as

  3. Advanced limiter test (ALT-1) in the TEXTOR tokamak: concept and experimental design

    SciTech Connect

    Conn, R.W.; Grontz, S.P.; Prinja, A.K.; Gauster, W.B.; Malinowski, H.E.; Pontau, A.E.; Blewer, R.S.; Whitley, J.B.; Dippel, K.H.; Fuchs, G.

    1983-01-01

    The concept and experimental design of a pump-limiter for the TEXTOR tokamak is described. The module is constructed of stainless steel with a compound curvature head designed to limit the maximum heat flux to 300 W/cm/sup 2/. The head is made of TiC-coated graphite containing a variable-aperture slot to admit plasma to a deflector plate for ballistic pumping action. The assembly is actively pumped using Zr-Al getters with an estimated hydrogen pumping speed of 3 x 10/sup 4/ 1/s. The aspect ratio of the pump duct and the length of the plasma channel are both variable to permit study of plasma plugging, ballistic scattering, and enhanced gas-conduction effects. The module can be moved radially by 10 cm to permit its operation either as the primary or secondary limiter. Major diagnostics include Langmuir and solid state probes, bolometers, infrared thermography, thermocouples, ion gauges, manometers, and a gas mass analyzer.

  4. Simulation of fast-ion-driven Alfvén eigenmodes on the Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Hu, Youjun; Todo, Y.; Pei, Youbin; Li, Guoqiang; Qian, Jinping; Xiang, Nong; Zhou, Deng; Ren, Qilong; Huang, Juan; Xu, Liqing

    2016-02-01

    Kinetic-MHD hybrid simulations are carried out to investigate possible fast-ion-driven modes on the Experimental Advanced Superconducting Tokamak. Three typical kinds of fast-ion-driven modes, namely, toroidicity-induced Alfvén eigenmodes, reversed shear Alfvén eigenmodes, and energetic-particle continuum modes, are observed simultaneously in the simulations. The simulation results are compared with the results of an ideal MHD eigenvalue code, which shows agreement with respect to the mode frequency, dominant poloidal mode numbers, and radial location. However, the modes in the hybrid simulations take a twisted structure on the poloidal plane, which is different from the results of the ideal MHD eigenvalue code. The twist is due to the radial phase variation of the eigenfunction, which may be attributed to the non-perturbative kinetic effects of the fast ions. By varying the stored energy of fast ions to change the fast ion drive in the simulations, it is demonstrated that the twist (i.e., the radial phase variation) is positively correlated with the fast ion drive.

  5. Experimental investigation of density behaviors in front of the lower hybrid launcher in experimental advanced superconducting tokamak

    SciTech Connect

    Zhang, L.; Ding, B. J.; Li, M. H.; Kong, E. H.; Wei, W.; Liu, F. K.; Shan, J. F.; Wu, Z. G.; Zhu, L.; Ma, W. D.; Tong, Y. Y.; Li, Y. C.; Wang, M.; Zhao, L. M.; Hu, H. C.; Liu, L.; Collaboration: EAST Team

    2013-06-15

    A triple Langmuir probe is mounted on the top of the Lower Hybrid (LH) antenna to measure the electron density near the LH grills in Experimental Advanced Superconducting Tokamak. In this work, the LH power density ranges from 2.3 MWm{sup −2} to 10.3 MWm{sup −2} and the rate of puffing gas varies from 1.7 × 10{sup 20} el/s to 14 × 10{sup 20} el/s. The relation between the edge density (from 0.3 × n{sub e-cutoff} to 20 × n{sub e-cutoff}, where n{sub e-cutoff} is the cutoff density, n{sub e-cutoff} = 0.74 × 10{sup 17} m{sup −3} for 2.45 GHz lower hybrid current drive) near the LH grill and the LH power reflection coefficients is investigated. The factors, including the gap between the LH grills and the last closed magnetic flux surface, line-averaged density, LH power, edge safety factor, and gas puffing, are analyzed. The experiments show that injection of LH power is beneficial for increasing edge density. Gas puffing is beneficial for increasing grill density but excess gas puffing is unfavorable for coupling and current drive.

  6. Edge localized mode characteristics during edge localized mode mitigation by supersonic molecular beam injection in Korea Superconducting Tokamak Advanced Research

    SciTech Connect

    Lee, H. Y.; Hong, J. H.; Jang, J. H.; Park, J. S.; Choe, Wonho; Hahn, S. H.; Bak, J. G.; Lee, J. H.; Ko, W. H.; Lee, K. D.; Lee, S. H.; Lee, H. H.; Juhn, J.-W.; Kim, H. S.; Yoon, S. W.; Han, H.; Ghim, Y.-C.

    2015-12-15

    It has been reported that supersonic molecular beam injection (SMBI) is an effective means of edge localized mode (ELM) mitigation. This paper newly reports the changes in the ELM, plasma profiles, and fluctuation characteristics during ELM mitigation by SMBI in Korea Superconducting Tokamak Advanced Research. During the mitigated ELM phase, the ELM frequency increased by a factor of 2–3 and the ELM size, which was estimated from the D{sub α} amplitude, the fractional changes in the plasma-stored energy and the line-averaged electron density, and divertor heat flux during an ELM burst, decreased by a factor of 0.34–0.43. Reductions in the electron and ion temperatures rather than in the electron density were observed during the mitigated ELM phase. In the natural ELM phase, frequency chirping of the plasma fluctuations was observed before the ELM bursts; however, the ELM bursts occurred without changes in the plasma fluctuation frequency in the mitigated ELM phase.

  7. Combined magnetic and kinetic control of advanced tokamak steady state scenarios based on semi-empirical modelling

    NASA Astrophysics Data System (ADS)

    Moreau, D.; Artaud, J. F.; Ferron, J. R.; Holcomb, C. T.; Humphreys, D. A.; Liu, F.; Luce, T. C.; Park, J. M.; Prater, R.; Turco, F.; Walker, M. L.

    2015-06-01

    This paper shows that semi-empirical data-driven models based on a two-time-scale approximation for the magnetic and kinetic control of advanced tokamak (AT) scenarios can be advantageously identified from simulated rather than real data, and used for control design. The method is applied to the combined control of the safety factor profile, q(x), and normalized pressure parameter, βN, using DIII-D parameters and actuators (on-axis co-current neutral beam injection (NBI) power, off-axis co-current NBI power, electron cyclotron current drive power, and ohmic coil). The approximate plasma response model was identified from simulated open-loop data obtained using a rapidly converging plasma transport code, METIS, which includes an MHD equilibrium and current diffusion solver, and combines plasma transport nonlinearity with 0D scaling laws and 1.5D ordinary differential equations. The paper discusses the results of closed-loop METIS simulations, using the near-optimal ARTAEMIS control algorithm (Moreau D et al 2013 Nucl. Fusion 53 063020) for steady state AT operation. With feedforward plus feedback control, the steady state target q-profile and βN are satisfactorily tracked with a time scale of about 10 s, despite large disturbances applied to the feedforward powers and plasma parameters. The robustness of the control algorithm with respect to disturbances of the H&CD actuators and of plasma parameters such as the H-factor, plasma density and effective charge, is also shown.

  8. Resistive edge mode instability in stellarator and tokamak geometries

    SciTech Connect

    Mahmood, M. Ansar; Rafiq, T.; Persson, M.; Weiland, J.

    2008-09-15

    Geometrical effects on linear stability of electrostatic resistive edge modes are investigated in the three-dimensional Wendelstein 7-X stellarator [G. Grieger et al., Plasma Physics and Controlled Nuclear Fusion Research 1990 (International Atomic Energy Agency, Vienna, 1991), Vol. 3, p. 525] and the International Thermonuclear Experimental Reactor [Progress in the ITER Physics Basis, Nucl. Fusion 7, S1, S285 (2007)]-like equilibria. An advanced fluid model is used for the ions together with the reduced Braghinskii equations for the electrons. Using the ballooning mode representation, the drift wave problem is set as an eigenvalue equation along a field line and is solved numerically using a standard shooting technique. A significantly larger magnetic shear and a less unfavorable normal curvature in the tokamak equilibrium are found to give a stronger finite-Larmor radius stabilization and a more narrow mode spectrum than in the stellarator. The effect of negative global magnetic shear in the tokamak is found to be stabilizing. The growth rate on a tokamak magnetic flux surface is found to be comparable to that on a stellarator surface with the same global magnetic shear but the eigenfunction in the tokamak is broader than in the stellarator due to the presence of large negative local magnetic shear (LMS) on the tokamak surface. A large absolute value of the LMS in a region of unfavorable normal curvature is found to be stabilizing in the stellarator, while in the tokamak case, negative LMS is found to be stabilizing and positive LMS destabilizing.

  9. Texas Experimental Tokamak

    SciTech Connect

    Wootton, A.J.

    1993-04-01

    This progress report covers the period from November 1, 1990 to April 30, 1993. During that period, TEXT was operated as a circular tokamak with a material limiter. It was devoted to the study of basic plasma physics, in particular to study of fluctuations, turbulence, and transport. The purpose is to operate and maintain TEXT Upgrade as a complete facility for applied tokamak physics, specifically to conduct a research program under the following main headings: (1) to elucidate the mechanisms of working gas, impurity, and thermal transport in tokamaks, in particular to understand the role of turbulence; (2) to study physics of the edge plasma, in particular the turbulence; (3) to study the physics or resonant magnetic fields (ergodic magnetic divertors, intra island pumping); and (4) to study the physics of electron cyclotron heating (ECRH). Results of studies in each of these areas are reported.

  10. Advanced Level Physics Students' Conceptions of Quantum Physics.

    ERIC Educational Resources Information Center

    Mashhadi, Azam

    This study addresses questions about particle physics that focus on the nature of electrons. Speculations as to whether they are more like particles or waves or like neither illustrate the difficulties with which students are confronted when trying to incorporate the concepts of quantum physics into their overall conceptual framework. Such…

  11. Dynamically stable, self-similarly evolving, and self-organized states of high beta tokamak and reversed pinch plasmas and advanced active control

    SciTech Connect

    Kondoh, Yoshiomi; Fukasawa, Toshinobu

    2009-11-15

    Generalized simultaneous eigenvalue equations derived from a generalized theory of self-organization are applied to a set of simultaneous equations for two-fluid model plasmas. An advanced active control by using theoretical time constants is proposed by predicting quantities to be controlled. Typical high beta numerical configurations are presented for the ultra low q tokamak plasmas and the reversed-field pinch (RFP) ones in cylindrical geometry by solving the set of simultaneous eigenvalue equations. Improved confinement with no detectable saw-teeth oscillations in tokamak experiments is reasonably explained by the shortest time constant of ion flow. The shortest time constant of poloidal ion flow is shown to be a reasonable mechanism for suppression of magnetic fluctuations by pulsed poloidal current drives in RFP experiments. The bifurcation from basic eigenmodes to mixed ones deduced from stability conditions for eigenvalues is shown to be a good candidate for the experimental bifurcation from standard RFP plasmas to their improved confinement regimes.

  12. Advancing Successful Physics Majors - The Physics First Year Seminar Experience

    NASA Astrophysics Data System (ADS)

    Deibel, Jason; Petkie, Douglas

    In 2012, the Wright State University physics curriculum introduced a new year-long seminar course required for all new physics majors. The goal of this course is to improve student retention and success via building a community of physics majors and provide them with the skills, mindset, and advising necessary to successfully complete a degree and transition to the next part of their careers. This new course sequence assembles a new cohort of majors annually. To prepare each cohort, students engage in a variety of activities that span from student success skills to more specific physics content while building an entrepreneurial mindset. Students participate in activities including study skills, career night, course planning, campus services, and a department social function. More importantly, students gain exposure to programming, literature searches, data analysis, technical writing, elevator pitches, and experimental design via hands-on projects. This includes the students proposing, designing, and conducting their own experiments. Preliminary evidence indicates increased retention, student success, and an enhanced sense of community among physics undergraduate students, The overall number of majors and students eventually completing their physics degrees has nearly tripled. Associate Professor, Department of Physics.

  13. Educating Scientifically - Advances in Physics Education Research

    ScienceCinema

    Finkelstein, Noah [University of Colorado, Colorado, USA

    2009-09-01

    It is now fairly well documented that traditionally taught, large-scale introductory physics courses fail to teach our students the basics. In fact, often these same courses have been found to teach students things we do not want. Building on a tradition of research in physics, the physics education research community has been researching the effects of educational practice and reforms at the undergraduate level for many decades. From these efforts and those within the fields of education, cognitive science, and psychology we have learned a great deal about student learning and environments that support learning for an increasingly diverse population of students in the physics classroom. This talk will introduce some of the ideas from physics education research, discuss a variety of effective classroom practices/ surrounding educational structures, and begin to examine why these do (and do not) work. I will present both a survey of physics education research and some of the exciting theoretical and experimental developments emerging from the University of Colorado.

  14. Educating Scientifically - Advances in Physics Education Research

    SciTech Connect

    Finkelstein, Noah

    2007-05-16

    It is now fairly well documented that traditionally taught, large-scale introductory physics courses fail to teach our students the basics. In fact, often these same courses have been found to teach students things we do not want. Building on a tradition of research in physics, the physics education research community has been researching the effects of educational practice and reforms at the undergraduate level for many decades. From these efforts and those within the fields of education, cognitive science, and psychology we have learned a great deal about student learning and environments that support learning for an increasingly diverse population of students in the physics classroom. This talk will introduce some of the ideas from physics education research, discuss a variety of effective classroom practices/ surrounding educational structures, and begin to examine why these do (and do not) work. I will present both a survey of physics education research and some of the exciting theoretical and experimental developments emerging from the University of Colorado.

  15. Educating Scientifically: Advances in Physics Education Research

    SciTech Connect

    Finkelstein, Noah

    2007-05-16

    It is now fairly well documented that traditionally taught, large-scale introductory physics courses fail to teach our students the basics. In fact, often these same courses have been found to teach students things we do not want. Building on a tradition of research in physics, the physics education research community has been researching the effects of educational practice and reforms at the undergraduate level for many decades. From these efforts and those within the fields of education, cognitive science, and psychology we have learned a great deal about student learning and environments that support learning for an increasingly diverse population of students in the physics classroom. This talk will introduce some of the ideas from physics education research, discuss a variety of effective classroom practices/ surrounding educational structures, and begin to examine why these do (and do not) work. I will present both a survey of physics education research and some of the exciting theoretical and experimental developments emerging from the University of Colorado.

  16. The Physics of Local Helicity Injection Non-Solenoidal Tokamak Startup

    NASA Astrophysics Data System (ADS)

    Redd, A. J.; Barr, J. L.; Bongard, M. W.; Fonck, R. J.; Hinson, E. T.; Jardin, S.

    2013-10-01

    Non-solenoidal startup via Local Helicity Injection (LHI) uses compact current injectors to produce toroidal plasma current Ip up to 170 kA in the PEGASUS Toroidal Experiment, driven by 4-8 kA injector current on timescales of 5-20 milliseconds. Increasing the Ip buildup duration enables experimental demonstration of plasma position control on timescales relevant for high-current startup. LHI-driven discharges exhibit bursty MHD activity, apparently line-tied kinking of LHI-driven field lines, with the bursts correlating with rapid equilibrium changes, sharp Ip rises, and sharp drops in the injector impedance. Preliminary NIMROD results suggest that helical LHI-driven current channels remain coherent, with Ip increases due to reconnection between adjacent helical turns forming axisymmetric plasmoids, and corresponding sharp drops in the bias circuit impedance. The DC injector impedance is consistent with a space charge limit at low bias current and a magnetic limit at high bias current. Internal measurements show the current density profile starts strongly hollow and rapidly fills in during Ip buildup. Simulations of LHI discharges using the Tokamak Simulation Code (TSC) will provide insight into the detailed current drive mechanism and guide experiments on PEFASUS and NSTX-U. Work supported by US DOE Grants DE-FG02-96ER54375 and DE-SC0006928.

  17. Burning plasma simulation and environmental assessment of tokamak, spherical tokamak and helical reactors

    NASA Astrophysics Data System (ADS)

    Yamazaki, K.; Uemura, S.; Oishi, T.; Garcia, J.; Arimoto, H.; Shoji, T.

    2009-05-01

    Reference 1-GWe DT reactors (tokamak TR-1, spherical tokamak ST-1 and helical HR-1 reactors) are designed using physics, engineering and cost (PEC) code, and their plasma behaviours with internal transport barrier operations are analysed using toroidal transport analysis linkage (TOTAL) code, which clarifies the requirement of deep penetration of pellet fuelling to realize steady-state advanced burning operation. In addition, economical and environmental assessments were performed using extended PEC code, which shows the advantage of high beta tokamak reactors in the cost of electricity (COE) and the advantage of compact spherical tokamak in life-cycle CO2 emission reduction. Comparing with other electric power generation systems, the COE of the fusion reactor is higher than that of the fission reactor, but on the same level as the oil thermal power system. CO2 reduction can be achieved in fusion reactors the same as in the fission reactor. The energy payback ratio of the high-beta tokamak reactor TR-1 could be higher than that of other systems including the fission reactor.

  18. Investigation of lower hybrid wave coupling and current drive experiments at different configurations in experimental advanced superconducting tokamak

    SciTech Connect

    Ding, B. J.; Qin, Y. L.; Li, W. K.; Li, M. H.; Kong, E. H.; Zhang, L.; Wang, M.; Xu, H. D.; Hu, H. C.; Xu, G. S.; Shan, J. F.; Liu, F. K.; Zhao, Y. P.; Wan, B. N.; Li, J. G.; Group, EAST; Ekedahl, A.; Peysson, Y.; Decker, J.

    2011-08-15

    Using a 2 MW 2.45 GHz lower hybrid wave (LHW) system installed in experimental advanced superconducting tokamak, we have systematically carried out LHW-plasma coupling and lower hybrid current drive experiments in both divertor (double null and lower single null) and limiter plasma configuration with plasma current (I{sub p}) {approx} 250 kA and central line averaged density (n{sub e}) {approx} 1.0-1.3 x 10{sup 19} m{sup -3} recently. Results show that the reflection coefficient (RC) first is flat up to some distance between plasma and LHW grill, and then increases with the distance. Studies indicate that with the same plasma parameters, the best coupling is obtained in the limiter case (with plasma leaning on the inner wall), followed by the lower single null, and the one with the worst coupling is the double null configuration, explained by different magnetic connection length. The RCs in the different poloidal rows show that they have different coupling characteristics, possibly due to local magnetic connection length. Current drive efficiency has been investigated by a least squares fit with N{sub //}{sup peak}=2.1, where N{sub //}{sup peak} is the peak value of parallel refractive index of the launched wave. Results show that there is no obvious difference in the current drive efficiency between double null and lower single null cases, whereas the efficiency is somewhat small in the limiter configuration. This is in agreement with the ray tracing/Fokker-Planck code simulation by LUKE/C3PO and can be interpreted by the power spectrum up-shift factor in different plasma configurations. A transformer recharge is realized with {approx}0.8 MW LHW power and the energy conversion efficiency from LHW to poloidal field energy is about 2%.

  19. Investigation of lower hybrid wave coupling and current drive experiments at different configurations in experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Ding, B. J.; Qin, Y. L.; Li, W. K.; Li, M. H.; Kong, E. H.; Zhang, L.; Ekedahl, A.; Peysson, Y.; Decker, J.; Wang, M.; Xu, H. D.; Hu, H. C.; Xu, G. S.; Shan, J. F.; Liu, F. K.; Zhao, Y. P.; Wan, B. N.; Li, J. G.; Group, EAST

    2011-08-01

    Using a 2 MW 2.45 GHz lower hybrid wave (LHW) system installed in experimental advanced superconducting tokamak, we have systematically carried out LHW-plasma coupling and lower hybrid current drive experiments in both divertor (double null and lower single null) and limiter plasma configuration with plasma current (Ip) ˜ 250 kA and central line averaged density (ne) ˜ 1.0-1.3 × 1019 m-3 recently. Results show that the reflection coefficient (RC) first is flat up to some distance between plasma and LHW grill, and then increases with the distance. Studies indicate that with the same plasma parameters, the best coupling is obtained in the limiter case (with plasma leaning on the inner wall), followed by the lower single null, and the one with the worst coupling is the double null configuration, explained by different magnetic connection length. The RCs in the different poloidal rows show that they have different coupling characteristics, possibly due to local magnetic connection length. Current drive efficiency has been investigated by a least squares fit with N//peak=2.1, where N//peak is the peak value of parallel refractive index of the launched wave. Results show that there is no obvious difference in the current drive efficiency between double null and lower single null cases, whereas the efficiency is somewhat small in the limiter configuration. This is in agreement with the ray tracing/Fokker-Planck code simulation by LUKE/C3PO and can be interpreted by the power spectrum up-shift factor in different plasma configurations. A transformer recharge is realized with ˜0.8 MW LHW power and the energy conversion efficiency from LHW to poloidal field energy is about 2%.

  20. Moving Divertor Plates in a Tokamak

    SciTech Connect

    S.J. Zweben, H. Zhang

    2009-02-12

    Moving divertor plates could help solve some of the problems of the tokamak divertor through mechanical ingenuity rather than plasma physics. These plates would be passively heated on each pass through the tokamak and cooled and reprocessed outside the tokamak. There are many design options using varying plate shapes, orientations, motions, coatings, and compositions.

  1. Advances in Measurement Technology at NIST's Physical Measurement Laboratory

    NASA Astrophysics Data System (ADS)

    Dehmer, Joseph

    2014-03-01

    The NIST mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology. The Physical Measurement Laboratory (PML) has responsibility for maintaining national standards for two dozen physical quantities needed for international trade; and, importantly, it carries out advanced research at the frontiers of measurement science to enable extending innovation into new realms and new markets. This talk will highlight advances being made across several sectors of technology; and it will describe how PML interacts with its many collaborators and clients in industry, government, and academe.

  2. Advanced in turbulence physics and modeling by direct numerical simulations

    NASA Technical Reports Server (NTRS)

    Reynolds, W. C.

    1987-01-01

    The advent of direct numerical simulations of turbulence has opened avenues for research on turbulence physics and turbulence modeling. Direct numerical simulation provides values for anything that the scientist or modeler would like to know about the flow. An overview of some recent advances in the physical understanding of turbulence and in turbulence modeling obtained through such simulations is presented.

  3. Advanced Computing Tools and Models for Accelerator Physics

    SciTech Connect

    Ryne, Robert; Ryne, Robert D.

    2008-06-11

    This paper is based on a transcript of my EPAC'08 presentation on advanced computing tools for accelerator physics. Following an introduction I present several examples, provide a history of the development of beam dynamics capabilities, and conclude with thoughts on the future of large scale computing in accelerator physics.

  4. Project for the Institution of an Advanced Course in Physics

    NASA Astrophysics Data System (ADS)

    Teodorani, M.; Nobili, G.

    2006-06-01

    A project for an advanced course in physics at the master level, is presented in great detail. The goal of this project is to create a specific and rigorous training for those who want to carry out experimental and theoretical research on "anomalies" in physical science, especially from the point of view of atmospheric physics, plasma physics, photonic physics, biophysics, astronomy and astrophysics. A specific training in powering mental skills is planned as well. The planned teaching program is presented as a two-year course where the following subjects are intended to be taught: cognitive techniques (I and II), radiation physics (I and II), biophysics (I and II), bioastronomy (I and II), history of physics (I and II), didactics of physics, physics of atmospheric plasmas, physics of non-stationary photonic events, physics of non-linear processes, complements of quantum mechanics, quantum informatics, research methodology in physics and astronomy, computer science methods in physics and astronomy, optoelectronics, radioelectronics. Detailed teaching programs, didactics methods, and performance evaluation, are presented for each subject. The technical content of this project is preceded by an ample introduction that shows all the reasons of this kind of physics course, particularly aimed at innovation in physical science.

  5. Advanced physical chemistry of carbon nanotubes.

    PubMed

    Li, Jun; Pandey, Gaind P

    2015-04-01

    The past decade has seen a surge of exciting research and applications of carbon nanotubes (CNTs) stimulated by deeper understanding of their fundamental properties and increasing production capability. The intrinsic properties of various CNTs were found to strongly depend on their internal microstructures. This review summarizes the fundamental structure-property relations of seamless tube-like single- and multiwalled CNTs and conically stacked carbon nanofibers, as well as the organized architectures of these CNTs (including randomly stacked thin films, parallel aligned thin films, and vertically aligned arrays). It highlights the recent development of CNTs as key components in selected applications, including nanoelectronics, filtration membranes, transparent conductive electrodes, fuel cells, electrical energy storage devices, and solar cells. Particular emphasis is placed on the link between the basic physical chemical properties of CNTs and the organized CNT architectures with their functions and performance in each application. PMID:25580625

  6. Advanced Physical Chemistry of Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Li, Jun; Pandey, Gaind P.

    2015-04-01

    The past decade has seen a surge of exciting research and applications of carbon nanotubes (CNTs) stimulated by deeper understanding of their fundamental properties and increasing production capability. The intrinsic properties of various CNTs were found to strongly depend on their internal microstructures. This review summarizes the fundamental structure-property relations of seamless tube-like single- and multiwalled CNTs and conically stacked carbon nanofibers, as well as the organized architectures of these CNTs (including randomly stacked thin films, parallel aligned thin films, and vertically aligned arrays). It highlights the recent development of CNTs as key components in selected applications, including nanoelectronics, filtration membranes, transparent conductive electrodes, fuel cells, electrical energy storage devices, and solar cells. Particular emphasis is placed on the link between the basic physical chemical properties of CNTs and the organized CNT architectures with their functions and performance in each application.

  7. Features and Initial Results of the DIII-D Advanced Tokamak Radiative Divertor

    SciTech Connect

    R.C. O'Neill; A.S. Bozek; M.E. Friend; C.B. Baxi; E.E. Reis; M.A. Mahdavi; D.G. Nilson; S.L. Allen; W.P. West

    1999-11-01

    The Radiative Divertor Program of DIII-D is in its final phase with the installation of the cryopump and baffle structure (Phase 1B Divertor) in the upper inner radius of the DIII-D vacuum vessel at the end of this calendar year. This divertor, in conjunction with the Advanced Divertor and the Phase 1A Divertor, located in the lower and upper outer radius of the DIII-D vacuum vessel respectively, provides pumping for density control of the plasma while minimizing the effects on the core confinement. Each divertor consists of a cryobelium cooling ring and a shielded protective structure. The cryo/helium-cooled pumps of all three diverters exhaust helium from the plasma. The protective shielded structure or baffle structure, in the case of the diverters located at the top of the vacuum vessel, provides baffling of neutral charged particles and minimize the flow of impurities back into the core of the plasma. The baffles, which consist of water-cooled panels that allow for the attachment of tiles of various sizes and shapes, house gas puff systems. The intent of the puffing systems is to inject gas in and around the divertor to minimize the heat flux on specific areas on the divertor and its components. The reduction of the heat flux on the divertor minimizes the impurities that are generated from excess heat on divertor components, specifically tiles. Experiments involving the gas puff systems and the divertor structures have shown the heat flux can be spread over a large area of the divertor, reducing the peak heat flux in specific areas. The three diverters also incorporate a variety of diagnostic tools such as halo current monitors, magnetic probes and thermocouples to monitor certain plasma characteristics as well as determine the effectiveness of the cryopumps and baffle configurations. The diverters were designed to optimize pumping performance and to withstand the electromagnetic loads from both halo currents and toroidal induced currents. Incorporated also

  8. Chapter 1: Recent Advances in Solar Physics

    NASA Astrophysics Data System (ADS)

    Dwivedi, B. N.

    2008-10-01

    For millennia, the Sun (and the universe) has been viewed in the visual light. As the bestower of light and life, the ancients made God out of the Sun. With the Babylonians, or with the multiple origins with the Chinese, Egyptians and Indians, quoting the Rig Veda:"All that exists was born from Sūrya, the God of gods.", we have come a long way to understanding the Sun. In the early seventeenth century, however, Galileo showed that the Sun was not an immaculate object. Thus began our scientific interests in our nearest stellar neighbour, the Sun (cf., Figure 1.1.), with its sunspots and the related solar activity. The observations of the Sun and their interpretations are of universal importance for at least two reasons: First, the Sun is the source of energy for the entire planetary system and all aspects of our life have direct impact on what happens on the Sun; and second, the Sun's proximity makes it unique among the billions of stars in the sky of which we can resolve its surface features and study physical processes at work...

  9. Recent Advances in Plasma Edge Physics Theory

    NASA Astrophysics Data System (ADS)

    Stacey, W. M.

    2015-11-01

    This presentation summarizes recent theory developments for interpreting plasma edge physics experiments in DIII-D. i) Radial and poloidal moment balance require that the radial particle flux be of a pinch-diffusive nature with the pinch representing the electromagnetic forces and external momentum input. Ion radial particle fluxes in experiment are found to be a smaller difference between large outward diffusion fluxes and inward pinch fluxes. When the pinch-diffusion relation is used in the continuity equation a new diffusion theory that preserves momentum balance is obtained. ii) The majority of thermalized ions and their energy cross the LCFS on ion loss orbits and are deposited in the SOL near the outboard midplane. The lost ions are predominantly ctr-current, producing a co-current intrinsic rotation of the remaining ions in the edge plasma. iii) While the contribution of the leading order parallel viscosity to toroidal momentum damping vanishes identically in axisymmetric plasmas, non-axisymmetric radial B-fields in the edge plasma enable parallel viscosity to enhance the damping of toroidal rotation. Work supported by the US DOE under DE-FG02-00ER54538, DE-FC02-04ER54698.

  10. Atomic physics at the advanced photon source

    SciTech Connect

    Berry, H.G.; Cowan, P.L.; Gemmell, D.S.

    1995-08-01

    Argonne`s 7-GeV synchrotron light source (APS) is expected to commence operations for research early in FY 1996. The Basic Energy Sciences Synchrotron Research Center (BESSRC) is likewise expected to start its research programs at that time. As members of the BESSRC CAT (Collaborative Access Team), we are preparing, together with atomic physicists from the University of Western Michigan, the University of Tennessee, and University of Notre Dame, to initiate a series of atomic physics experiments that exploit the unique capabilities of the APS, especially its high brilliance for photon energies extending from about 3 keV to more than 50 keV. Most of our early work will be conducted on an undulator beam line and we are thus concentrating on various aspects of that beam line and its associated experimental areas. Our group has undertaken responsibilities in such areas as hutch design, evaluation of undulator performance, user policy, interfacing and instrumentation, etc. Initial experiments will probably utilize existing apparatus. We are, however, planning to move rapidly to more sophisticated measurements involving, for example, ion-beam targets, simultaneous laser excitation, and the spectroscopy of emitted photons.

  11. FIRE, A Test Bed for ARIES-RS/AT Advanced Physics and Plasma Technology

    SciTech Connect

    Dale M. Meade

    2004-10-21

    The overall vision for FIRE [Fusion Ignition Research Experiment] is to develop and test the fusion plasma physics and plasma technologies needed to realize capabilities of the ARIES-RS/AT power plant designs. The mission of FIRE is to attain, explore, understand and optimize a fusion dominated plasma which would be satisfied by producing D-T [deuterium-tritium] fusion plasmas with nominal fusion gains {approx}10, self-driven currents of {approx}80%, fusion power {approx}150-300 MW, and pulse lengths up to 40 s. Achieving these goals will require the deployment of several key fusion technologies under conditions approaching those of ARIES-RS/AT. The FIRE plasma configuration with strong plasma shaping, a double null pumped divertor and all metal plasma-facing components is a 40% scale model of the ARIES-RS/AT plasma configuration. ''Steady-state'' advanced tokamak modes in FIRE with high beta, high bootstrap fraction, and 100% noninductive current drive are suitable for testing the physics of the ARIES-RS/A T operating modes. The development of techniques to handle power plant relevant exhaust power while maintaining low tritium inventory is a major objective for a burning plasma experiment. The FIRE high-confinement modes and AT-modes result in fusion power densities from 3-10 MWm{sup -3} and neutron wall loading from 2-4 MWm{sup -2} which are at the levels expected from the ARIES-RS/AT design studies.

  12. A fast-time-response extreme ultraviolet spectrometer for measurement of impurity line emissions in the Experimental Advanced Superconducting Tokamak.

    PubMed

    Zhang, Ling; Morita, Shigeru; Xu, Zong; Wu, Zhenwei; Zhang, Pengfei; Wu, Chengrui; Gao, Wei; Ohishi, Tetsutarou; Goto, Motoshi; Shen, Junsong; Chen, Yingjie; Liu, Xiang; Wang, Yumin; Dong, Chunfeng; Zhang, Hongmin; Huang, Xianli; Gong, Xianzu; Hu, Liqun; Chen, Junlin; Zhang, Xiaodong; Wan, Baonian; Li, Jiangang

    2015-12-01

    A flat-field extreme ultraviolet (EUV) spectrometer working in the 20-500 Å wavelength range with fast time response has been newly developed to measure line emissions from highly ionized tungsten in the Experimental Advanced Superconducting Tokamak (EAST) with a tungsten divertor, while the monitoring of light and medium impurities is also an aim in the present development. A flat-field focal plane for spectral image detection is made by a laminar-type varied-line-spacing concave holographic grating with an angle of incidence of 87°. A back-illuminated charge-coupled device (CCD) with a total size of 26.6 × 6.6 mm(2) and pixel numbers of 1024 × 255 (26 × 26 μm(2)/pixel) is used for recording the focal image of spectral lines. An excellent spectral resolution of Δλ0 = 3-4 pixels, where Δλ0 is defined as full width at the foot position of a spectral line, is obtained at the 80-400 Å wavelength range after careful adjustment of the grating and CCD positions. The high signal readout rate of the CCD can improve the temporal resolution of time-resolved spectra when the CCD is operated in the full vertical binning mode. It is usually operated at 5 ms per frame. If the vertical size of the CCD is reduced with a narrow slit, the time response becomes faster. The high-time response in the spectral measurement therefore makes possible a variety of spectroscopic studies, e.g., impurity behavior in long pulse discharges with edge-localized mode bursts. An absolute intensity calibration of the EUV spectrometer is also carried out with a technique using the EUV bremsstrahlung continuum at 20-150 Å for quantitative data analysis. Thus, the high-time resolution tungsten spectra have been successfully observed with good spectral resolution using the present EUV spectrometer system. Typical tungsten spectra in the EUV wavelength range observed from EAST discharges are presented with absolute intensity and spectral identification. PMID:26724029

  13. A fast-time-response extreme ultraviolet spectrometer for measurement of impurity line emissions in the Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Zhang, Ling; Xu, Zong; Wu, Zhenwei; Zhang, Pengfei; Wu, Chengrui; Gao, Wei; Shen, Junsong; Chen, Yingjie; Liu, Xiang; Wang, Yumin; Gong, Xianzu; Hu, Liqun; Chen, Junlin; Zhang, Xiaodong; Wan, Baonian; Li, Jiangang; Morita, Shigeru; Ohishi, Tetsutarou; Goto, Motoshi; Dong, Chunfeng; and others

    2015-12-15

    A flat-field extreme ultraviolet (EUV) spectrometer working in the 20-500 Å wavelength range with fast time response has been newly developed to measure line emissions from highly ionized tungsten in the Experimental Advanced Superconducting Tokamak (EAST) with a tungsten divertor, while the monitoring of light and medium impurities is also an aim in the present development. A flat-field focal plane for spectral image detection is made by a laminar-type varied-line-spacing concave holographic grating with an angle of incidence of 87°. A back-illuminated charge-coupled device (CCD) with a total size of 26.6 × 6.6 mm{sup 2} and pixel numbers of 1024 × 255 (26 × 26 μm{sup 2}/pixel) is used for recording the focal image of spectral lines. An excellent spectral resolution of Δλ{sub 0} = 3-4 pixels, where Δλ{sub 0} is defined as full width at the foot position of a spectral line, is obtained at the 80-400 Å wavelength range after careful adjustment of the grating and CCD positions. The high signal readout rate of the CCD can improve the temporal resolution of time-resolved spectra when the CCD is operated in the full vertical binning mode. It is usually operated at 5 ms per frame. If the vertical size of the CCD is reduced with a narrow slit, the time response becomes faster. The high-time response in the spectral measurement therefore makes possible a variety of spectroscopic studies, e.g., impurity behavior in long pulse discharges with edge-localized mode bursts. An absolute intensity calibration of the EUV spectrometer is also carried out with a technique using the EUV bremsstrahlung continuum at 20-150 Å for quantitative data analysis. Thus, the high-time resolution tungsten spectra have been successfully observed with good spectral resolution using the present EUV spectrometer system. Typical tungsten spectra in the EUV wavelength range observed from EAST discharges are presented with absolute intensity and spectral identification.

  14. A fast-time-response extreme ultraviolet spectrometer for measurement of impurity line emissions in the Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Zhang, Ling; Morita, Shigeru; Xu, Zong; Wu, Zhenwei; Zhang, Pengfei; Wu, Chengrui; Gao, Wei; Ohishi, Tetsutarou; Goto, Motoshi; Shen, Junsong; Chen, Yingjie; Liu, Xiang; Wang, Yumin; Dong, Chunfeng; Zhang, Hongmin; Huang, Xianli; Gong, Xianzu; Hu, Liqun; Chen, Junlin; Zhang, Xiaodong; Wan, Baonian; Li, Jiangang

    2015-12-01

    A flat-field extreme ultraviolet (EUV) spectrometer working in the 20-500 Å wavelength range with fast time response has been newly developed to measure line emissions from highly ionized tungsten in the Experimental Advanced Superconducting Tokamak (EAST) with a tungsten divertor, while the monitoring of light and medium impurities is also an aim in the present development. A flat-field focal plane for spectral image detection is made by a laminar-type varied-line-spacing concave holographic grating with an angle of incidence of 87°. A back-illuminated charge-coupled device (CCD) with a total size of 26.6 × 6.6 mm2 and pixel numbers of 1024 × 255 (26 × 26 μm2/pixel) is used for recording the focal image of spectral lines. An excellent spectral resolution of Δλ0 = 3-4 pixels, where Δλ0 is defined as full width at the foot position of a spectral line, is obtained at the 80-400 Å wavelength range after careful adjustment of the grating and CCD positions. The high signal readout rate of the CCD can improve the temporal resolution of time-resolved spectra when the CCD is operated in the full vertical binning mode. It is usually operated at 5 ms per frame. If the vertical size of the CCD is reduced with a narrow slit, the time response becomes faster. The high-time response in the spectral measurement therefore makes possible a variety of spectroscopic studies, e.g., impurity behavior in long pulse discharges with edge-localized mode bursts. An absolute intensity calibration of the EUV spectrometer is also carried out with a technique using the EUV bremsstrahlung continuum at 20-150 Å for quantitative data analysis. Thus, the high-time resolution tungsten spectra have been successfully observed with good spectral resolution using the present EUV spectrometer system. Typical tungsten spectra in the EUV wavelength range observed from EAST discharges are presented with absolute intensity and spectral identification.

  15. BOOK REVIEW: Astrophysics (Advanced Physics Readers)

    NASA Astrophysics Data System (ADS)

    Kibble, Bob

    2000-07-01

    Here is a handy and attractive reader to support students on post-16 courses. It covers the astrophysics, astronomy and cosmology that are demanded at A-level and offers anyone interested in these fields an interesting and engaging reference book. The author and the production team deserve credit for producing such an attractive book. The content, in ten chapters, covers what one would expect at this level but it is how it is presented that struck me as the book's most powerful asset. Each chapter ends with a summary of key ideas. Line drawings are clear and convey enough information to make them more than illustrations - they are as valuable as the text in conveying information. Full colour is used throughout to enhance illustrations and tables and to lift key sections of the text. A number of colour photographs complement the material and serve to maintain interest and remind readers that astrophysics is about real observable phenomena. Included towards the end is a set of tables offering information on physical and astronomical data, mathematical techniques and constellation names and abbreviations. This last table puzzled me as to its value. There is a helpful bibliography which includes society contacts and a website related to the text. Perhaps my one regret is that there is no section where students are encouraged to actually do some real astronomy. Astrophysics is in danger of becoming an armchair and calculator interest. There are practical projects that students could undertake either for school assessment or for personal interest. Simple astrophotography to capture star trails, observe star colours and estimate apparent magnitudes is an example, as is a simple double-star search. There are dozens more. However, the author's style is friendly and collaborative. He befriends the reader as they journey together through the ideas. There are progress questions at the end of each chapter. Their style tends to be rather closed and they emphasize factual recall

  16. New results in atomic physics at the Advanced Light Source

    SciTech Connect

    Schlachter, A.S.

    1995-01-01

    The Advanced Light Source is the world's first low-energy third-generation synchrotron radiation source. It has been running reliably and exceeding design specifications since it began operation in October 1993. It is available to a wide community of researchers in many scientific fields, including atomic and molecular science and chemistry. Here, new results in atomic physics at the Advanced Light Source demonstrate the opportunities available in atomic and molecular physics at this synchrotron light source. The unprecedented brightness allows experiments with high flux, high spectral resolution, and nearly 100% linear polarization.

  17. First Engineering Commissioning of EAST Tokamak

    NASA Astrophysics Data System (ADS)

    Wan, Yuanxi; Li, Jiangang; Weng, Peide; EAST Team

    2006-05-01

    Experimental Advanced Superconducting Tokamak (EAST) is the first fully superconducting tokamak. The first commissioning started on Feb. 1st of 2006 and finished on March 30th of 2006 at the Institute of Plasma Physics, Chinese Academy of Sciences. It consists of leakage testing at both room temperature and low temperature, pumping down, cooling down all coils, current leads, bus bar and the thermal shielding, exciting all the coils, measuring magnetic configuration and warming up the magnets. The electromagnetic, thermal hydraulic and mechanical performance of EAST Toroidal Field (TF) and Poloidal Field (PF) magnets have also been tested. All sub-systems, including pumping system, cryogenic system, PF& TF power supply systems, magnet instrumentation system, quench detection and protection system, water cooling system, data acquisition system, main control system, plasma control system (PCS), interlock and safety system have been successfully tested.

  18. 2004 Physics and Advanced Technologies In the News

    SciTech Connect

    Hazi, A

    2005-11-01

    Several outstanding research activities in the Physics and Advanced Technology Directorate in 2004 were featured in ''Science & Technology Review'', the monthly publication of the Lawrence Livermore National Laboratory. Reprints of those articles accompany this report. Here we summarize other science and technology highlights, as well as the awards and recognition received by members of the Directorate in 2004.

  19. Teaching Physics at Advanced Level: A Question of Style.

    ERIC Educational Resources Information Center

    Newton, Leonard; Rogers, Laurence

    1996-01-01

    Questions whether didactic methods employed for teaching physics at the advanced level can adequately match the variety of needs of students in the contemporary context. Offers a framework for promoting a style of teaching that is responsive and versatile. Contains 14 references. (Author/JRH)

  20. 2005 Physics and Advanced Technologies in the News

    SciTech Connect

    Hazi, A U

    2006-12-19

    Several outstanding research activities in the Physics and Advanced Technologies Directorate in 2005 were featured in ''Science and Technology Review'', the monthly publication of Lawrence Livermore National Laboratory. Reprints of those articles accompany this report. Here we summarize other science and technology highlights, as well as the awards and recognition received by members of the Directorate in 2005. As part of the World Year of Physics commemorating the 100th anniversary of Einstein's ''miraculous year'', we also highlight ongoing physics research that would not be possible without Einstein's pioneering accomplishments.

  1. SPECIAL TOPIC: A two-time-scale dynamic-model approach for magnetic and kinetic profile control in advanced tokamak scenarios on JET

    NASA Astrophysics Data System (ADS)

    Moreau, D.; Mazon, D.; Ariola, M.; DeTommasi, G.; Laborde, L.; Piccolo, F.; Sartori, F.; Tala, T.; Zabeo, L.; Boboc, A.; Bouvier, E.; Brix, M.; Brzozowski, J.; Challis, C. D.; Cocilovo, V.; Cordoliani, V.; Crisanti, F.; DeLa Luna, E.; Felton, R.; Hawkes, N.; King, R.; Litaudon, X.; Loarer, T.; Mailloux, J.; Mayoral, M.; Nunes, I.; Surrey, E.; Zimmerman, O.; EFDA Contributors, JET

    2008-10-01

    Real-time simultaneous control of several radially distributed magnetic and kinetic plasma parameters is being investigated on JET, in view of developing integrated control of advanced tokamak scenarios. This paper describes the new model-based profile controller which has been implemented during the 2006-2007 experimental campaigns. The controller aims to use the combination of heating and current drive (H&CD) systems—and optionally the poloidal field (PF) system—in an optimal way to regulate the evolution of plasma parameter profiles such as the safety factor, q(x), and gyro-normalized temperature gradient, \\rho _Te^*(x) . In the first part of the paper, a technique for the experimental identification of a minimal dynamic plasma model is described, taking into account the physical structure and couplings of the transport equations, but making no quantitative assumptions on the transport coefficients or on their dependences. To cope with the high dimensionality of the state space and the large ratio between the time scales involved, the model identification procedure and the controller design both make use of the theory of singularly perturbed systems by means of a two-time-scale approximation. The second part of the paper provides the theoretical basis for the controller design. The profile controller is articulated around two composite feedback loops operating on the magnetic and kinetic time scales, respectively, and supplemented by a feedforward compensation of density variations. For any chosen set of target profiles, the closest self-consistent state achievable with the available actuators is uniquely defined. It is reached, with no steady state offset, through a near-optimal proportional-integral control algorithm. Conventional optimal control is recovered in the limiting case where the ratio of the plasma confinement time to the resistive diffusion time tends to zero. Closed-loop simulations of the controller response have been performed in

  2. Imaging key aspects of fast ion physics in the DIII-D tokamak

    NASA Astrophysics Data System (ADS)

    Van Zeeland, M. A.; Yu, J. H.; Heidbrink, W. W.; Brooks, N. H.; Burrell, K. H.; Chu, M. S.; Hyatt, A. W.; Muscatello, C.; Nazikian, R.; Pablant, N. A.; Pace, D. C.; Solomon, W. M.; Wade, M. R.

    2010-08-01

    Visible imaging has been used to provide the 2D spatial structure and temporal evolution of the profile of high-energy neutrals introduced by neutral beam injection, the fast ion profile and a variety of plasma instabilities in DIII-D plasmas; the combination of these techniques form a comprehensive fast ion physics diagnostic suite. The injected neutral profile is imaged in Doppler shifted Dα light induced by collisional excitation. Fast ion profile information was obtained through imaging of Doppler shifted fast ion Dα light (FIDA) emitted by re-neutralized energetic ions. Imaging of FIDA emission during sawtooth events shows a large central depletion following sawtooth crashes—indicative of a broad redistribution of fast ions. Two examples of instability structure measurements are given. Measurements of the detailed 2D poloidal structure of rotating tearing modes were obtained using spectrally filtered fast imaging of broadband visible bremsstrahlung emission, a method which is capable of imaging with high resolution the structure of coherent oscillations in the core of current and next-step fusion plasma experiments and can be applied to virtually any mode with a finite perturbed bremsstrahlung emissivity and frequency in the laboratory frame. Measurements are also presented of the n = 0 energetic particle geodesic acoustic mode which were made by observing fluctuations in active emission.

  3. Flow Shear Effects in the Onset Physics of Resistive MHD Instabilities in Tokamaks. Final report

    SciTech Connect

    Brennan, Dylan P.

    2013-04-24

    The progress in this research centers around the computational analysis of flow shear effects in the onset of a 3/2 mode driven by a 1/1 mode in DIII-D equilibria. The initial idea was to try and calculate, via nonlinear simulations with NIMROD, the effects of rotation shear on driven 3/2 and 2/1 seed island physics, in experimentally relevant DIIID equilibria. The simulations indicated that very small seed islands were directly driven, as shielding between the sawtooth and the surfaces is significant at the high Lundquist numbers of the experiment. Instead, long after the initial crash the difference in linear stability of the 3/2, which remained prevalent despite the flattening of the core profiles from the sawtooth, contributed to a difference in the eventual seed island evolution. Essentially the seed islands grew or decayed long after the sawtooth crash, and not directly from it. Effectively the dominant 1/1 mode was found to be dragging the coupled modes surrounding it at a high rate through the plasma at their surfaces. The 1/1 mode is locked to the local frame of the plasma in the core, where the flow rate is greatest. The resonant perturbations at the surrounding surfaces propagate in the 'high slip regime' in the language of Fitzpatrick. Peaked flux averaged jxb forces (see Figs. 1 and 2) agree with localized flow modifications at the surfaces in analogy with Ebrahimi, PRL 2007. We track the mode into nonlinear saturation and have found oscillatory states in the evolution. During a visit (11/09) to Tulsa by R.J. LaHaye (GA), it became clear that similar oscillatory states are observed in DIII-D for these types of discharges.

  4. Problems with the rush toward advanced physics in high schools

    NASA Astrophysics Data System (ADS)

    Gollub, Jerry

    2003-04-01

    The Advanced Placement (AP) Program has a major impact on the physics experience of many high school students. It affects admission to college, course choices and performance in college, and subsequent career decisions. A study committee of the National Research Council published a review of these programs in 2002, and concluded that while the program has many positive features, important problems need to be addressed. [1] The programs are not currently consistent with what we have learned about student learning from cognitive research. Students are often poorly prepared for AP courses, because of lack of coordination within schools. The Physics AP-B (non-calculus) program is too broad to allow most high school students to achieve an adequate level of conceptual understanding. Participation by minority students in these programs is far below that of other students. The AP exams need to be re-evaluated to insure that they actually measure conceptual understanding and complex reasoning. The AP exams are sometimes used inappropriately to rate teachers or schools. College and high school courses are poorly coordinated, with the result that students often take an introductory physics survey as many as three times. Policies on college credit for AP courses differ widely. These problems cannot be fixed by the College Board alone. [1] Jerry P. Gollub and Robin Spital, "Advanced Physics in the High Schools", Physics Today, May 2002.

  5. Design of the radiation shielding for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Du, T. F.; Chen, Z. J.; Peng, X. Y.; Yuan, X.; Zhang, X.; Hu, Z. M.; Cui, Z. Q.; Xie, X. F.; Ge, L. J.; Li, X. Q.; Zhang, G. H.; Chen, J. X.; Fan, T. S.; Gorini, G.; Nocente, M.; Tardocchi, M.; Hu, L. Q.; Zhong, G. Q.; Lin, S. Y.; Wan, B. N.

    2014-11-15

    A radiation shielding has been designed to reduce scattered neutrons and background gamma-rays for the new double-ring Time Of Flight Enhanced Diagnostics (TOFED). The shielding was designed based on simulation with the Monte Carlo code MCNP5. Dedicated model of the EAST tokamak has been developed together with the emission neutron source profile and spectrum; the latter were simulated with the Nubeam and GENESIS codes. Significant reduction of background radiation at the detector can be achieved and this satisfies the requirement of TOFED. The intensities of the scattered and direct neutrons in the line of sight of the TOFED neutron spectrometer at EAST are studied for future data interpretation.

  6. Monte Carlo simulation of a Bonner sphere spectrometer for application to the determination of neutron field in the Experimental Advanced Superconducting Tokamak experimental halla)

    NASA Astrophysics Data System (ADS)

    Hu, Z. M.; Xie, X. F.; Chen, Z. J.; Peng, X. Y.; Du, T. F.; Cui, Z. Q.; Ge, L. J.; Li, T.; Yuan, X.; Zhang, X.; Hu, L. Q.; Zhong, G. Q.; Lin, S. Y.; Wan, B. N.; Gorini, G.; Li, X. Q.; Zhang, G. H.; Chen, J. X.; Fan, T. S.

    2014-11-01

    To assess the neutron energy spectra and the neutron dose for different positions around the Experimental Advanced Superconducting Tokamak (EAST) device, a Bonner Sphere Spectrometer (BSS) was developed at Peking University, with totally nine polyethylene spheres and a SP9 3He counter. The response functions of the BSS were calculated by the Monte Carlo codes MCNP and GEANT4 with dedicated models, and good agreement was found between these two codes. A feasibility study was carried out with a simulated neutron energy spectrum around EAST, and the simulated "experimental" result of each sphere was obtained by calculating the response with MCNP, which used the simulated neutron energy spectrum as the input spectrum. With the deconvolution of the "experimental" measurement, the neutron energy spectrum was retrieved and compared with the preset one. Good consistence was found which offers confidence for the application of the BSS system for dose and spectrum measurements around a fusion device.

  7. Monte Carlo simulation of a Bonner sphere spectrometer for application to the determination of neutron field in the Experimental Advanced Superconducting Tokamak experimental hall.

    PubMed

    Hu, Z M; Xie, X F; Chen, Z J; Peng, X Y; Du, T F; Cui, Z Q; Ge, L J; Li, T; Yuan, X; Zhang, X; Hu, L Q; Zhong, G Q; Lin, S Y; Wan, B N; Gorini, G; Li, X Q; Zhang, G H; Chen, J X; Fan, T S

    2014-11-01

    To assess the neutron energy spectra and the neutron dose for different positions around the Experimental Advanced Superconducting Tokamak (EAST) device, a Bonner Sphere Spectrometer (BSS) was developed at Peking University, with totally nine polyethylene spheres and a SP9 (3)He counter. The response functions of the BSS were calculated by the Monte Carlo codes MCNP and GEANT4 with dedicated models, and good agreement was found between these two codes. A feasibility study was carried out with a simulated neutron energy spectrum around EAST, and the simulated "experimental" result of each sphere was obtained by calculating the response with MCNP, which used the simulated neutron energy spectrum as the input spectrum. With the deconvolution of the "experimental" measurement, the neutron energy spectrum was retrieved and compared with the preset one. Good consistence was found which offers confidence for the application of the BSS system for dose and spectrum measurements around a fusion device. PMID:25430324

  8. Monte Carlo simulation of a Bonner sphere spectrometer for application to the determination of neutron field in the Experimental Advanced Superconducting Tokamak experimental hall

    SciTech Connect

    Hu, Z. M.; Xie, X. F.; Chen, Z. J.; Peng, X. Y.; Du, T. F.; Cui, Z. Q.; Ge, L. J.; Li, T.; Yuan, X.; Zhang, X.; Li, X. Q.; Zhang, G. H.; Chen, J. X.; Fan, T. S.; Hu, L. Q.; Zhong, G. Q.; Lin, S. Y.; Wan, B. N.; Gorini, G.

    2014-11-15

    To assess the neutron energy spectra and the neutron dose for different positions around the Experimental Advanced Superconducting Tokamak (EAST) device, a Bonner Sphere Spectrometer (BSS) was developed at Peking University, with totally nine polyethylene spheres and a SP9 {sup 3}He counter. The response functions of the BSS were calculated by the Monte Carlo codes MCNP and GEANT4 with dedicated models, and good agreement was found between these two codes. A feasibility study was carried out with a simulated neutron energy spectrum around EAST, and the simulated “experimental” result of each sphere was obtained by calculating the response with MCNP, which used the simulated neutron energy spectrum as the input spectrum. With the deconvolution of the “experimental” measurement, the neutron energy spectrum was retrieved and compared with the preset one. Good consistence was found which offers confidence for the application of the BSS system for dose and spectrum measurements around a fusion device.

  9. Experimental determination of some equilibrium parameter of Damavand tokamak by magnetic probe measurements for representing a physical model for plasma vertical movement.

    PubMed

    Farahani, N Darestani; Davani, F Abbasi

    2015-10-01

    This investigation is about plasma modeling for the control of vertical instabilities in Damavand tokamak. This model is based on online magnetic measurement. The algebraic equation defining the vertical position in this model is based on instantaneous force-balance. Two parameters in this equation, including decay index, n, and lambda, Λ, have been considered as functions of time-varying poloidal field coil currents and plasma current. Then these functions have been used in a code generated for modeling the open loop response of plasma. The main restriction of the suitability analysis of the model is that the experiments always have to be performed in the presence of a control loop for stabilizing vertical position. As a result, open loop response of the system has been identified from closed loop experimental data by nonlinear neural network identification method. The results of comparison of physical model with identified open loop response from closed loop experiments show root mean square error percentage less than 10%. The results are satisfying that the physical model is useful as a Damavand tokamak vertical movement simulator. PMID:26520958

  10. A Trial of Physics Education for Liberal Arts Students Using the Advancing Physics

    NASA Astrophysics Data System (ADS)

    Ochi, Nobuaki

    A new approach to physics education for liberal arts students was performed in a Japanese university. The Advancing Physics, a modern textbook developed by the Institute of Physics, was employed as the base of this approach. The textbook includes a variety of modern topics about science and technology with beautiful pictures, while the use of math is kept to a minimum. From results of the questionnaire after one-semester lectures, it turned out that students' interest in science and technology rose substantially. On the other hand, there were some difficulties in lecturing, mathematical techniques in particular, which should be modified by the next trial. This result is an indication of a potential of the Advancing Physics for liberal arts education.

  11. Tokamak Physics EXperiment (TPX): Toroidal field magnet design, development and manufacture. SDRL 15, System design description. Volume 1

    SciTech Connect

    1995-09-22

    This System Design Description, prepared in accordance with the TPX Project Management Plan provides a summary or TF Magnet System design features at the conclusion of Phase I, Preliminary Design and Manufacturing Research. The document includes the analytical and experimental bases for the design, and plans for implementation in final design, manufacturing, test, and magnet integration into the tokamak. Requirements for operation and maintenance are outlined, and references to sources of additional information are provided.

  12. Linear optimal control of tokamak fusion devices

    SciTech Connect

    Kessel, C.E.; Firestone, M.A.; Conn, R.W.

    1989-05-01

    The control of plasma position, shape and current in a tokamak fusion reactor is examined using linear optimal control. These advanced tokamaks are characterized by non up-down symmetric coils and structure, thick structure surrounding the plasma, eddy currents, shaped plasmas, superconducting coils, vertically unstable plasmas, and hybrid function coils providing ohmic heating, vertical field, radial field, and shaping field. Models of the electromagnetic environment in a tokamak are derived and used to construct control gains that are tested in nonlinear simulations with initial perturbations. The issues of applying linear optimal control to advanced tokamaks are addressed, including complex equilibrium control, choice of cost functional weights, the coil voltage limit, discrete control, and order reduction. Results indicate that the linear optimal control is a feasible technique for controlling advanced tokamaks where the more common classical control will be severely strained or will not work. 28 refs., 13 figs.

  13. Transport in gyrokinetic tokamaks

    SciTech Connect

    Mynick, H.E.; Parker, S.E.

    1995-01-01

    A comprehensive study of transport in full-volume gyrokinetic (gk) simulations of ion temperature gradient driven turbulence in core tokamak plasmas is presented. Though this ``gyrokinetic tokamak`` is much simpler than experimental tokamaks, such simplicity is an asset, because a dependable nonlinear transport theory for such systems should be more attainable. Toward this end, we pursue two related lines of inquiry. (1) We study the scalings of gk tokamaks with respect to important system parameters. In contrast to real machines, the scalings of larger gk systems (a/{rho}{sub s} {approx_gt} 64) with minor radius, with current, and with a/{rho}{sub s} are roughly consistent with the approximate theoretical expectations for electrostatic turbulent transport which exist as yet. Smaller systems manifest quite different scalings, which aids in interpreting differing mass-scaling results in other work. (2) With the goal of developing a first-principles theory of gk transport, we use the gk data to infer the underlying transport physics. The data indicate that, of the many modes k present in the simulation, only a modest number (N{sub k} {approximately} 10) of k dominate the transport, and for each, only a handful (N{sub p} {approximately} 5) of couplings to other modes p appear to be significant, implying that the essential transport physics may be described by a far simpler system than would have been expected on the basis of earlier nonlinear theory alone. Part of this analysis is the inference of the coupling coefficients M{sub kpq} governing the nonlinear mode interactions, whose measurement from tokamak simulation data is presented here for the first time.

  14. ECH tokamak

    SciTech Connect

    Firestone, M.A.; Mau, T.K.; Conn, R.W.

    1985-04-01

    A small steady-state tokamak capable of producing power in the 100 to 300 MWe range and relying on electron cyclotron RF heating (ECH) for both heating and current drive is described. Working in the first MHD stability regime for tokamaks, the approach adheres to the recently discovered maximum beta limit. An appropriate figure of merit is the ratio of the fusion power to absorbed RF power. Efficient devices are feasible at both small and large values of fusion power, thereby pointing to a development path for an attractive commercial fusion reactor.

  15. Fabrication and Characterization of Samples for a Material Migration Experiment on the Experimental Advanced Superconducting Tokamak (EAST).

    SciTech Connect

    Wampler, William R.; Van Deusen, Stuart B.

    2015-12-01

    This report documents work done for the ITER International Fusion Energy Organization (Sponsor) under a Funds-In Agreement FI 011140916 with Sandia National Laboratories. The work consists of preparing and analyzing samples for an experiment to measure material erosion and deposition in the EAST Tokamak. Sample preparation consisted of depositing thin films of carbon and aluminum onto molybdenum tiles. Analysis consists of measuring the thickness of films before and after exposure to helium plasma in EAST. From these measurements the net erosion and deposition of material will be quantified. Film thickness measurements are made at the Sandia Ion Beam Laboratory using Rutherford backscattering spectrometry and nuclear reaction analysis, as described in this report. This report describes the film deposition and pre-exposure analysis. Results from analysis after plasma exposure will be given in a subsequent report.

  16. Incorporation of Advanced Laboratory Equipment into Introductory Physics Labs

    NASA Astrophysics Data System (ADS)

    Gilbert, John; Bellis, Matt; Cummings, John

    2015-04-01

    Siena College recently completed construction of the Stewart's Advanced Instrumentation and Technology Center (SAInt Center) which includes both a scanning electron microscope (SEM) and an atomic force microscope (AFM). The goal of this project is to design laboratory exercises for introductory physics courses that make use of this equipment. Early involvement with the SAInt center aims to increase undergraduate lab skills and expand research possibilities. These lab exercises are tested on select students and evaluated as to their effectiveness in contributing to the learning goals.The current status of this work is presented here.

  17. Recent Progress of HT-7U Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Weng, Pei-de

    2002-12-01

    HT-7U is a superconducting tokamak, which is being constructed in Institute of Plasma Physics, Chinese Academy of Sciences. The mission of the HT-7U project is to develop a scientific and engineering basis of the steady state operation of advanced tokamak. The engineering design of the device has been optimized. The R&D program is going on. Short samples of the conductor and a CS model coil were tested. All the TF and PF coils will be manufactured and tested in Institute of Plasma Physics. Therefore, a 600-meter long jacketing line for cable-in-conduit conductors along with two winding machines, a set of VPI equipment and a test facility for the TF and PF coils are ready in ASIPP now. In this paper, the recent progress of the HT-7U is described.

  18. Coal surface control for advanced physical fine coal cleaning technologies

    SciTech Connect

    Morsi, B.I.; Chiang, S.H.; Sharkey, A.; Blachere, J.; Klinzing, G.; Araujo, G.; Cheng, Y.S.; Gray, R.; Streeter, R.; Bi, H.; Campbell, P.; Chiarlli, P.; Ciocco, M.; Hittle, L.; Kim, S.; Kim, Y.; Perez, L.; Venkatadri, R.

    1992-01-01

    This final report presents the research work carried out on the Coal Surface Control for Advanced Physical Fine Coal Cleaning Technologies project, sponsored by the US Department of Energy, Pittsburgh Energy Technology Center (DOE/PETC). The project was to support the engineering development of the selective agglomeration technology in order to reduce the sulfur content of US coals for controlling SO[sub 2] emissions (i.e., acid rain precursors). The overall effort was a part of the DOE/PETCs Acid Rain Control Initiative (ARCI). The overall objective of the project is to develop techniques for coal surface control prior to the advanced physical fine coal cleaning process of selective agglomeration in order to achieve 85% pyrite sulfur rejection at an energy recovery greater than 85% based on run-of-mine coal. The surface control is meant to encompass surface modification during grinding and laboratory beneficiation testing. The project includes the following tasks: Project planning; methods for analysis of samples; development of standard beneficiation test; grinding studies; modification of particle surface; and exploratory R D and support. The coal samples used in this project include three base coals, Upper Freeport - Indiana County, PA, Pittsburgh NO. 8 - Belmont County, OH, and Illinois No. 6 - Randolph County, IL, and three additional coals, Upper Freeport - Grant County- WV, Kentucky No. 9 Hopkins County, KY, and Wyodak - Campbell County, WY. A total of 149 drums of coal were received.

  19. Steady State Tokamak Equilibria without Current Drive

    SciTech Connect

    Shaing, K.C.; Aydemir, A.Y.; Lin-Liu, Y.R.; Miller, R.L.

    1997-11-01

    Steady state tokamak equilibria without current drive are found. This is made possible by including the potato bootstrap current close to the magnetic axis. Tokamaks with this class of equilibria do not need seed current or current drive, and are intrinsically steady state. {copyright} {ital 1997} {ital The American Physical Society}

  20. Local Physics Basis of Confinement Degradation in JET ELMy H-Mode Plasmas and Implications for Tokamak Reactors

    SciTech Connect

    Budny, R.V.; Alper, B.; Borba, D.; Cordey, J.G.; Ernst, D.R.; Gowers, C.

    2001-02-02

    First results of gyrokinetic analysis of JET [Joint European Torus] ELMy [Edge Localized Modes] H-mode [high-confinement modes] plasmas are presented. ELMy H-mode plasmas form the basis of conservative performance predictions for tokamak reactors of the size of ITER [International Thermonuclear Experimental Reactor]. Relatively high performance for long duration has been achieved and the scaling appears to be favorable. It will be necessary to sustain low Z(subscript eff) and high density for high fusion yield. This paper studies the degradation in confinement and increase in the anomalous heat transport observed in two JET plasmas: one with an intense gas puff and the other with a spontaneous transition between Type I to III ELMs at the heating power threshold. Linear gyrokinetic analysis gives the growth rate, gamma(subscript lin) of the fastest growing modes. The flow-shearing rate omega(subscript ExB) and gamma(subscript lin) are large near the top of the pedestal. Their ratio decreases approximately when the confinement degrades and the transport increases. This suggests that tokamak reactors may require intense toroidal or poloidal torque input to maintain sufficiently high |gamma(subscript ExB)|/gamma(subscript lin) near the top of the pedestal for high confinement.

  1. Principles of Technology Student Achievement in Advanced Physics Measured by a Normed Physics Test.

    NASA Astrophysics Data System (ADS)

    Nicholson, James Alan

    1991-02-01

    The Principles of Technology (PT) curriculum, now in approximately 1,200 schools, has produced a profound change in the delivery of applied physics. If high school PT programs and traditional physics courses deliver comparable student outcomes, as some research suggests, the PT curriculum may find wider acceptance in vocational programs and postsecondary schools may have rationale for accepting PT as physics. This study measured PT student performance on an advanced physics test, after they have had one year (7 units) of PT. The 1988R version of the National Association of Physics Teachers and National Science Teachers Association physics test, with more than 7500 copies sold, was selected as the research instrument. This test covers advanced aspects of traditional high school physics. A secondary enquiry included an attempt to link PT teacher preparation and credentialing and/or PT site demographics to variation in PT student scores on the 1988R test. The 10 PT sites in this study were self-selected from the 29 PT field study schools, the most mature PT sites. The researcher determined, that the 1988R physics test lacked content validity for the PT students tested. The PT students tested had a composite mean score of 17.67 questions correct out of 80, (below the second percentile), not statistically different than a chance score. No differences were found between site mean scores. Interpretation of the results regarding the effect of teachers, or demographics was not justified. The value of PT to the vocational-technical programs that it was designed for was not measured, nor was the awarding of general science credit for PT completion. One year of the PT curriculum, at the sampled schools, has not prepared students in the advanced scientific aspects of traditional physics found on the 1988R examination. The primary implication is that educators should not expect year one PT to prepare students for classes or curricula that include traditional physics as a

  2. Advanced Ground Systems Maintenance Physics Models For Diagnostics Project

    NASA Technical Reports Server (NTRS)

    Perotti, Jose M.

    2015-01-01

    The project will use high-fidelity physics models and simulations to simulate real-time operations of cryogenic and systems and calculate the status/health of the systems. The project enables the delivery of system health advisories to ground system operators. The capability will also be used to conduct planning and analysis of cryogenic system operations. This project will develop and implement high-fidelity physics-based modeling techniques tosimulate the real-time operation of cryogenics and other fluids systems and, when compared to thereal-time operation of the actual systems, provide assessment of their state. Physics-modelcalculated measurements (called “pseudo-sensors”) will be compared to the system real-timedata. Comparison results will be utilized to provide systems operators with enhanced monitoring ofsystems' health and status, identify off-nominal trends and diagnose system/component failures.This capability can also be used to conduct planning and analysis of cryogenics and other fluidsystems designs. This capability will be interfaced with the ground operations command andcontrol system as a part of the Advanced Ground Systems Maintenance (AGSM) project to helpassure system availability and mission success. The initial capability will be developed for theLiquid Oxygen (LO2) ground loading systems.

  3. Climate Solutions based on advanced scientific discoveries of Allatra physics

    NASA Astrophysics Data System (ADS)

    Vershigora, Valery

    2016-05-01

    Global climate change is one of the most important international problems of the 21st century. The overall rapid increase in the dynamics of cataclysms, which have been observed in recent decades, is particularly alarming. Howdo modern scientists predict the occurrence of certain events? In meteorology, unusually powerful cumulonimbus clouds are one of the main conditions for the emergence of a tornado. The former, in their turn, are formed during the invasion of cold air on the overheated land surface. The satellite captures the cloud front, and, based on these pictures, scientists make assumptions about the possibility of occurrence of the respective natural phenomena. In fact, mankind visually observes and draws conclusions about the consequences of the physical phenomena which have already taken place in the invisible world, so the conclusions of scientists are assumptions by their nature, rather than precise knowledge of the causes of theorigin of these phenomena in the physics of microcosm. The latest research in the field of the particle physics and neutrino astrophysics, which was conducted by a working team of scientists of ALLATRA International Public Movement (hereinafter ALLATRA SCIENCE group)allatra-science.org, last accessed 10 April 2016. , offers increased opportunities for advanced fundamental and applied research in climatic engineering.

  4. Reflection on problem solving in introductory and advanced physics

    NASA Astrophysics Data System (ADS)

    Mason, Andrew J.

    Reflection is essential in order to learn from problem solving. This thesis explores issues related to how reflective students are and how we can improve their capacity for reflection on problem solving. We investigate how students naturally reflect in their physics courses about problem solving and evaluate strategies that may teach them reflection as an integral component of problem-solving. Problem categorization based upon similarity of solution is a strategy to help them reflect about the deep features of the problems related to the physics principles involved. We find that there is a large overlap between the introductory and graduate students in their ability to categorize. Moreover, introductory students in the calculus-based courses performed better categorization than those in the algebra-based courses even though the categorization task is conceptual. Other investigations involved exploring if reflection could be taught as a skill on individual and group levels. Explicit self-diagnosis in recitation investigated how effectively students could diagnose their own errors on difficult problems, how much scaffolding was necessary for this purpose, and how effective transfer was to other problems employing similar principles. Difficulty in applying physical principles and difference between the self-diagnosed and transfer problems affected performance. We concluded that a sustained intervention is required to learn effective problem-solving strategies. Another study involving reflection on problem solving with peers suggests that those who reflected with peers drew more diagrams and had a larger gain from the midterm to final exam. Another study in quantum mechanics involved giving common problems in midterm and final exams and suggested that advanced students do not automatically reflect on their mistakes. Interviews revealed that even advanced students often focus mostly on exams rather than learning and building a robust knowledge structure. A survey was

  5. Effects of heating power on divertor in-out asymmetry and scrape-off layer flow in reversed field on Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Liu, S. C. Wang, H. Q.; Gan, K. F.; Xia, T. Y.; Xu, G. S.; Liu, Z. X.; Chen, L.; Zhang, W.; Chen, R.; Shao, L. M.; Ding, S.; Hu, G. H.; Liu, Y. L.; Zhao, N.; Li, Y. L.; Gong, X. Z.; Gao, X.; Guo, H. Y.; Wang, L.; Xu, X. Q.; and others

    2014-12-15

    The dependence of divertor asymmetry and scrape-off layer (SOL) flow on heating power has been investigated in the Experimental Advanced Superconducting Tokamak (EAST). Divertor plasma exhibits an outboard-enhanced in-out asymmetry in heat flux in lower single null configuration for in reversed (ion ∇B drift direction toward the upper X-point) field directions. Upper single null exhibits an inboard-favored asymmetry in low heating power condition, while exhibits an outboard-favored asymmetry when increasing the heating power. Double null has the strongest in-out asymmetry in heat flux, favoring the outer divertor. The in-out asymmetry ratios of q{sub t,out}/q{sub t,in} and P{sub out}/P{sub total} increase with the power across the separatrix P{sub loss}, which is probably induced by the enhanced radial particle transport due to a large pressure gradient. The characteristics of the measured SOL parallel flow under various discharge conditions are consistent with the Pfirsch-Schlüter (PS) flow with the parallel Mach number M{sub ∥} decreasing with the line averaged density but increasing with P{sub loss}, in the same direction as the PS flow. The contributions of both poloidal E×B drift and parallel flow on poloidal particle transport in SOL on EAST are also assessed.

  6. Preliminary investigation of the effects of lower hybrid power on asymmetric behaviors in the scrape-off layer in experimental advanced superconducting tokamak

    SciTech Connect

    Zhang, L.; Ding, B. J. Li, M. H.; Liu, F. K.; Shan, J. F.; Wei, W.; Li, Y. C.; Yang, J. H.; Wu, Z. G.; Liu, L.; Wang, M.; Zhao, L. M.; Ma, W. D.; Xiu, H. D.; Wang, X. J.; Jia, H.; Yang, Y.; Cheng, M.; Wu, D. J.; Xu, L.; and others

    2014-02-15

    The striations in front of the lower hybrid (LH) launcher have been observed during LH injection by a visible video camera in the Experimental Advanced Superconducting Tokamak. Edge density at the top of the LH launcher tends to be much larger in reversed magnetic field (B{sub t}) than that in the normal B{sub t}. To study the mechanisms of the observations, the diffusive-convective model is employed. Simulations show that the LH power makes the density in scrape-off layer asymmetric in poloidal direction with five density peaks. The locations of the striations are approximately in agreement with the locations of the density peaks in different directions of B{sub t}. Higher LH power strengths the asymmetry of the density and leads to a bad coupling which is in conflict with the experimental results showing a good coupling with a higher power. Furthermore, an ionization term is introduced into this model and the increase of edge density with LH power can be qualitatively explained. The simulations also show that the density peaks in front of the waveguides become clearer when taking into account gas puffing.

  7. Preliminary R&D on flat-type W/Cu plasma-facing materials and components for Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Xie, C. Y.; Qin, S. G.; Song, J. P.; Li, Q.; Zhao, S. X.; Liu, G. H.; Wang, T. J.; Yu, Y.; Luo, G.-N.

    2014-04-01

    To upgrade the Experimental Advanced Superconducting Tokamak dome and first-wall, flat-type W/Cu plasma-facing components will be installed in the coming years in order to exhaust the increasing heat flux. Mock-ups with an interlayer of oxygen-free Cu (OFC) made by vacuum hot pressing have been developed and the bonding strength was found to be over 100 MPa. The behavior of the mock-ups under steady-state high heat flux loads has been studied. No crack or exfoliation occurred on the W surface and W/OFC/CuCrZr interfaces after screening tests with heat fluxes of 2.24-7.73 MW m-2. The mock-up survived up to 1000 cycles heat load of 3.24 MW m-2 with cooling water of 4 m s-1, 20 °C. However, cracks appeared in W around the gaps at about the 300th cycle under a heat load of 5.37 MW m-2. We have also studied the chemical vapor deposition W coated CuCrZr with an OFC interlayer. It has been found that: (i) the OFC interlayer plays a significant role in achieving coatings without any crack, (ii) the deposition rate was about 0.3-0.5 mm h-1 at 490-580 °C and (iii) a bonding strength of 53.7 MPa was achieved with laser surfi-sculpt.

  8. Advanced Silicon Solar Cell Device Physics and Design

    NASA Astrophysics Data System (ADS)

    Deceglie, Michael Gardner

    A fundamental challenge in the development and deployment of solar photovoltaic technology is a reduction in cost enabling direct competition with fossil-fuel-based energy sources. A key driver in this cost reduction is optimized device efficiency, because increased energy output leverages all photovoltaic system costs, from raw materials and module manufacturing to installation and maintenance. To continue progress toward higher conversion efficiencies, solar cells are being fabricated with increasingly complex designs, including engineered nanostructures, heterojunctions, and novel contacting and passivation schemes. Such advanced designs require a comprehensive and unified understanding of the optical and electrical device physics at the microscopic scale. This thesis focuses on a microscopic understanding of solar cell optoelectronic performance and its impact on cell optimization. We consider this in three solar cell platforms: thin-film crystalline silicon, amorphous/crystalline silicon heterojunctions, and thin-film cells with nanophotonic light trapping. The work described in this thesis represents a powerful design paradigm, based on a detailed physical understanding of the mechanisms governing solar cell performance. Furthermore, we demonstrate the importance of understanding not just the individual mechanisms, but also their interactions. Such an approach to device optimization is critical for the efficiency and competitiveness of future generations of solar cells.

  9. Local Physics Basis of Confinement Degradation in JET ELMy H-Mode Plasmas and Implications for Tokamak Reactors

    SciTech Connect

    R.V. Budny

    2000-11-15

    ELMy H-mode plasmas form the basis of conservative performance predictions for tokalmak reactors of the size of ITER. Relatively high performace for long durations has been achieved and the scaling is favorable. It will be necessary to sustain low Zeff and high density for high fusion yield. This paper studies the degradation in confinement and increase in the anomalous heat transport observed in two JET plasmas: one in which the degradation occurs with an intense gas puff, and the other with a spontaneous transition at the heating power threshold from Type I to III ELMs. Linear gryokinetic analysis gives the growth rate, glin of the fastest growing mode. Our results indicate that the flow-shearing rate wExB and glin are large near the top of the pedestal. Their ratio decreases approximately when the confinement degrades and the transport increases. This suggests that tokamak reactors may require intense toroidal or poloidal torque input to maintain sufficiently high *wExB*/glin near the top of the pedestal for high confinement.

  10. Advancing reservoir operation description in physically based hydrological models

    NASA Astrophysics Data System (ADS)

    Anghileri, Daniela; Giudici, Federico; Castelletti, Andrea; Burlando, Paolo

    2016-04-01

    Last decades have seen significant advances in our capacity of characterizing and reproducing hydrological processes within physically based models. Yet, when the human component is considered (e.g. reservoirs, water distribution systems), the associated decisions are generally modeled with very simplistic rules, which might underperform in reproducing the actual operators' behaviour on a daily or sub-daily basis. For example, reservoir operations are usually described by a target-level rule curve, which represents the level that the reservoir should track during normal operating conditions. The associated release decision is determined by the current state of the reservoir relative to the rule curve. This modeling approach can reasonably reproduce the seasonal water volume shift due to reservoir operation. Still, it cannot capture more complex decision making processes in response, e.g., to the fluctuations of energy prices and demands, the temporal unavailability of power plants or varying amount of snow accumulated in the basin. In this work, we link a physically explicit hydrological model with detailed hydropower behavioural models describing the decision making process by the dam operator. In particular, we consider two categories of behavioural models: explicit or rule-based behavioural models, where reservoir operating rules are empirically inferred from observational data, and implicit or optimization based behavioural models, where, following a normative economic approach, the decision maker is represented as a rational agent maximising a utility function. We compare these two alternate modelling approaches on the real-world water system of Lake Como catchment in the Italian Alps. The water system is characterized by the presence of 18 artificial hydropower reservoirs generating almost 13% of the Italian hydropower production. Results show to which extent the hydrological regime in the catchment is affected by different behavioural models and reservoir

  11. Recent advances in Rydberg physics using alkaline-earth atoms

    NASA Astrophysics Data System (ADS)

    Dunning, F. B.; Killian, T. C.; Yoshida, S.; Burgdörfer, J.

    2016-06-01

    In this brief review, the opportunities that the alkaline-earth elements offer for studying new aspects of Rydberg physics are discussed. For example, the bosonic alkaline-earth isotopes have zero nuclear spin which eliminates many of the complexities present in alkali Rydberg atoms, permitting simpler and more direct comparison between theory and experiment. The presence of two valence electrons allows the production of singlet and triplet Rydberg states that can exhibit a variety of attractive or repulsive interactions. The availability of weak intercombination lines is advantageous for laser cooling and for applications such as Rydberg dressing. Excitation of one electron to a Rydberg state leaves behind an optically active core ion allowing, for high-L states, the optical imaging of Rydberg atoms and their (spatial) manipulation using light scattering. The second valence electron offers the possibility of engineering long-lived doubly excited states such as planetary atoms. Recent advances in both theory and experiment are highlighted together with a number of possible directions for the future.

  12. Third Advances in Solar Physics Euroconference: Magnetic Fields and Oscillations

    NASA Astrophysics Data System (ADS)

    Schmieder, B.; Hofmann, A.; Staude, J.

    The third Advances in Solar Physics Euroconference (ASPE) "Magnetic Fields and Oscillations"concluded a series of three Euroconferences sponsored by the European Union. The meeting took place in Caputh near Potsdam, Germany, on September 22-25, 1998, followed by the JOSO (Joint Organization for Solar Observations) 30th Annual Board Meeting on September 26, 1998. The ASPE formula is attractive and compares well with other meetings with "show-and-tell" character. This meeting had 122 participants coming from 26 countries; 36 participants came from countries formerly behind the Iron Curtain; a "politically incorrect" estimate says that 48 participants were below 35 years of age, with an unusually large female-to-male ratio. This characteristic of youngness is the more striking since solar physics is a perhaps overly established field exhibiting an overly senior age profile. It was a good opportunity to train this young generation in Solar Physics. The conference topic "Magnetic Fields and Oscillations" obviously was wide enough to cater to many an interest. These proceedings are organized according to the structure of the meeting. They include the topics 'High resolution spectropolarimetry and magnetometry', 'Flux-tube dynamics', 'Modelling of the 3-D magnetic field structure', 'Mass motions and magnetic fields in sunspot penumbral structures', 'Sunspot oscillations', 'Oscillations in active regions - diagnostics and seismology', 'Network and intranetwork structure and dynamics', and 'Waves in magnetic structures'. These topics covered the first 2.5 days of the conference. The reviews, oral contributions, and poster presentations were by no means all of the meeting. The ASPE formula also adds extensive plenary sessions of JOSO Working groups on topics that involve planning of Europe-wide collaboration. At this meeting these concerned solar observing techniques, solar data bases, coordination between SOHO and ground-based observing, and preparations for August 11, 1999

  13. Advanced quantitative measurement methodology in physics education research

    NASA Astrophysics Data System (ADS)

    Wang, Jing

    The ultimate goal of physics education research (PER) is to develop a theoretical framework to understand and improve the learning process. In this journey of discovery, assessment serves as our headlamp and alpenstock. It sometimes detects signals in student mental structures, and sometimes presents the difference between expert understanding and novice understanding. Quantitative assessment is an important area in PER. Developing research-based effective assessment instruments and making meaningful inferences based on these instruments have always been important goals of the PER community. Quantitative studies are often conducted to provide bases for test development and result interpretation. Statistics are frequently used in quantitative studies. The selection of statistical methods and interpretation of the results obtained by these methods shall be connected to the education background. In this connecting process, the issues of educational models are often raised. Many widely used statistical methods do not make assumptions on the mental structure of subjects, nor do they provide explanations tailored to the educational audience. There are also other methods that consider the mental structure and are tailored to provide strong connections between statistics and education. These methods often involve model assumption and parameter estimation, and are complicated mathematically. The dissertation provides a practical view of some advanced quantitative assessment methods. The common feature of these methods is that they all make educational/psychological model assumptions beyond the minimum mathematical model. The purpose of the study is to provide a comparison between these advanced methods and the pure mathematical methods. The comparison is based on the performance of the two types of methods under physics education settings. In particular, the comparison uses both physics content assessments and scientific ability assessments. The dissertation includes three

  14. UCLA program in reactor studies: The ARIES tokamak reactor study

    SciTech Connect

    Not Available

    1991-01-01

    The ARIES research program is a multi-institutional effort to develop several visions of tokamak reactors with enhanced economic, safety, and environmental features. The aims are to determine the potential economics, safety, and environmental features of a range of possible tokamak reactors, and to identify physics and technology areas with the highest leverage for achieving the best tokamak reactor. Four ARIES visions are currently planned for the ARIES program. The ARIES-1 design is a DT-burning reactor based on modest'' extrapolations from the present tokamak physics database and relies on either existing technology or technology for which trends are already in place, often in programs outside fusion. ARIES-2 and ARIES-4 are DT-burning reactors which will employ potential advances in physics. The ARIES-2 and ARIES-4 designs employ the same plasma core but have two distinct fusion power core designs; ARIES-2 utilize the lithium as the coolant and breeder and vanadium alloys as the structural material while ARIES-4 utilizes helium is the coolant, solid tritium breeders, and SiC composite as the structural material. Lastly, the ARIES-3 is a conceptual D-{sup 3}He reactor. During the period Dec. 1, 1990 to Nov. 31, 1991, most of the ARIES activity has been directed toward completing the technical work for the ARIES-3 design and documenting the results and findings. We have also completed the documentation for the ARIES-1 design and presented the results in various meetings and conferences. During the last quarter, we have initiated the scoping phase for ARIES-2 and ARIES-4 designs.

  15. Tokamak and RFP ignition requirements

    SciTech Connect

    Werley, K.A.

    1991-01-01

    A plasma model is applied to calculate numerically transport- confinement (n{tau}{sub E}) requirements and steady-state operation tokamak. The CIT tokamak and RFP ignition conditions are examined. Physics differences between RFP and tokamaks, and their consequences for a DT ignition machine, are discussed. The ignition RFP, compared to a tokamak, has many physics advantages, including ohmic heating to ignition (no need for auxiliary heating systems), higher beta, low ignition current, less sensitivity of ignition requirements to impurity effects, no hard disruptions (associated with beta or density limits), and successful operation with high radiation fractions (f{sub RAD} {approximately} 0.95). These physics advantages, coupled with important engineering advantages associated with lower external magnetic fields, larger aspect ratios, and smaller plasma cross sections translate into significant cost reductions for both ignition and power reactor. The primary drawback of the RFP is the uncertainty that the present confinement scaling will extrapolate to reactor regimes. The 4-MA ZTH was expected to extend the n{tau}{sub E} transport scaling data three order of magnitude above ZT-40M results, and if the present scaling held, to achieve a DT-equivalent scientific energy breakeven, Q=1. A basecase RFP ignition point is identified with a plasma current of 8.1 MA and no auxiliary heating. 16 refs., 4 figs., 1 tab.

  16. TIMSS Advanced 2015 and Advanced Placement Calculus & Physics. A Framework Analysis. Research in Review 2016-1

    ERIC Educational Resources Information Center

    Lazzaro, Christopher; Jones, Lee; Webb, David C.; Grover, Ryan; Di Giacomo, F. Tony; Marino, Katherine Adele

    2016-01-01

    This report will determine to what degree the AP Physics 1 and 2 and AP Calculus AB and BC frameworks are aligned with the Trends in International Mathematics and Science Study (TIMSS) Advanced Physics and Mathematics frameworks. This will enable an exploration of any differences in content coverage and levels of complexity, and will set the stage…

  17. Observation of Molybdenum Emission from Impurity-Induced Long-Lived m = 1 Mode on the Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Yong-Cai, Shen; Bo, Lyu; Fu-Di, Wang; Yue-Jiang, Shi; Bin, Wu; Ying-Ying, Li; Jia, Fu; Bao-Nian, Wan; EAST Team

    2016-06-01

    Not Available Supported by the National Magnetic Confinement Fusion Science Program of China under Grant Nos 2013GB112004 and 2015GB103002, the Natural Science Research Key Project of Education Department of Anhui Province under Grant No KJ2016A434, the Doctoral Scientific Research Foundation of Anqing Normal University under Grant No 044-140001000024, the National Natural Science Foundation of China under Grant Nos 11275231, 11305212, 11405212 and 11261140328, the Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology under Grant No 2014FXCX003, and the Hefei Science Center CAS Users with Potential Project under Grant No 2015HSC-UP007.

  18. Prospects for pilot plants based on the tokamak, spherical tokamak and stellarator.

    SciTech Connect

    Menard, J. E.; Bromberg, L.; Brown, T.; Burgess, Thomas W; Dix, D.; El-GuebalyUniv. Wisco, L.; Gerrity, T.; Goldston, R. J.; Hawryluk, R.; Kastner, R.; Kessel, C.; Malang, S.; Minervini, J.; Neilson, G. H.; Neumeyer, C. L.; Prager, S.; Sawan, M.; Sheffield, J.; Sternlieb, A.; Waganer, L.; Whyte, D. G.; Zarnstorff, M. C.

    2011-01-01

    A potentially attractive next-step towards fusion commercialization is a pilot plant, i.e. a device ultimately capable of small net electricity production in as compact a facility as possible and in a configuration scalable to a full-size power plant. A key capability for a pilot-plant programme is the production of high neutron fluence enabling fusion nuclear science and technology (FNST) research. It is found that for physics and technology assumptions between those assumed for ITER and nth-of-a-kind fusion power plant, it is possible to provide FNST-relevant neutron wall loading in pilot devices. Thus, it may be possible to utilize a single facility to perform FNST research utilizing reactor-relevant plasma, blanket, coil and auxiliary systems and maintenance schemes while also targeting net electricity production. In this paper three configurations for a pilot plant are considered: the advanced tokamak, spherical tokamak and compact stellarator. A range of configuration issues is considered including: radial build and blanket design, magnet systems, maintenance schemes, tritium consumption and self-sufficiency, physics scenarios and a brief assessment of research needs for the configurations.

  19. Prospects for pilot plants based on the tokamak, spherical tokamak and stellarator

    NASA Astrophysics Data System (ADS)

    Menard, J. E.; Bromberg, L.; Brown, T.; Burgess, T.; Dix, D.; El-Guebaly, L.; Gerrity, T.; Goldston, R. J.; Hawryluk, R. J.; Kastner, R.; Kessel, C.; Malang, S.; Minervini, J.; Neilson, G. H.; Neumeyer, C. L.; Prager, S.; Sawan, M.; Sheffield, J.; Sternlieb, A.; Waganer, L.; Whyte, D.; Zarnstorff, M.

    2011-10-01

    A potentially attractive next-step towards fusion commercialization is a pilot plant, i.e. a device ultimately capable of small net electricity production in as compact a facility as possible and in a configuration scalable to a full-size power plant. A key capability for a pilot-plant programme is the production of high neutron fluence enabling fusion nuclear science and technology (FNST) research. It is found that for physics and technology assumptions between those assumed for ITER and nth-of-a-kind fusion power plant, it is possible to provide FNST-relevant neutron wall loading in pilot devices. Thus, it may be possible to utilize a single facility to perform FNST research utilizing reactor-relevant plasma, blanket, coil and auxiliary systems and maintenance schemes while also targeting net electricity production. In this paper three configurations for a pilot plant are considered: the advanced tokamak, spherical tokamak and compact stellarator. A range of configuration issues is considered including: radial build and blanket design, magnet systems, maintenance schemes, tritium consumption and self-sufficiency, physics scenarios and a brief assessment of research needs for the configurations.

  20. CURRICULUM GUIDES IN PHYSICS--GENERAL ADVANCED PLACEMENT, COLLEGE LEVEL.

    ERIC Educational Resources Information Center

    WESNER, GORDON E.

    THE GENERAL PHYSICS CURRICULUM IS PLANNED FOR THOSE WHOSE GENERAL ABILITY IS BETTER THAN AVERAGE AND IS OFFERED IN GRADES 11 OR 12. GENERAL OBJECTIVES ARE, TO DEVELOP CRITICAL THINKING THROUGH THE SCIENTIFIC METHOD, TO UNDERSTAND BASIC PHYSICAL LAWS AND MAN'S PLACE IN THE UNIVERSE, AND TO DEVELOP A SCIENTIFIC ABILITY AND INTEREST. ELEVEN UNITS OF…

  1. Tokamak Systems Code

    SciTech Connect

    Reid, R.L.; Barrett, R.J.; Brown, T.G.; Gorker, G.E.; Hooper, R.J.; Kalsi, S.S.; Metzler, D.H.; Peng, Y.K.M.; Roth, K.E.; Spampinato, P.T.

    1985-03-01

    The FEDC Tokamak Systems Code calculates tokamak performance, cost, and configuration as a function of plasma engineering parameters. This version of the code models experimental tokamaks. It does not currently consider tokamak configurations that generate electrical power or incorporate breeding blankets. The code has a modular (or subroutine) structure to allow independent modeling for each major tokamak component or system. A primary benefit of modularization is that a component module may be updated without disturbing the remainder of the systems code as long as the imput to or output from the module remains unchanged.

  2. Key Enabling Physical Layer Technologies for LTE-Advanced

    NASA Astrophysics Data System (ADS)

    Jiang, Meilong; Prasad, Narayan; Xin, Yan; Yue, Guosen; Khojastepour, Amir; Liu, Le; Inoue, Takamichi; Koyanagi, Kenji; Kakura, Yoshikazu

    The 3GPP Long Term Evolution Advanced (LTE-A) system, as compared to the LTE system, is anticipated to include several new features and enhancements, such as the usage of channel bandwidth beyond 20MHz (up 100MHz), higher order multiple input multiple output (MIMO) for both downlink and uplink transmissions, larger capacity especially for cell edge user equipment, and voice over IP (VoIP) users, and wider coverage and etc. This paper presents some key enabling technologies including flexible uplink access schemes, advanced uplink MIMO receiver designs, cell search, adaptive hybrid ARQ, and multi-resolution MIMO precoding, for the LTE-A system.

  3. Physics design of a 100 keV acceleration grid system for the diagnostic neutral beam for international tokamak experimental reactor

    SciTech Connect

    Singh, M. J.; De Esch, H. P. L.

    2010-01-15

    This paper describes the physics design of a 100 keV, 60 A H{sup -} accelerator for the diagnostic neutral beam (DNB) for international tokamak experimental reactor (ITER). The accelerator is a three grid system comprising of 1280 apertures, grouped in 16 groups with 80 apertures per beam group. Several computer codes have been used to optimize the design which follows the same philosophy as the ITER Design Description Document (DDD) 5.3 and the 1 MeV heating and current drive beam line [R. Hemsworth, H. Decamps, J. Graceffa, B. Schunke, M. Tanaka, M. Dremel, A. Tanga, H. P. L. De Esch, F. Geli, J. Milnes, T. Inoue, D. Marcuzzi, P. Sonato, and P. Zaccaria, Nucl. Fusion 49, 045006 (2009)]. The aperture shapes, intergrid distances, and the extractor voltage have been optimized to minimize the beamlet divergence. To suppress the acceleration of coextracted electrons, permanent magnets have been incorporated in the extraction grid, downstream of the cooling water channels. The electron power loads on the extractor and the grounded grids have been calculated assuming 1 coextracted electron per ion. The beamlet divergence is calculated to be 4 mrad. At present the design for the filter field of the RF based ion sources for ITER is not fixed, therefore a few configurations of the same have been considered. Their effect on the transmission of the electrons and beams through the accelerator has been studied. The OPERA-3D code has been used to estimate the aperture offset steering constant of the grounded grid and the extraction grid, the space charge interaction between the beamlets and the kerb design required to compensate for this interaction. All beamlets in the DNB must be focused to a single point in the duct, 20.665 m from the grounded grid, and the required geometrical aimings and aperture offsets have been calculated.

  4. Physics design of a 100 keV acceleration grid system for the diagnostic neutral beam for international tokamak experimental reactor.

    PubMed

    Singh, M J; De Esch, H P L

    2010-01-01

    This paper describes the physics design of a 100 keV, 60 A H(-) accelerator for the diagnostic neutral beam (DNB) for international tokamak experimental reactor (ITER). The accelerator is a three grid system comprising of 1280 apertures, grouped in 16 groups with 80 apertures per beam group. Several computer codes have been used to optimize the design which follows the same philosophy as the ITER Design Description Document (DDD) 5.3 and the 1 MeV heating and current drive beam line [R. Hemsworth, H. Decamps, J. Graceffa, B. Schunke, M. Tanaka, M. Dremel, A. Tanga, H. P. L. De Esch, F. Geli, J. Milnes, T. Inoue, D. Marcuzzi, P. Sonato, and P. Zaccaria, Nucl. Fusion 49, 045006 (2009)]. The aperture shapes, intergrid distances, and the extractor voltage have been optimized to minimize the beamlet divergence. To suppress the acceleration of coextracted electrons, permanent magnets have been incorporated in the extraction grid, downstream of the cooling water channels. The electron power loads on the extractor and the grounded grids have been calculated assuming 1 coextracted electron per ion. The beamlet divergence is calculated to be 4 mrad. At present the design for the filter field of the RF based ion sources for ITER is not fixed, therefore a few configurations of the same have been considered. Their effect on the transmission of the electrons and beams through the accelerator has been studied. The OPERA-3D code has been used to estimate the aperture offset steering constant of the grounded grid and the extraction grid, the space charge interaction between the beamlets and the kerb design required to compensate for this interaction. All beamlets in the DNB must be focused to a single point in the duct, 20.665 m from the grounded grid, and the required geometrical aimings and aperture offsets have been calculated. PMID:20113091

  5. Advances in the physics basis for the European DEMO design

    NASA Astrophysics Data System (ADS)

    Wenninger, R.; Arbeiter, F.; Aubert, J.; Aho-Mantila, L.; Albanese, R.; Ambrosino, R.; Angioni, C.; Artaud, J.-F.; Bernert, M.; Fable, E.; Fasoli, A.; Federici, G.; Garcia, J.; Giruzzi, G.; Jenko, F.; Maget, P.; Mattei, M.; Maviglia, F.; Poli, E.; Ramogida, G.; Reux, C.; Schneider, M.; Sieglin, B.; Villone, F.; Wischmeier, M.; Zohm, H.

    2015-06-01

    In the European fusion roadmap, ITER is followed by a demonstration fusion power reactor (DEMO), for which a conceptual design is under development. This paper reports the first results of a coherent effort to develop the relevant physics knowledge for that (DEMO Physics Basis), carried out by European experts. The program currently includes investigations in the areas of scenario modeling, transport, MHD, heating & current drive, fast particles, plasma wall interaction and disruptions.

  6. Amphiphile nanoarchitectonics: from basic physical chemistry to advanced applications

    SciTech Connect

    Ramanathan, Nathan Muruganathan; Shrestha, Lok Kumar; Mori, Taizo; Ji, Dr. Qingmin; Hill, Dr. Jonathan P; Ariga, Katsuhiko

    2013-01-01

    Amphiphiles, either synthetic or natural, are structurally simple molecules with the unprecedented capacity to self-assemble into complex, hierarchical geometries in nanospace. Effective self-assembly processes of amphiphiles are often used to mimic biological systems, such as, assembly of lipids and proteins, which has paved a way for bottom-up nanotechnology with bio-like advanced functions. Recent developments on nanostructure formation combine simple processes of assembly with the more advanced concept of nanoarchitectonics. In this pespective, we summarize research on self-assembly of amphiphilic molecules such as lipids, surfactants or block copolymers that are a focus of interest for many colloid, polymer, and materials scientists and which have become increasingly important in emerging nanotechnology. Because the fundamental science of amphiphiles was initially developed for their solution assembly then transferred to assemblies on surfaces as a development of nanotechnological technique, this perspective attempts to mirro this development by introducing solution systems and progressing to interfacial systems, which are roughly categorized as (i) basic properties of amphiphiles, (ii) self-assembly of amphiphiles in bulk phases, (iii) assembly on static surfaces, (iv) assembly at dynamic interfaces, and (v) advanced topics from simulation to application. This progression also represents the evolution of amphiphile science and technology from simple assemblies to advanced assemblies to nanoarchitectonics.

  7. Amphiphile nanoarchitectonics: from basic physical chemistry to advanced applications.

    PubMed

    Ramanathan, Muruganathan; Shrestha, Lok Kumar; Mori, Taizo; Ji, Qingmin; Hill, Jonathan P; Ariga, Katsuhiko

    2013-07-14

    Amphiphiles, either synthetic or natural, are structurally simple molecules with the unprecedented capacity to self-assemble into complex, hierarchical geometries in nanospace. Effective self-assembly processes of amphiphiles are often used to mimic biological systems, such as assembly of lipids and proteins, which has paved a way for bottom-up nanotechnology with bio-like advanced functions. Recent developments in nanostructure formation combine simple processes of assembly with the more advanced concept of nanoarchitectonics. In this perspective, we summarize research on self-assembly of amphiphilic molecules such as lipids, surfactants or block copolymers that are a focus of interest for many colloid, polymer, and materials scientists and which have become increasingly important in emerging nanotechnology and practical applications, latter of which are often accomplished by amphiphile-like polymers. Because the fundamental science of amphiphiles was initially developed for their solution assembly then transferred to assemblies on surfaces as a development of nanotechnological techniques, this perspective attempts to mirror this development by introducing solution systems and progressing to interfacial systems, which are roughly categorized as (i) basic properties of amphiphiles, (ii) self-assembly of amphiphiles in bulk phases, (iii) assembly on static surfaces, (iv) assembly at dynamic interfaces, and (v) advanced topics from simulation to application. This progression also represents the evolution of amphiphile science and technology from simple assemblies to advanced assemblies to nanoarchitectonics. PMID:23639971

  8. Engineering design and analysis of advanced physical fine coal cleaning technologies

    SciTech Connect

    Not Available

    1992-01-20

    This project is sponsored by the United States Department of Energy (DOE) for the Engineering Design and Analysis of Advanced Physical Fine Coal Cleaning Technologies. The major goal is to provide the simulation tools for modeling both conventional and advanced coal cleaning technologies. This DOE project is part of a major research initiative by the Pittsburgh Energy Technology Center (PETC) aimed at advancing three advanced coal cleaning technologies-heavy-liquid cylconing, selective agglomeration, and advanced froth flotation through the proof-of-concept (POC) level.

  9. Working with Advanced Primary School Students in Physics

    NASA Astrophysics Data System (ADS)

    Jankovic, Ljiljana; Cucic, Dragoljub

    2010-01-01

    Working with students who have special needs is the type of work that requires special engagement and skills of those who perform it. Working with gifted children requires outstanding knowledge of a teacher and above all the teachers should be very well informed on the subject they teach, Physics in our case. This work also requires great pedagogical and psychological skills so that these talented students would be approached in a suitable way. In this paper we will present to you our methods of teaching Physics to these talented children (13 years old), in the Regional Center for Talents "Mihajlo Pupin" in Pancevo.

  10. Burn Control Mechanisms in Tokamaks

    NASA Astrophysics Data System (ADS)

    Hill, Maxwell; Stacey, Weston

    2013-10-01

    Burn control and passive safety in accident scenarios will be an important design consideration in future tokamaks, especially those used as a neutron source for fusion-fission hybrid reactors, such as the Subcritical Advanced Burner Reactor (SABR) concept. At Georgia Tech, we are developing a new burning plasma dynamics code to investigate passive safety mechanisms that could prevent power excursions in tokamak reactors. This code solves the coupled set of balance equations governing burning plasmas in conjunction with a two-point SOL-divertor model. Predictions have been benchmarked against data from DIII-D. We are examining several potential negative feedback mechanisms to limit power excursions: i) ion-orbit loss, ii) thermal instabilities, iii) the degradation of alpha-particle confinement resulting from ripples in the toroidal field, iv) modifications to the radial current profile, v) ``divertor choking'' and vi) Type 1 ELMs.

  11. Using Tiered Assignments to Engage Learners in Advanced Placement Physics

    ERIC Educational Resources Information Center

    Geddes, Kimberly A.

    2010-01-01

    This article presents lesson plans that incorporate tiered objectives and brainstorming techniques as means for differentiating instruction and ensuring that learners are challenged at levels commensurate with their abilities even though they are developing an understanding of the same physics concepts. A listing of materials and resources…

  12. Advanced Ground Systems Maintenance Physics Models for Diagnostics Project

    NASA Technical Reports Server (NTRS)

    Harp, Janicce Leshay

    2014-01-01

    The project will use high-fidelity physics models and simulations to simulate real-time operations of cryogenic and systems and calculate the status/health of the systems. The project enables the delivery of system health advisories to ground system operators. The capability will also be used to conduct planning and analysis of cryogenic system operations.

  13. The Consortium for the Advancement of Physics Education

    ERIC Educational Resources Information Center

    Spangler, John D.; Hathaway, C. E.

    1971-01-01

    Describes programs that have been initiated between Kansas State University and six non-Ph.D. granting institutions. Special attention is given to an undergraduate program on low-energy accelerator physics, student symposia, seminar research grants and assistantships, and faculty fellowships and symposia. (DS)

  14. Advanced Quantitative Measurement Methodology in Physics Education Research

    ERIC Educational Resources Information Center

    Wang, Jing

    2009-01-01

    The ultimate goal of physics education research (PER) is to develop a theoretical framework to understand and improve the learning process. In this journey of discovery, assessment serves as our headlamp and alpenstock. It sometimes detects signals in student mental structures, and sometimes presents the difference between expert understanding and…

  15. A Model for Improving "Advanced" Courses in Physics

    ERIC Educational Resources Information Center

    Friedman, Charles P.

    1972-01-01

    Individualized instruction similar to the Keller plan with two additional features: (1) student freedom in selecting his own procedure for mastering the course material; (2) some variety in topics studied by each student. Describes two successful trials of this plan in an atomic physics course at MIT. (Author/DF)

  16. Recent progress on the Compact Ignition Tokamak (CIT)

    SciTech Connect

    Ignat, D.W.

    1987-01-01

    This report describes work done on the Compact Ignition Tokamak (CIT), both at the Princeton Plasma Physics Laboratory (PPPL) and at other fusion laboratories in the United States. The goal of CIT is to reach ignition in a tokamak fusion device in the mid-1990's. Scientific and engineering features of the design are described, as well as projected cost and schedule.

  17. Project T.E.A.M. (Technical Education Advancement Modules). Introduction to Industrial Physics.

    ERIC Educational Resources Information Center

    Whisenhunt, James E.

    This instructional guide, one of a series developed by the Technical Education Advancement Modules (TEAM) project, is a 20-hour introduction to industrial physics that explains and demonstrates to industrial maintenance mechanics the direct relationship of physics to machinery. Project TEAM is intended to upgrade basic technical competencies of…

  18. Advanced reactor physics methods for heterogeneous reactor cores

    NASA Astrophysics Data System (ADS)

    Thompson, Steven A.

    To maintain the economic viability of nuclear power the industry has begun to emphasize maximizing the efficiency and output of existing nuclear power plants by using longer fuel cycles, stretch power uprates, shorter outage lengths, mixed-oxide (MOX) fuel and more aggressive operating strategies. In order to accommodate these changes, while still satisfying the peaking factor and power envelope requirements necessary to maintain safe operation, more complexity in commercial core designs have been implemented, such as an increase in the number of sub-batches and an increase in the use of both discrete and integral burnable poisons. A consequence of the increased complexity of core designs, as well as the use of MOX fuel, is an increase in the neutronic heterogeneity of the core. Such heterogeneous cores introduce challenges for the current methods that are used for reactor analysis. New methods must be developed to address these deficiencies while still maintaining the computational efficiency of existing reactor analysis methods. In this thesis, advanced core design methodologies are developed to be able to adequately analyze the highly heterogeneous core designs which are currently in use in commercial power reactors. These methodological improvements are being pursued with the goal of not sacrificing the computational efficiency which core designers require. More specifically, the PSU nodal code NEM is being updated to include an SP3 solution option, an advanced transverse leakage option, and a semi-analytical NEM solution option.

  19. Advances in beam physics and technology: Colliders of the future

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Swapan

    1996-02-01

    Beams may be viewed as directed and focussed flow of energy and information, carried by particles and electromagnetic radiation fields (i.e. photons). Often, they are brought into interaction with each other (e.g. in high energy colliders) or with other forms of matter (e.g. in fixed target physics, synchrotron radiation sciences, neutron scattering experiments, laser chemistry and physics, medical therapy, etc.). The whole art and science of beams revolve around the fundamental quest for, and ultimate implementation of, mechanisms of production, storage, control and observation of beams—always directed towards studies of the basic structures and processes of the natural world and various practical applications. Tremendous progress has been made in all aspects of beam physics and technology in the last decades—nonlinear dynamics, superconducting magnets and radio frequency cavities, beam instrumentation and control, novel concepts and collider paradigms, to name a few. We will illustrate this progress via a few examples and remark on the emergence of new collider scenarios where some of these progress might come to use—the Gamma-Gamma Collider, the Muon Collider, laser acceleration, etc. We will close with an outline of future opportunities and outlook.

  20. Climate Solutions based on advanced scientific discoveries of Allatra physics

    NASA Astrophysics Data System (ADS)

    Vershigora, Valery

    2016-05-01

    Global climate change is one of the most important international problems of the 21st century. The overall rapid increase in the dynamics of cataclysms, which have been observed in recent decades, is particularly alarming. Howdo modern scientists predict the occurrence of certain events? In meteorology, unusually powerful cumulonimbus clouds are one of the main conditions for the emergence of a tornado. The former, in their turn, are formed during the invasion of cold air on the overheated land surface. The satellite captures the cloud front, and, based on these pictures, scientists make assumptions about the possibility of occurrence of the respective natural phenomena. In fact, mankind visually observes and draws conclusions about the consequences of the physical phenomena which have already taken place in the invisible world, so the conclusions of scientists are assumptions by their nature, rather than precise knowledge of the causes of theorigin of these phenomena in the physics of microcosm. The latest research in the field of the particle physics and neutrino astrophysics, which was conducted by a working team of scientists of ALLATRA International Public Movement (hereinafter ALLATRA SCIENCE group) allatra-science.org, last accessed 10 April 2016.

  1. Advances in reactor physics education: Visualization of reactor parameters

    SciTech Connect

    Snoj, L.; Kromar, M.; Zerovnik, G.

    2012-07-01

    Modern computer codes allow detailed neutron transport calculations. In combination with advanced 3D visualization software capable of treating large amounts of data in real time they form a powerful tool that can be used as a convenient modern educational tool for reactor operators, nuclear engineers, students and specialists involved in reactor operation and design. Visualization is applicable not only in education and training, but also as a tool for fuel management, core analysis and irradiation planning. The paper treats the visualization of neutron transport in different moderators, neutron flux and power distributions in two nuclear reactors (TRIGA type research reactor and a typical PWR). The distributions are calculated with MCNP and CORD-2 computer codes and presented using Amira software. (authors)

  2. Density limit disruptions in tokamaks

    NASA Astrophysics Data System (ADS)

    Kleva, Robert G.; Drake, J. F.

    1991-02-01

    Magnetohydrodynamic simulations are presented which reproduce the rapid drop in the central temperature observed during density limit disruptions in tokamaks. The loss of central confinement is triggered by edge radiation which destabilizes a q=1 kink mode. A bubble of cold plasma is injected from the edge into the center by the q=1 kink. This bubble bears a striking resemblance to the cold plasma that is observed to move from the edge into the center during density limit disruptions on the JET tokamak [Plasma Physics and Controlled Nuclear Fusion Research 1986 (IAEA, Vienna, 1987), Vol. 1, p. 433], initiating the loss of central confinement. The bubble profile produced by the q=1 kink is unstable to a broad spectrum of modes which progressively reduce the magnetic shear between the q=2 surface and the center. The q=2 mode then grows across the center, broadening the current and throwing the hot plasma to the wall.

  3. Advances in beam physics and technology: Colliders of the future

    SciTech Connect

    Chattopadhyay, S.

    1994-11-01

    Beams may be viewed as directed and focussed flow of energy and information, carried by particles and electromagnetic radiation fields (ie, photons). Often, they interact with each other (eg, in high energy colliders) or with other forms of matter (eg, in fixed targets, sychrotron radiation, neutron scattering, laser chemistry/physics, medical therapy, etc.). The whole art and science of beams revolve around the fundamental quest for, and ultimate implementation of, mechanisms of production, storage, control and observation of beams -- always directed towards studies of the basic structures and processes of the natural world and various practical applications. Tremendous progress has been made in all aspects of beam physics and technology in the last decades -- nonlinear dynamics, superconducting magnets and rf cavities, beam instrumentation and control, novel concepts and collider praradigms, to name a few. We illustrate this progress with a few examples and remark on the emergence of new collider scenarios where some of these progress might come to use -- the Gamma-Gamma Collider, the Muon Collider, laser acceleration, etc. We close with an outline of future oppotunities and outlook.

  4. Tokamak Spectroscopy for X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Fournier, Kevin B.; Finkenthal, M.; Pacella, D.; May, M. J.; Soukhanovskii, V.; Mattioli, M.; Leigheb, M.; Rice, J. E.

    2000-01-01

    This paper presents the measured x-ray and Extreme Ultraviolet (XUV) spectra of three astrophysically abundant elements (Fe, Ca and Ne) from three different tokamak plasmas. In every case, each spectrum touches on an issue of atomic physics that is important for simulation codes to be used in the analysis of high spectral resolution data from current and future x-ray telescopes. The utility of the tokamak as a laboratory test bed for astrophysical data is demonstrated. Simple models generated with the HULLAC suite of codes demonstrate how the atomic physics issues studied can affect the interpretation of astrophysical data.

  5. The ARIES-III D- sup 3 He tokamak reactor: Design-point determination and parametric studies

    SciTech Connect

    Bathke, C.G.; Werley, K.A.; Miller, R.L.; Krakowski, R.A. ); Santarius, J.F. )

    1991-01-01

    The multi-institutional ARIES study has generated a conceptual design of another tokamak fusion reactor in a series that varies the assumed advances in technology and physics. The ARIES-3 design uses a D-{sup 3}He fuel cycle and requires advances in technology and physics for economical attractiveness. The optimal design was characterized through systems analyses for eventual conceptual engineering design. Results from the systems analysis are summarized, and a comparison with the high-field, D-T fueled ARIES-1 is included. 11 refs., 5 figs.

  6. Magnetic control of magnetohydrodynamic instabilities in tokamaks

    SciTech Connect

    Strait, E. J.

    2015-02-15

    Externally applied, non-axisymmetric magnetic fields form the basis of several relatively simple and direct methods to control magnetohydrodynamic (MHD) instabilities in a tokamak, and most present and planned tokamaks now include a set of non-axisymmetric control coils for application of fields with low toroidal mode numbers. Non-axisymmetric applied fields are routinely used to compensate small asymmetries (δB/B∼10{sup −3} to 10{sup −4}) of the nominally axisymmetric field, which otherwise can lead to instabilities through braking of plasma rotation and through direct stimulus of tearing modes or kink modes. This compensation may be feedback-controlled, based on the magnetic response of the plasma to the external fields. Non-axisymmetric fields are used for direct magnetic stabilization of the resistive wall mode—a kink instability with a growth rate slow enough that feedback control is practical. Saturated magnetic islands are also manipulated directly with non-axisymmetric fields, in order to unlock them from the wall and spin them to aid stabilization, or position them for suppression by localized current drive. Several recent scientific advances form the foundation of these developments in the control of instabilities. Most fundamental is the understanding that stable kink modes play a crucial role in the coupling of non-axisymmetric fields to the plasma, determining which field configurations couple most strongly, how the coupling depends on plasma conditions, and whether external asymmetries are amplified by the plasma. A major advance for the physics of high-beta plasmas (β = plasma pressure/magnetic field pressure) has been the understanding that drift-kinetic resonances can stabilize the resistive wall mode at pressures well above the ideal-MHD stability limit, but also that such discharges can be very sensitive to external asymmetries. The common physics of stable kink modes has brought significant unification to the topics of static error

  7. Magnetic control of magnetohydrodynamic instabilities in tokamaks

    NASA Astrophysics Data System (ADS)

    Strait, E. J.

    2015-02-01

    Externally applied, non-axisymmetric magnetic fields form the basis of several relatively simple and direct methods to control magnetohydrodynamic (MHD) instabilities in a tokamak, and most present and planned tokamaks now include a set of non-axisymmetric control coils for application of fields with low toroidal mode numbers. Non-axisymmetric applied fields are routinely used to compensate small asymmetries ( δB /B ˜10-3 to 10-4 ) of the nominally axisymmetric field, which otherwise can lead to instabilities through braking of plasma rotation and through direct stimulus of tearing modes or kink modes. This compensation may be feedback-controlled, based on the magnetic response of the plasma to the external fields. Non-axisymmetric fields are used for direct magnetic stabilization of the resistive wall mode—a kink instability with a growth rate slow enough that feedback control is practical. Saturated magnetic islands are also manipulated directly with non-axisymmetric fields, in order to unlock them from the wall and spin them to aid stabilization, or position them for suppression by localized current drive. Several recent scientific advances form the foundation of these developments in the control of instabilities. Most fundamental is the understanding that stable kink modes play a crucial role in the coupling of non-axisymmetric fields to the plasma, determining which field configurations couple most strongly, how the coupling depends on plasma conditions, and whether external asymmetries are amplified by the plasma. A major advance for the physics of high-beta plasmas ( β = plasma pressure/magnetic field pressure) has been the understanding that drift-kinetic resonances can stabilize the resistive wall mode at pressures well above the ideal-MHD stability limit, but also that such discharges can be very sensitive to external asymmetries. The common physics of stable kink modes has brought significant unification to the topics of static error fields at low

  8. Advanced physical fine coal cleaning spherical agglomeration. Final report

    SciTech Connect

    Not Available

    1990-09-01

    The project included process development, engineering, construction, and operation of a 1/3 tph proof-of-concept (POC) spherical agglomeration test module. The POC tests demonstrated that physical cleaning of ultrafine coal by agglomeration using heptane can achieve: (1) Pyritic sulfur reductions beyond that possible with conventional coal cleaning methods; (2) coal ash contents below those which can be obtained by conventional coal cleaning methods at comparable energy recoveries; (3) energy recoveries of 80 percent or greater measured against the raw coal energy content; (4) complete recovery of the heptane bridging liquid from the agglomerates; and (5) production of agglomerates with 3/8-inch size and less than 30 percent moisture. Test results met or exceeded all of the program objectives. Nominal 3/8-inch size agglomerates with less than 20 percent moisture were produced. The clean coal ash content varied between 1.5 to 5.5 percent by weight (dry basis) depending on feed coal type. Ash reductions of the run-of-mine (ROM) coal were 77 to 83 percent. ROM pyritic sulfur reductions varied from 86 to 90 percent for the three test coals, equating to total sulfur reductions of 47 to 72 percent.

  9. Princeton Plasma Physics Laboratory annual report, October 1, 1991--September 30, 1992

    SciTech Connect

    Not Available

    1992-12-31

    This report discusses the following topics: Principal parameters achieved in experimental devices for fiscal year 1992; tokamak fusion test reactor; princeton beta experiment-modification; current drive experiment-upgrade; tokamak physics experiment/steady-state advanced tokamak; international thermonuclear experimental reactor; international collaboration; x-ray laser studies; plasma processing: Deposition and etching of thin films; pure electron plasma experiments; theoretical studies; tokamak modeling; high-field magnet project; engineering department; environment, safety, and health and quality assurance; technology transfer; office of human resources and administration; PPPL invention disclosures for fiscal year 1992; office of resource management; graduate education: plasma physics; graduate education: program in plasma science and technology; and science education program.

  10. BOOK REVIEW: New Understanding Physics for Advanced Level

    NASA Astrophysics Data System (ADS)

    Breithaupt, Jim

    2000-09-01

    Breithaupt's new book is big: at 727 pages, it will be a hefty addition to any student's bag. According to the preface, the book is designed to help students achieve the transition from GCSE to A-level and to succeed well at this level. It also aims to cover the requirements of the compulsory parts of all new syllabuses and to cover most of the optional material, too. The book is organized into seven themes along traditional lines: mechanics, materials, fields, waves, electricity, inside the atom, and physics in medicine. Each theme begins with a colourful title page that outlines what the theme is about, lists the applications that students will meet in their reading, identifies prior learning from GCSE and gives a checklist of what students should be able to do once they have finished their reading of the theme. This is all very useful. The text of the book is illustrated with many colourful photographs, pictures and cartoons, but despite this it looks very dense. There are a lot of words on every page in a small font that makes them seem very unfriendly, and although the book claims to be readable I rather doubt that the layout will encourage voluntary reading of the text. Each chapter ends with a useful summary and a selection of short questions that allow students to test their understanding. Each theme has a set of multiple choice and long questions. Some of the questions have an icon referring the student to the accompanying CD (more of this later). There is much up-to-date material in the book. For example, the section on cosmology gives a brief description of the inflationary scenario within the Big Bang model of the origin of the universe, although no mechanism for the inflation is given, which might prove unsatisfying to some students. I do have some reservations about the presentation of some topics within the book: the discussion of relativistic mass, for example, states that `Einstein showed that the mass ... is given by the formula ...' and quotes

  11. Magnetic geometry and physics of advanced divertors: The X-divertor and the snowflake

    SciTech Connect

    Kotschenreuther, Mike; Valanju, Prashant; Covele, Brent; Mahajan, Swadesh

    2013-10-15

    Advanced divertors are magnetic geometries where a second X-point is added in the divertor region to address the serious challenges of burning plasma power exhaust. Invoking physical arguments, numerical work, and detailed model magnetic field analysis, we investigate the magnetic field structure of advanced divertors in the physically relevant region for power exhaust—the scrape-off layer. A primary result of our analysis is the emergence of a physical “metric,” the Divertor Index DI, which quantifies the flux expansion increase as one goes from the main X-point to the strike point. It clearly separates three geometries with distinct consequences for divertor physics—the Standard Divertor (DI = 1), and two advanced geometries—the X-Divertor (XD, DI > 1) and the Snowflake (DI < 1). The XD, therefore, cannot be classified as one variant of the Snowflake. By this measure, recent National Spherical Torus Experiment and DIIID experiments are X-Divertors, not Snowflakes.

  12. Advanced Experiments in Nuclear Science, Volume I: Advanced Nuclear Physics and Chemistry Experiments.

    ERIC Educational Resources Information Center

    Duggan, Jerome L.; And Others

    The experiments in this manual represent state-of-the-art techniques which should be within the budgetary constraints of a college physics or chemistry department. There are fourteen experiments divided into five modules. The modules are on X-ray fluorescence, charged particle detection, neutron activation analysis, X-ray attenuation, and…

  13. Electron cyclotron emission diagnostics on KSTAR tokamak.

    PubMed

    Jeong, S H; Lee, K D; Kogi, Y; Kawahata, K; Nagayama, Y; Mase, A; Kwon, M

    2010-10-01

    A new electron cyclotron emission (ECE) diagnostics system was installed for the Second Korea Superconducting Tokamak Advanced Research (KSTAR) campaign. The new ECE system consists of an ECE collecting optics system, an overmode circular corrugated waveguide system, and 48 channel heterodyne radiometer with the frequency range of 110-162 GHz. During the 2 T operation of the KSTAR tokamak, the electron temperatures as well as its radial profiles at the high field side were measured and sawtooth phenomena were also observed. We also discuss the effect of a window on in situ calibration. PMID:21033954

  14. Electron cyclotron emission diagnostics on KSTAR tokamak

    SciTech Connect

    Jeong, S. H.; Lee, K. D.; Kwon, M.; Kogi, Y.; Kawahata, K.; Nagayama, Y.; Mase, A.

    2010-10-15

    A new electron cyclotron emission (ECE) diagnostics system was installed for the Second Korea Superconducting Tokamak Advanced Research (KSTAR) campaign. The new ECE system consists of an ECE collecting optics system, an overmode circular corrugated waveguide system, and 48 channel heterodyne radiometer with the frequency range of 110-162 GHz. During the 2 T operation of the KSTAR tokamak, the electron temperatures as well as its radial profiles at the high field side were measured and sawtooth phenomena were also observed. We also discuss the effect of a window on in situ calibration.

  15. Recent advances in nuclear physics through on-line isotope separation

    NASA Astrophysics Data System (ADS)

    Jenkins, David Gareth

    2014-12-01

    Nuclear physics is advancing rapidly at the precision frontier, where measurements of nuclear observables are challenging state-of-the-art nuclear models. A major contribution is associated with the increasing availability of accelerated beams of radioactive ions produced using the isotope separation on-line technique. These advances have come hand in hand with significant progress in the development of high-efficiency detector systems and improved target technologies which are invaluable in exploiting these beams to their full advantage. This article reviews some of the recent highlights in the field of nuclear structure profiting from these technological advances.

  16. Proceedings of the 1992 topical meeting on advances in reactor physics. Volume 2

    SciTech Connect

    Not Available

    1992-04-01

    This document, Volume 2, presents proceedings of the 1992 Topical Meeting on Advances in Reactor Physics on March 8--11, 1992 at Charleston, SC. Session topics were as follows: Transport Theory; Fast Reactors; Plant Analyzers; Integral Experiments/Measurements & Analysis; Core Computational Systems; Reactor Physics; Monte Carlo; Safety Aspects of Heavy Water Reactors; and Space-Time Core Kinetics. The individual reports have been cataloged separately. (FI)

  17. Probing the scale of new physics by Advanced LIGO/VIRGO

    NASA Astrophysics Data System (ADS)

    Dev, P. S. Bhupal; Mazumdar, A.

    2016-05-01

    We show that if the new physics beyond the standard model is associated with a first-order phase transition around 107- 108 GeV , the energy density stored in the resulting stochastic gravitational waves and the corresponding peak frequency are within the projected final sensitivity of the advanced LIGO/VIRGO detectors. We discuss some possible new physics scenarios that could arise at such energies, and in particular, the consequences for Peccei-Quinn and supersymmetry breaking scales.

  18. Multi-physics nuclear reactor simulator for advanced nuclear engineering education

    SciTech Connect

    Yamamoto, A.

    2012-07-01

    Multi-physics nuclear reactor simulator, which aims to utilize for advanced nuclear engineering education, is being introduced to Nagoya Univ.. The simulator consists of the 'macroscopic' physics simulator and the 'microscopic' physics simulator. The former performs real time simulation of a whole nuclear power plant. The latter is responsible to more detail numerical simulations based on the sophisticated and precise numerical models, while taking into account the plant conditions obtained in the macroscopic physics simulator. Steady-state and kinetics core analyses, fuel mechanical analysis, fluid dynamics analysis, and sub-channel analysis can be carried out in the microscopic physics simulator. Simulation calculations are carried out through dedicated graphical user interface and the simulation results, i.e., spatial and temporal behaviors of major plant parameters are graphically shown. The simulator will provide a bridge between the 'theories' studied with textbooks and the 'physical behaviors' of actual nuclear power plants. (authors)

  19. Banana drift transport in tokamaks with ripple

    SciTech Connect

    Linsker, R.; Boozer, A.H.

    1982-01-01

    Ripple transport in tokamaks is discussed for the ''banana drift'' collisionality regime, which lies below the ripple plateau regime treated earlier. The physical mechanisms that dominate banana drift transport are found to differ from those considered in previous work on this regime, and consequently the resulting transport coefficients can differ by several orders of magnitude.

  20. Banana drift transport in tokamaks with ripple

    SciTech Connect

    Linsker, R.; Boozer, A.H.

    1981-04-01

    Ripple transport in tokamaks is discussed for the banana drift collisionality regime, which lies below the ripple plateau regime treated earlier. The physical mechanisms that dominate banana drift transport are found to differ from those considered in previous work on this regime, and the resulting transport coefficients can consequently differ by several orders of magnitude.

  1. Short Animation Movies as Advance Organizers in Physics Teaching: A Preliminary Study

    ERIC Educational Resources Information Center

    Koscianski, Andre; Ribeiro, Rafael Joao; da Silva, Sani Carvalho Rutz

    2012-01-01

    Background: Advance organizers are instructional materials that help students use previous knowledge to make links with new information. Short animation movies are a possible format and are well suited for physics, as they can portray dynamic phenomena and represent abstract concepts. Purpose: The study aimed to determine guidelines for the…

  2. Physical Features of Soil: Advanced Crop and Soil Science. A Course of Study.

    ERIC Educational Resources Information Center

    Miller, Larry E.

    The course of study represents the second of six modules in advanced crop and soil science and introduces the agriculture student to the subject of physical features of the soil. Upon completing the two day lesson, the student will be able to determine the texture and structural types of soil, list the structural classes of the soil and where they…

  3. Identifying correlates and determinants of physical activity in youth: How can we advance the field?

    PubMed

    Atkin, Andrew J; van Sluijs, Esther M F; Dollman, James; Taylor, Wendell C; Stanley, Rebecca M

    2016-06-01

    This commentary provides a critical discussion of current research investigating the correlates and determinants of physical activity in young people, with specific focus on conceptual, theoretical and methodological issues. We draw on current child and adolescent literature and our own collective expertise to illustrate our discussion. We conclude with recommendations that will strengthen future research and help to advance the field. PMID:26940254

  4. Building an advanced climate model: Program plan for the CHAMMP (Computer Hardware, Advanced Mathematics, and Model Physics) Climate Modeling Program

    SciTech Connect

    Not Available

    1990-12-01

    The issue of global warming and related climatic changes from increasing concentrations of greenhouse gases in the atmosphere has received prominent attention during the past few years. The Computer Hardware, Advanced Mathematics, and Model Physics (CHAMMP) Climate Modeling Program is designed to contribute directly to this rapid improvement. The goal of the CHAMMP Climate Modeling Program is to develop, verify, and apply a new generation of climate models within a coordinated framework that incorporates the best available scientific and numerical approaches to represent physical, biogeochemical, and ecological processes, that fully utilizes the hardware and software capabilities of new computer architectures, that probes the limits of climate predictability, and finally that can be used to address the challenging problem of understanding the greenhouse climate issue through the ability of the models to simulate time-dependent climatic changes over extended times and with regional resolution.

  5. Breakdown in the pretext tokamak

    SciTech Connect

    Benesch, J.F.

    1981-06-01

    Data are presented on the application of ion cyclotron resonance RF power to preionization in tokamaks. We applied 0.3-3 kW at 12 MHz to hydrogen and obtained a visible discharge, but found no scaling of breakdown voltage with any parameter we were able to vary. A possible explanation for this, which implies that higher RF power would have been much more effective, is discussed. Finally, we present our investigation of the dV/dt dependence of breakdown voltage in PRETEXT, a phenomenon also seen in JFT-2. The breakdown is discussed in terms of the physics of Townsend discharges.

  6. Bifurcated helical core equilibrium states in tokamaks

    NASA Astrophysics Data System (ADS)

    Cooper, W. A.; Chapman, I. T.; Schmitz, O.; Turnbull, A. D.; Tobias, B. J.; Lazarus, E. A.; Turco, F.; Lanctot, M. J.; Evans, T. E.; Graves, J. P.; Brunetti, D.; Pfefferlé, D.; Reimerdes, H.; Sauter, O.; Halpern, F. D.; Tran, T. M.; Coda, S.; Duval, B. P.; Labit, B.; Pochelon, A.; Turnyanskiy, M. R.; Lao, L.; Luce, T. C.; Buttery, R.; Ferron, J. R.; Hollmann, E. M.; Petty, C. C.; van Zeeland, M.; Fenstermacher, M. E.; Hanson, J. M.; Lütjens, H.

    2013-07-01

    Tokamaks with weak to moderate reversed central shear in which the minimum inverse rotational transform (safety factor) qmin is in the neighbourhood of unity can trigger bifurcated magnetohydrodynamic equilibrium states, one of which is similar to a saturated ideal internal kink mode. Peaked prescribed pressure profiles reproduce the ‘snake’ structures observed in many tokamaks which has led to a novel explanation of the snake as a bifurcated equilibrium state. Snake equilibrium structures are computed in simulations of the tokamak à configuration variable (TCV), DIII-D and mega amp spherical torus (MAST) tokamaks. The internal helical deformations only weakly modulate the plasma-vacuum interface which is more sensitive to ripple and resonant magnetic perturbations. On the other hand, the external perturbations do not alter the helical core deformation in a significant manner. The confinement of fast particles in MAST simulations deteriorate with the amplitude of the helical core distortion. These three-dimensional bifurcated solutions constitute a paradigm shift that motivates the applications of tools developed for stellarator research in tokamak physics investigations.

  7. Learning Through Doing: Teaching Advanced Physics Concepts Through Freshmen Research Immersion

    NASA Astrophysics Data System (ADS)

    Wahila, Matthew; Piper, Louis; Amey, Jennifer; Jones, Wayne; Fegley, Megan; Stamp, Nancy

    Often undergraduates have difficulty grasping advanced concepts in physics due to the seemingly abstract and foreign nature of the time and length scales involved. The ``Smart Energy'' Freshmen Research Immersion (FRI) program at Binghamton University was created as a way to address this issue and, in turn, improve undergraduate performance and retention in physics and chemistry. Using real-world research problems as a wider context to frame their understanding, we have developed a course sequence providing a more intuitive and comprehensive understanding of core physics and chemistry concepts over the course of the program. Advanced condensed matter topics, such as optical band gaps, crystal and electronic structure, and electron/hole conduction are introduced to students through hands-on, authentic research activities incorporating materials for real-world device applications. I will discuss how employing p-n junctions as a model device can allow for a natural and intuitive progression from basic to advanced physics and chemistry concepts. This approach illustrates how shifting exotic concepts into a more relatable form through the use of analogy is important for fostering a more intuitive understanding of physical phenomena.

  8. Physical Activity in Patients With Advanced-Stage Cancer: A Systematic Review of the Literature

    PubMed Central

    Albrecht, Tara A.; Taylor, Ann Gill

    2014-01-01

    The importance of physical activity for chronic disease prevention and management has become generally well accepted. The number of research interventions and publications examining the benefits of physical activity for patients with cancer has been rising steadily. However, much of that research has focused on the impact of physical activity either prior to or early in the cancer diagnosis, treatment, and survivorship process. Research focusing on the effects of physical activity, specifically for patients with advanced-stage cancer and poorer prognostic outcomes, has been addressed only recently. The purpose of this article is to examine the state of the science for physical activity in the advanced-stage disease subset of the cancer population. Exercise in a variety of intensities and forms, including yoga, walking, biking, and swimming, has many health benefits for people, including those diagnosed with cancer. Research has shown that, for people with cancer (including advanced-stage cancer), exercise can decrease anxiety, stress, and depression while improving levels of pain, fatigue, shortness of breath, constipation, and insomnia. People diagnosed with cancer should discuss with their oncologist safe, easy ways they can incorporate exercise into their daily lives. PMID:22641322

  9. Physical activity in patients with advanced-stage cancer: a systematic review of the literature.

    PubMed

    Albrecht, Tara A; Taylor, Ann Gill

    2012-06-01

    The importance of physical activity for chronic disease prevention and management has become generally well accepted. The number of research interventions and publications examining the benefits of physical activity for patients with cancer has been rising steadily. However, much of that research has focused on the impact of physical activity either prior to or early in the cancer diagnosis, treatment, and survivorship process. Research focusing on the effects of physical activity, specifically for patients with advanced-stage cancer and poorer prognostic outcomes, has been addressed only recently. The purpose of this article is to examine the state of the science for physical activity in the advanced-stage disease subset of the cancer population. Exercise in a variety of intensities and forms, including yoga, walking, biking, and swimming, has many health benefits for people, including those diagnosed with cancer. Research has shown that, for people with cancer (including advanced-stage cancer), exercise can decrease anxiety, stress, and depression while improving levels of pain, fatigue, shortness of breath, constipation, and insomnia. People diagnosed with cancer should discuss with their oncologist safe, easy ways they can incorporate exercise into their daily lives. PMID:22641322

  10. Modular tokamak magnetic system

    DOEpatents

    Yang, Tien-Fang

    1988-01-01

    A modular tokamak system comprised of a plurality of interlocking moldules. Each module is comprised of a vacuum vessel section, a toroidal field coil, moldular saddle coils which generate a poloidal magnetic field and ohmic heating coils.

  11. Physics-model-based nonlinear actuator trajectory optimization and safety factor profile feedback control for advanced scenario development in DIII-D

    NASA Astrophysics Data System (ADS)

    Barton, J. E.; Boyer, M. D.; Shi, W.; Wehner, W. P.; Schuster, E.; Ferron, J. R.; Walker, M. L.; Humphreys, D. A.; Luce, T. C.; Turco, F.; Penaflor, B. G.; Johnson, R. D.

    2015-09-01

    DIII-D experimental results are reported to demonstrate the potential of physics-model-based safety factor profile control for robust and reproducible sustainment of advanced scenarios. In the absence of feedback control, variability in wall conditions and plasma impurities, as well as drifts due to external disturbances, can limit the reproducibility of discharges with simple pre-programmed scenario trajectories. The control architecture utilized is a feedforward + feedback scheme where the feedforward commands are computed off-line and the feedback commands are computed on-line. In this work, a first-principles-driven (FPD), physics-based model of the q profile and normalized beta ({β\\text{N}} ) dynamics is first embedded into a numerical optimization algorithm to design feedforward actuator trajectories that steer the plasma through the tokamak operating space to reach a desired stationary target state that is characterized by the achieved q profile and {β\\text{N}} . Good agreement between experimental results and simulations demonstrates the accuracy of the models employed for physics-model-based control design. Second, a feedback algorithm for q profile control is designed following an FPD approach, and the ability of the controller to achieve and maintain a target q profile evolution is tested in DIII-D high confinement (H-mode) experiments. The controller is shown to be able to effectively control the q profile when {β\\text{N}} is relatively close to the target, indicating the need for integrated q profile and {β\\text{N}} control to further enhance the ability to achieve robust scenario execution. The ability of an integrated q profile + {β\\text{N}} feedback controller to track a desired target is demonstrated through simulation.

  12. Tokamaks: from A D Sakharov to the present (the 60-year history of tokamaks)

    NASA Astrophysics Data System (ADS)

    Azizov, E. A.

    2012-02-01

    The paper is prepared on the basis of the report presented at the session of the Physical Sciences Division of the Russian Academy of Sciences (RAS) at the Lebedev Physical Institute, RAS on 25 May 2011, devoted to the 90-year jubilee of Academician Andrei D Sakharov - the initiator of controlled nuclear fusion research in the USSR. The 60-year history of plasma research work in toroidal devices with a longitudinal magnetic field suggested by Andrei D Sakharov and Igor E Tamm in 1950 for the confinement of fusion plasma and known at present as tokamaks is described in brief. The recent (2006) agreement among Russia, the EU, the USA, Japan, China, the Republic of Korea, and India on the joint construction of the international thermonuclear experimental reactor (ITER) in France based on the tokamak concept is discussed. Prospects for using the tokamak as a thermonuclear (14 MeV) neutron source are examined.

  13. Innovative experimental particle physics through technological advances: Past, present and future

    SciTech Connect

    Cheung, Harry W.K.; /Fermilab

    2005-01-01

    This mini-course gives an introduction to the techniques used in experimental particle physics with an emphasis on the impact of technological advances. The basic detector types and particle accelerator facilities will be briefly covered with examples of their use and with comparisons. The mini-course ends with what can be expected in the near future from current technology advances. The mini-course is intended for graduate students and post-docs and as an introduction to experimental techniques for theorists.

  14. Reactor Physics and Criticality Benchmark Evaluations for Advanced Nuclear Fuel - Final Technical Report

    SciTech Connect

    William Anderson; James Tulenko; Bradley Rearden; Gary Harms

    2008-09-11

    The nuclear industry interest in advanced fuel and reactor design often drives towards fuel with uranium enrichments greater than 5 wt% 235U. Unfortunately, little data exists, in the form of reactor physics and criticality benchmarks, for uranium enrichments ranging between 5 and 10 wt% 235U. The primary purpose of this project is to provide benchmarks for fuel similar to what may be required for advanced light water reactors (LWRs). These experiments will ultimately provide additional information for application to the criticality-safety bases for commercial fuel facilities handling greater than 5 wt% 235U fuel.

  15. Engineering development of advanced physical fine coal cleaning for premium fuel applications

    SciTech Connect

    Smit, F.J.; Jha, M.C.; Phillips, D.I.; Yoon, R.H.

    1997-04-25

    The goal of this project is engineering development of two advanced physical fine coal cleaning processes, column flotation and selective agglomeration, for premium fuel applications. Its scope includes laboratory research and bench-scale testing on six coals to optimize these processes, followed by design and construction of a 2 t/h process development unit (PDU). Large lots of clean coal are to be produced in the PDU from three project coals. Investigation of the near-term applicability of the two advanced fine coal cleaning processes in an existing coal preparation plant is another goal of the project and is the subject of this report.

  16. Lipid membranes and single ion channel recording for the advanced physics laboratory

    NASA Astrophysics Data System (ADS)

    Klapper, Yvonne; Nienhaus, Karin; Röcker, Carlheinz; Ulrich Nienhaus, G.

    2014-05-01

    We present an easy-to-handle, low-cost, and reliable setup to study various physical phenomena on a nanometer-thin lipid bilayer using the so-called black lipid membrane technique. The apparatus allows us to precisely measure optical and electrical properties of free-standing lipid membranes, to study the formation of single ion channels, and to gain detailed information on the ion conduction properties of these channels using statistical physics and autocorrelation analysis. The experiments are well suited as part of an advanced physics or biophysics laboratory course; they interconnect physics, chemistry, and biology and will be appealing to students of the natural sciences who are interested in quantitative experimentation.

  17. Advances in BAC-Based Physical Mapping and Map Integration Strategies in Plants

    PubMed Central

    Ariyadasa, Ruvini; Stein, Nils

    2012-01-01

    In the advent of next-generation sequencing (NGS) platforms, map-based sequencing strategy has been recently suppressed being too expensive and laborious. The detailed studies on NGS drafts alone indicated these assemblies remain far from gold standard reference quality, especially when applied on complex genomes. In this context the conventional BAC-based physical mapping has been identified as an important intermediate layer in current hybrid sequencing strategy. BAC-based physical map construction and its integration with high-density genetic maps have benefited from NGS and high-throughput array platforms. This paper addresses the current advancements of BAC-based physical mapping and high-throughput map integration strategies to obtain densely anchored well-ordered physical maps. The resulted maps are of immediate utility while providing a template to harness the maximum benefits of the current NGS platforms. PMID:22500080

  18. SYSTEM PERFORMANCE AND EXPERIMENTS WITH THE 110 GHZ MICROWAVE INSTALLATION ON THE DIII-D TOKAMAK

    SciTech Connect

    J.M. LOHR; F.W. BAITY,JR.; G.C. BARBER; R.W. CALLIS; I. GORELOV; C.M. GREENFIELD; R.A. LEGG; T.C. LUCE; C.C. PETTY; D. PONCE; R. PRATER

    2000-09-01

    A powerful microwave system operating at the second harmonic of the electron cyclotron frequency has been commissioned on the DIII-D tokamak. The primary mission of the microwave system is to permit current profile control leading to the improved performance of advanced tokamak operation in quasi-steady state. Initial performance tests and experiments on current drive both near and away from the tokamak axis and on transport have been performed.

  19. Critical issues for modeling dust transport in tokamaks.

    PubMed

    Bacharis, Minas; Coppins, Michael; Allen, John E

    2010-08-01

    Dust produced in tokamaks is an important issue for fusion. Dust particles can introduce health and safety issues when in the same time can have an impact on reactor performance. Apart from the associated problems there are also potential benefits that make the better understanding of their behavior important. In this work the dust transport code Dust in TOKamakS will be used to explore the effect that variations in the plasma background and the physical model, describing the plasma-dust interaction, have on their predicted trajectories. PMID:20866922

  20. High Performance Computing Modeling Advances Accelerator Science for High-Energy Physics

    SciTech Connect

    Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

    2014-07-28

    The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space, and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing are essential for accurately modeling them. In the past decade, the US Department of Energy's SciDAC program has produced accelerator-modeling tools that have been employed to tackle some of the most difficult accelerator science problems. The authors discuss the Synergia framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable of handling the entire spectrum of beam dynamics simulations. Our authors present Synergia's design principles and its performance on HPC platforms.

  1. High Performance Computing Modeling Advances Accelerator Science for High-Energy Physics

    DOE PAGESBeta

    Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

    2014-07-28

    The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space, and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing are essential for accurately modeling them. In the past decade, the US Department of Energy's SciDAC program has produced accelerator-modeling tools that have been employed to tackle some of the most difficult accelerator science problems. The authors discuss the Synergia framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable ofmore » handling the entire spectrum of beam dynamics simulations. Our authors present Synergia's design principles and its performance on HPC platforms.« less

  2. DAWN (Design Assistant Workstation) for advanced physical-chemical life support systems

    NASA Technical Reports Server (NTRS)

    Rudokas, Mary R.; Cantwell, Elizabeth R.; Robinson, Peter I.; Shenk, Timothy W.

    1989-01-01

    This paper reports the results of a project supported by the National Aeronautics and Space Administration, Office of Aeronautics and Space Technology (NASA-OAST) under the Advanced Life Support Development Program. It is an initial attempt to integrate artificial intelligence techniques (via expert systems) with conventional quantitative modeling tools for advanced physical-chemical life support systems. The addition of artificial intelligence techniques will assist the designer in the definition and simulation of loosely/well-defined life support processes/problems as well as assist in the capture of design knowledge, both quantitative and qualitative. Expert system and conventional modeling tools are integrated to provide a design workstation that assists the engineer/scientist in creating, evaluating, documenting and optimizing physical-chemical life support systems for short-term and extended duration missions.

  3. UCLA Tokamak Program Close Out Report.

    SciTech Connect

    Taylor, Robert John

    2014-02-04

    The results of UCLA experimental fusion program are summarized. Starting with smaller devices like Microtor, Macrotor, CCT and ending the research on the large (5 m) Electric Tokamak. CCT was the most diagnosed device for H-mode like physics and the effects of rotation induced radial fields. ICRF heating was also studied but plasma heating of University Type Tokamaks did not produce useful results due to plasma edge disturbances of the antennae. The Electric Tokamak produced better confinement in the seconds range. However, it presented very good particle confinement due to an "electric particle pinch". This effect prevented us from reaching a quasi steady state. This particle accumulation effect was numerically explained by Shaing's enhanced neoclassical theory. The PI believes that ITER will have a good energy confinement time but deleteriously large particle confinement time and it will disrupt on particle pinching at nominal average densities. The US fusion research program did not study particle transport effects due to its undue focus on the physics of energy confinement time. Energy confinement time is not an issue for energy producing tokamaks. Controlling the ash flow will be very expensive.

  4. Advances in deep-space telecommunications technology at the Applied Physics Laboratory

    NASA Astrophysics Data System (ADS)

    Bokulic, R. S.; Reinhart, M. J.; Willey, C. E.; Stilwell, R. K.; Penn, J. E.; Norton, J. R.; Cheng, S.; DeCicco, D. J.; Schulze, R. C.

    2003-01-01

    This paper reviews recent advances in RF telecommunications technology at the Applied Physics Laboratory. These advances, which address the miniaturization and high data rate needs of NASA, fall into three major areas: (1) transceiver-based systems, (2) antennas, and (3) solid-state power amplifiers. In the transceiver area, a deep-space transceiver system being developed for the Comet Nucleus Tour (CONTOUR) spacecraft is described. In addition, the development progress of a low-power S/X-band digital receiver and an advanced ultrastable oscillator quartz resonator are described. In the antenna area, an X-band phased array system being developed for the Mercury Surface, Space Environment, Geochemistry and Ranging (MESSENGER) spacecraft is described, along with the concept for a K a-band hybrid inflatable antenna. In the solid-state power amplifier area, the development of X- and K a-band amplifiers suitable for phased array applications is described.

  5. Design and fabrication of advanced hybrid circuits for high energy physics

    SciTech Connect

    Haller, G.M.; Moss, J.; Freytag, D.R.; Nelson, D.; Yim, A.; Lo, C.C.

    1987-10-01

    Current design and fabrication techniques of hybrid devices are explained for the Drift Chamber and the Liquid Argon Calorimeter for the Stanford Linear Collider Large Detector (SLD) at SLAC. Methods of developing layouts, ranging from hand-cut templates to advanced designs utilizing CAD tools with special hybrid design software were applied. Physical and electrical design rules for good yield and performance are discussed. Fabrication and assembly of the SLD hybrids are described. 7 refs., 10 figs.

  6. SOFTWARE REVIEW: The Advanced Physics Virtual Laboratory Series: CD-ROM Thermodynamics and Molecular Physics

    NASA Astrophysics Data System (ADS)

    Dobson, Ken

    1998-09-01

    The program installed easily although the inexperienced might be as terrified as I was by the statements threatening to delete various files it had found on my machine. However, I ignored these and all went well. The user is faced with a menu of 14 simulations covering molecular topics such as the Kinetic Model of an Ideal Gas, Diffusion (through a variable diameter aperture) and a Semi-permeable Membrane, the Maxwell Distribution and Brownian Motion. Thermodynamics is covered by simulations of ideal-gas behaviour at constant pressure, volume and temperature. This is extended to deal with adiabatic changes, the work done by and on a gas, specific heats, work cycles, and to the behaviour of real gases in evaporation and condensation. Finally there are short video-clips of actual experiments showing gas and vapour behaviour. Each simulation is displayed in a `picture window' which gives a qualitative display of how molecules are moving in a container, or how a parameter changes as conditions are varied, as appropriate. Attached (somewhat loosely as it turned out) to these are relevant graphs showing how the important variables such as temperature, volume and pressure change as conditions are changed. The simulations are dynamic and set off by clicking on a RUN button. The simulation can be stopped at any stage and reset to change parameters. It is easy to change the conditions of the simulation by moving sliders along a scale. I particularly liked the simulations of molecular behaviour and the isotherms of a real gas - an ideal case for animation. Each simulation has a short spoken commentary which you can switch in, a brief drop-down text describing the simulation, and a single question. This is where, I felt, things started to go wrong. The simulation displays are informative and give a good visual impression of a part of physics that students find abstract and difficult. But the supporting commentary and text are much too thin for, say, `supported self

  7. SOFTWARE REVIEW: The Advanced Physics Virtual Laboratory Series: CD-ROM Thermodynamics and Molecular Physics

    NASA Astrophysics Data System (ADS)

    Dobson, Ken

    1998-09-01

    The program installed easily although the inexperienced might be as terrified as I was by the statements threatening to delete various files it had found on my machine. However, I ignored these and all went well. The user is faced with a menu of 14 simulations covering molecular topics such as the Kinetic Model of an Ideal Gas, Diffusion (through a variable diameter aperture) and a Semi-permeable Membrane, the Maxwell Distribution and Brownian Motion. Thermodynamics is covered by simulations of ideal-gas behaviour at constant pressure, volume and temperature. This is extended to deal with adiabatic changes, the work done by and on a gas, specific heats, work cycles, and to the behaviour of real gases in evaporation and condensation. Finally there are short video-clips of actual experiments showing gas and vapour behaviour. Each simulation is displayed in a `picture window' which gives a qualitative display of how molecules are moving in a container, or how a parameter changes as conditions are varied, as appropriate. Attached (somewhat loosely as it turned out) to these are relevant graphs showing how the important variables such as temperature, volume and pressure change as conditions are changed. The simulations are dynamic and set off by clicking on a RUN button. The simulation can be stopped at any stage and reset to change parameters. It is easy to change the conditions of the simulation by moving sliders along a scale. I particularly liked the simulations of molecular behaviour and the isotherms of a real gas - an ideal case for animation. Each simulation has a short spoken commentary which you can switch in, a brief drop-down text describing the simulation, and a single question. This is where, I felt, things started to go wrong. The simulation displays are informative and give a good visual impression of a part of physics that students find abstract and difficult. But the supporting commentary and text are much too thin for, say, `supported self

  8. Engineering design and analysis of advanced physical fine coal cleaning technologies

    SciTech Connect

    Gallier, P.W.

    1993-01-20

    This project is sponsored by the United States Department of Energy (DOE) for the Engineering Design and Analysis of Advanced Physical Fine Coal Cleaning Technologies: The major goal is to provide the simulation tools for modeling both conventional and advanced coal cleaning technologies. This DOE project is part of a major research initiative by the Pittsburgh Energy Technology Center (PETC) aimed at advancing three advanced coal cleaning technologies-heavy-liquid cycloning, selective agglomeration, and advanced froth flotation through the proof-of-concept (POC) level. The commercially available ASPEN PLUS process simulation package will be extended to handle coal cleaning applications. Algorithms for predicting the process performance, equipment size, and flowsheet economics of commercial coal cleaning devices and related ancillary equipment will be incorporated into the coal cleaning simulator. This report is submitted to document the progress of Aspen Technology, Inc. (AspenTech), its contractor, ICF Kaiser Engineers, Inc.,(ICF KE) and CQ Inc., a subcontractor to ICF KE, for the period of October through December 1992. ICF KE is providing coal preparation consulting and processing engineering services in this work and they are responsible for recommending the design of models to represent conventional coal cleaning equipment and costing of these models. CQ Inc. is a subcontractor to ICF KE on Tasks 1-5.

  9. Tokamak coordinate conventions: COCOS

    NASA Astrophysics Data System (ADS)

    Sauter, O.; Medvedev, S. Yu.

    2013-02-01

    Dealing with electromagnetic fields, in particular current and related magnetic fields, yields "natural" physical vector relations in 3-D. However, when it comes to choosing local coordinate systems, the "usual" right-handed systems are not necessarily the best choices, which means that there are several options being chosen. In the magnetic fusion community such a difficulty exists for the choices of the cylindrical and of the toroidal coordinate systems. In addition many codes depend on knowledge of an equilibrium. In particular, the Grad-Shafranov axisymmetric equilibrium solution for tokamak plasmas, ψ, does not depend on the sign of the plasma current Ip nor that of the magnetic field B0. This often results in ill-defined conventions. Moreover the sign, amplitude and offset of ψ are of less importance, since the free sources in the equation depend on the normalized radial coordinate. The signs of the free sources, dp/dψ and dF2/dψ (p being the pressure, ψ the poloidal magnetic flux and F=RBφ), must be consistent to generate the current density profile. For example, RF and CD calculations (Radio Frequency heating and Current Drive) require an exact sign convention in order to calculate a co- or counter-CD component. It is shown that there are over 16 different coordinate conventions. This paper proposes a unique identifier, the COCOS convention, to distinguish between the 16 most-commonly used options. Given the present worldwide efforts towards code integration, the proposed new index COCOS defining uniquely the COordinate COnventionS required as input by a given code or module is particularly useful. As codes use different conventions, it is useful to allow different sign conventions for equilibrium code input and output, equilibrium being at the core of any calculations in magnetic fusion. Additionally, given two different COCOS conventions, it becomes simple to transform between them. The relevant transformations are described in detail.

  10. Texas Experimental Tokamak. Technical progress report, April 1990--April 1993

    SciTech Connect

    Wootton, A.J.

    1993-04-01

    This progress report covers the period from November 1, 1990 to April 30, 1993. During that period, TEXT was operated as a circular tokamak with a material limiter. It was devoted to the study of basic plasma physics, in particular to study of fluctuations, turbulence, and transport. The purpose is to operate and maintain TEXT Upgrade as a complete facility for applied tokamak physics, specifically to conduct a research program under the following main headings: (1) to elucidate the mechanisms of working gas, impurity, and thermal transport in tokamaks, in particular to understand the role of turbulence; (2) to study physics of the edge plasma, in particular the turbulence; (3) to study the physics or resonant magnetic fields (ergodic magnetic divertors, intra island pumping); and (4) to study the physics of electron cyclotron heating (ECRH). Results of studies in each of these areas are reported.

  11. Technical Basis for Physical Fidelity of NRC Control Room Training Simulators for Advanced Reactors

    SciTech Connect

    Minsk, Brian S.; Branch, Kristi M.; Bates, Edward K.; Mitchell, Mark R.; Gore, Bryan F.; Faris, Drury K.

    2009-10-09

    The objective of this study is to determine how simulator physical fidelity influences the effectiveness of training the regulatory personnel responsible for examination and oversight of operating personnel and inspection of technical systems at nuclear power reactors. It seeks to contribute to the U.S. Nuclear Regulatory Commission’s (NRC’s) understanding of the physical fidelity requirements of training simulators. The goal of the study is to provide an analytic framework, data, and analyses that inform NRC decisions about the physical fidelity requirements of the simulators it will need to train its staff for assignment at advanced reactors. These staff are expected to come from increasingly diverse educational and experiential backgrounds.

  12. Predictive Modeling of Tokamak Configurations*

    NASA Astrophysics Data System (ADS)

    Casper, T. A.; Lodestro, L. L.; Pearlstein, L. D.; Bulmer, R. H.; Jong, R. A.; Kaiser, T. B.; Moller, J. M.

    2001-10-01

    The Corsica code provides comprehensive toroidal plasma simulation and design capabilities with current applications [1] to tokamak, reversed field pinch (RFP) and spheromak configurations. It calculates fixed and free boundary equilibria coupled to Ohm's law, sources, transport models and MHD stability modules. We are exploring operations scenarios for both the DIII-D and KSTAR tokamaks. We will present simulations of the effects of electron cyclotron heating (ECH) and current drive (ECCD) relevant to the Quiescent Double Barrier (QDB) regime on DIII-D exploring long pulse operation issues. KSTAR simulations using ECH/ECCD in negative central shear configurations explore evolution to steady state while shape evolution studies during current ramp up using a hyper-resistivity model investigate startup scenarios and limitations. Studies of high bootstrap fraction operation stimulated by recent ECH/ECCD experiments on DIIID will also be presented. [1] Pearlstein, L.D., et al, Predictive Modeling of Axisymmetric Toroidal Configurations, 28th EPS Conference on Controlled Fusion and Plasma Physics, Madeira, Portugal, June 18-22, 2001. * Work performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

  13. Completely bootstrapped tokamak

    SciTech Connect

    Weening, R.H. ); Boozer, A.H. )

    1992-01-01

    Numerical simulations of the evolution of large-scale magnetic fields have been developed using a mean-field Ohm's law. The Ohm's law is coupled to a {Delta}{prime} stabilty analysis and a magnetic island growth equation in order to simulate the behavior of tokamak plasmas that are subject to tearing modes. In one set of calculations, the magnetohydrodynamic (MHD)-stable regime of the tokamak is examined via the construction of an {ital l}{sub {ital i}} -{ital q}{sub {ital a}} diagram. The results confirm previous calculations that show that tearing modes introduce a stability boundary into the {ital l}{sub {ital i}} -{ital q}{sub {ital a}} space. In another series of simulations, the interaction between tearing modes and the bootstrap current is investigated. The results indicate that a completely bootstrapped tokamak may be possible, even in the absence of any externally applied loop voltage or current drive.

  14. Burn Control Mechanisms in Tokamaks

    NASA Astrophysics Data System (ADS)

    Hill, M. A.; Stacey, W. M.

    2015-11-01

    Burn control and passive safety in accident scenarios will be an important design consideration in future tokamak reactors, in particular fusion-fission hybrid reactors, e.g. the Subcritical Advanced Burner Reactor. We are developing a burning plasma dynamics code to explore various aspects of burn control, with the intent to identify feedback mechanisms that would prevent power excursions. This code solves the coupled set of global density and temperature equations, using scaling relations from experimental fits. Predictions of densities and temperatures have been benchmarked against DIII-D data. We are examining several potential feedback mechanisms to limit power excursions: i) ion-orbit loss, ii) thermal instability density limits, iii) MHD instability limits, iv) the degradation of alpha-particle confinement, v) modifications to the radial current profile, vi) ``divertor choking'' and vii) Type 1 ELMs. Work supported by the US DOE under DE-FG02-00ER54538, DE-FC02-04ER54698.

  15. Reducing anxiety and enhancing physical performance by using an advanced version of EMDR: a pilot study

    PubMed Central

    Rathschlag, Marco; Memmert, Daniel

    2014-01-01

    Background The main aim of this pilot study was to investigate an advanced version of eye movement desensitization and reprocessing (EMDR) for reducing anxiety. Methods Fifty participants were asked at two times of measurement (T1 and T2 with a rest of 4 weeks) to generate anxiety via the recall of autobiographical memories according to their anxiety. Furthermore, the participants were randomly assigned to an experimental group and a control group, and the experimental group received an intervention of 1–2 h with the advanced version of EMDR in order to their anxiety 2 weeks after T1. At T1 as well as T2, we measured the intensity of participants' anxiety with a Likert scale (LS) and collected participants' state (temporary) and trait (chronic) anxiety with the State-Trait Anxiety Inventory (STAI). In addition, we measured participants' physical performance in a test for the finger musculature under the induction of their anxiety. Results The results showed that participant's ratings of their perceived intensity of anxiety (measured by a 9-point LS) and the state and trait anxiety decreased significantly in the experimental group but not in the control group from T1 to T2. Moreover, the physical performance under the induction of participants' anxiety increased significantly in the experimental group from T1 to T2 and there were no significant changes in the control group. Conclusions The study could show that the advanced version of EMDR is an appropriate method to reduce anxiety. PMID:24944864

  16. Integration of Advanced Probabilistic Analysis Techniques with Multi-Physics Models

    SciTech Connect

    Cetiner, Mustafa Sacit; none,; Flanagan, George F.; Poore III, Willis P.; Muhlheim, Michael David

    2014-07-30

    An integrated simulation platform that couples probabilistic analysis-based tools with model-based simulation tools can provide valuable insights for reactive and proactive responses to plant operating conditions. The objective of this work is to demonstrate the benefits of a partial implementation of the Small Modular Reactor (SMR) Probabilistic Risk Assessment (PRA) Detailed Framework Specification through the coupling of advanced PRA capabilities and accurate multi-physics plant models. Coupling a probabilistic model with a multi-physics model will aid in design, operations, and safety by providing a more accurate understanding of plant behavior. This represents the first attempt at actually integrating these two types of analyses for a control system used for operations, on a faster than real-time basis. This report documents the development of the basic communication capability to exchange data with the probabilistic model using Reliability Workbench (RWB) and the multi-physics model using Dymola. The communication pathways from injecting a fault (i.e., failing a component) to the probabilistic and multi-physics models were successfully completed. This first version was tested with prototypic models represented in both RWB and Modelica. First, a simple event tree/fault tree (ET/FT) model was created to develop the software code to implement the communication capabilities between the dynamic-link library (dll) and RWB. A program, written in C#, successfully communicates faults to the probabilistic model through the dll. A systems model of the Advanced Liquid-Metal Reactor–Power Reactor Inherently Safe Module (ALMR-PRISM) design developed under another DOE project was upgraded using Dymola to include proper interfaces to allow data exchange with the control application (ConApp). A program, written in C+, successfully communicates faults to the multi-physics model. The results of the example simulation were successfully plotted.

  17. Decommissioning the Tokamak Fusion Test Reactor

    SciTech Connect

    Spampinato, P.T.; Walton, G.R.

    1993-10-01

    The Tokamak Fusion Test Reactor (TFTR) at Princeton Plasma Physics Laboratory (PPPL) will complete its experimental lifetime with a series of deuterium-tritium pulses in 1994. As a result, the machine structures will become radioactive, and vacuum components will also be contaminated with tritium. Dose rate levels will range from less than 1 mr/h for external structures to hundreds of mr/h for the vacuum vessel. Hence, decommissioning operations will range from hands on activities to the use of remotely operated equipment. After 21 months of cool down, decontamination and decommissioning (D and D) operations will commence and continue for approximately 15 months. The primary objective is to render the test cell complex re-usable for the next machine, the Tokamak Physics Experiment (TPX). This paper presents an overview of decommissioning TFTR and discusses the D and D objectives.

  18. Advances of Yemeni women in physics: Climbing toward a better status

    NASA Astrophysics Data System (ADS)

    Fakhraddin, S.; Alsowidi, N. A.

    2013-03-01

    In the three years since the last IUPAP Women in Physics Conference in 2008, the overall status of women in physics in Yemen has improved. The enrollment of women in the Department of Physics at Sana'a University has increased at both the undergraduate and graduate levels. At the graduate level, female enrollment has been equal to (50%) or greater than (57%) male enrollment in recent years. In addition, four of the leading state universities already have female faculty members with a PhD in physics who hold the title of assistant professor or better. These women in academia have made remarkable progress by publishing their work in distinctive journals as well as by winning national and regional scientific awards. We can be rather satisfied with the overall advances of Yemeni women in physics, as well, at every step up the academic ladder, but we simultaneously acknowledge their significant underrepresentation in the highest scientific positions as well as in decision-making positions at the faculty or administrative level of universities.

  19. Recent Advances in Free-Living Physical Activity Monitoring: A Review

    PubMed Central

    Andre, David; Wolf, Donna L.

    2007-01-01

    It has become clear recently that the epidemic of type 2 diabetes sweeping the globe is associated with decreased levels of physical activity and an increase in obesity. Incorporating appropriate and sufficient physical activity into one's life is an essential component of achieving and maintaining a healthy weight and overall health, especially for those with type II diabetes mellitus. Regular physical activity can have a positive impact by lowering blood glucose, helping the body to be more efficient at using insulin. There are other substantial benefits for patients with diabetes, including prevention of cardiovascular disease, hyperlipidemia, hypertension, and obesity. Several complications of utilizing a self-care treatment methodology involving exercise include (1) patients may not know how much activity that they engage in and (2) health-care providers do not have objective measurements of how much activity their patients perform. However, several technological advances have brought a variety of activity monitoring devices to the market that can address these concerns. Ranging from simple pedometers to multisensor devices, the different technologies offer varying levels of accuracy, comfort, and reliability. The key notion is that by providing feedback to the patient, motivation can be increased and targets can be set and aimed toward. Although these devices are not specific to the treatment of diabetes, the importance of physical activity in treating the disease makes an understanding of these devices important. This article reviews these physical activity monitors and describes the advantages and disadvantages of each. PMID:19885145

  20. PREFACE: 15th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT2013)

    NASA Astrophysics Data System (ADS)

    Wang, Jianxiong

    2014-06-01

    This volume of Journal of Physics: Conference Series is dedicated to scientific contributions presented at the 15th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2013) which took place on 16-21 May 2013 at the Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China. The workshop series brings together computer science researchers and practitioners, and researchers from particle physics and related fields to explore and confront the boundaries of computing and of automatic data analysis and theoretical calculation techniques. This year's edition of the workshop brought together over 120 participants from all over the world. 18 invited speakers presented key topics on the universe in computer, Computing in Earth Sciences, multivariate data analysis, automated computation in Quantum Field Theory as well as computing and data analysis challenges in many fields. Over 70 other talks and posters presented state-of-the-art developments in the areas of the workshop's three tracks: Computing Technologies, Data Analysis Algorithms and Tools, and Computational Techniques in Theoretical Physics. The round table discussions on open-source, knowledge sharing and scientific collaboration stimulate us to think over the issue in the respective areas. ACAT 2013 was generously sponsored by the Chinese Academy of Sciences (CAS), National Natural Science Foundation of China (NFSC), Brookhaven National Laboratory in the USA (BNL), Peking University (PKU), Theoretical Physics Cernter for Science facilities of CAS (TPCSF-CAS) and Sugon. We would like to thank all the participants for their scientific contributions and for the en- thusiastic participation in all its activities of the workshop. Further information on ACAT 2013 can be found at http://acat2013.ihep.ac.cn. Professor Jianxiong Wang Institute of High Energy Physics Chinese Academy of Science Details of committees and sponsors are available in the PDF

  1. Self-Organized Stationary States of Tokamaks.

    PubMed

    Jardin, S C; Ferraro, N; Krebs, I

    2015-11-20

    We demonstrate that in a 3D resistive magnetohydrodynamic simulation, for some parameters it is possible to form a stationary state in a tokamak where a saturated interchange mode in the center of the discharge drives a near helical flow pattern that acts to nonlinearly sustain the configuration by adjusting the central loop voltage through a dynamo action. This could explain the physical mechanism for maintaining stationary nonsawtoothing "hybrid" discharges, often referred to as "flux pumping." PMID:26636854

  2. Self-Organized Stationary States of Tokamaks

    SciTech Connect

    Jardin, S. C.; Ferraro, N.; Krebs, I.

    2015-11-01

    We demonstrate that in a 3D resistive magnetohydrodynamic simulation, for some parameters it is possible to form a stationary state in a tokamak where a saturated interchange mode in the center of the discharge drives a near helical flow pattern that acts to nonlinearly sustain the configuration by adjusting the central loop voltage through a dynamo action. This could explain the physical mechanism for maintaining stationary nonsawtoothing "hybrid" discharges, often referred to as "flux pumping."

  3. Heavy ion beam probe systems for tight aspect ratio tokamaks

    SciTech Connect

    Melnikov, A.V.; Zimeleva, L.G.; Krupnik, L.I.; Nedzelskij, I.S.; Trofimenko, Y.V.; Minaev, V.B.

    1997-01-01

    We discuss the specific features of the application of heavy ion beam probe (HIBP) systems to tight aspect ratio tokamaks. We present and compare the HIBP projects for the TUMAN-3, GLOBUS, and COMPASS, where the inner part of the plasma is not available for regular chord diagnostics, so the HIBP becomes very desirable. All existing tight aspect ratio facilities and projects have a low (less than 1.9 T) toroidal field that requires a comparatively low beam energy range. The natural elongation and triangularity in tight aspect ratio tokamaks require an accurate calculation of the three-dimensional magnetic field for probing optimization. In comparison with traditional tokamaks, the detector grids have a wider energy interval. In general, the trajectories and detector grids for tight aspect ratio tokamaks become similar to the stellarator ones. Traditional and new probing schemes are suggested and discussed. {copyright} {ital 1997 American Institute of Physics.}

  4. Clinical Specialists and Advanced Practitioners in Physical Therapy: A Survey of Physical Therapists and Employers of Physical Therapists in Ontario, Canada

    PubMed Central

    Gordon, Robert; Freeburn, Ryan; So, Colleen; Beauchamp, David; Landry, Michel D.; Switzer-McIntyre, Sharon; Evans, Cathy; Brooks, Dina

    2008-01-01

    Purpose: Opportunities to expand the role of physical therapists (PTs) have evolved to include clinical specialists and advanced practitioners, although the literature on these roles is limited. We examined perceptions of PTs and PT employers in Ontario regarding clinical specialization and advanced practice. Methods: Using a modified Dillman approach, a cross-sectional survey was conducted with 500 PTs and 500 PT employers in Ontario. Questionnaires were tailored to address specific issues related to each cohort. Results: Sixty percent of PTs and 53% of PT employers responded to the survey. Thirty-three percent of PT respondents already considered themselves “clinical specialists” (CS), and 8% considered themselves “advanced practitioners” (AP), although neither role is yet formally recognized in Canada. Both groups had substantial interest in pursuing formal recognition of CS and AP status. Respondents indicated that their primary motivation to pursue such roles was to enhance clinical reasoning skills with the goal of improving client outcomes (82% for the role of CS, 71% for the role of AP). Respondents supported the involvement of academic institutions in the process (60% for CS, 70% for AP). Conclusion: PTs and PT employers are supportive of the roles of the CS and AP within the profession, even though there is currently no formal recognition of either role in Canada. PMID:20145755

  5. Underwater acoustic wireless sensor networks: advances and future trends in physical, MAC and routing layers.

    PubMed

    Climent, Salvador; Sanchez, Antonio; Capella, Juan Vicente; Meratnia, Nirvana; Serrano, Juan Jose

    2014-01-01

    This survey aims to provide a comprehensive overview of the current research on underwater wireless sensor networks, focusing on the lower layers of the communication stack, and envisions future trends and challenges. It analyzes the current state-of-the-art on the physical, medium access control and routing layers. It summarizes their security threads and surveys the currently proposed studies. Current envisioned niches for further advances in underwater networks research range from efficient, low-power algorithms and modulations to intelligent, energy-aware routing and medium access control protocols. PMID:24399155

  6. The Advanced Light Source: A new tool for research in atomic and molecular physics

    SciTech Connect

    Schlachter, F.; Robinson, A.

    1991-04-01

    The Advanced Light Source at the Lawrence Berkeley Laboratory will be the world's brightest synchrotron radiation source in the extreme ultraviolet and soft x-ray regions of the spectrum when it begins operation in 1993. It will be available as a national user facility to researchers in a broad range of disciplines, including materials science, atomic and molecular physics, chemistry, biology, imaging, and technology. The high brightness of the ALS will be particularly well suited to high-resolution studies of tenuous targets, such as excited atoms, ions, and clusters. 13 figs., 4 tabs.

  7. Reactor physics analyses of the advanced neutron source three-element core

    SciTech Connect

    Gehin, J.C.

    1995-08-01

    A reactor physics analysis was performed for the Advanced Neutron Source reactor with a three-element core configuration. The analysis was performed with a two-dimensional r-z 20-energy-group finite-difference diffusion theory model of the 17-d fuel cycle. The model included equivalent r-z geometry representations of the central control rods, the irradiation and production targets, and reflector components. Calculated quantities include fuel cycle parameters, fuel element power distributions, unperturbed neutron fluxes in the reflector and target regions, reactivity perturbations, and neutron kinetics parameters.

  8. Underwater Acoustic Wireless Sensor Networks: Advances and Future Trends in Physical, MAC and Routing Layers

    PubMed Central

    Climent, Salvador; Sanchez, Antonio; Capella, Juan Vicente; Meratnia, Nirvana; Serrano, Juan Jose

    2014-01-01

    This survey aims to provide a comprehensive overview of the current research on underwater wireless sensor networks, focusing on the lower layers of the communication stack, and envisions future trends and challenges. It analyzes the current state-of-the-art on the physical, medium access control and routing layers. It summarizes their security threads and surveys the currently proposed studies. Current envisioned niches for further advances in underwater networks research range from efficient, low-power algorithms and modulations to intelligent, energy-aware routing and medium access control protocols. PMID:24399155

  9. Princeton Plasma Physics Laboratory:

    SciTech Connect

    Phillips, C.A.

    1986-01-01

    This paper discusses progress on experiments at the Princeton Plasma Physics Laboratory. The projects and areas discussed are: Principal Parameters Achieved in Experimental Devices, Tokamak Fusion Test Reactor, Princeton Large Torus, Princeton Beta Experiment, S-1 Spheromak, Current-Drive Experiment, X-ray Laser Studies, Theoretical Division, Tokamak Modeling, Spacecraft Glow Experiment, Compact Ignition Tokamak, Engineering Department, Project Planning and Safety Office, Quality Assurance and Reliability, and Administrative Operations.

  10. Tearing Modes in Tokamaks

    NASA Astrophysics Data System (ADS)

    White, R. B.

    2008-05-01

    This lecture gives a basic introduction to magnetic £elds, magnetic surface destruction, toroidal equilibrium and tearing modes in a tokamak, including the linear and nonlinear development of these modes and their modi£cation by current drive and bootstrap current, and sawtooth oscillations and disruptions.

  11. The Advanced Placement Physics Examinations: Test Development and Free-Response Section Readings

    NASA Astrophysics Data System (ADS)

    McMurray, Terri; Cain, L. S.

    2003-11-01

    The Advanced Placement Physics B and C Examinations are developed by a Test Development Committee consisting of both high school and college teachers appointed by The College Board. We will discuss the creation of the tests from their conception to their administration to more than 60,000 high school students each year. We will also discuss the reading of the free response sections for each exam. A group of readers, consisting of interested and motivated high school AP physics teachers and college instructors who teach comparable courses, is appointed to read the free response sections during June of each year. Two experienced readers, one of whom is a member of the Test Development Committee, will share information in this talk on becoming involved with the AP program as a reader.

  12. Opportunities for Regenerative Rehabilitation and Advanced Technologies in Physical Therapy: Perspective From Academia.

    PubMed

    Norland, Ryan; Muchnick, Matthew; Harmon, Zachary; Chin, Tiffany; Kakar, Rumit Singh

    2016-04-01

    As rehabilitation specialists, physical therapists must continue to stay current with advances in technologies to provide appropriate rehabilitation protocols, improve patient outcomes, and be the preferred clinician of choice. To accomplish this vision, the physical therapy profession must begin to develop a culture of lifelong learning at the early stages of education and clinical training in order to embrace cutting-edge advancements such as stem cell therapies, tissue engineering, and robotics, to name a few. The purposes of this article are: (1) to provide a current perspective on faculty and graduate student awareness of regenerative rehabilitation concepts and (2) to advocate for increased integration of these emerging technologies within the doctor of physical therapy (DPT) curriculum. An online survey was designed to gauge awareness of principles in regenerative rehabilitation and to determine whether the topic was included and assessed in doctoral curricula. The survey yielded 1,006 responses from 82 DPT programs nationwide and indicated a disconnect in familiarity with the term "regenerative rehabilitation" and awareness of the inclusion of this material in the curriculum. To resolve this disconnect, the framework of the curriculum can be used to integrate new material via guest lecturers, interdisciplinary partnerships, and research opportunities. Successfully mentoring a generation of clinicians and rehabilitation scientists who incorporate new medical knowledge and technology into their own clinical and research practice depends greatly on sharing the responsibility among graduate students, professors, the American Physical Therapy Association (APTA), and DPT programs. Creating an interdisciplinary culture and integrating regenerative medicine and rehabilitation concepts into the curriculum will cultivate individuals who will be advocates for interprofessional behaviors and will ensure that the profession meets the goals stated in APTA Vision 2020

  13. PREFACE: 16th International workshop on Advanced Computing and Analysis Techniques in physics research (ACAT2014)

    NASA Astrophysics Data System (ADS)

    Fiala, L.; Lokajicek, M.; Tumova, N.

    2015-05-01

    This volume of the IOP Conference Series is dedicated to scientific contributions presented at the 16th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2014), this year the motto was ''bridging disciplines''. The conference took place on September 1-5, 2014, at the Faculty of Civil Engineering, Czech Technical University in Prague, Czech Republic. The 16th edition of ACAT explored the boundaries of computing system architectures, data analysis algorithmics, automatic calculations, and theoretical calculation technologies. It provided a forum for confronting and exchanging ideas among these fields, where new approaches in computing technologies for scientific research were explored and promoted. This year's edition of the workshop brought together over 140 participants from all over the world. The workshop's 16 invited speakers presented key topics on advanced computing and analysis techniques in physics. During the workshop, 60 talks and 40 posters were presented in three tracks: Computing Technology for Physics Research, Data Analysis - Algorithms and Tools, and Computations in Theoretical Physics: Techniques and Methods. The round table enabled discussions on expanding software, knowledge sharing and scientific collaboration in the respective areas. ACAT 2014 was generously sponsored by Western Digital, Brookhaven National Laboratory, Hewlett Packard, DataDirect Networks, M Computers, Bright Computing, Huawei and PDV-Systemhaus. Special appreciations go to the track liaisons Lorenzo Moneta, Axel Naumann and Grigory Rubtsov for their work on the scientific program and the publication preparation. ACAT's IACC would also like to express its gratitude to all referees for their work on making sure the contributions are published in the proceedings. Our thanks extend to the conference liaisons Andrei Kataev and Jerome Lauret who worked with the local contacts and made this conference possible as well as to the program

  14. High Beta Tokamaks

    SciTech Connect

    Cowley, S.

    1998-11-14

    Perhaps the ideal tokamak would have high {beta} ({beta} {approx}> 1) and classical confinement. Such a tokamak has not been found, and we do not know if one does exist. We have searched for such a possibility, so far without success. In 1990, we obtained analytic equilibrium solutions for large aspect ratio tokamaks at {beta} {approx} {Omicron}(1) [1]. These solutions and the extension at high {beta} poloidal to finite aspect ratio [2] provided a basis for the study of high {beta} tokamaks. We have shown that these configurations can be stable to short scale MHD modes [3], and that they have reduced neoclassical transport [4]. Microinstabilities (such as the {del}T{sub i} mode) seem to be stabilized at high {beta} [5] - this is due to the large local shear [3] and the magnetic well. We have some concerns about modes associated with the compressional branch which may appear at high {beta}. Bill Dorland and Mike Kotschenreuther have studied this issue and our concerns may be unfounded. It is certainly tantalizing, especially given the lowered neoclassical transport values, that these configurations could have no microinstabilities and, one could assume, no anomalous transport. Unfortunately, while this work is encouraging, the key question for high {beta} tokamaks is the stability to large scale kink modes. The MHD {beta} limit (Troyon limit) for kink modes at large aspect ratio is problematically low. There is ample evidence from computations that the limit exists. However, it is not known if stable equilibria exist at much higher {beta}--none have been found. We have explored this question in the asymptotic high {beta} poloidal limit. Unfortunately, we are unable to find stable equilibrium and also unable to show that they don't exist. The results of these calculations will be published when a more definitive answer is found.

  15. Successful aging: Advancing the science of physical independence in older adults.

    PubMed

    Anton, Stephen D; Woods, Adam J; Ashizawa, Tetso; Barb, Diana; Buford, Thomas W; Carter, Christy S; Clark, David J; Cohen, Ronald A; Corbett, Duane B; Cruz-Almeida, Yenisel; Dotson, Vonetta; Ebner, Natalie; Efron, Philip A; Fillingim, Roger B; Foster, Thomas C; Gundermann, David M; Joseph, Anna-Maria; Karabetian, Christy; Leeuwenburgh, Christiaan; Manini, Todd M; Marsiske, Michael; Mankowski, Robert T; Mutchie, Heather L; Perri, Michael G; Ranka, Sanjay; Rashidi, Parisa; Sandesara, Bhanuprasad; Scarpace, Philip J; Sibille, Kimberly T; Solberg, Laurence M; Someya, Shinichi; Uphold, Connie; Wohlgemuth, Stephanie; Wu, Samuel Shangwu; Pahor, Marco

    2015-11-01

    The concept of 'successful aging' has long intrigued the scientific community. Despite this long-standing interest, a consensus definition has proven to be a difficult task, due to the inherent challenge involved in defining such a complex, multi-dimensional phenomenon. The lack of a clear set of defining characteristics for the construct of successful aging has made comparison of findings across studies difficult and has limited advances in aging research. A consensus on markers of successful aging is furthest developed is the domain of physical functioning. For example, walking speed appears to be an excellent surrogate marker of overall health and predicts the maintenance of physical independence, a cornerstone of successful aging. The purpose of the present article is to provide an overview and discussion of specific health conditions, behavioral factors, and biological mechanisms that mark declining mobility and physical function and promising interventions to counter these effects. With life expectancy continuing to increase in the United States and developed countries throughout the world, there is an increasing public health focus on the maintenance of physical independence among all older adults. PMID:26462882

  16. PREFACE: 14th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2011)

    NASA Astrophysics Data System (ADS)

    Teodorescu, Liliana; Britton, David; Glover, Nigel; Heinrich, Gudrun; Lauret, Jérôme; Naumann, Axel; Speer, Thomas; Teixeira-Dias, Pedro

    2012-06-01

    ACAT2011 This volume of Journal of Physics: Conference Series is dedicated to scientific contributions presented at the 14th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2011) which took place on 5-7 September 2011 at Brunel University, UK. The workshop series, which began in 1990 in Lyon, France, brings together computer science researchers and practitioners, and researchers from particle physics and related fields in order to explore and confront the boundaries of computing and of automatic data analysis and theoretical calculation techniques. It is a forum for the exchange of ideas among the fields, exploring and promoting cutting-edge computing, data analysis and theoretical calculation techniques in fundamental physics research. This year's edition of the workshop brought together over 100 participants from all over the world. 14 invited speakers presented key topics on computing ecosystems, cloud computing, multivariate data analysis, symbolic and automatic theoretical calculations as well as computing and data analysis challenges in astrophysics, bioinformatics and musicology. Over 80 other talks and posters presented state-of-the art developments in the areas of the workshop's three tracks: Computing Technologies, Data Analysis Algorithms and Tools, and Computational Techniques in Theoretical Physics. Panel and round table discussions on data management and multivariate data analysis uncovered new ideas and collaboration opportunities in the respective areas. This edition of ACAT was generously sponsored by the Science and Technology Facility Council (STFC), the Institute for Particle Physics Phenomenology (IPPP) at Durham University, Brookhaven National Laboratory in the USA and Dell. We would like to thank all the participants of the workshop for the high level of their scientific contributions and for the enthusiastic participation in all its activities which were, ultimately, the key factors in the

  17. UCLA program in reactor studies: The ARIES tokamak reactor study. Progress report, December 1, 1990--November 30, 1991

    SciTech Connect

    Not Available

    1991-12-01

    The ARIES research program is a multi-institutional effort to develop several visions of tokamak reactors with enhanced economic, safety, and environmental features. The aims are to determine the potential economics, safety, and environmental features of a range of possible tokamak reactors, and to identify physics and technology areas with the highest leverage for achieving the best tokamak reactor. Four ARIES visions are currently planned for the ARIES program. The ARIES-1 design is a DT-burning reactor based on ``modest`` extrapolations from the present tokamak physics database and relies on either existing technology or technology for which trends are already in place, often in programs outside fusion. ARIES-2 and ARIES-4 are DT-burning reactors which will employ potential advances in physics. The ARIES-2 and ARIES-4 designs employ the same plasma core but have two distinct fusion power core designs; ARIES-2 utilize the lithium as the coolant and breeder and vanadium alloys as the structural material while ARIES-4 utilizes helium is the coolant, solid tritium breeders, and SiC composite as the structural material. Lastly, the ARIES-3 is a conceptual D-{sup 3}He reactor. During the period Dec. 1, 1990 to Nov. 31, 1991, most of the ARIES activity has been directed toward completing the technical work for the ARIES-3 design and documenting the results and findings. We have also completed the documentation for the ARIES-1 design and presented the results in various meetings and conferences. During the last quarter, we have initiated the scoping phase for ARIES-2 and ARIES-4 designs.

  18. Physics of Spherical Torus Plasmas

    SciTech Connect

    Peng, Yueng Kay Martin

    2000-01-01

    Broad and important progress in plasma tests, theory, new experiments, and future visions of the spherical torus (ST, or very low aspect ratio tokamaks) have recently emerged. These have substantially improved our understanding of the potential properties of the ST plasmas, since the preliminary calculation of the ST magnetohydrodynamic equilibria more than a decade ago. Exciting data have been obtained from concept exploration level ST experiments of modest capabilities (with major radii up to 35 cm), making important scientific contributions to toroidal confinement in general. The results have helped approval and construction of new and/or more powerful ST experiments, and stimulated an increasing number of theoretical calculations of interest to magnetic fusion energy. Utilizing the broad knowledge base from the successful tokamak and advanced tokamak research, a wide range of new ST physics features has been suggested. These properties of the ST plasma will be tested at the 1 MA level with major radius up to similar to 80 cm in the new proof of principle devices National Spherical Torus Experiment (NSTX, U.S.) [M. Peng , European Conf. Abst. 22C, 451 (1998); S. M. Kaye , Fusion Technol. 36, 16 (1999); M. Ono , "Exploration of Spherical Torus Physics in the NSTX Device," 17th IAEA Fusion Energy Conf., paper IAEA-CN-69/ICP/01 (R), Yokohama, Japan (1998)], Mega Ampere Spherical Tokamak (MAST, U.K.) [A. C. Darke , Fusion Technol. 1, 799 (1995); Q. W. Morris , Proc. Int. Workshop on ST (Ioffe Inst., St. Petersburg, 1997), Vol. 1, p. 290], and Globus-M (R.F.) [V. K. Gusev , European Conf. Abst. 22C, 576 (1998)], which have just started full experimental operation. New concept exploration experiments, such as Pegasus (University of Wisconsin) [R. Fonck and the PEGASUS Team, Bull. Am. Phys. Soc. 44, 267 (1999)], Helicity Injected Tokamak-II (HIT-II, University of Washington) [T. R. Jarboe , Phys. Plasmas 5, 1807 (1998)], and Current Drive Experiment-Upgrade (CDX

  19. A driver linac for the Advanced Exotic Beam Laboratory : physics design and beam dynamics simulations.

    SciTech Connect

    Ostroumov, P. N.; Mustapha, B.; Nolen, J.; Physics

    2007-01-01

    The Advanced Exotic Beam Laboratory (AEBL) being developed at ANL consists of an 833 MV heavy-ion driver linac capable of producing uranium ions up to 200 MeV/u and protons to 580 MeV with 400 kW beam power. We have designed all accelerator components including a two charge state LEBT, an RFQ, a MEBT, a superconducting linac, a stripper station and chicane. We present the results of an optimized linac design and end-to-end simulations including machine errors and detailed beam loss analysis. The Advanced Exotic Beam Laboratory (AEBL) has been proposed at ANL as a reduced scale of the original Rare Isotope Accelerator (RIA) project with about half the cost but the same beam power. AEBL will address 90% or more of RIA physics but with reduced multi-users capabilities. The focus of this paper is the physics design and beam dynamics simulations of the AEBL driver linac. The reported results are for a multiple charge state U{sup 238} beam.

  20. Insights into the physical chemistry of materials from advances in HAADF-STEM

    SciTech Connect

    Sohlberg, Karl; Pennycook, Timothy J.; Zhou, Wu; Pennycook, Stephen J.

    2014-11-13

    The observation that, ‘‘New tools lead to new science’’[P. S. Weiss, ACS Nano., 2012, 6(3), 1877–1879], is perhaps nowhere more evident than in scanning transmission electron microscopy (STEM). Advances in STEM have endowed this technique with several powerful and complimentary capabilities. For example, the application of high-angle annular dark-field imaging has made possible real-space imaging at subangstrom resolution with Z-contrast (Z = atomic number). Further advances have wrought: simultaneous real-space imaging and elemental identification by using electron energy loss spectroscopy (EELS); 3-dimensional (3D) mapping by depth sectioning; monitoring of surface diffusion by time-sequencing of images; reduced electron energy imaging for probing graphenes; etc. In this paper we review how these advances, often coupled with first-principles theory, have led to interesting and important new insights into the physical chemistry of materials. We then review in detail a few specific applications that highlight some of these STEM capabilities.

  1. Insights into the physical chemistry of materials from advances in HAADF-STEM

    DOE PAGESBeta

    Sohlberg, Karl; Pennycook, Timothy J.; Zhou, Wu; Pennycook, Stephen J.

    2014-11-13

    The observation that, ‘‘New tools lead to new science’’[P. S. Weiss, ACS Nano., 2012, 6(3), 1877–1879], is perhaps nowhere more evident than in scanning transmission electron microscopy (STEM). Advances in STEM have endowed this technique with several powerful and complimentary capabilities. For example, the application of high-angle annular dark-field imaging has made possible real-space imaging at subangstrom resolution with Z-contrast (Z = atomic number). Further advances have wrought: simultaneous real-space imaging and elemental identification by using electron energy loss spectroscopy (EELS); 3-dimensional (3D) mapping by depth sectioning; monitoring of surface diffusion by time-sequencing of images; reduced electron energy imaging formore » probing graphenes; etc. In this paper we review how these advances, often coupled with first-principles theory, have led to interesting and important new insights into the physical chemistry of materials. We then review in detail a few specific applications that highlight some of these STEM capabilities.« less

  2. Engineering development of advanced physical fine coal cleaning for premium fuel applications

    SciTech Connect

    Shields, G.L.; Smit, F.J.; Jha, M.C.

    1997-08-28

    The primary goal of this project is the engineering development of two advanced physical fine coal cleaning processes, column flotation and selective agglomeration, for premium fuel applications. The project scope included laboratory research and bench-scale testing on six coals to optimize these processes, followed by the design, construction and operation of 2 t/hr process development unit (PDU). This report represents the findings of the PDU Advanced Column Flotation Testing and Evaluation phase of the program and includes a discussion of the design and construction of the PDU. Three compliance steam coals, Taggart, Indiana VII and Hiawatha, were processed in the PDU to determine performance and design parameters for commercial production of premium fuel by advanced flotation. Consistent, reliable performance of the PDU was demonstrated by 72-hr production runs on each of the test coals. Its capacity generally was limited by the dewatering capacity of the clean coal filters during the production runs rather than by the flotation capacity of the Microcel column. The residual concentrations of As, Pb, and Cl were reduced by at least 25% on a heating value basis from their concentrations in the test coals. The reduction in the concentrations of Be, Cd, Cr, Co, Mn, Hg, Ni and Se varied from coal to coal but the concentrations of most were greatly reduced from the concentrations in the ROM parent coals. The ash fusion temperatures of the Taggart and Indiana VII coals, and to a much lesser extent the Hiawatha coal, were decreased by the cleaning.

  3. Study of solid oxide fuel cell interconnects, protective coatings and advanced physical vapor deposition techniques

    NASA Astrophysics Data System (ADS)

    Gannon, Paul Edward

    High energy conversion efficiency, decreased environmentally-sensitive emissions and fuel flexibility have attracted increasing attention toward solid oxide fuel cell (SOFC) systems for stationary, transportation and portable power generation. Critical durability and cost issues, however, continue to impede wide-spread deployment. Many intermediate temperature (600-800°C) planar SOFC systems employ metallic alloy interconnect components, which physically connect individual fuel cells into electric series, facilitate gas distribution to appropriate SOFC electrode chambers (fuel/anode and oxidant[air]/cathode) and provide SOFC stack mechanical support. These demanding multifunctional requirements challenge commercially-available and inexpensive metallic alloys due to corrosion and related effects. Many ongoing investigations are aimed at enabling inexpensive metallic alloys (via bulk and/or surface modifications) as SOFC interconnects (SOFC(IC)s). In this study, two advanced physical vapor deposition (PVD) techniques: large area filtered vacuum arc deposition (LAFAD), and filtered arc plasma-assisted electron beam PVD (FA-EBPVD) were used to deposit a wide-variety of protective nanocomposite (amorphous/nanocrystalline) ceramic thin-film (<5microm) coatings on commercial and specialty stainless steels with different surface finishes. Both bare and coated steel specimens were subjected to SOFC(IC)-relevant exposures and evaluated using complimentary surface analysis techniques. Significant improvements were observed under simulated SOFC(IC) exposures with many coated specimens at ˜800°C relative to uncoated specimens: stable surface morphology; low area specific resistance (ASR <100mO·cm 2 >1,000 hours); and, dramatically reduced Cr volatility (>30-fold). Analyses and discussions of SOFC(IC) corrosion, advanced PVD processes and protective coating behavior are intended to advance understanding and accelerate the development of durable and commercially-viable SOFC

  4. Advanced Mesh-Enabled Monte carlo capability for Multi-Physics Reactor Analysis

    SciTech Connect

    Wilson, Paul; Evans, Thomas; Tautges, Tim

    2012-12-24

    This project will accumulate high-precision fluxes throughout reactor geometry on a non- orthogonal grid of cells to support multi-physics coupling, in order to more accurately calculate parameters such as reactivity coefficients and to generate multi-group cross sections. This work will be based upon recent developments to incorporate advanced geometry and mesh capability in a modular Monte Carlo toolkit with computational science technology that is in use in related reactor simulation software development. Coupling this capability with production-scale Monte Carlo radiation transport codes can provide advanced and extensible test-beds for these developments. Continuous energy Monte Carlo methods are generally considered to be the most accurate computational tool for simulating radiation transport in complex geometries, particularly neutron transport in reactors. Nevertheless, there are several limitations for their use in reactor analysis. Most significantly, there is a trade-off between the fidelity of results in phase space, statistical accuracy, and the amount of computer time required for simulation. Consequently, to achieve an acceptable level of statistical convergence in high-fidelity results required for modern coupled multi-physics analysis, the required computer time makes Monte Carlo methods prohibitive for design iterations and detailed whole-core analysis. More subtly, the statistical uncertainty is typically not uniform throughout the domain, and the simulation quality is limited by the regions with the largest statistical uncertainty. In addition, the formulation of neutron scattering laws in continuous energy Monte Carlo methods makes it difficult to calculate adjoint neutron fluxes required to properly determine important reactivity parameters. Finally, most Monte Carlo codes available for reactor analysis have relied on orthogonal hexahedral grids for tallies that do not conform to the geometric boundaries and are thus generally not well

  5. The Spherical Tokamak MEDUSA for Mexico

    NASA Astrophysics Data System (ADS)

    Ribeiro, C.; Salvador, M.; Gonzalez, J.; Munoz, O.; Tapia, A.; Arredondo, V.; Chavez, R.; Nieto, A.; Gonzalez, J.; Garza, A.; Estrada, I.; Jasso, E.; Acosta, C.; Briones, C.; Cavazos, G.; Martinez, J.; Morones, J.; Almaguer, J.; Fonck, R.

    2011-10-01

    The former spherical tokamak MEDUSA (Madison EDUcation Small Aspect.ratio tokamak, R < 0.14m, a < 0.10m, BT < 0.5T, Ip < 40kA, 3ms pulse) is currently being recomissioned at the Universidad Autónoma de Nuevo León, Mexico, as part of an agreement between the Faculties of Mech.-Elect. Eng. and Phy. Sci.-Maths. The main objective for having MEDUSA is to train students in plasma physics & technical related issues, aiming a full design of a medium size device (e.g. Tokamak-T). Details of technical modifications and a preliminary scientific programme will be presented. MEDUSA-MX will also benefit any developments in the existing Mexican Fusion Network. Strong liaison within national and international plasma physics communities is expected. New activities on plasma & engineering modeling are expected to be developed in parallel by using the existing facilities such as a multi-platform computer (Silicon Graphics Altix XE250, 128G RAM, 3.7TB HD, 2.7GHz, quad-core processor), ancillary graph system (NVIDIA Quadro FE 2000/1GB GDDR-5 PCI X16 128, 3.2GHz), and COMSOL Multiphysics-Solid Works programs.

  6. Tokamak foundation in USSR/Russia 1950-1990

    NASA Astrophysics Data System (ADS)

    Smirnov, V. P.

    2010-01-01

    In the USSR, nuclear fusion research began in 1950 with the work of I.E. Tamm, A.D. Sakharov and colleagues. They formulated the principles of magnetic confinement of high temperature plasmas, that would allow the development of a thermonuclear reactor. Following this, experimental research on plasma initiation and heating in toroidal systems began in 1951 at the Kurchatov Institute. From the very first devices with vessels made of glass, porcelain or metal with insulating inserts, work progressed to the operation of the first tokamak, T-1, in 1958. More machines followed and the first international collaboration in nuclear fusion, on the T-3 tokamak, established the tokamak as a promising option for magnetic confinement. Experiments continued and specialized machines were developed to test separately improvements to the tokamak concept needed for the production of energy. At the same time, research into plasma physics and tokamak theory was being undertaken which provides the basis for modern theoretical work. Since then, the tokamak concept has been refined by a world-wide effort and today we look forward to the successful operation of ITER.

  7. Boundary Plasma Turbulence Simulations for Tokamaks

    SciTech Connect

    Xu, X; Umansky, M; Dudson, B; Snyder, P

    2008-05-15

    The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T{sub e}; T{sub i}) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.

  8. System studies of Compact Ignition Tokamaks

    SciTech Connect

    Galambos, J.D.; Peng, Y.K.M.; Blackfield, D.T.

    1986-11-01

    The Fusion Engineering Design Center (FEDC) Tokamak Systems Code is used to perform trade studies in accordance with the Compact Ignition Tokamak (CIT) physics and engineering guidelines. The authors examine various toroidal field coil (TFC) configurations, preload levels, and coil materials. Use of Inconel-copper composite material results in the smallest sized devices for both bucked and wedged TFCs and wedged-only TFCs. Preload levels of 23 Mkg are needed for the minimum sized devices, and for the lower strength materials, the minimum size is sensitive to the preload level. Results from these trade studies help lead to the choice of the baseline CIT point at R = 1.25 m and B = 10.4 T.

  9. Tritium catalyzed deuterium tokamaks

    SciTech Connect

    Greenspan, E.; Miley, G.H.; Jung, J.; Gilligan, J.

    1984-04-01

    A preliminary assessment of the promise of the Tritium Catalyzed Deuterium (TCD) tokamak power reactors relative to that of deuterium-tritium (D-T) and catalyzed deuterium (Cat-D) tokamaks is undertaken. The TCD mode of operation is arrived at by converting the /sup 3/He from the D(D,n)/sup 3/He reaction into tritium, by neutron capture in the blanket; the tritium thus produced is fed into the plasma. There are three main parts to the assessment: blanket study, reactor design and economic analysis and an assessment of the prospects for improvements in the performance of TCD reactors (and in the promise of the TCD mode of operation, in general).

  10. The Source Physics Experiments and Advances in Seismic Explosion Monitoring Predictive Capabilities

    NASA Astrophysics Data System (ADS)

    Walter, W. R.; Ford, S. R.; Antoun, T.; Pitarka, A.; Xu, H.; Vorobiev, O.; Rodgers, A.; Pyle, M. L.

    2012-12-01

    Despite many years of study, a number of seismic explosion phenomena remain incompletely understood. These include the generation of S-waves, the variation of absolute amplitudes with emplacement media differences, and the occasional generation of reversed Rayleigh waves. Advances in numerical methods and increased computational power have improved the physics contained in the modeling software and it is possible to couple non-linear source-region effects to far-field propagation codes to predict seismic observables, thereby allowing end-to-end modeling. However, despite the many sensor records from prior nuclear tests, the data available to develop and validate the simulation codes remain limited in important ways. This is particularly the case for the range of both scaled depths of burial and of source media, especially where full near-field to far-field records are available along with key quantitative parameter data such as depth, material properties and yield. For example, two of the most widely used seismic source models, both derived from the best empirical data, Mueller and Murphy (1971) and Denny and Johnson (1989), predict very different amplitudes for greatly overburied explosions. To provide new data to advance predictive explosion modeling capabilities, the National Nuclear Security Administration (NNSA) is carrying out a series of seven chemical explosions over a range of depths and sizes in the Source Physics Experiments (SPE). These shots are taking place in the Climax Stock granite at the Nevada National Security Site, the location where reversed Rayleigh waves from a nuclear test were first observed in the 1962 HARDHAT event (e.g. Brune and Pomeroy, 1963). Three of the SPE shots have successfully occurred so far, and were well-recorded by an extensive set of instrumentation including seismic, acoustic, EM, and remote sensing. In parallel, detailed site characterization has been conducted using geologic mapping and sampling, borehole geophysics

  11. Energy confinement in tokamaks

    SciTech Connect

    Sugihara, M.; Singer, C.

    1986-08-01

    A straightforward generalization is made of the ohmic heating energy confinement scalings of Pfeiffer and Waltz and Blackwell et. al. The resulting model is systematically calibrated to published data from limiter tokamaks with ohmic, electron cyclotron, and neutral beam heating. With considerably fewer explicitly adjustable free parameters, this model appears to give a better fit to the available data for limiter discharges than the combined ohmic/auxiliary heating model of Goldston.

  12. COMPRES Mineral Physics Educational Modules for Advanced Undergraduates and Graduate Students

    NASA Astrophysics Data System (ADS)

    Burnley, P. C.; Thomas, S.

    2012-12-01

    The Consortium for Materials Properties Research in Earth Sciences (COMPRES) is a community-based consortium whose goal is to advance and facilitate experimental high pressure research in the Earth Sciences. An important aspect of this goal is sharing our knowledge with the next generation of researchers. To facilitate this, we have created a group of web-based educational modules on mineral physics topics. The modules reside in the On Cutting Edge, Teaching Mineralogy collection on the Science Education Resource Center (SERC) website. Although the modules are designed to function as part of a full semester course, each module can also stand alone. Potential users of the modules include mineral physics faculty teaching "bricks and mortar" classes at their own institutions, or in distance education setting, mineralogy teachers interested in including supplementary material in their mineralogy class, undergraduates doing independent study projects and graduate students and colleagues in other sub-disciplines who wish to brush up on a mineral physics topic. We used the modules to teach an on-line course entitled "Introduction to Mineral Physics" during the spring 2012 semester. More than 20 students and postdocs as well as 15 faculty and senior scientists participated in the course which met twice weekly as a webinar. Recordings of faculty lectures and student-led discussions of journal articles are now available upon request and edited versions of the lectures will be incorporated into the educational modules. Our experience in creating the modules and the course indicates that the use of 1) community-generated internet-based resources and 2) webinars to enable shared teaching between faculty at different universities, has the potential to both enrich graduate education and create efficiencies for university faculty.;

  13. Performance and development of the DIII-D tokamak core

    SciTech Connect

    Anderson, P.M.; Johnson, W.R.; Busath, J.L.; Allen, S.L.

    1998-07-01

    The DIII-D tokamak is an upgrade of the Doublet III configuration which has operated since early 1986. This paper presents recent advances in performance using the upper divertor, fabrication development for vanadium components, operation of the helium leak checking in a high deuterium background, and restoration of the damaged Ohmic heating solenoid.

  14. Spherical tokamaks with plasma centre-post

    NASA Astrophysics Data System (ADS)

    Ribeiro, Celso

    2013-10-01

    The metal centre-post (MCP) in tokamaks is a structure which carries the total toroidal field current and also houses the Ohmic heating solenoid in conventional or low aspect ratio (Spherical)(ST) tokamaks. The MCP and solenoid are critical components for producing the toroidal field and for the limited Ohmic flux in STs. Constraints for a ST reactor related to these limitations lead to a minimum plasma aspect ratio of 1.4 which reduces the benefit of operation at higher betas in a more compact ST reactor. Replacing the MCP is of great interest for reactor-based ST studies since the device is simplified, compactness increased, and maintenance reduced. An experiment to show the feasibility of using a plasma centre-post (PCP) is being currently under construction and involves a high level of complexity. A preliminary study of a very simple PCP, which is ECR(Electron Cyclotron Resonance)-assisted and which includes an innovative fuelling system based on pellet injection, has recently been reported. This is highly suitable for an ultra-low aspect ratio tokamak (ULART) device. Advances on this PCP ECR-assisted concept within a ULART and the associated fuelling system are presented here, and will include the field topology for the PCP ECR-assisted scheme, pellet ablation modeling, and a possible global equilibrium simulation. VIE-ITCR, IAEA-CRP contr.17592, National Instruments-Costa Rica.

  15. PREFACE: FLUIDOS 2010: XI Meeting on Recent Advances in the Physics of Fluids and their Applications

    NASA Astrophysics Data System (ADS)

    Bove, Italo; Cabeza, Cecilia; Martí, Arturo C.; Sarasúa, Gustavo

    2011-04-01

    The papers published in this volume of the Journal of Physics: Conference Series were selected from the manuscripts submitted to the XI Meeting on Recent Advances in the Physics of Fluids and their Applications (FLUIDOS2010), which was held in Colonia del Sacramento, Uruguay, 3-5 November 2010. FLUIDOS takes place every two years, usually in November, with the aim of gathering together researchers from all areas of the Physics of Fluids, to update themselves on the latest technical developments and applications, share knowledge and stimulate new ideas. This 11th meeting continues the successful experience of the previous ones which were held in different Argentinian cities. For the first time, the meeting was celebrated in Uruguay, more specifically, in the peaceful town of Colonia del Sacramento, designated a World Heritage Site by UNESCO. The conference presented an outstanding program of papers covering the most recent advances in Physics of Fluids in the following areas: General Fluid Dynamics General and non-Newtonian Flows Magnetohydrodynamics Electrohydrodynamics and Plasmas Hydraulics, Thermohydraulics and Multiple Phase Flows A website with full details of the conference program, abstracts and other information can be found at http://fluidos2010.fisica.edu.uy. We would like to thank all the participants, especially those who contributed with talks, posters and manuscripts, for making FLUDOS2010 such a successful conference. Our thanks also go to our colleagues for their support and encouragement, particularly in the refereeing of papers. We would like to acknowledge additional financial support from Comisión Sectorial de Investigación Científica (Universidad de la República, Uruguay), Programa de Desarrollo de las Ciencias Básicas (Uruguay) and the Centro Latinoamericano de Física (CLAF). Our thanks are extended to the local government of Colonia del Sacramento. The next FLUIDOS conference will be held in November 2013, in Buenos Aires, Argentina. We

  16. [Important bio-thermal physical problems and latest advancement in laser cell engineering].

    PubMed

    Li, H J; Liu, J; Zhang, X X

    2001-10-01

    The recently emerging technique of laser microsurgery (optical tweezers, optical scissors, etc.) is providing a new precise, sterile method for the cell engineering practices such as introduction of external gene into an object cell, cell-fusion, and trapping or transportation of microscopic objects (cells or chromosomes etc.). The thermal effects thus induced usually proved to be critical factors for successful operation of this method. In order to meet the requirement for the rapid development in this territory, some important bio-thermal physical problems and the corresponding research subjects in this area were comprehensively summarized. Difficulties and critical issues were discussed. The latest advancement of the laser cell engineering was also described. This review is attempted to bridge up the gap between bioengineering and thermal science fields and then to enhance the rapid progress of laser microsurgery. PMID:11845828

  17. Plasma/Liquid-Metal Interactions During Tokamak Operation

    SciTech Connect

    Hassanein, A.; Allain, J.P.; Insepov, Z.; Konkashbaev, I.

    2005-04-15

    One of the critical technological challenges of future tokamak fusion devices is the ability for plasma-facing components to handle both normal and abnormal plasma/surface interaction events that compromise their lifetime and operation of the machine. Under normal operation plasma/surface interactions that are important include: sputtering, particle implantation and recycling, He pumping and ELM (edge localized modes)-induced erosion. In abnormal or off-normal operation: disruptions and vertical displacement events (VDEs) are important. To extend PFC lifetime under these conditions, liquid-metals have been considered as candidate PFCs (Plasma-Facing Components), including: liquid lithium, tin-lithium, gallium and tin.Liquid lithium has been measured to have nonlinear increase of physical sputtering with rise in temperature. Such increase can be a result of exposure to ELM-level particle fluxes. The significant increase in particle flux to the divertor and nearby PFCs can enhance sputtering erosion by an order of magnitude or more. In addition from the standpoint of hydrogen recycling and helium pumping liquid lithium appears to be a good candidate plasma-facing material (PFM). Advanced designs of first wall and divertor systems propose the application of liquid-metals as an alternate PFC to contend with high-heat flux constraints of large-scale tokamak devices. Additional issues include PFC operation under disruptions and long temporal instabilities such as VDEs. A comprehensive two-fluid model is developed to integrate core and SOL (scrape-off layer) parameters during ELMs with PFC surface evolution using the HEIGHTS package. Special emphasis is made on the application of lithium as a candidate plasma-facing liquid-metal.

  18. Plasma/liquid metal interactions during tokamak operation.

    SciTech Connect

    Hassanein, A.; Allain, J. P.; Insepov, Z.; Konkashbaev, I.; Energy Technology

    2005-04-01

    One of the critical technological challenges of future tokamak fusion devices is the ability for plasma-facing components to handle both normal and abnormal plasma/surface interaction events that compromise their lifetime and operation of the machine. Under normal operation plasma/surface interactions that are important include: sputtering, particle implantation and recycling, He pumping and ELM (edge localized modes)-induced erosion. In abnormal or off-normal operation: disruptions and vertical displacement events (VDEs) are important. To extend PFC lifetime under these conditions, liquid-metals have been considered as candidate PFCs (Plasma-Facing Components), including: liquid lithium, tin-lithium, gallium and tin. Liquid lithium has been measured to have nonlinear increase of physical sputtering with rise in temperature. Such increase can be a result of exposure to ELM-level particle fluxes. The significant increase in particle flux to the divertor and nearby PFCs can enhance sputtering erosion by an order of magnitude or more. In addition from the standpoint of hydrogen recycling and helium pumping liquid lithium appears to be a good candidate plasma-facing material (PFM). Advanced designs of first wall and divertor systems propose the application of liquid-metals as an alternate PFC to contend with high-heat flux constraints of large-scale tokamak devices. Additional issues include PFC operation under disruptions and long temporal instabilities such as VDEs. A comprehensive two-fluid model is developed to integrate core and SOL (scrape-off layer) parameters during ELMs with PFC surface evolution using the HEIGHTS package. Special emphasis is made on the application of lithium as a candidate plasma-facing liquid-metal.

  19. Engineering development of advanced physical fine coal cleaning technologies: Froth flotation

    SciTech Connect

    Not Available

    1990-01-01

    a study conducted by Pittsburgh Energy Technology Center of sulfur emissions from about 1300 United States coal-fired utility boilers indicated that half of the emissions were the result of burning coals having greater than 1.2 pounds of SO{sub 2} per million BTU. This was mainly attributed to the high pyritic sulfur content of the boiler fuel. A significant reduction in SO{sub 2} emissions could be accomplished by removing the pyrite from the coals by advanced physical fine coal cleaning. An engineering development project was prepared to build upon the basic research effort conducted under a solicitation for research into Fine Coal Surface Control. The engineering development project is intended to use general plant design knowledge and conceptualize a plant to utilize advanced froth flotation technology to process coal and produce a product having maximum practical pyritic sulfur reduction consistent with maximum practical BTU recovery. This document is the eighth quarterly report prepared in accordance with the project reporting requirements covering the period from July 1,1990 to September 30, 1990. The overall project scope of the engineering development project is to conceptually develop a commercial flowsheet to maximize pyritic sulfur reduction at practical energy recovery values. The data from the basic research on coal surfaces, bench scale testing and proof-of-concept scale testing will be utilized to design a final conceptual flowsheet. The economics of the flowsheet will be determined to enable industry to assess the feasibility of incorporating the advanced fine coal cleaning technology into the production of clean coal for generating electricity. 22 figs., 11 tabs.

  20. The Science of Spherical Tokamak Plasmas: Progress and Promise

    NASA Astrophysics Data System (ADS)

    Sykes, Alan

    2008-11-01

    The talk will summarize the development of the low aspect ratio `Spherical' Tokamak (ST) from early linear magnetic confinement devices, through toroidal pinches, to the emergence of the tokamak in the 1960's. Theoretical predictions given by Peng and Strickler of the exciting physics of extreme low aspect ratio tokamaks (supported by early experiments involving centre rods inserted into existing Rotamaks, Spheromaks and other small-scale experiments), led to the pioneering START experiment at Culham which convincingly demonstrated the potential of the ST concept. There are now many STs world-wide. The largest among these are MA-scale devices NSTX and MAST with plasmas of cross-section comparable to DIII-D and Asdex-Upgrade. The major results include development of start-up methods; the refinement of scaling laws; improved understanding of general tokamak phenomena such as Edge Localised Modes and development of heating and current drive schemes. ST research on over 20 devices has extended the tokamak plasma regime in many ways, notably a factor 4 increase in stable toroidal average beta, and large increases in the Alfven Mach number and ExB flow shear. By exploiting such features, joint experiments with tokamaks of conventional aspect ratio are resolving several key degeneracies of interest to ITER, DEMO and larger future ST devices. Present STs have low toroidal fields sufficient for most physics studies, but for high fusion yield or energy production higher fields are required; importantly, studies on both NSTX and MAST indicate a stronger than expected improvement of performance with toroidal field. Both devices are planning exciting upgrades which feature a considerable increase of toroidal field. Recent designs for a D-T Component Test Facility based on the Spherical Tokamak show the promise of low Tritium consumption and minimum build cost. Such a facility would provide valuable R&D on the scientific and technical issues of fusion power.

  1. The Dynamic Mutation Characteristics of Thermonuclear Reaction in Tokamak

    PubMed Central

    Li, Jing; Quan, Tingting; Zhang, Wei; Deng, Wei

    2014-01-01

    The stability and bifurcations of multiple limit cycles for the physical model of thermonuclear reaction in Tokamak are investigated in this paper. The one-dimensional Ginzburg-Landau type perturbed diffusion equations for the density of the plasma and the radial electric field near the plasma edge in Tokamak are established. First, the equations are transformed to the average equations with the method of multiple scales and the average equations turn to be a Z2-symmetric perturbed polynomial Hamiltonian system of degree 5. Then, with the bifurcations theory and method of detection function, the qualitative behavior of the unperturbed system and the number of the limit cycles of the perturbed system for certain groups of parameter are analyzed. At last, the stability of the limit cycles is studied and the physical meaning of Tokamak equations under these parameter groups is given. PMID:24892099

  2. The dynamic mutation characteristics of thermonuclear reaction in Tokamak.

    PubMed

    Li, Jing; Quan, Tingting; Zhang, Wei; Deng, Wei

    2014-01-01

    The stability and bifurcations of multiple limit cycles for the physical model of thermonuclear reaction in Tokamak are investigated in this paper. The one-dimensional Ginzburg-Landau type perturbed diffusion equations for the density of the plasma and the radial electric field near the plasma edge in Tokamak are established. First, the equations are transformed to the average equations with the method of multiple scales and the average equations turn to be a Z 2-symmetric perturbed polynomial Hamiltonian system of degree 5. Then, with the bifurcations theory and method of detection function, the qualitative behavior of the unperturbed system and the number of the limit cycles of the perturbed system for certain groups of parameter are analyzed. At last, the stability of the limit cycles is studied and the physical meaning of Tokamak equations under these parameter groups is given. PMID:24892099

  3. Advances in H-mode physics for long-pulse operation on EAST

    NASA Astrophysics Data System (ADS)

    Wan, Baonian; Li, Jiangang; Guo, Houyang; Liang, Yunfeng; Xu, Guosheng; Wang, Liang; Gong, Xianzu; Andrea Garofalothe EAST Team; Collaborators

    2015-10-01

    Since the 2012 International Atomic Energy Agency Fusion Energy Conference (IAEA-FEC), significant advances in both physics and technology has been made on the Experimental Advanced Superconducting Tomakak (EAST) toward a long-pulse stable high-confinement (H-mode) plasma regime. The experimental capabilities of EAST have been technically upgraded with the power enhancement (source power up to 26 MW) of the continuous-wave heating and current drive system, replacement of the upper graphite divertor with an ITER-like W monoblock divertor, and installation of a new internal cryopump in the upper divertor and a set of 16 in-vessel resonant magnetic perturbation (RMP) coils. This new upgrade enables EAST to be a unique operating device capable of investigating ITER-relevant long-pulse high-performance operations with dominant electron heating and low torque input within the next 5 years. Remarkable physics progress in controlling transient and steady-state divertor heat fluxes has been achieved on EAST, e.g. (i) edge-localized mode (ELM) mitigation/suppression with a number of attractive methods including lower hybrid wave (LHW), supersonic molecular beam injection (SMBI), RMPs, and real-time Li aerosol injection; and (ii) active control of steady-state power distribution by the synergy of LHW and SMBI. In the 2014 experimental campaign, a long-pulse high-performance H-mode plasma with H98 ˜ 1.2 has been obtained with a duration over 28 s (˜200 times the energy confinement time). In addition, several new experimental advances have been achieved in the last EAST campaign, including: (i) high-performance H-mode with βN ˜ 2 and stored plasma energy ˜220 kJ (ii) H-mode plasma sustained by neutral beam injection (NBI) alone or modulated NBI with lower hybrid current drive (LHCD), for the first time in EAST; (iii) high current drive efficiency and nearly full noninductive plasmas maintained by the new 4.6 GHz LHCD system; (iv) demonstration of a quasi-snowflake divertor

  4. Student Estimates of Probability and Uncertainty in Advanced Laboratory and Statistical Physics Courses

    NASA Astrophysics Data System (ADS)

    Mountcastle, Donald B.; Bucy, Brandon R.; Thompson, John R.

    2007-11-01

    Equilibrium properties of macroscopic systems are highly predictable as n, the number of particles approaches and exceeds Avogadro's number; theories of statistical physics depend on these results. Typical pedagogical devices used in statistical physics textbooks to introduce entropy (S) and multiplicity (ω) (where S = k ln(ω)) include flipping coins and/or other equivalent binary events, repeated n times. Prior to instruction, our statistical mechanics students usually gave reasonable answers about the probabilities, but not the relative uncertainties, of the predicted outcomes of such events. However, they reliably predicted that the uncertainty in a measured continuous quantity (e.g., the amount of rainfall) does decrease as the number of measurements increases. Typical textbook presentations assume that students understand that the relative uncertainty of binary outcomes will similarly decrease as the number of events increases. This is at odds with our findings, even though most of our students had previously completed mathematics courses in statistics, as well as an advanced electronics laboratory course that included statistical analysis of distributions of dart scores as n increased.

  5. Design and Analysis of the Thermal Shield of EAST Tokamak

    NASA Astrophysics Data System (ADS)

    Xie, Han; Liao, Ziying

    2008-04-01

    EAST (Experimental Advanced Superconducting Tokamak) is a tokamak with superconducting toroidal and poloidal magnets operated at 4.5 K. In order to reduce the thermal load applied on the surfaces of all cryogenically cooled components and keep the heat load of the cryogenic system at a minimum, a continuous radiation shield system located between the magnet system and warm components is adopted. The main loads to which the thermal shield system is subjected are gravity, seismic, electromagnetic and thermal gradients. This study employed NASTRAN and ANSYS finite element codes to analyze the stress under a spectrum of loading conditions and combinations, providing a theoretical basis for an optimization design of the structure.

  6. Adaptive grid finite element model of the tokamak scrapeoff layer

    SciTech Connect

    Kuprat, A.P.; Glasser, A.H.

    1995-07-01

    The authors discuss unstructured grids for application to transport in the tokamak edge SOL. They have developed a new metric with which to judge element elongation and resolution requirements. Using this method, the authors apply a standard moving finite element technique to advance the SOL equations while inserting/deleting dynamically nodes that violate an elongation criterion. In a tokamak plasma, this method achieves a more uniform accuracy, and results in highly stretched triangular finite elements, except near separatrix X-point where transport is more isotropic.

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

    SciTech Connect

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

    2015-10-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

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

    DOE PAGESBeta

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

    2015-10-15

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

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

    SciTech Connect

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

    2015-10-01

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

  11. Polarization spectroscopy of tokamak plasmas

    SciTech Connect

    Wroblewski, D.

    1991-09-01

    Measurements of polarization of spectral lines emitted by tokamak plasmas provide information about the plasma internal magnetic field and the current density profile. The methods of polarization spectroscopy, as applied to the tokamak diagnostic, are reviewed with emphasis on the polarimetry of motional Stark effect in hydrogenic neutral beam emissions. 25 refs., 7 figs.

  12. Calculation of rf current drive in tokamaks

    NASA Astrophysics Data System (ADS)

    Peysson, Y.; Decker, J.

    2008-11-01

    The toroidal plasma current is a key parameter for controlling MHD stability and fusion performances in tokamaks. Among the various methods for driving current, rf waves are a flexible and powerful tool. Therefore, their role in the design and optimization of advanced scenarios is considerable. The universal ray-tracing code C3PO coupled with the fully implicit linearized 3-D bounce-averaged relativistic electron Fokker-Planck solver LUKE is an illustration of the present day effort for performing fast and realistic calculations of the rf driven plasma current. The versatility of this tool is highlighted by simulations concerning the lower hybrid and electron cyclotron waves.

  13. Prediction of density limit disruptions on the J-TEXT tokamak

    NASA Astrophysics Data System (ADS)

    Wang, S. Y.; Chen, Z. Y.; Huang, D. W.; Tong, R. H.; Yan, W.; Wei, Y. N.; Ma, T. K.; Zhang, M.; Zhuang, G.

    2016-05-01

    Disruption mitigation is essential for the next generation of tokamaks. The prediction of plasma disruption is the key to disruption mitigation. A neural network combining eight input signals has been developed to predict the density limit disruptions on the J-TEXT tokamak. An optimized training method has been proposed which has improved the prediction performance. The network obtained has been tested on 64 disruption shots and 205 non-disruption shots. A successful alarm rate of 82.8% with a false alarm rate of 12.3% can be achieved at 4.8 ms prior to the current spike of the disruption. It indicates that more physical parameters than the current physical scaling should be considered for predicting the density limit. It was also found that the critical density for disruption can be predicted several tens of milliseconds in advance in most cases. Furthermore, if the network is used for real-time density feedback control, more than 95% of the density limit disruptions can be avoided by setting a proper threshold.

  14. Edge-localized-modes in tokamaks

    SciTech Connect

    Leonard, A. W.

    2014-09-15

    Edge-localized-modes (ELMs) are a ubiquitous feature of H-mode in tokamaks. When gradients in the H-mode transport barrier grow to exceed the MHD stability limit the ELM instability grows explosively, rapidly transporting energy and particles onto open field lines and material surfaces. Though ELMs provide additional particle and impurity transport through the H-mode transport barrier, enabling steady operation, the resulting heat flux transients to plasma facing surfaces project to large amplitude in future low collisionality burning plasma tokamaks. Measurements of the ELM heat flux deposition onto material surfaces in the divertor and main chamber indicate significant broadening compared to inter-ELM heat flux, with a timescale for energy deposition that is consistent with sonic ion flow and numerical simulation. Comprehensive ELM simulation is highlighting the important physics processes of ELM transport including parallel transport due to magnetic reconnection and turbulence resulting from collapse of the H-mode transport barrier. Encouraging prospects for ELM control and/or suppression in future tokamaks include intrinsic modes of ELM free operation, ELM triggering with frequent small pellet injection and the application of 3D magnetic fields.

  15. Nonlinear Simulation Studies of Tokamaks and STs

    SciTech Connect

    W. Park; J. Breslau; J. Chen; G.Y. Fu; S.C. Jardin; S. Klasky; J. Menard; A. Pletzer; B.C. Stratton; D. Stutman; H.R. Strauss; L.E. Sugiyama

    2003-07-07

    The multilevel physics, massively parallel plasma simulation code, M3D, has been used to study spherical tori (STs) and tokamaks. The magnitude of outboard shift of density profiles relative to electron temperature profiles seen in NSTX [National Spherical Torus Experiment] under strong toroidal flow is explained. Internal reconnection events in ST discharges can be classified depending on the crash mechanism, just as in tokamak discharges; a sawtooth crash, disruption due to stochasticity, or high-beta disruption. Toroidal shear flow can reduce linear growth of internal kink. It has a strong stabilizing effect nonlinearly and causes mode saturation if its profile is maintained, e.g., through a fast momentum source. Normally, however, the flow profile itself flattens during the reconnection process, allowing a complete reconnection to occur. In some cases, the maximum density and pressure spontaneously occur inside the island and cause mode saturation. Gyrokinetic hot particle/MHD hybrid studies of NSTX show the effects of fluid compression on a fast-ion-driven n = 1 mode. MHD studies of recent tokamak experiments with a central current hole indicate that the current clamping is due to sawtooth-like crashes, but with n = 0.

  16. Recent experimental results from the HL-1M tokamak and progress in the HL-2A project

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Yan, J. C.; Zhou, C. P.; Ding, X. T.; Wang, S. J.; Wang, E. Y.; Yao, L. H.; Mao, W. C.; Pan, C. H.; HL-1M Team; HL-2A Team

    2004-02-01

    Recent experimental results from the HL-1M tokamak and progress in the HL-2A project are presented in this paper. In HL-1M, strong fishbone instability was observed during off-axis electron cyclotron resonance heating (ECRH). This is the first observation of fishbone instability purely driven by energetic electrons produced by ECRH. The molecular beam injection (MBI) was first proposed and demonstrated in HL-1M. Recently, new results of the MBI experiment were obtained by increasing the pressure of the gas. A stair-shaped density increment was obtained with high-pressure multi-pulse MBI just like the density evolution behaviour during multi-pellet injection. It is shown that injected particles penetrated into the core region of the plasma. HL-2A is a divertor tokamak constructed at SWIP based on the original ASDEX main components. The mission of the HL-2A project is to explore the physics issues involved in an advanced tokamak. For the first phase, divertor (edge plasma) and confinement research will be emphasized. The major parameters of HL-2A are R = 1.65 m, a = 0.4 m, Bt = 2.8 T, IP = 0.48 MA. The main parameters and characteristics of the subsystems such as power supply, pumping, diagnostics and auxiliary heating are presented in this paper. The first plasma of HL-2A was obtained at the end of 2002.

  17. RAPTOR: Optimization, real-time simulation and control of the tokamak q profile evolution using a simplified transport model

    NASA Astrophysics Data System (ADS)

    Felici, Federico; Sauter, Olivier; Goodman, Timothy; Paley, James

    2010-11-01

    Control of the plasma current density and safety factor profile evolution in a tokamak is crucial for accessing advanced regimes. The evolution of the current density profile is steered by a combination of inductive voltage and auxiliary current drive actuators, and is nonlinearly coupled to the evolution of the (ion/electron) temperature and density profiles. Using appropriate simplifications, a model has been obtained which can be simulated on time scales faster than the tokamak discharge itself, but still retains the essential physics describing the nonlinear coupling between the profiles. This model, dubbed RAPTOR (Rapid Plasma Transport simulatOR) has been implemented in the new real-time control system on the TCV tokamak at CRPP, and can be used for real-time reconstruction and model-based control of the q profile. It can also be used off-line to determine optimal actuator trajectories in open loop simulations to steer the plasma profiles towards their required steady-state shapes while remaining within a constrained set of allowable profiles.

  18. Polarized fusion, its implications, and plans for a proof-of-principle experiment at the DIII-D tokamak

    NASA Astrophysics Data System (ADS)

    Sandorfi, A. M.; Deur, A.; Lowry, M. M.; Wei, X.; Pace, D.; Eidietis, N.; Hyatt, A.; Jackson, G. L.; Lanctot, M.; Smith, S.; St-John, H.; Miller, G. W.; Zheng, X.; Baylor, L. R.

    2015-10-01

    The cross section for the primary fusion reaction in a tokamak, D+t --> α +n, would increase by a factor of 1.5 if the fuels were spin polarized parallel to the local field, rather than randomly oriented. Simulations show further gains in reaction rate would accompany this increase in large-scale machines such as ITER, due to increased alpha heating. The potential realization of such benefits rests on the crucial question of the survival of spin polarization for periods comparable to the energy containment time. Despite encouraging calculations, technical challenges in preparing and handling polarized materials have prevented any direct tests. Advances in three areas - polarized material technologies developed for nuclear and particle physics as well as medical imaging, polymer pellets developed for Inertial Confinement, and cryogenic injection guns developed for fueling tokamaks - have matured to the point where a direct in situ measurement is possible using the mirror reaction, D+3He --> α +p. Designs and simulations of a proof-of-principle experiment at the DIII-D tokamak in San Diego will be discussed. Work carried out under US DOE Contract DE-AC05-06OR23177 supporting Jefferson Lab and General Atomics Internal R&D funding.

  19. The tokamak as a neutron source

    SciTech Connect

    Hendel, H.W.; Jassby, D.L.

    1989-11-01

    This paper describes the tokamak in its role as a neutron source, with emphasis on experimental results for D-D neutron production. The sections summarize tokamak operation, sources of fusion and non-fusion neutrons, principal neutron detection methods and their calibration, neutron energy spectra and fluxes outside the tokamak plasma chamber, history of neutron production in tokamaks, neutron emission and fusion power gain from JET and TFTR (the largest present-day tokamaks), and D-T neutron production from burnup of D-D tritons. This paper also discusses the prospects for future tokamak neutron production and potential applications of tokamak neutron sources. 100 refs., 16 figs., 4 tabs.

  20. Starlite figures of merit for tokamak current drive - economic analysis of pulsed and steady state power plants with various engineering and physics performance parameters

    SciTech Connect

    Ehst, D.A.

    1995-09-01

    The physics efficiency of current drive ({gamma}{sub B} {proportional_to} n{sub e} I{sub o} R{sub o}/P{sub CD}), including the bootstrap effect, needs to exceed certain goals in order to provide economical steady state operation compared to pulsed power plants. The goal for {gamma}{sub B} depends not only on engineering performance of the current drive system, but also on normalized beta and the effective safety factor of the achievable MHD equilibrium.

  1. STARLITE figures of merit for tokamak current drive -- Economic analysis of pulsed and steady state power plants with various engineering and physics performance parameters

    SciTech Connect

    Ehst, D.A.; Jardin, S.; Kessel, C.

    1995-10-01

    The physics efficiency of current drive ({gamma}{sub B} {proportional_to} n{sub e} I{sub 0} R{sub 0}/P{sub CD}), including the bootstrap effect, needs to exceed certain goals in order to provide economical steady state operation compared to pulsed power plants. The goal for {gamma}{sub B} depends not only on engineering performance of the current drive system, but also on normalized beta and the effective safety factor of the achievable MHD equilibrium.

  2. Investigation of the Flow Physics Driving Stall-Side Flutter in Advanced Forward Swept Fan Designs

    NASA Technical Reports Server (NTRS)

    Sanders, Albert J.; Liu, Jong S.; Panovsky, Josef; Bakhle, Milind A.; Stefko, George; Srivastava, Rakesh

    2003-01-01

    Flutter-free operation of advanced transonic fan designs continues to be a challenging task for the designers of aircraft engines. In order to meet the demands of increased performance and lighter weight, these modern fan designs usually feature low-aspect ratio shroudless rotor blade designs that make the task of achieving adequate flutter margin even more challenging for the aeroelastician. This is especially true for advanced forward swept designs that encompass an entirely new design space compared to previous experience. Fortunately, advances in unsteady computational fluid dynamic (CFD) techniques over the past decade now provide an analysis capability that can be used to quantitatively assess the aeroelastic characteristics of these next generation fans during the design cycle. For aeroelastic applications, Mississippi State University and NASA Glenn Research Center have developed the CFD code TURBO-AE. This code is a time-accurate three-dimensional Euler/Navier-Stokes unsteady flow solver developed for axial-flow turbomachinery that can model multiple blade rows undergoing harmonic oscillations with arbitrary interblade phase angles, i.e., nodal diameter patterns. Details of the code can be found in Chen et al. (1993, 1994), Bakhle et al. (1997, 1998), and Srivastava et al. (1999). To assess aeroelastic stability, the work-per-cycle from TURBO-AE is converted to the critical damping ratio since this value is more physically meaningful, with both the unsteady normal pressure and viscous shear forces included in the work-per-cycle calculation. If the total damping (aerodynamic plus mechanical) is negative, then the blade is unstable since it extracts energy from the flow field over the vibration cycle. TURBO-AE is an integral part of an aeroelastic design system being developed at Honeywell Engines, Systems & Services for flutter and forced response predictions, with test cases from development rig and engine tests being used to validate its predictive

  3. Resistive X-point modes in tokamak boundary plasmas

    SciTech Connect

    Myra, J. R.; D'Ippolito, D. A.; Xu, X. Q.; Cohen, R. H.

    2000-06-01

    It is shown that the boundary (edge and scrape-off-layer) plasma in a typical low (L) mode diverted tokamak discharge is unstable to a new class of modes called resistive X-point (RX) modes. The RX mode is a type of resistive ballooning mode that exploits a synergism between resistivity and the magnetic geometry of the X-point region. The RX modes are shown to give robust instabilities at moderate mode numbers, and therefore are expected to be the dominant contributors to turbulent diffusion in the boundary plasma of a diverted tokamak. (c) 2000 American Institute of Physics.

  4. Kinetic energy principle and neoclassical toroidal torque in tokamaks

    SciTech Connect

    Park, Jong-Kyu

    2011-11-15

    It is shown that when tokamaks are perturbed, the kinetic energy principle is closely related to the neoclassical toroidal torque by the action invariance of particles. Especially when tokamaks are perturbed from scalar pressure equilibria, the imaginary part of the potential energy in the kinetic energy principle is equivalent to the toroidal torque by the neoclassical toroidal viscosity. A unified description therefore should be made for both physics. It is also shown in this case that the potential energy operator can be self-adjoint and thus the stability calculation can be simplified by minimizing the potential energy.

  5. Kinetic Energy Principle And Neoclassical Toroidal Torque In Tokamaks

    SciTech Connect

    Jong-Kyu Park

    2011-11-07

    It is shown that when tokamaks are perturbed the kinetic energy principle is closely related to the neoclassical toroidal torque by the action invariance of particles. Especially when tokamaks are perturbed from scalar pressure equilibria, the imaginary part of the potential energy in the kinetic energy principle is equivalent to the toroidal torque by the Neoclassical Toroidal Viscosity (NTV). A unified description therefore should be made for both physics. It is also shown in this case that the potential energy operator can be self-adjoint and thus the stability calculation can be simplified by minimizing the potential energy

  6. Dust Measurements in Tokamaks

    SciTech Connect

    Rudakov, D; Yu, J; Boedo, J; Hollmann, E; Krasheninnikov, S; Moyer, R; Muller, S; Yu, A; Rosenberg, M; Smirnov, R; West, W; Boivin, R; Bray, B; Brooks, N; Hyatt, A; Wong, C; Fenstermacher, M; Groth, M; Lasnier, C; McLean, A; Stangeby, P; Ratynskaia, S; Roquemore, A; Skinner, C; Solomon, W M

    2008-04-23

    Dust production and accumulation impose safety and operational concerns for ITER. Diagnostics to monitor dust levels in the plasma as well as in-vessel dust inventory are currently being tested in a few tokamaks. Dust accumulation in ITER is likely to occur in hidden areas, e.g. between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering resolves size of particles between 0.16-1.6 {micro}m in diameter; the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast-framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in 2D with a single camera or 3D using multiple cameras, but determination of particle size is problematic. In order to calibrate diagnostics and benchmark dust dynamics modeling, pre-characterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase of carbon atomic, C2 dimer, and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.

  7. Sawtooth oscillation in tokamaks

    SciTech Connect

    Park, W.; Monticello, D.A.

    1989-03-01

    A three-dimensional nonlinear toroidal full MHD code, MH3D, has been used to study sawtooth oscillations in tokamaks. The profile evolution during the sawtooth crash phase compares well with experiment, but only if neoclassical resistivity is used in the rise phase. (Classical resistivity has been used in most of the previous theoretical sawtooth studies.) With neoclassical resistivity, the q value at the axis drops from 1 to about 0.8 before the crash phase, and then resets to 1 through a Kadomtsev-type complete reconnection process. This ..delta..q/sub 0/ approx. = 0.2 is much larger than ..delta..q/sub o/ approx. = 0.01, which is obtained if classical resistivity is used. The current profile is strongly peaked at the axis with a flat region around the singular surface, and is similar to the Textor profile. To understand this behavior, approximate formulas for the time behavior of current and q values are derived. A functional dependence of sawtooth period scaling is also derived. A semi-empirical scaling is found which fits the experimental data from various tokamaks. Some evidence is presented which indicates that the fast crash time is due to enhanced effective resistivity inside the singular current sheet, generated by, e.g., microinstability and electron parallel viscosity with stochastic fields at the x-point. 16 refs., 5 figs.

  8. ITER tokamak device

    NASA Astrophysics Data System (ADS)

    Doggett, J.; Salpietro, E.; Shatalov, G.

    1991-07-01

    The results of the Conceptual Design Activities for the International Thermonuclear Experimental Reactor (ITER) are summarized. These activities, carried out between April 1988 and December 1990, produced a consistent set of technical characteristics and preliminary plans for co-ordinated research and development support of ITER, a conceptual design, a description of design requirements and a preliminary construction schedule and cost estimate. After a description of the design basis, an overview is given of the tokamak device, its auxiliary systems, facility and maintenance. The interrelation and integration of the various subsystems that form the ITER tokamak concept are discussed. The 16 ITER equatorial port allocations, used for nuclear testing, diagnostics, fueling, maintenance, and heating and current drive, are given, as well as a layout of the reactor building. Finally, brief descriptions are given of the major ITER sub-systems, i.e., (1) magnet systems (toroidal and poloidal field coils and cryogenic systems), (2) containment structures (vacuum and cryostat vessels, machine gravity supports, attaching locks, passive loops and active coils), (3) first wall, (4) divertor plate (design and materials, performance and lifetime, a.o.), (5) blanket/shield system, (6) maintenance equipment, (7) current drive and heating, (8) fuel cycle system, and (9) diagnostics.

  9. Using an Advanced Computational Laboratory Experiment to Extend and Deepen Physical Chemistry Students' Understanding of Atomic Structure

    ERIC Educational Resources Information Center

    Hoffman, Gary G.

    2015-01-01

    A computational laboratory experiment is described, which involves the advanced study of an atomic system. The students use concepts and techniques typically covered in a physical chemistry course but extend those concepts and techniques to more complex situations. The students get a chance to explore the study of atomic states and perform…

  10. Advanced Summer School on Microelectronics: Physics and Technology for VLSI, Espoo, Finland, June 8-12, 1987, Proceedings

    NASA Astrophysics Data System (ADS)

    Stubb, Tor; Paananen, Riitta

    The conference presents papers on process integration for submicron CMOS, metallurgical topics in silicon device interconnections, and silicon oxidation. Consideration is also given to advanced photolithography for VSLI's and physics and modeling of submicron semiconductor devices. Other topics include the stability and electronic structure of ultrathin superlattices and alloys and time-dependent tunneling in heterostructures.

  11. Self-Organized Stationary States of Tokamaks

    SciTech Connect

    Jardin, S. C.; Ferraro, N.; Krebs, I.

    2015-11-17

    We demonstrate that in a 3D resistive magnetohydrodynamic (MHD) simulation, for some parameters it is possible to form a stationary state in a tokamak where a saturated interchange mode in the center of the discharge drives a near helical flow pattern that acts to non-linearly sustain the configuration by adjusting the central loop voltage through a dynamo action. This could explain the physical mechanism for maintaining stationary non-sawtoothing “hybrid” discharges, often referred to as “flux-pumping”.

  12. Physics of the Advanced Plasma Source: a review of recent experimental and modeling approaches

    NASA Astrophysics Data System (ADS)

    Brinkmann, R. P.; Harhausen, J.; Schröder, B.; Lapke, M.; Storch, R.; Styrnoll, T.; Awakowicz, P.; Foest, R.; Hannemann, M.; Loffhagen, D.; Ohl, A.

    2016-01-01

    The Advanced Plasma Source (APS), a gridless hot cathode glow discharge capable of generating an ion beam with an energy of up to 150 eV and a flux of 1019s‑1, is a standard industrial tool for the process of plasma ion-assisted deposition (PIAD). This manuscript details the results of recent experimental and modeling work aimed at a physical understanding of the APS. A three-zone model is proposed which consists of (i) the ionization zone (the source itself) where the plasma is very dense, hot, and has a high ionization rate, (ii) the acceleration zone (of  ∼20 cm extension) where a strong outward-directed electric field accelerates the primary ions to a high kinetic energy, and (iii) a drift zone (the rest of the process chamber) where the emerging plasma beam is further modified by resonant charge exchange collisions that neutralize some of the energetic ions and generate, at the same time, a flux of slow ions.

  13. Prospects and status of low-aspect-ratio tokamaks

    SciTech Connect

    Peng, Y.K.M.

    1994-12-31

    The prospects for the low-aspect-ratio (A) tokamak to fulfill the requirements of viable fusion power plants are considered relative to the present status in data and modeling. Desirable physics and design features for an attractive Blanket Test Facility and power reactors are estimated for low-A tokamaks based on calculations improved with the latest data from small pioneering experiments. While these experiments have confirmed some of the recent predictions for low-A, they also identify the remaining issues that require verification before reliable projections can be made for these deuterium-tritium applications. The results show that the low-A regime of small size, modest field, and high current offers a path complementary to the standard and high A tokamaks in developing the full potential of fusion power.

  14. The Spherical Tokamak MEDUSA for Costa Rica

    NASA Astrophysics Data System (ADS)

    Ribeiro, Celso; Vargas, Ivan; Guadamuz, Saul; Mora, Jaime; Ansejo, Jose; Zamora, Esteban; Herrera, Julio; Chaves, Esteban; Romero, Carlos

    2012-10-01

    The former spherical tokamak (ST) MEDUSA (Madison EDUcation Small Aspect.ratio tokamak, R<0.14m, a<0.10m, BT<0.5T, Ip<40kA, 3ms pulse)[1] is in a process of donation to Costa Rica Institute of Technology. The main objective of MEDUSA is to train students in plasma physics /technical related issues which will help all tasks of the very low aspect ratio stellarator SCR-1(A≡R/>=3.6, under design[2]) and also the ongoing activities in low temperature plasmas. Courses in plasma physics at undergraduate and post-graduate joint programme levels are regularly conducted. The scientific programme is intend to clarify several issues in relevant physics for conventional and mainly STs, including transport, heating and current drive via Alfv'en wave, and natural divertor STs with ergodic magnetic limiter[3,4]. [1] G.D.Garstka, PhD thesis, University of Wisconsin at Madison, 1997 [2] L.Barillas et al., Proc. 19^th Int. Conf. Nucl. Eng., Japan, 2011 [3] C.Ribeiro et al., IEEJ Trans. Electrical and Electronic Eng., 2012(accepted) [4] C.Ribeiro et al., Proc. 39^th EPS Conf. Contr. Fusion and Plasma Phys., Sweden, 2012

  15. On the physical interconnection of Seismic Electric Signals with seismicity: Recent advances

    NASA Astrophysics Data System (ADS)

    Sarlis, Nicholas; Skordas, Efthimios; Lazaridou, Mary; Varotsos, Panayiotis

    2013-04-01

    We review the recent advances on Seismic Electric Signals (SES) which are low frequency (˜ 1Hz) signals that precede earthquakes [1-3]. Since the 1980's Varotsos and Alexopoulos proposed [4] that SES are generated in the future focal area when the stress reaches a critical value, thus causing a cooperative orientation of the electric dipoles that anyhow exist in the focal area due to lattice imperfections in the ionic constituents of the rocks. A series of such signals within a short time are termed SES activity [5] and usually appear before major earthquakes. The combination of their physical properties enable the determination of the epicentral region and the magnitude well in advance. Natural time analysis introduced a decade ago [6, 7] may uncover novel dynamic features hidden behind time series in complex systems [8]. By employing this analysis, several advances have been made towards a better understanding of the SES properties. For example, it has been found [6, 8] that the natural time analysis of the seismicity subsequent to the initiation of a SES activity enables the determination of the occurrence time of an impending major mainshock within a time window of around one week. On this basis, predictions -including the magnitude, epicenter and time window of the expected event- have been documented well in advance for all five mainshocks with M_w×6.4 in Greece since 2001 [8, 9]. In addition, by applying natural time analysis to the time series of earthquakes, we recently found [10] that the order parameter of seismicity exhibits a unique change approximately at the date at which SES activities have been reported to initiate. This is the first time that before the occurrence of major earthquakes, anomalous changes are found to appear almost simultaneously in two different geophysical observables. 1. P. Varotsos and K. Alexopoulos, Tectonophysics 110, 73-98, 1984a. 2. P. Varotsos and K. Alexopoulos, Tectonophysics 110, 99-125, 1984b. 3. P.A. Varotsos, N

  16. NEXT-GENERATION PLASMA CONTROL IN THE DIII-D TOKAMAK

    SciTech Connect

    WALKER, ML; FERRON, JR; HUMPHREYS, DA; JOHNSON, RD; LEUER, JA; PENAFLOR, BG; PIGLOWSKI, DA; ARIOLA, M; PIRONTI, A; SCHUSTER, E

    2002-10-01

    OAK A271 NEXT-GENERATION PLASMA CONTROL IN THE DIII-D TOKAMAK. The advanced tokamak (AT) operating mode which is the principal focus of the DIII-D tokamak requires highly integrated and complex plasma control. Simultaneous high performance regulation of the plasma boundary and internal profiles requires multivariable control techniques to account for the highly coupled influences of equilibrium shape, profile, and stability control. This paper describes progress towards the DIII-D At mission goal through both significantly improved real-time computational hardware and control algorithm capability.

  17. Theory of "clumps" in drift-wave turbulence in tokamak plasma

    NASA Astrophysics Data System (ADS)

    Wang, Xiaogang; Qiu, Xiaoming; X, M. Qhiu

    1986-08-01

    Basing on the new method of trajectory stochastic treatment advanced by one of the authors of this paper, the theory of "clumps" in driftwave turbulence in tokamak plasmas has been developed. It is shown that, as a longer time behaviour, plasmas in tokamaks will have the same "clumps" effects as those in uniform magnetic fields, although the diffusion crossing magnetic field lines in tokamaks will be enhanced. The influence of the non-uniformity of the magnetic field, such as curvature, shear, etc., on the transverse diffusion and the "clump" life-time is discussed.

  18. Princeton Plasma Physics Laboratory

    SciTech Connect

    Not Available

    1990-01-01

    This report discusses the following topics: principal parameters achieved in experimental devices fiscal year 1990; tokamak fusion test reactor; compact ignition tokamak; Princeton beta experiment- modification; current drive experiment-upgrade; international collaboration; x-ray laser studies; spacecraft glow experiment; plasma processing: deposition and etching of thin films; theoretical studies; tokamak modeling; international thermonuclear experimental reactor; engineering department; project planning and safety office; quality assurance and reliability; technology transfer; administrative operations; PPPL patent invention disclosures for fiscal year 1990; graduate education; plasma physics; graduate education: plasma science and technology; science education program; and Princeton Plasma Physics Laboratory reports fiscal year 1990.

  19. ECH by FEL and gyrotron sources on the Microwave Tokamak Experiment (MTX) tokamak

    SciTech Connect

    Stallard, B.W.; Turner, W.C.; Allen, S.L.; Byers, J.A.; Felker, B.; Fenstermacher, M.E.; Ferguson, S.W.; Hooper, E.G.; Thomassen, K.I.; Throop, A.L. ); Makowski, M.A. )

    1990-08-09

    The Microwave Tokamak Experiment (MTX) at LLNL is studying the physics of intense pulse ECH is a high-density tokamak plasma using a microwave FEL. Related technology development includes the FEL, a windowless quasi-optical transmission system, and other microwave components. Initial plasma experiments have been carried out at 140 GHz with single rf pulses generated using the ETA-II accelerator and the ELF wiggler. Peak power levels up to 0.2 GW and pulse durations up to 10 ns were achieved for injection into the plasma using as untapered wiggler. FEL pulses were transmitted over 33 m from the FEL to MTX using six mirrors mounted in a 50-cm-diam evacuated pipe. Measurements of the microwave beam and transmission through the plasma were carried out. For future rapid pulse experiments at high average power (4 GW peak power, 5kHz pulse rate, and {bar P} > 0.5 MW) using the IMP wiggler with tapered magnetic field, a gyrotron (140 GHz, 400 kW cw or up to 1 MW short pulse) is being installed to drive the FEL input or to directly heat the tokamak plasma at full gyrotron power. Quasi-optic techniques will be used to couple the gyrotron power. For direct plasma heating, the gyrotron will couple into the existing mirror transport system. Using both sources of rf generation, experiments are planned to investigate intense pulse absorption and tokamak physics, such as the ECH of a pellet-fueled plasma and plasma control using localized heating. 12 refs., 9 figs.

  20. The Computational Physics Program of the national MFE Computer Center

    SciTech Connect

    Mirin, A.A.

    1989-01-01

    Since June 1974, the MFE Computer Center has been engaged in a significant computational physics effort. The principal objective of the Computational Physics Group is to develop advanced numerical models for the investigation of plasma phenomena and the simulation of present and future magnetic confinement devices. Another major objective of the group is to develop efficient algorithms and programming techniques for current and future generations of supercomputers. The Computational Physics Group has been involved in several areas of fusion research. One main area is the application of Fokker-Planck/quasilinear codes to tokamaks. Another major area is the investigation of resistive magnetohydrodynamics in three dimensions, with applications to tokamaks and compact toroids. A third area is the investigation of kinetic instabilities using a 3-D particle code; this work is often coupled with the task of numerically generating equilibria which model experimental devices. Ways to apply statistical closure approximations to study tokamak-edge plasma turbulence have been under examination, with the hope of being able to explain anomalous transport. Also, we are collaborating in an international effort to evaluate fully three-dimensional linear stability of toroidal devices. In addition to these computational physics studies, the group has developed a number of linear systems solvers for general classes of physics problems and has been making a major effort at ascertaining how to efficiently utilize multiprocessor computers. A summary of these programs are included in this paper. 6 tabs.

  1. Causes of major tokamak disruptions

    SciTech Connect

    White, R.B.; Monticello, D.A.

    1980-07-01

    The nonlinear saturation theory of the tearing mode is used to examine the necessary conditions for the occurrence of a major tokamak disruption. The results are compared with full three-dimensional numerical simulations, and with experimental data.

  2. [Fusion research/tokamak]. Final report, 1 May 1988--30 April 1994

    SciTech Connect

    1994-12-31

    The objectives of the Fusion Research Center Program are: (1) to advance /the transport studies of tokamaks, including the development and maintenance of the Magnetic Fusion Energy Database, and (2) to provide theoretical interpretation, modeling and equilibrium and stability studies for the text-upgrade tokamak. Work is described on five basic categories: (1) magnetic fusion energy database; (2) computational support and numerical modeling; (3) support for TEXT-upgrade and diagnostics; (4) transport studies; and (5) Alfven waves.

  3. Coping with Physical and Psychological Symptoms: A Qualitative Study of Advanced Lung Cancer Patients and their Family Caregivers

    PubMed Central

    Mosher, Catherine E.; Ott, Mary A.; Hanna, Nasser; Jalal, Shadia I.; Champion, Victoria L.

    2014-01-01

    Purpose Advanced lung cancer patients have high rates of multiple physical and psychological symptoms, and many of their family caregivers experience significant distress. However, little is known about strategies that these patients and their family caregivers employ to cope with physical and psychological symptoms. This study aimed to identify strategies for coping with various physical and psychological symptoms among advanced, symptomatic lung cancer patients and their primary family caregivers. Methods Patients identified their primary family caregiver. Individual semi-structured qualitative interviews were conducted with 21 advanced, symptomatic lung cancer patients and primary family caregivers. Thematic analysis of interview data was framed by stress and coping theory. Results Patients and caregivers reported maintaining a normal routine and turning to family and friends for support with symptom management, which often varied in its effectiveness. Whereas support from healthcare professionals and complementary and alternative medicine were viewed favorably, reactions to Internet and in-person support groups were mixed due to the tragic nature of participants’ stories. Several cognitive coping strategies were frequently reported (i.e., changing expectations, maintaining positivity, and avoiding illness-related thoughts) as well as religious coping strategies. Conclusions Results suggest that advanced lung cancer patients and caregivers may be more receptive to cognitive and religious approaches to symptom management and less receptive to peer support. Interventions should address the perceived effectiveness of support from family and friends. PMID:25527242

  4. Advances in implosion physics, alternative targets design, and neutron effects on heavy ion fusion reactors

    NASA Astrophysics Data System (ADS)

    Velarde, G.; Perlado, J. M.; Alonso, E.; Alonso, M.; Domínguez, E.; Rubiano, J. G.; Gil, J. M.; Gómez del Rio, J.; Lodi, D.; Malerba, L.; Marian, J.; Martel, P.; Martínez-Val, J. M.; Mínguez, E.; Piera, M.; Ogando, F.; Reyes, S.; Salvador, M.; Sanz, J.; Sauvan, P.; Velarde, M.; Velarde, P.

    2001-05-01

    The coupling of a new radiation transport (RT) solver with an existing multimaterial fluid dynamics code (ARWEN) using Adaptive Mesh Refinement named DAFNE, has been completed. In addition, improvements were made to ARWEN in order to work properly with the RT code, and to make it user-friendlier, including new treatment of Equations of State, and graphical tools for visualization. The evaluation of the code has been performed, comparing it with other existing RT codes (including the one used in DAFNE, but in the single-grid version). These comparisons consist in problems with real input parameters (mainly opacities and geometry parameters). Important advances in Atomic Physics, Opacity calculations and NLTE atomic physics calculations, with participation in significant experiments in this area, have been obtained. Early published calculations showed that a DT x fuel with a small tritium initial content ( x<3%) could work in a catalytic regime in Inertial Fusion Targets, at very high burning temperatures (≫100 keV). Otherwise, the cross-section of DT remains much higher than that of DD and no internal breeding of tritium can take place. Improvements in the calculation model allow to properly simulate the effect of inverse Compton scattering which tends to lower Te and to enhance radiation losses, reducing the plasma temperature, Ti. The neutron activation of all natural elements in First Structural Wall (FSW) component of an Inertial Fusion Energy (IFE) reactor for waste management, and the analysis of activation of target debris in NIF-type facilities has been completed. Using an original efficient modeling for pulse activation, the FSW behavior in inertial fusion has been studied. A radiological dose library coupled to the ACAB code is being generated for assessing impact of environmental releases, and atmospheric dispersion analysis from HIF reactors indicate the uncertainty in tritium release parameters. The first recognition of recombination barriers in Si

  5. Relations of morale and physical function to advanced activities of daily living in health promotion class participants

    PubMed Central

    Yajima, Masahide; Asakawa, Yasuyoshi; Yamaguchi, Haruyasu

    2016-01-01

    [Purpose] The aim of this study was to clarify the relations of morale and physical function to the presence/absence of advanced activities of daily living. [Subjects] The subjects were 86 elderly community residents participating in health promotion classes. [Methods] A questionnaire survey on age, gender, presence/absence of advanced activities of daily living, and Philadelphia Geriatric Center Morale Scale score was conducted, in addition to assessment of fitness, consisting of measurement of height, body weight, grip and knee extensor muscle strength, functional reach, one-leg standing time, and Timed Up and Go test. Furthermore, multiple logistic regression analysis was performed with the presence/absence of advanced activities of daily living as a dependent variable. [Results] Grip strength and Timed Up and Go time were identified as variables influencing the presence/absence of advanced activities of daily living. [Conclusion] Physical function represented by grip strength and Timed Up and Go time was higher among subjects performing advanced activities of daily living. PMID:27065541

  6. Feedback stabilization of the resistive shell mode in a tokamak fusion reactor

    SciTech Connect

    Fitzpatrick, R.

    1997-07-01

    Stabilization of the {open_quotes}resistive shell mode{close_quotes} is vital to the success of the {open_quotes}advanced tokamak{close_quotes} concept. The most promising reactor relevant approach is to apply external feedback using, for instance, the previously proposed {open_quotes}fake rotating shell{close_quotes} scheme [R. Fitzpatrick and T. H. Jensen, Phys. Plasmas {bold 3}, 2641 (1996)]. This scheme, like other simple feedback schemes, only works if the feedback controlled conductors are located inside the {open_quotes}critical radius{close_quotes} at which a perfectly conducting shell is just able to stabilize the ideal external kink mode. In general, this is not possible in a reactor, since engineering constraints demand that any feedback controlled conductors be placed {ital outside} the neutron shielding blanket (i.e., relatively far from the edge of the plasma). It is demonstrated that the fake rotating shell feedback scheme can be modified so that it works even when the feedback controlled conductors are located well beyond the critical radius. The gain, bandwidth, current, and total power requirements of such a feedback system for a reactor sized plasma are estimated to be less than 100, a few Hz, a fews tens of kA, and a few MW, respectively. These requirements could easily be met using existing technology. It is concluded that feedback stabilization of the resistive shell mode is possible in a tokamak fusion reactor. {copyright} {ital 1997 American Institute of Physics.}

  7. Tokamak magneto-hydrodynamics and reference magnetic coordinates for simulations of plasma disruptions

    NASA Astrophysics Data System (ADS)

    Zakharov, Leonid E.; Li, Xujing

    2015-06-01

    This paper formulates the Tokamak Magneto-Hydrodynamics (TMHD), initially outlined by X. Li and L. E. Zakharov [Plasma Science and Technology 17(2), 97-104 (2015)] for proper simulations of macroscopic plasma dynamics. The simplest set of magneto-hydrodynamics equations, sufficient for disruption modeling and extendable to more refined physics, is explained in detail. First, the TMHD introduces to 3-D simulations the Reference Magnetic Coordinates (RMC), which are aligned with the magnetic field in the best possible way. The numerical implementation of RMC is adaptive grids. Being consistent with the high anisotropy of the tokamak plasma, RMC allow simulations at realistic, very high plasma electric conductivity. Second, the TMHD splits the equation of motion into an equilibrium equation and the plasma advancing equation. This resolves the 4 decade old problem of Courant limitations of the time step in existing, plasma inertia driven numerical codes. The splitting allows disruption simulations on a relatively slow time scale in comparison with the fast time of ideal MHD instabilities. A new, efficient numerical scheme is proposed for TMHD.

  8. Deuterium-Tritium Simulations of the Enhanced Reversed Shear Mode in the Tokamak Fusion Test Reactor

    SciTech Connect

    Mikkelsen, D.R.; Manickam, J.; Scott, S.D.; Zarnstorff

    1997-04-01

    The potential performance, in deuterium-tritium plasmas, of a new enhanced con nement regime with reversed magnetic shear (ERS mode) is assessed. The equilibrium conditions for an ERS mode plasma are estimated by solving the plasma transport equations using the thermal and particle dif- fusivities measured in a short duration ERS mode discharge in the Tokamak Fusion Test Reactor [F. M. Levinton, et al., Phys. Rev. Letters, 75, 4417, (1995)]. The plasma performance depends strongly on Zeff and neutral beam penetration to the core. The steady state projections typically have a central electron density of {approx}2:5x10 20 m{sup -3} and nearly equal central electron and ion temperatures of {approx}10 keV. In time dependent simulations the peak fusion power, {approx} 25 MW, is twice the steady state level. Peak performance occurs during the density rise when the central ion temperature is close to the optimal value of {approx} 15 keV. The simulated pressure profiles can be stable to ideal MHD instabilities with toroidal mode number n = 1, 2, 3, 4 and {infinity} for {beta}{sub norm} up to 2.5; the simulations have {beta}{sub norm} {le} 2.1. The enhanced reversed shear mode may thus provide an opportunity to conduct alpha physics experiments in conditions imilar to those proposed for advanced tokamak reactors.

  9. Tokamak magneto-hydrodynamics and reference magnetic coordinates for simulations of plasma disruptions

    SciTech Connect

    Zakharov, Leonid E.; Li, Xujing

    2015-06-15

    This paper formulates the Tokamak Magneto-Hydrodynamics (TMHD), initially outlined by X. Li and L. E. Zakharov [Plasma Science and Technology 17(2), 97–104 (2015)] for proper simulations of macroscopic plasma dynamics. The simplest set of magneto-hydrodynamics equations, sufficient for disruption modeling and extendable to more refined physics, is explained in detail. First, the TMHD introduces to 3-D simulations the Reference Magnetic Coordinates (RMC), which are aligned with the magnetic field in the best possible way. The numerical implementation of RMC is adaptive grids. Being consistent with the high anisotropy of the tokamak plasma, RMC allow simulations at realistic, very high plasma electric conductivity. Second, the TMHD splits the equation of motion into an equilibrium equation and the plasma advancing equation. This resolves the 4 decade old problem of Courant limitations of the time step in existing, plasma inertia driven numerical codes. The splitting allows disruption simulations on a relatively slow time scale in comparison with the fast time of ideal MHD instabilities. A new, efficient numerical scheme is proposed for TMHD.

  10. Tokamak profile prediction using direct gyrokinetic and neoclassical simulation

    SciTech Connect

    Candy, J.; Waltz, R. E.; Belli, E.; Holland, C.; Fahey, M. R.

    2009-06-15

    Tokamak transport modeling scenarios, including ITER [ITER Physics Basis Editors, Nucl. Fusion 39, 2137 (1999)] performance predictions, are based exclusively on reduced models for core thermal and particle transport. The reason for this is simple: computational cost. A typical modeling scenario may require the evaluation of thousands of individual transport fluxes (local transport models calculate the energy and particle fluxes across a specified flux surface given fixed profiles). Despite continuous advances in direct gyrokinetic simulation, the cost of an individual simulation remains so high that direct gyrokinetic transport calculations have been avoided. By developing a steady-state iteration scheme suitable for direct gyrokinetic and neoclassical simulations, we can now compute steady-state temperature profiles for DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] plasmas given known plasma sources. The new code, TGYRO, encapsulates the GYRO[J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] code, for turbulent transport, and the NEO[E. A. Belli and J. Candy, Plasma Phys. Controlled Fusion 50, 095010 (2008)] code, for kinetic neoclassical transport. Results for DIII-D L-mode discharge 128913 are given, with computational and experimental results consistent in the region 0{<=}r/a{<=}0.8.

  11. System studies of compact ignition tokamaks

    SciTech Connect

    Galambos, J.D.; Peng, Y.K.M.; Blackfield, D.T.

    1986-01-01

    A new version of the FEDC Tokamak System Code (TSC) has been developed to analyze the Compact Ignition Tokamak (CIT). These proposed experiments have small (major radius F 1.5m) and high magnetic fields (B J 10T), and are characterized by reduced cost. Key design constraints of CIT include limits to the high stress levels in the magnetic coils, limits to the large temperature rises in the coils and on the first wall or divertor plate, minimizing power supply requirements, and assuring adequate plasma performance in fusion ignition and burn time consistent with the latest physics understanding. We present systems code level studies of CIT parameter space here for a range of design options with various design constraints. The present version of the TSC incorporates new models for key components of CIT. For example, new algorithms have been incorporated for calculating stress levels in the TFC and ohmic solenoid, temperature rise in the magnetic coils, peak power requirements, plasma MHD equilibrium and volt-second capability. The code also incorporates a numerical optimizer to find combinations of engineering quantities (device size, coil sizes, coil current densities etc.) and physics quantities (plasma density temperature, and beta, etc.) which satisfy all the constraints and can minimize or maximize a figure of merit (e.g., the major radius). This method was recently used in a mirror reactor system code (3) for the Minimara concept development.

  12. The physics of spherical torus plasmas

    NASA Astrophysics Data System (ADS)

    Peng, Y.-K. M.

    2000-05-01

    Broad and important progress in plasma tests, theory, new experiments, and future visions of the spherical torus (ST, or very low aspect ratio tokamaks) have recently emerged. These have substantially improved our understanding of the potential properties of the ST plasmas, since the preliminary calculation of the ST magnetohydrodynamic equilibria more than a decade ago. Exciting data have been obtained from concept exploration level ST experiments of modest capabilities (with major radii up to 35 cm), making important scientific contributions to toroidal confinement in general. The results have helped approval and construction of new and/or more powerful ST experiments, and stimulated an increasing number of theoretical calculations of interest to magnetic fusion energy. Utilizing the broad knowledge base from the successful tokamak and advanced tokamak research, a wide range of new ST physics features has been suggested. These properties of the ST plasma will be tested at the 1 MA level with major radius up to ˜80 cm in the new proof of principle devices National Spherical Torus Experiment (NSTX, U.S.) [M. Peng et al., European Conf. Abst. 22C, 451 (1998); S. M. Kaye et al., Fusion Technol. 36, 16 (1999); M. Ono et al., "Exploration of Spherical Torus Physics in the NSTX Device," 17th IAEA Fusion Energy Conf., paper IAEA-CN-69/ICP/01 (R), Yokohama, Japan (1998)], Mega Ampere Spherical Tokamak (MAST, U.K.) [A. C. Darke et al., Fusion Technol. 1, 799 (1995); Q. W. Morris et al., Proc. Int. Workshop on ST (Ioffe Inst., St. Petersburg, 1997), Vol. 1, p. 290], and Globus-M (R.F.) [V. K. Gusev et al., European Conf. Abst. 22C, 576 (1998)], which have just started full experimental operation. New concept exploration experiments, such as Pegasus (University of Wisconsin) [R. Fonck and the PEGASUS Team, Bull. Am. Phys. Soc. 44, 267 (1999)], Helicity Injected Tokamak-II (HIT-II, University of Washington) [T. R. Jarboe et al., Phys. Plasmas 5, 1807 (1998)], and Current

  13. Fractal structure of films deposited in a tokamak

    NASA Astrophysics Data System (ADS)

    Budaev, V. P.; Khimchenko, L. N.

    2007-04-01

    The surface of amorphous films deposited in the T-10 tokamak was studied in a scanning tunnel microscope. The surface relief on a scale from 10 nm to 100 μm showed a stochastic surface topography and revealed a hierarchy of grains. The observed variety of irregular structures of the films was studied within the framework of the concept of scale invariance using the methods of fractal geometry and statistical physics. The experimental probability density distribution functions of the surface height variations are close in shape to the Cauchy distribution. The stochastic surface topography of the films is characterized by a Hurst parameter of H = 0.68-0.85, which is evidence of a nontrivial self-similarity of the film structure. The fractal character and porous structure of deposited irregular films must be considered as an important issue related to the accumulation of tritium in the ITER project. The process of film growth on the surface of tokamak components exposed to plasma has been treated within the framework of the general concept of inhomogeneous surface growth. A strong turbulence of the edge plasma in tokamaks can give rise to fluctuations in the incident flux of particles, which leads to the growth of fractal films with grain dimensions ranging from nano-to micrometer scale. The shape of the surface of some films found in the T-10 tokamak has been interpreted using a model of diffusion-limited aggregation (DLA). The growth of films according to the discrete DLA model was simulated using statistics of fluctuations observed in a turbulent edge plasma of the T-10 tokamak. The modified DLA model reproduces well the main features of the surface of some films deposited in tokamaks.

  14. Engineering development of advanced physical fine coal cleaning for premium fuel applications. Quarterly report, April 1--June 30, 1997

    SciTech Connect

    Moro, N.; Shields, G.L.; Smit, F.J.; Jha, M.C.

    1997-12-31

    The primary goal of this project is the engineering development of two advanced physical fine coal cleaning processes, column flotation and selective agglomeration, for premium fuel applications. The project scope includes laboratory research and bench-scale testing on six coals to optimize these processes, followed by the design, construction, and operation of a 2 t/hr process development unit (PDU). Accomplishments during the quarter are described on the following tasks and subtasks: Development of near-term applications (engineering development and dewatering studies); Engineering development of selective agglomeration (bench-scale testing and process scale-up); PDU and advanced column flotation module (coal selection and procurement and advanced flotation topical report); Selective agglomeration module (module operation and clean coal production with Hiawatha, Taggart, and Indiana 7 coals); Disposition of the PDU; and Project final report. Plans for next quarter are discussed and agglomeration results of the three tested coals are presented.

  15. Mirnov Coil Analysis by Singular Value Decomposition Method in IR-T1 Tokamak

    NASA Astrophysics Data System (ADS)

    Salemi, Mohammad K.; Saadat, Shervin; Ghoranneviss, Mahmoud; Tabadar, Alireza

    2010-10-01

    The spatial and temporal structures of magnetic signal in the tokamak is analyzed using recently developed singular value decomposition (SVD) technique to determine the structure of current perturbation as the discharge progresses. In this work we use SVD technique for that purpose in IR-T1 tokamak.ootnotetextC. Nardonet, ``Multichannel Fluctuation Data Analysis By The Singular Value Decomposition Method Application To MHD Modes In Jet,'' Plasma Physics & Controlled Fusion, V. 34, No. 9, 1992, 1447-1465

  16. Resistive instabilities in tokamaks

    SciTech Connect

    Rutherford, P.H.

    1985-10-01

    Low-m tearing modes constitute the dominant instability problem in present-day tokamaks. In this lecture, the stability criteria for representative current profiles with q(0)-values slightly less than unit are reviewed; ''sawtooth'' reconnection to q(0)-values just at, or slightly exceeding, unity is generally destabilizing to the m = 2, n = 1 and m = 3, n = 2 modes, and severely limits the range of stable profile shapes. Feedback stabilization of m greater than or equal to 2 modes by rf heating or current drive, applied locally at the magnetic islands, appears feasible; feedback by island current drive is much more efficient, in terms of the radio-frequency power required, then feedback by island heating. Feedback stabilization of the m = 1 mode - although yielding particularly beneficial effects for resistive-tearing and high-beta stability by allowing q(0)-values substantially below unity - is more problematical, unless the m = 1 ideal-MHD mode can be made positively stable by strong triangular shaping of the central flux surfaces. Feedback techniques require a detectable, rotating MHD-like signal; the slowing of mode rotation - or the excitation of non-rotating modes - by an imperfectly conducting wall is also discussed.

  17. Status of tokamak experiments

    SciTech Connect

    Wolf, G.H.

    1996-03-01

    Plasma-wall interaction, heat removal and ash exhaust have emerged as the dominant problems still to be solved in order to achieve ignition and - even more difficult - to maintain a state of self-sustained thermo-nuclear burn. This is of particular delicacy, since those operational regimes which yield the best energy confinement correspond to an even better particle confinement and confinement of impurities, which then tend to accumulate in the plasma core and to result in disruption or degradation of the tokamak discharge. Therefore, plasma-wall interaction, heat removal and particle exhaust will determine not only the structure and configuration of the plasma edge region, of the wall system and of the materials facing the plasma, but also the final choice of useful confinement regimes. Moreover, the potential effect of powerful {alpha}-particle heating on plasma stability and confinement has to be kept below critical values. For the latter requirement, a final answer can only be obtained in an ITER-type device where ignition and burn will become accessible. 72 refs., 12 figs.

  18. Limitations of power conversion systems under transient loads and impact on the pulsed tokamak power reactor

    NASA Astrophysics Data System (ADS)

    Sager, G. T.; Wong, C. P. C.; Kapich, D. D.; McDonald, C. F.; Schleicher, R. W.

    1993-11-01

    The impact of cyclic loading of the power conversion system of a helium-cooled, pulsed tokamak power plant is assessed. Design limits of key components of heat transport systems employing Rankine and Brayton thermodynamic cycles are quantified based on experience in gas-cooled fission reactor design and operation. Cyclic loads due to pulsed tokamak operation are estimated. Expected performance of the steam generator is shown to be incompatible with pulsed tokamak operation without load leveling thermal energy storage. The close cycle gas turbine is evaluated qualitatively based on performance of existing industrial and aeroderivative gas turbines. Advances in key technologies which significantly improve prospects for operation with tokamak fusion plants are reviewed.

  19. ITER tokamak buildings and equipment layout

    SciTech Connect

    Ahlfeld, C.E.; Dilling, D.A.; Ishimoto, Kazuyuki; Tanaka, Eiichi; Stoner, S.

    1996-12-31

    The International Thermonuclear Experimental Reactor (ITER) design has evolved to a level of maturity that has enabled the building designers to define the major dimensions and characteristics of the cluster of buildings that contain the tokamak and adjacent support equipment. Three-dimensional building models developed in a CATIA database provide the framework for the equipment layout. This article describes the preliminary layout of all major pieces of equipment, large bore pipes, ducts, busbars and other services. It is anticipated that some features of the layout will change as equipment design is advanced and future decisions are made, but these changes are not expected to alter the basic building design and any necessary changes are facilitated by the 3-D CATIA models. 1 ref., 6 figs.

  20. Preface to Special Topic: Advances in Radio Frequency Physics in Fusion Plasmas

    SciTech Connect

    Tuccillo, Angelo A.; Ceccuzzi, Silvio; Phillips, Cynthia K.

    2014-06-15

    It has long been recognized that auxiliary plasma heating will be required to achieve the high temperature, high density conditions within a magnetically confined plasma in which a fusion “burn” may be sustained by copious fusion reactions. Consequently, the application of radio and microwave frequency electromagnetic waves to magnetically confined plasma, commonly referred to as RF, has been a major part of the program almost since its inception in the 1950s. These RF waves provide heating, current drive, plasma profile control, and Magnetohydrodynamics (MHD) stabilization. Fusion experiments employ electromagnetic radiation in a wide range of frequencies, from tens of MHz to hundreds of GHz. The fusion devices containing the plasma are typically tori, axisymmetric or non, in which the equilibrium magnetic fields are composed of a strong toroidal magnetic field generated by external coils, and a poloidal field created, at least in the symmetric configurations, by currents flowing in the plasma. The waves are excited in the peripheral regions of the plasma, by specially designed launching structures, and subsequently propagate into the core regions, where resonant wave-plasma interactions produce localized heating or other modification of the local equilibrium profiles. Experimental studies coupled with the development of theoretical models and advanced simulation codes over the past 40+ years have led to an unprecedented understanding of the physics of RF heating and current drive in the core of magnetic fusion devices. Nevertheless, there are serious gaps in our knowledge base that continue to have a negative impact on the success of ongoing experiments and that must be resolved as the program progresses to the next generation devices and ultimately to “demo” and “fusion power plant.” A serious gap, at least in the ion cyclotron (IC) range of frequencies and partially in the lower hybrid frequency ranges, is the difficulty in coupling large amount of

  1. Preface to Special Topic: Advances in Radio Frequency Physics in Fusion Plasmas

    NASA Astrophysics Data System (ADS)

    Tuccillo, Angelo A.; Phillips, Cynthia K.; Ceccuzzi, Silvio

    2014-06-01

    It has long been recognized that auxiliary plasma heating will be required to achieve the high temperature, high density conditions within a magnetically confined plasma in which a fusion "burn" may be sustained by copious fusion reactions. Consequently, the application of radio and microwave frequency electromagnetic waves to magnetically confined plasma, commonly referred to as RF, has been a major part of the program almost since its inception in the 1950s. These RF waves provide heating, current drive, plasma profile control, and Magnetohydrodynamics (MHD) stabilization. Fusion experiments employ electromagnetic radiation in a wide range of frequencies, from tens of MHz to hundreds of GHz. The fusion devices containing the plasma are typically tori, axisymmetric or non, in which the equilibrium magnetic fields are composed of a strong toroidal magnetic field generated by external coils, and a poloidal field created, at least in the symmetric configurations, by currents flowing in the plasma. The waves are excited in the peripheral regions of the plasma, by specially designed launching structures, and subsequently propagate into the core regions, where resonant wave-plasma interactions produce localized heating or other modification of the local equilibrium profiles. Experimental studies coupled with the development of theoretical models and advanced simulation codes over the past 40+ years have led to an unprecedented understanding of the physics of RF heating and current drive in the core of magnetic fusion devices. Nevertheless, there are serious gaps in our knowledge base that continue to have a negative impact on the success of ongoing experiments and that must be resolved as the program progresses to the next generation devices and ultimately to "demo" and "fusion power plant." A serious gap, at least in the ion cyclotron (IC) range of frequencies and partially in the lower hybrid frequency ranges, is the difficulty in coupling large amount of power to the

  2. Recent experiments in the EAST and HT-7 superconducting tokamaks

    NASA Astrophysics Data System (ADS)

    Wan, Baonian; International EAST Collaborators; HT-7 Teams

    2009-10-01

    First divertor plasma configuration in Experimental Advanced Superconducting Tokamak (EAST) was obtained in the second campaign after the last IAEA meeting. To achieve long pulse diverted plasma discharges, new capabilities including the fully actively water cooled in-vessel components, current drive and heating systems, diagnostics and real-time plasma control algorithm were developed. Pre-programmed shape and feedback control of plasma position and current (RZIP) produced a variety of shaped plasma configurations, covering most of the configurations foreseen at the design stage of the machine. Control algorithm based on real-time equilibrium reconstruction and iso-flux control for the last closed magnetic flux surface (RTEFIT/ISOFLUX) has also been realized. A number of operational issues, such as plasma initiation and ramp up under constraints of superconducting coils were successfully investigated. First LHCD experiments demonstrated long pulse discharges longer than 20 s and nearly full non-inductive current drive. The physical engineering capability on the superconducting magnetic system was assessed by simulating discharges. Since the last IAEA meeting, experiments in HT-7 have been focusing on long pulse operation to support the EAST experiments on both physics and technical aspects. Long pulse discharges up to 400 s have now been achieved in HT-7. Investigation of sawtooth activities in ohmic and LHCD plasmas supports the turbulence model instead of the fast reconnection of the m = 1 magnetic island. Coexistence of electron mode and ion mode in high density ohmic plasmas has been observed by 2D ECE imaging (ECEI) in HT-7. The spectral characteristics of geodesic acoustic mode at the plasma boundary have been investigated by Langmuir probe arrays.

  3. Physics Basis and Simulation of Burning Plasma Physics for the Fusion Ignition Research Experiment (FIRE)

    SciTech Connect

    C.E. Kessel; D. Meade; S.C. Jardin

    2002-01-18

    The FIRE [Fusion Ignition Research Experiment] design for a burning plasma experiment is described in terms of its physics basis and engineering features. Systems analysis indicates that the device has a wide operating space to accomplish its mission, both for the ELMing H-mode reference and the high bootstrap current/high beta advanced tokamak regimes. Simulations with 1.5D transport codes reported here both confirm and constrain the systems projections. Experimental and theoretical results are used to establish the basis for successful burning plasma experiments in FIRE.

  4. Advanced Pubertal Status at Age 11 and Lower Physical Activity in Adolescent Girls

    PubMed Central

    Baker, Birgitta L.; Birch, Leann L.; Trost, Stewart G.; Davison, Kirsten Krahnstoever

    2008-01-01

    Objective To examine the relationship between pubertal timing and physical activity. Study design A longitudinal sample of 143 adolescent girls was assessed at ages 11 and 13 years. Girls' pubertal development was assessed at age 11 with blood estradiol levels, Tanner breast staging criteria, and parental report of pubertal development. Girls were classified as early maturers (n = 41) or later maturers (n = 102) on the basis of their scores on the 3 pubertal development measures. Dependent variables measured at age 13 were average minutes/day of moderate to vigorous and vigorous physical activity as measured by the ActiGraph accelerometer. Results Early-maturing girls had significantly lower self-reported physical activity and accumulated fewer minutes of moderate to vigorous and vigorous physical activity and accelerometer counts per day at age 13 than later maturing girls. These effects were independent of differences in percentage body fat and self-reported physical activity at age 11. Conclusion Girls experiencing early pubertal maturation at age 11 reported lower subsequent physical activity at age 13 than their later maturing peers. Pubertal maturation, in particular early maturation relative to peers, may lead to declines in physical activity among adolescent girls. PMID:17961691

  5. A comparative analysis of teacher-authored websites in high school honors and Advanced Placement physics for Web-design and NSES content and process standards

    NASA Astrophysics Data System (ADS)

    Persin, Ronald C.

    The purpose of this study was to investigate whether statistically significant differences existed between high school Honors Physics websites and those of Advanced Placement (AP) Physics in terms of Web-design, National Science Education Standards (NSES) Physics content, and NSES Science Process standards. The procedure began with the selection of 152 sites comprising two groups with equal sample sizes of 76 for Honors Physics and for Advanced Placement Physics. The websites used in the study were accumulated using the Google(TM) search engine. To find Honors Physics websites, the search words "honors physics high school" were entered as the query into the search engine. To find sites for Advanced Placement Physics, the query, "advanced placement physics high school," was entered into the search engine. The evaluation of each website was performed using an instrument developed by the researcher based on three attributes: Web-design, NSES Physics content, and NSES Science Process standards. A "1" was scored if the website was found to have each attribute, otherwise a "0" was given. This process continued until all 76 websites were evaluated for each of the two types of physics websites, Honors and Advanced Placement. Subsequently the data were processed using Excel functions and the SPSS statistical software program. The mean and standard deviation were computed individually for the three attributes under consideration. Three, 2-tailed, independent samples t tests were performed to compare the two groups of physics websites separately on the basis of Web Design, Physics Content, and Science Process. The results of the study indicated that there was only one statistically significant difference between high school Honors Physics websites and those of AP Physics. The only difference detected was in terms of National Science Education Standards Physics content. It was found that Advanced Placement Physics websites contained more NSES physics content than Honors

  6. Advanced Analytical/Physics Tools to Characterize Tire Materials and Behavior

    NASA Astrophysics Data System (ADS)

    Gerspacher, Michel

    2001-10-01

    Tires are assembled with common materials like polymers, fillers, reinforcing fibers and various chemicals which are used to cure the rubber compound, and also, to protect the finished tire from oxydative degradation. This is certainly more related to chemistry than to physics. Nevertheless, a finished tire on the road is becoming a fascinating object of physics if one wants to understand its behavior. Indeed, it is its viscoelastic nature which confers to the tire its unique capabilities. The lecture will be centered on the usage of physical methods, not only to study the visco- elasticity of the composite, but also the nature of the interactions between the materials composing the tires. It will be shown that the usage of physics has tremendously helped to better understand the tire and also participated in developing new generations of tires.

  7. Controlling fusion yield in tokamaks with spin polarized fuel, and feasibility studies on the DIII-D tokamak

    SciTech Connect

    Pace, D. C.; Lanctot, M. J.; Jackson, G. L.; Sandorfi, Andy M.; Smith, S. P.; Wei, Xiangdong

    2015-09-21

    The march towards electricity production through tokamaks requires the construction of new facilities and the inevitable replacement of the previous generation. There are, however, research topics that are better suited to the existing tokamaks, areas of great potential that are not sufficiently mature for implementation in high power machines, and these provide strong support for a balanced policy that includes the redirection of existing programs. Spin polarized fusion, in which the nuclei of tokamak fuel particles are spin-aligned and favorably change both the fusion cross-section and the distribution of initial velocity vectors of charged fusion products, is described here as an example of a technological and physics topic that is ripe for development in a machine such as the DIII-D tokamak. In this study, such research and development experiments may not be efficient at the ITER-scale, while the plasma performance, diagnostic access, and collaborative personnel available within the United States’ magnetic fusion research program, and at the DIII-D facility in particular, provide a unique opportunity to further fusion progress.

  8. Controlling fusion yield in tokamaks with spin polarized fuel, and feasibility studies on the DIII-D tokamak

    DOE PAGESBeta

    Pace, D. C.; Lanctot, M. J.; Jackson, G. L.; Sandorfi, Andy M.; Smith, S. P.; Wei, Xiangdong

    2015-09-21

    The march towards electricity production through tokamaks requires the construction of new facilities and the inevitable replacement of the previous generation. There are, however, research topics that are better suited to the existing tokamaks, areas of great potential that are not sufficiently mature for implementation in high power machines, and these provide strong support for a balanced policy that includes the redirection of existing programs. Spin polarized fusion, in which the nuclei of tokamak fuel particles are spin-aligned and favorably change both the fusion cross-section and the distribution of initial velocity vectors of charged fusion products, is described here asmore » an example of a technological and physics topic that is ripe for development in a machine such as the DIII-D tokamak. In this study, such research and development experiments may not be efficient at the ITER-scale, while the plasma performance, diagnostic access, and collaborative personnel available within the United States’ magnetic fusion research program, and at the DIII-D facility in particular, provide a unique opportunity to further fusion progress.« less

  9. Engineering design and analysis of advanced physical fine coal cleaning technologies

    SciTech Connect

    Gallier, P.W.

    1990-10-20

    The major goal is to provide the simulation tools for modeling both conventional and advanced coal cleaning technologies. This project is part of a major research initiative by the Pittsburgh Energy Technology Center (PETC) aimed at advancing three advanced coal cleaning technologies-heavy-liquid cycloning, selective agglomeration, and advanced froth flotation through the proof-of-concept (POC) level. The ASPEN PLUS process simulation package will be extended to handle coal cleaning applications. Algorithms for predicting the process performance, equipment size, and flowsheet economics of commercial coal cleaning devices and related ancillary equipment will be incorporated into the coal cleaning simulator. The work plan for the froth quarter called for completion of the washability interpolation routine, gravity separation models, and dewatering models. As these items were completed, work in the areas of size reduction, classification and froth flotation were scheduled to begin. As each model was completed, testing and validation procedures were scheduled to begin. Costing models were also planned to be implemented and tested as each of the gravity separation models were completed. 1 tab.

  10. Physics Comes to Winnipeg: The 1909 Meeting of the British Association for the Advancement of Science

    ERIC Educational Resources Information Center

    Klassen, Stephen; Dietrich, Sarah

    2010-01-01

    History of science can be used to bring scientific concepts to school science in a way that humanizes the protagonists and provides an appropriate context. The authors have researched the 1909 meeting of the British Association for the Advancement of Science (BAAS) in Winnipeg, a significant event in the city's history that has remained largely…

  11. Engineering development of advanced physical fine coal cleaning for premium fuel applications

    SciTech Connect

    Smit, F.J.; Jha, M.C.

    1993-01-18

    This project is a step in the Department of Energy's program to show that ultra-clean fuel can be produced from selected coals and that the fuel will be a cost-effective replacement for oil and natural gas now fueling boilers in this country. The replacement of premium fossil fuels with coal can only be realized if retrofit costs are kept to a minimum and retrofit boiler emissions meet national goals for clean air. These concerns establish the specifications for maximum ash and sulfur levels and combustion properties of the ultra-clean coal. The primary objective is to develop the design base for prototype commercial advanced fine coal cleaning facilities capable of producing ultra-clean coals suitable for conversion to coal-water slurry fuel. The fine coal cleaning technologies are advanced column flotation and selective agglomeration. A secondary objective is to develop the design base for near-term commercial integration of advanced fine coal cleaning technologies in new or existing coal preparation plants for economically and efficiently processing minus 28-mesh coal fines. A third objective is to determine the distribution of toxic trace elements between clean coal and refuse when applying the advance column flotation and selective agglomeration technologies. The project team consists of Amax Research Development Center (Amax R D), Amax Coal industries, Bechtel Corporation, Center for Applied Energy Research (CAER) at the University of Kentucky, and Arcanum Corporation.

  12. Producing sorghum cellulosic feedstock for advanced biofuels production and its impact on soil physical properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    According Energy Policy Act of 2005, the U.S. must produce 21 billion gallons of advanced biofuels in 2022. Cellulosic material is considered a renewable and environmental improved alternative source for energy production. Sorghum (Sorghum bicolor L.) is considered a high cellulosic biomass producti...

  13. U.S. Poised to Sit Out TIMSS Test: Physics, Advanced Math Gauged in Global Study

    ERIC Educational Resources Information Center

    Viadero, Debra

    2007-01-01

    This article reports on reactions to the U.S. Department of Education's first time decision to sit out an international study designed to show how advanced high school students around the world measure up in math and science. Mark S. Schneider, the commissioner of the department's National Center for Education Statistics, which normally takes the…

  14. Using Computer-Assisted Argumentation Mapping to develop effective argumentation skills in high school advanced placement physics

    NASA Astrophysics Data System (ADS)

    Heglund, Brian

    Educators recognize the importance of reasoning ability for development of critical thinking skills, conceptual change, metacognition, and participation in 21st century society. There is a recognized need for students to improve their skills of argumentation, however, argumentation is not explicitly taught outside logic and philosophy---subjects that are not part of the K-12 curriculum. One potential way of supporting the development of argumentation skills in the K-12 context is through incorporating Computer-Assisted Argument Mapping to evaluate arguments. This quasi-experimental study tested the effects of such argument mapping software and was informed by the following two research questions: 1. To what extent does the collaborative use of Computer-Assisted Argumentation Mapping to evaluate competing theories influence the critical thinking skill of argument evaluation, metacognitive awareness, and conceptual knowledge acquisition in high school Advanced Placement physics, compared to the more traditional method of text tables that does not employ Computer-Assisted Argumentation Mapping? 2. What are the student perceptions of the pros and cons of argument evaluation in the high school Advanced Placement physics environment? This study examined changes in critical thinking skills, including argumentation evaluation skills, as well as metacognitive awareness and conceptual knowledge, in two groups: a treatment group using Computer-Assisted Argumentation Mapping to evaluate physics arguments, and a comparison group using text tables to evaluate physics arguments. Quantitative and qualitative methods for collecting and analyzing data were used to answer the research questions. Quantitative data indicated no significant difference between the experimental groups, and qualitative data suggested students perceived pros and cons of argument evaluation in the high school Advanced Placement physics environment, such as self-reported sense of improvement in argument

  15. Recent developments in Bayesian inference of tokamak plasma equilibria and high-dimensional stochastic quadratures

    NASA Astrophysics Data System (ADS)

    von Nessi, G. T.; Hole, M. J.; The MAST Team

    2014-11-01

    We present recent results and technical breakthroughs for the Bayesian inference of tokamak equilibria using force-balance as a prior constraint. Issues surrounding model parameter representation and posterior analysis are discussed and addressed. These points motivate the recent advancements embodied in the Bayesian Equilibrium Analysis and Simulation Tool (BEAST) software being presently utilized to study equilibria on the Mega-Ampere Spherical Tokamak (MAST) experiment in the UK (von Nessi et al 2012 J. Phys. A 46 185501). State-of-the-art results of using BEAST to study MAST equilibria are reviewed, with recent code advancements being systematically presented though out the manuscript.

  16. Advanced computations of multi-physics, multi-scale effects in beam dynamics

    SciTech Connect

    Amundson, J.F.; Macridin, A.; Spentzouris, P.; Stern, E.G.; /Fermilab

    2009-01-01

    Current state-of-the-art beam dynamics simulations include multiple physical effects and multiple physical length and/or time scales. We present recent developments in Synergia2, an accelerator modeling framework designed for multi-physics, multi-scale simulations. We summarize recent several recent results in multi-physics beam dynamics, including simulations of three Fermilab accelerators: the Tevatron, the Main Injector and the Debuncher. Early accelerator simulations focused on single-particle dynamics. To a first approximation, the forces on the particles in an accelerator beam are dominated by the external fields due to magnets, RF cavities, etc., so the single-particle dynamics are the leading physical effects. Detailed simulations of accelerators must include collective effects such as the space-charge repulsion of the beam particles, the effects of wake fields in the beam pipe walls and beam-beam interactions in colliders. These simulations require the sort of massively parallel computers that have only become available in recent times. We give an overview of the accelerator framework Synergia2, which was designed to take advantage of the capabilities of modern computational resources and enable simulations of multiple physical effects. We also summarize some recent results utilizing Synergia2 and BeamBeam3d, a tool specialized for beam-beam simulations.

  17. Engineering design and analysis of advanced physical fine coal cleaning technologies. Quarterly technical progress report No. 9, October--December 1991

    SciTech Connect

    Not Available

    1992-01-20

    This project is sponsored by the United States Department of Energy (DOE) for the ``Engineering Design and Analysis of Advanced Physical Fine Coal Cleaning Technologies. The major goal is to provide the simulation tools for modeling both conventional and advanced coal cleaning technologies. This DOE project is part of a major research initiative by the Pittsburgh Energy Technology Center (PETC) aimed at advancing three advanced coal cleaning technologies-heavy-liquid cylconing, selective agglomeration, and advanced froth flotation through the proof-of-concept (POC) level.

  18. Mathematical Physics of Complex Coevolutionary Systems: Theoretical Advances and Applications to Multiscale Hydroclimate Dynamics

    NASA Astrophysics Data System (ADS)

    Perdigão, Rui A. P.

    2016-04-01

    The fundamental stochastic-dynamic coevolution laws governing complex coevolutionary systems are introduced in a mathematical physics framework formally unifying nonlinear stochastic physics with fundamental deterministic interaction laws among spatiotemporally distributed processes. The methodological developments are then used to shed light onto fundamental interactions underlying complex spatiotemporal behaviour and emergence in multiscale hydroclimate dynamics. For this purpose, a mathematical physics framework is presented predicting evolving distributions of hydrologic quantities under nonlinearly coevolving geophysical processes. The functional formulation is grounded on first principles regulating the dynamics of each system constituent and their interactions, therefore its applicability is general and data-independent, not requiring local calibrations. Moreover, it enables the dynamical estimation of hydroclimatic variations in space and time from knowledge at different spatiotemporal conditions, along with the associated uncertainties. This paves the way for a robust physically based prediction of hydroclimatic changes in unsupervised areas (e.g. ungauged basins). Validation is achieved by producing, with the mathematical physics framework, a comprehensive spatiotemporal legacy consistent with the observed distributions along with their statistic-dynamic relations. The similarity between simulated and observed distributions is further assessed with novel robust nonlinear information-theoretic diagnostics. The present study brings to light emerging signatures of structural change in hydroclimate dynamics arising from nonlinear synergies across multiple spatiotemporal scales, and contributes to a better dynamical understanding and prediction of spatiotemporal regimes, transitions, structural changes and extremes in complex coevolutionary systems. This study further sheds light onto a diversity of emerging properties from harmonic to hyper-chaotic in general

  19. Interest and preferences for using advanced physical activity tracking devices: results of a national cross-sectional survey

    PubMed Central

    Alley, Stephanie; Schoeppe, Stephanie; Guertler, Diana; Jennings, Cally; Vandelanotte, Corneel

    2016-01-01

    Objectives Pedometers are an effective self-monitoring tool to increase users' physical activity. However, a range of advanced trackers that measure physical activity 24 hours per day have emerged (eg, Fitbit). The current study aims to determine people's current use, interest and preferences for advanced trackers. Design and participants A cross-sectional national telephone survey was conducted in Australia with 1349 respondents. Outcome measures Regression analyses were used to determine whether tracker interest and use, and use of advanced trackers over pedometers is a function of demographics. Preferences for tracker features and reasons for not wanting to wear a tracker are also presented. Results Over one-third of participants (35%) had used a tracker, and 16% are interested in using one. Multinomial regression (n=1257) revealed that the use of trackers was lower in males (OR=0.48, 95% CI 0.36 to 0.65), non-working participants (OR=0.43, 95% CI 0.30 to 0.61), participants with lower education (OR=0.52, 95% CI 0.38 to 0.72) and inactive participants (OR=0.52, 95% CI 0.39 to 0.70). Interest in using a tracker was higher in younger participants (OR=1.73, 95% CI 1.15 to 2.58). The most frequently used tracker was a pedometer (59%). Logistic regression (n=445) revealed that use of advanced trackers compared with pedometers was higher in males (OR=1.67, 95% CI 1.01 to 2.79) and younger participants (OR=2.96, 95% CI 1.71 to 5.13), and lower in inactive participants (OR=0.35, 95% CI 0.19 to 0.63). Over half of current or interested tracker users (53%) prefer to wear it on their wrist, 31% considered counting steps the most important function and 30% regarded accuracy as the most important characteristic. The main reasons for not wanting to use a tracker were, ‘I don't think it would help me’ (39%), and ‘I don't want to increase my activity’ (47%). Conclusions Activity trackers are a promising tool to engage people in self-monitoring a physical activity

  20. Decommissioning of the Tokamak Fusion Test Reactor

    SciTech Connect

    E. Perry; J. Chrzanowski; C. Gentile; R. Parsells; K. Rule; R. Strykowsky; M. Viola

    2003-10-28

    The Tokamak Fusion Test Reactor (TFTR) at the Princeton Plasma Physics Laboratory was operated from 1982 until 1997. The last several years included operations with mixtures of deuterium and tritium. In September 2002, the three year Decontamination and Decommissioning (D&D) Project for TFTR was successfully completed. The need to deal with tritium contamination as well as activated materials led to the adaptation of many techniques from the maintenance work during TFTR operations to the D&D effort. In addition, techniques from the decommissioning of fission reactors were adapted to the D&D of TFTR and several new technologies, most notably the development of a diamond wire cutting process for complex metal structures, were developed. These techniques, along with a project management system that closely linked the field crews to the engineering staff who developed the techniques and procedures via a Work Control Center, resulted in a project that was completed safely, on time, and well below budget.

  1. Instrumentation and controls of an ignited tokamak

    SciTech Connect

    Becraft, W.R.; Golzy, J.; Houlberg, W.A.; Kukielka, C.A.; Onega R.J.; Raju, G.V.S.; Stone, R.S.

    1980-10-01

    The instrumentation and controls (I and C) of an ignited plasma magnetically confined in a tokamak configuration needs increased emphasis in the following areas: (1) physics implications for control; (2) plasma shaping/position control; and (3) control to prevent disruptive instabilities. This document reports on the FY 1979 efforts in these and other areas. Also presented are discusssions in the areas of: (1) diagnostics suitable for the Engineering Test Facility (ETF); and (2) future research and development (R and D) needs. The appendices focus attention on some preliminary ideas about the measurement of the deuteron-triton (D-T) ratio in the plasma, synchrotron radiation, and divertor control. Finally, an appendix documenting the thermal consequences to the first wall of a MPD is presented.

  2. Tearing mode analysis in tokamaks, revisited

    SciTech Connect

    Nishimura, Y.; Callen, J.D.; Hegna, C.C.

    1998-12-01

    A new {Delta}{sup {prime}} shooting code has been developed to investigate tokamak plasma tearing mode stability in a cylinder and large aspect ratio ({epsilon}{le}0.25) toroidal geometries, neglecting toroidal mode coupling. A different computational algorithm is used (shooting out from the singular surface instead of into it) to resolve the strong singularities at the mode rational surface, particularly in the presence of the finite pressure term. Numerical results compare favorably with Furth {ital et al.} [H. P. Furth {ital et al.}, Phys. Fluids {bold 16}, 1054 (1973)] results. The effects of finite pressure, which are shown to decrease {Delta}{sup {prime}}, are discussed. It is shown that the distortion of the flux surfaces by the Shafranov shift, which modifies the geometry metric elements, stabilizes the tearing mode significantly, even in a low-{beta} regime before the toroidal magnetic curvature effects come into play. {copyright} {ital 1998 American Institute of Physics.}

  3. Fuels for Advanced Combustion Engines Research Diesel Fuels: Analysis of Physical and Chemical Properties

    SciTech Connect

    Gallant, Tom; Franz, Jim; Alnajjar, Mikhail; Storey, John Morse; Lewis Sr, Samuel Arthur; Sluder, Scott; Cannella, William C; Fairbridge, Craig; Hager, Darcy; Dettman, Heather; Luecke, Jon; Ratcliff, Matthew A.; Zigler, Brad

    2009-01-01

    The CRC Fuels for Advanced Combustion Engines working group has worked to identify a matrix of research diesel fuels for use in advanced combustion research applications. Nine fuels were specified and formulated to investigate the effects of cetane number aromatic content and 90% distillation fraction. Standard ASTM analyses were performed on the fuels as well as GC/MS and /u1H//u1/u3C NMR analyses and thermodynamic characterizations. Details of the actual results of the fuel formulations compared with the design values are presented, as well as results from standard analyses, such as heating value, viscosity and density. Cetane number characterizations were accomplished by using both the engine method and the Ignition Quality Tester (IQT/sT) apparatus.

  4. Fusion programs in Applied Plasma Physics

    SciTech Connect

    Not Available

    1992-07-01

    The Applied Plasma Physics (APP) program at General Atomics (GA) described here includes four major elements: (a) Applied Plasma Physics Theory Program, (b) Alpha Particle Diagnostic, (c) Edge and Current Density Diagnostic, and (d) Fusion User Service Center (USC). The objective of the APP theoretical plasma physics research at GA is to support the DIII-D and other tokamak experiments and to significantly advance our ability to design a commercially-attractive fusion reactor. We categorize our efforts in three areas: magnetohydrodynamic (MHD) equilibria and stability; plasma transport with emphasis on H-mode, divertor, and boundary physics; and radio frequency (rf). The objective of the APP alpha particle diagnostic is to develop diagnostics of fast confined alpha particles using the interactions with the ablation cloud surrounding injected pellets and to develop diagnostic systems for reacting and ignited plasmas. The objective of the APP edge and current density diagnostic is to first develop a lithium beam diagnostic system for edge fluctuation studies on the Texas Experimental Tokamak (TEXT). The objective of the Fusion USC is to continue to provide maintenance and programming support to computer users in the GA fusion community. The detailed progress of each separate program covered in this report period is described in the following sections.

  5. On the physics, chemistry and toxicology of ultrafine anthropogenic, atmospheric aerosols (UAAA): new advances.

    PubMed

    Spurny, K R

    1998-08-01

    The existing data about the epidemiology, toxicology, physics and chemistry of atmospheric particulate pollutants were recently essentially completed and extended. They do support the hypothesis that the fine and very fine dispersed fraction of the atmospheric anthropogenic aerosols (UAAA) are responsible for the aggravation of the health risk potential of the polluted atmosphere during the last decade. The recently published data dealing primarily with the physics, chemistry, sampling and analysis of these highly dispersed particulate air pollutants are reviewed, summarized and critically evaluated. PMID:9820675

  6. Specification of the Advanced Burner Test Reactor Multi-Physics Coupling Demonstration Problem

    SciTech Connect

    Shemon, E. R.; Grudzinski, J. J.; Lee, C. H.; Thomas, J. W.; Yu, Y. Q.

    2015-12-21

    This document specifies the multi-physics nuclear reactor demonstration problem using the SHARP software package developed by NEAMS. The SHARP toolset simulates the key coupled physics phenomena inside a nuclear reactor. The PROTEUS neutronics code models the neutron transport within the system, the Nek5000 computational fluid dynamics code models the fluid flow and heat transfer, and the DIABLO structural mechanics code models structural and mechanical deformation. The three codes are coupled to the MOAB mesh framework which allows feedback from neutronics, fluid mechanics, and mechanical deformation in a compatible format.

  7. Advances in terrestrial physics research at NASA/Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Salomonson, Vincent V.

    1987-01-01

    Some past, current, and future terrestrial physics research activities at NASA/Goddard Space Flight Center are described. The uses of satellites and sensors, such as Tiros, Landsat, Nimbus, and SMMR, for terrestrial physics research are discussed. The spaceborne data are applicable for monitoring and studying vegetation, snow, and ice dynamics; geological features; soil moisture; water resources; the geoid of the earth; and the earth's magnetic field. Consideration is given to improvements in remote sensing systems and data records and the Earth Observing System sensor concepts.

  8. Self-organized stationary states of tokamaks

    NASA Astrophysics Data System (ADS)

    Jardin, Stephen

    2015-11-01

    We report here on a nonlinear mechanism that forms and maintains a self-organized stationary (sawtooth free) state in tokamaks. This process was discovered by way of extensive long-time simulations using the M3D-C1 3D extended MHD code in which new physics diagnostics have been added. It is well known that most high-performance modes of tokamak operation undergo ``sawtooth'' cycles, in which the peaking of the toroidal current density triggers a periodic core instability which redistributes the current density. However, certain modes of operation are known, such as the ``hybrid'' mode in DIII-D, ASDEX-U, JT-60U and JET, and the long-lived modes in NSTX and MAST, which do not experience this cycle of instability. Empirically, it is observed that these modes maintain a non-axisymmetric equilibrium which somehow limits the peaking of the toroidal current density. The physical mechanism responsible for this has not previously been understood, but is often referred to as ``flux-pumping,'' in which poloidal flux is redistributed in order to maintain q0 >1. In this talk, we show that in long-time simulations of inductively driven plasmas, a steady-state magnetic equilibrium may be obtained in which the condition q0 >1 is maintained by a dynamo driven by a stationary marginal core interchange mode. This interchange mode, unstable because of the pressure gradient in the ultra-low shear region in the center region, causes a (1,1) perturbation in both the electrostatic potential and the magnetic field, which nonlinearly cause a (0,0) component in the loop voltage that acts to sustain the configuration. This hybrid mode may be a preferred mode of operation for ITER. We present parameter scans that indicate when this sawtooth-free operation can be expected.

  9. Physical and Chemical Properties of the Copper-Alanine System: An Advanced Laboratory Project

    ERIC Educational Resources Information Center

    Farrell, John J.

    1977-01-01

    An integrated physical-analytical-inorganic chemistry laboratory procedure for use with undergraduate biology majors is described. The procedure requires five to six laboratory periods and includes acid-base standardizations, potentiometric determinations, computer usage, spectrophotometric determinations of crystal-field splitting…

  10. Advanced Magnetic Resonance Imaging of the Physical Processes in Human Glioblastoma

    PubMed Central

    Emblem, Kyrre E.; Andronesi, Ovidiu; Rosen, Bruce

    2014-01-01

    The most common malignant primary brain tumor, glioblastoma (GBM) is a devastating disease with a grim prognosis. Patient survival is typically less than 2 years and fewer than 10% of patients survive more than 5 years. Magnetic Resonance Imaging (MRI) can have great utility in the diagnosis, grading and management of patients with GBM as many of the physical manifestations of the pathological processes in GBM can be visualized and quantified using MRI. Newer MRI techniques such as dynamic contrast enhanced (DCE) and dynamic susceptibility contrast (DSC) MRI provide functional information regarding the tumor hemodynamic status. Diffusion MRI can shed light on tumor cellularity and the disruption of white matter tracts in the proximity of tumors. MR spectroscopy can be used to study new tumor tissue markers such as IDH mutations. MRI is helping to noninvasively explore the link between the molecular basis of gliomas and the imaging characteristics of their physical processes. We will review several approaches to MR-based imaging and discuss the potential for these techniques to quantify the physical processes in glioblastoma including tumor cellularity and vascularity, metabolite expression, and patterns of tumor growth and recurrence. We will conclude with challenges and opportunities for further research in applying physical principles to better understand the biological process in this deadly disease. PMID:25183787

  11. Conditions for Building a Community of Practice in an Advanced Physics Laboratory

    ERIC Educational Resources Information Center

    Irving, Paul W.; Sayre, Eleanor C.

    2014-01-01

    We use the theory of communities of practice and the concept of accountable disciplinary knowledge to describe how a learning community develops in the context of an upper-division physics laboratory course. The change in accountable disciplinary knowledge motivates students' enculturation into a community of practice. The enculturation…

  12. 20 years of research on the Alcator C-Mod tokamak

    SciTech Connect

    Greenwald, M.; Baek, S.; Barnard, H.; Beck, W.; Bonoli, P.; Brunner, D.; Burke, W.; Ennever, P.; Ernst, D.; Faust, I.; Fiore, C.; Fredian, T.; Gao, C.; Golfinopoulos, T.; Granetz, R.; Hartwig, Z.; Hubbard, A.; Hughes, J.; Hutchinson, I.; Irby, J.; and others

    2014-11-15

    The object of this review is to summarize the achievements of research on the Alcator C-Mod tokamak [Hutchinson et al., Phys. Plasmas 1, 1511 (1994) and Marmar, Fusion Sci. Technol. 51, 261 (2007)] and to place that research in the context of the quest for practical fusion energy. C-Mod is a compact, high-field tokamak, whose unique design and operating parameters have produced a wealth of new and important results since it began operation in 1993, contributing data that extends tests of critical physical models into new parameter ranges and into new regimes. Using only high-power radio frequency (RF) waves for heating and current drive with innovative launching structures, C-Mod operates routinely at reactor level power densities and achieves plasma pressures higher than any other toroidal confinement device. C-Mod spearheaded the development of the vertical-target divertor and has always operated with high-Z metal plasma facing components—approaches subsequently adopted for ITER. C-Mod has made ground-breaking discoveries in divertor physics and plasma-material interactions at reactor-like power and particle fluxes and elucidated the critical role of cross-field transport in divertor operation, edge flows and the tokamak density limit. C-Mod developed the I-mode and the Enhanced Dα H-mode regimes, which have high performance without large edge localized modes and with pedestal transport self-regulated by short-wavelength electromagnetic waves. C-Mod has carried out pioneering studies of intrinsic rotation and demonstrated that self-generated flow shear can be strong enough in some cases to significantly modify transport. C-Mod made the first quantitative link between the pedestal temperature and the H-mode's performance, showing that the observed self-similar temperature profiles were consistent with critical-gradient-length theories and followed up with quantitative tests of nonlinear gyrokinetic models. RF research highlights include direct experimental

  13. Energetic particle physics in fusion research in preparation for burning plasma experiments

    NASA Astrophysics Data System (ADS)

    Gorelenkov, N. N.; Pinches, S. D.; Toi, K.

    2014-12-01

    The area of energetic particle (EP) physics in 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 Heidbrink and Sadler (1994 Nucl. Fusion 34 535). That review coincided with the start of deuterium-tritium (DT) experiments on the 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 Alfvén eigenmodes (AEs), in particular by the toroidicity-induced AE (TAE) modes and reversed shear AEs (RSAEs). In the present paper we attempt a broad review of the progress that has been made in EP physics in tokamaks and spherical tori since the first DT experiments on TFTR and JET (Joint European Torus), including stellarator/helical devices. Introductory discussions on the 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 of the advanced topics of EP physics. At the end we cover important and interesting physics issues related to the burning plasma experiments such as ITER (International Thermonuclear Experimental Reactor).

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

    SciTech Connect

    Gorelenkov, Nikolai N

    2013-06-01

    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).

  15. Coal surface control for advanced physical fine coal cleaning technologies. Final report, September 19, 1988--August 31, 1992

    SciTech Connect

    Morsi, B.I.; Chiang, S.H.; Sharkey, A.; Blachere, J.; Klinzing, G.; Araujo, G.; Cheng, Y.S.; Gray, R.; Streeter, R.; Bi, H.; Campbell, P.; Chiarlli, P.; Ciocco, M.; Hittle, L.; Kim, S.; Kim, Y.; Perez, L.; Venkatadri, R.

    1992-12-31

    This final report presents the research work carried out on the Coal Surface Control for Advanced Physical Fine Coal Cleaning Technologies project, sponsored by the US Department of Energy, Pittsburgh Energy Technology Center (DOE/PETC). The project was to support the engineering development of the selective agglomeration technology in order to reduce the sulfur content of US coals for controlling SO{sub 2} emissions (i.e., acid rain precursors). The overall effort was a part of the DOE/PETCs Acid Rain Control Initiative (ARCI). The overall objective of the project is to develop techniques for coal surface control prior to the advanced physical fine coal cleaning process of selective agglomeration in order to achieve 85% pyrite sulfur rejection at an energy recovery greater than 85% based on run-of-mine coal. The surface control is meant to encompass surface modification during grinding and laboratory beneficiation testing. The project includes the following tasks: Project planning; methods for analysis of samples; development of standard beneficiation test; grinding studies; modification of particle surface; and exploratory R&D and support. The coal samples used in this project include three base coals, Upper Freeport - Indiana County, PA, Pittsburgh NO. 8 - Belmont County, OH, and Illinois No. 6 - Randolph County, IL, and three additional coals, Upper Freeport - Grant County- WV, Kentucky No. 9 Hopkins County, KY, and Wyodak - Campbell County, WY. A total of 149 drums of coal were received.

  16. Some advances in the silver physical development of latent prints on paper

    NASA Astrophysics Data System (ADS)

    Cantu, Antonio A.; Leben, Deborah A.; Wilson, Kelley

    2003-09-01

    Silver physical development, a now-abandoned technique used for developing photographic film or paper, is one of the most powerful methods for visualizing latent prints on paper. The method develops the water-insoluble components in the print residue. These components include the "fats and oils" or lipids found on the skin of fingers. The resulting developed print, referred to as a silver physically developed (Ag-PD) print, is made up of (gray to black) silver particles adhered to the fingerprint residue. Such prints are usually intensified (made darker) with a hypochlorite treatment. This process converts silver to silver oxide making the Ag-PD print become a Ag2O-PD prints. Often such (Ag-PD or Ag2O-PD) prints are found on areas with heavy or patterned printing making them difficult to see. This work resolves this problem by chemically lightening the print and darkening (suppressing) the interfering background.

  17. Power and promise of narrative for advancing physical therapist education and practice.

    PubMed

    Greenfield, Bruce H; Jensen, Gail M; Delany, Clare M; Mostrom, Elizabeth; Knab, Mary; Jampel, Ann

    2015-06-01

    This perspective article provides a justification for and an overview of the use of narrative as a pedagogical tool for educators to help physical therapist students, residents, and clinicians develop skills of reflection and reflexivity in clinical practice. The use of narratives is a pedagogical approach that provides a reflective and interpretive framework for analyzing and making sense of texts, stories, and other experiences within learning environments. This article describes reflection as a well-established method to support critical analysis of clinical experiences; to assist in uncovering different perspectives of patients, families, and health care professionals involved in patient care; and to broaden the epistemological basis (ie, sources of knowledge) for clinical practice. The article begins by examining how phronetic (ie, practical and contextual) knowledge and ethical knowledge are used in physical therapy to contribute to evidence-based practice. Narrative is explored as a source of phronetic and ethical knowledge that is complementary but irreducible to traditional objective and empirical knowledge-the type of clinical knowledge that forms the basis of scientific training. The central premise is that writing narratives is a cognitive skill that should be learned and practiced to develop critical reflection for expert practice. The article weaves theory with practical application and strategies to foster narrative in education and practice. The final section of the article describes the authors' experiences with examples of integrating the tools of narrative into an educational program, into physical therapist residency programs, and into a clinical practice. PMID:25524869

  18. Advancement of physical process by mental activation: a prospective controlled study.

    PubMed

    Lehrl, S; Gusinde, J; Schulz-Drost, S; Rein, A; Schlechtweg, P M; Jacob, H; Krinner, S; Gelse, K; Pauser, J; Brem, Matthias H

    2012-01-01

    According to the literature, patients who are significantly impaired by physical mobility limitations can be rehabilitated if the patient's working memory is used to capacity. The conclusion that periodic mental activity improves physical rehabilitation should be evaluated. This is a prospective, controlled, and randomized open study of patients who underwent a total hip arthroplasty (THA). Sixteen patients who played the video game Dr. Kawashima's Brain Training: How Old Is Your Brain? were compared in terms of rehabilitation progress to 16 individuals who did not play. Harris Hip and Merle d'Aubigné scores were evaluated 1 d preoperation and again 12 +/- 1 d postoperation. Preoperation, no significant differences in hip scores between the gaming and control groups were found (median Harris Hip score: 39 vs 33, respectively, p = 0.304; median Merle D'Aubigné score: 12 vs 9, respectively, p = 0.254). Postoperation, there were significant differences between the gaming and control groups (median Harris Hip score: 76.0 vs 56.5, respectively, p = 0.001; median Merle D'Aubigné score: 16.0 vs 13.5, respectively, p = 0.014). Within both groups, the posttest scores significantly improved; however, the increase for the gaming group was greater for both measures. Because the influence of age, sex, and level of education can be excluded, it can be assumed that mental activities can improve physical rehabilitation after THA. PMID:23341314

  19. Measurements of the parallel wavenumber of lower hybrid waves in the scrape-off layer of a high-density tokamak

    NASA Astrophysics Data System (ADS)

    Baek, S. G.; Wallace, G. M.; Shinya, T.; Parker, R. R.; Shiraiwa, S.; Bonoli, P. T.; Brunner, D.; Faust, I.; LaBombard, B. L.; Takase, Y.; Wukitch, S.

    2016-05-01

    In lower hybrid current drive (LHCD) experiments on tokamaks, the parallel wavenumber of lower hybrid waves is an important physics parameter that governs the wave propagation and absorption physics. However, this parameter has not been experimentally well-characterized in the present-day high density tokamaks, despite the advances in the wave physics modeling. In this paper, we present the first measurement of the dominant parallel wavenumber of lower hybrid waves in the scrape-off layer (SOL) of the Alcator C-Mod tokamak with an array of magnetic loop probes. The electric field strength measured with the probe in typical C-Mod plasmas is about one-fifth of that of the electric field at the mouth of the grill antenna. The amplitude and phase responses of the measured signals on the applied power spectrum are consistent with the expected wave energy propagation. At higher density, the observed k|| increases for the fixed launched k||, and the wave amplitude decreases rapidly. This decrease is correlated with the loss of LHCD efficiency at high density, suggesting the presence of loss mechanisms. Evidence of the spectral broadening mechanisms is observed in the frequency spectra. However, no clear modifications in the dominant k|| are observed in the spectrally broadened wave components, as compared to the measured k|| at the applied frequency. It could be due to (1) the probe being in the SOL and (2) the limited k|| resolution of the diagnostic. Future experiments are planned to investigate the roles of the observed spectral broadening mechanisms on the LH density limit problem in the strong single pass damping regime.

  20. A NATIONAL COLLABORATORY TO ADVANCE THE SCIENCE OF HIGH TEMPERATURE PLASMA PHYSICS FOR MAGNETIC FUSION

    SciTech Connect

    Allen R. Sanderson; Christopher R. Johnson

    2006-08-01

    This report summarizes the work of the University of Utah, which was a member of the National Fusion Collaboratory (NFC) Project funded by the United States Department of Energy (DOE) under the Scientific Discovery through Advanced Computing Program (SciDAC) to develop a persistent infrastructure to enable scientific collaboration for magnetic fusion research. A five year project that was initiated in 2001, it the NFC built on the past collaborative work performed within the U.S. fusion community and added the component of computer science research done with the USDOE Office of Science, Office of Advanced Scientific Computer Research. The project was itself a collaboration, itself uniting fusion scientists from General Atomics, MIT, and PPPL and computer scientists from ANL, LBNL, and Princeton University, and the University of Utah to form a coordinated team. The group leveraged existing computer science technology where possible and extended or created new capabilities where required. The complete finial report is attached as an addendum. The In the collaboration, the primary technical responsibility of the University of Utah in the collaboration was to develop and deploy an advanced scientific visualization service. To achieve this goal, the SCIRun Problem Solving Environment (PSE) is used on FusionGrid for an advanced scientific visualization service. SCIRun is open source software that gives the user the ability to create complex 3D visualizations and 2D graphics. This capability allows for the exploration of complex simulation results and the comparison of simulation and experimental data. SCIRun on FusionGrid gives the scientist a no-license-cost visualization capability that rivals present day commercial visualization packages. To accelerate the usage of SCIRun within the fusion community, a stand-alone application built on top of SCIRun was developed and deployed. This application, FusionViewer, allows users who are unfamiliar with SCIRun to quickly create

  1. Bootstrapped tokamak with oscillating field current drive

    SciTech Connect

    Weening, R.H. )

    1993-07-01

    A magnetic helicity conserving mean-field Ohm's law is used to study bootstrapped tokamaks with oscillating field current drive. The Ohm's law leads to the conclusion that the tokamak bootstrap effect can convert the largely alternating current of oscillating field current drive into a direct toroidal plasma current. This plasma current rectification is due to the intrinsically nonlinear nature of the tokamak bootstrap effect, and suggests that it may be possible to maintain the toroidal current of a tokamak reactor by supplementing the bootstrap current with oscillating field current drive. Steady-state tokamak fusion reactors operating with oscillating field current drive could provide an alternative to tokamak reactors operating with external current drive.

  2. Advances in astronomy (Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 27 February 2013)

    NASA Astrophysics Data System (ADS)

    2013-07-01

    A scientific session of the Division of Physical Sciences of the Russian Academy of Sciences (RAS), entitled "Advances in Astronomy" was held on 27 February 2013 at the conference hall of the Lebedev Physical Institute, RAS. The following reports were put on the session agenda posted on the website http://www.gpad.ac.ru of the RAS Physical Sciences Division: (1) Chernin A D (Sternberg Astronomical Institute, Moscow State University, Moscow) "Dark energy in the local Universe: HST data, nonlinear theory, and computer simulations"; (2) Gnedin Yu N (Main (Pulkovo) Astronomical Observatory, RAS, St. Petersburg) "A new method of supermassive black hole studies based on polarimetric observations of active galactic nuclei"; (3) Efremov Yu N (Sternberg Astronomical Institute, Moscow State University, Moscow) "Our Galaxy: grand design and moderately active nucleus"; (4) Gilfanov M R (Space Research Institute, RAS, Moscow) "X-ray binaries, star formation, and type-Ia supernova progenitors"; (5) Balega Yu Yu (Special Astrophysical Observatory, RAS, Nizhnii Arkhyz, Karachaevo-Cherkessia Republic) "The nearest 'star factory' in the Orion Nebula"; (6) Bisikalo D V (Institute of Astronomy, RAS, Moscow) "Atmospheres of giant exoplanets"; (7) Korablev O I (Space Research Institute, RAS, Moscow) "Spectroscopy of the atmospheres of Venus and Mars: new methods and new results"; (8) Ipatov A V (Institute of Applied Astronomy, RAS, St. Petersburg) "A new-generation radio interferometer for fundamental and applied research". Summaries of the papers based on reports 1, 2, 4, 7, 8 are given below. • Dark energy in the nearby Universe: HST data, nonlinear theory, and computer simulations, A D Chernin Physics-Uspekhi, 2013, Volume 56, Number 7, Pages 704-709 • Investigating supermassive black holes: a new method based on the polarimetric observations of active galactic nuclei, Yu N Gnedin Physics-Uspekhi, 2013, Volume 56, Number 7, Pages 709-714 • X-ray binaries and star formation, M R

  3. The requirements of a next step large steady state tokamak

    NASA Astrophysics Data System (ADS)

    Janeschitz, G.; Barabaschi, P.; Federici, G.; Ioki, K.; Ladd, P.; Mukhovatov, V.; Sugihara, M.; Tivey, R.; ITER-JCT; Home Team

    2000-06-01

    After a decision by the ITER parties to investigate the possibility of designing a reduced cost version of ITER several possible machine layouts with different aspect ratios were studied. Relatively early in this process it became clear that there is no significant cost difference between different aspect ratios and that there is a maximum realistically possible aspect ratio for a machine with 6 m major radius and rather high plasma shaping. Following this study a machine with an intermediate aspect ratio (3.1) called the ITER Fusion Energy Advanced Tokamak (ITER FEAT) was chosen as the basis for the outline design of a reduced cost ITER. Several potential steady state scenarios can be investigated in ITER FEAT, i.e. monotonic or reversed shear at full or reduced minor radius. In addition, so-called hybrid discharges, are feasible where a mixture of inductive and non-inductive current drive as well as bootstrap current allows long pulse discharges of the order of 2500 s. The βN values and H factors required for these discharges are in the same range as those observed on present machines, which provides confidence that such discharges can be studied in ITER FEAT. However, due to uncertainties in physics knowledge, for example the current drive efficiency off-axis, it is impossible at present to generate a completely self-consistent scenario taking all boundary conditions, for example engineering or heating system constraints, into account. In addition, all of these regimes have a potential problem with divertor operation compatibility (low edge density) and with helium exhaust which has to be addressed in existing experiments. For the engineering design of the in-vessel components and for the balance of the plant there is practically no difference between inductive (500 s) and steady state operation. However, the choice of heating systems and the distribution of power between them will be strongly influenced by the envisaged steady state scenarios.

  4. PREFACE: International Conference on Advancement in Science and Technology 2012 (iCAST): Contemporary Mathematics, Mathematical Physics and their Applications

    NASA Astrophysics Data System (ADS)

    Ganikhodjaev, Nasir; Mukhamedov, Farrukh; Hee, Pah Chin

    2013-04-01

    The 4th International Conference on the Advancement of Science and Technology 2012 (iCAST 2012), with theme 'Contemporary Mathematics, Mathematical Physics and their Applications', took place in Kuantan, Malaysia, from Wednesday 7 to Friday 9 November 2012. The conference was attended by more than 100 participants, and hosted about 160 oral and poster papers by more than 140 pre-registered authors. The key topics of the 4th iCAST 2012 include Pure Mathematics, Applied Mathematics, Theoretical/Mathematical Physics, Dynamical Systems, Statistics and Financial Mathematics. The scientific program was rather full since after the Keynote and Invited Talks in the morning, four parallel sessions ran every day. However, according to all attendees, the program was excellent with a high level of talks and the scientific environment was fruitful; thus all attendees had a creative time. The conference aimed to promote the knowledge and development of high-quality research in mathematical fields concerned with the application of other scientific fields as well as modern technological trends in physics, chemistry, biology, medicine, economics, sociology and environmental sciences. We would like to thank the Keynote and the Invited Speakers for their significant contributions to 4th iCAST 2012. We would also like to thank the members of the International Scientific Committee and the members of the Organizing Committee. We cannot end without expressing our many thanks to International Islamic University Malaysia and our sponsors for their financial support . This volume presents selected papers which have been peer-reviewed. The editors hope that it may be useful and fruitful for scholars, researchers, and advanced technical members of the industrial laboratory facilities for developing new tools and products. Guest Editors Nasir Ganikhodjaev, Farrukh Mukhamedov and Pah Chin Hee The PDF contains the committee lists, board list and biographies of the plenary speakers.

  5. Equilibrium reconstruction based on core magnetic measurement and its applications on equilibrium transition in Joint-TEXT tokamak

    SciTech Connect

    Chen, J.; Zhuang, G. Jian, X.; Li, Q.; Liu, Y.; Gao, L.; Wang, Z. J.

    2014-10-15

    Evaluation and reconstruction of plasma equilibrium, especially to resolve the safety factor profile, is imperative for advanced tokamak operation and physics study. Based on core magnetic measurement by the high resolution laser polarimeter-interferometer system (POLARIS), the equilibrium of Joint-TEXT (J-TEXT) plasma is reconstructed and profiles of safety factor, current density, and electron density are, therefore, obtained with high accuracy and temporal resolution. The equilibrium reconstruction procedure determines the equilibrium flux surfaces essentially from the data of POLARIS. Refraction of laser probe beam, a major error source of the reconstruction, has been considered and corrected, which leads to improvement of accuracy more than 10%. The error of reconstruction has been systematically assessed with consideration of realistic diagnostic performance and scrape-off layer region of plasma, and its accuracy has been verified. Fast equilibrium transitions both within a single sawtooth cycle and during the penetration of resonant magnetic perturbation have been investigated.

  6. TOKAMAK EQUILIBRIA WITH CENTRAL CURRENT HOLES AND NEGATIVE CURRENT DRIVE

    SciTech Connect

    CHU, M.S.; PARKS, P.B.

    2002-06-01

    OAK B202 TOKAMAK EQUILIBRIA WITH CENTRAL CURRENT HOLES AND NEGATIVE CURRENT DRIVE. Several tokamak experiments have reported the development of a central region with vanishing currents (the current hole). Straightforward application of results from the work of Greene, Johnson and Weimer [Phys. Fluids, 3, 67 (1971)] on tokamak equilibrium to these plasmas leads to apparent singularities in several physical quantities including the Shafranov shift and casts doubts on the existence of this type of equilibria. In this paper, the above quoted equilibrium theory is re-examined and extended to include equilibria with a current hole. It is shown that singularities can be circumvented and that equilibria with a central current hole do satisfy the magnetohydrodynamic equilibrium condition with regular behavior for all the physical quantities and do not lead to infinitely large Shafranov shifts. Isolated equilibria with negative current in the central region could exist. But equilibria with negative currents in general do not have neighboring equilibria and thus cannot have experimental realization, i.e. no negative currents can be driven in the central region.

  7. Microwave Tokamak Experiment: Overview and status

    SciTech Connect

    Not Available

    1990-05-01

    The Microwave Tokamak Experiment, now under construction at the Laboratory, will use microwave heating from a free-electron laser. The intense microwave pulses will be injected into the tokamak to realize several goals, including a demonstration of the effects of localized heat deposition within magnetically confined plasma, a better understanding of energy confinement in tokamaks, and use of the new free-electron laser technology for plasma heating. 3 figs., 3 tabs.

  8. Maintenance concept development for the Compact Ignition Tokamak

    SciTech Connect

    Macdonald, D.

    1988-01-01

    The Compact Ignition Tokamak (CIT), located at the Princeton Plasma Physics Laboratory, will be the next major experimental machine in the US Fusion Program. Its use of deuterium-tritium (D-T) fuel requires the use of remote handling technology to carry out maintenance operations on the machine. These operations consist of removing and repairing such components as diagnostic equipment modules by using remotely operated maintenance equipment. The major equipment being developed for maintenance external to the vacuum vessel includes both bridge-mounted and floor-mounted manipulator systems. Additionally, decontamination (decon) equipment, hot cell repair facilities, and equipment for handling and packaging solid radioactive waste (rad-waste) are being developed. Recent design activities have focused on establishing maintenance system interfaces with the facility design, developing manipulator system requirements, and using mock-ups to support the tokamak configuration design. 3 refs., 8 figs.

  9. Commissioning of heating neutral beams for COMPASS-D tokamak

    SciTech Connect

    Deichuli, P.; Davydenko, V.; Belov, V.; Gorbovsky, A.; Dranichnikov, A.; Ivanov, A.; Sorokin, A.; Mishagin, V.; Abdrashitov, A.; Kolmogorov, V.; Kondakov, A.

    2012-02-15

    Two neutral beam injectors have been developed for plasma heating on COMPASS-D tokamak (Institute of Plasma Physics, Prague). The 4-electrodes multihole ion-optical system with beam focusing was chosen to provide the low divergence 300 kW power in both deuterium and hydrogen atoms. The accelerating voltage is 40 kV at extracted ion current up to 15 A. The power supply system provides the continuous and modulated mode of the beam injection at a maximal pulse length 300 ms. The optimal arrangement of the cryopanels and the beam duct elements provides sufficiently short-length beamline which reduces the beam losses. The evolution of the impurities and molecular fraction content is studied in the process of the high voltage conditioning of the newly made ion sources. Two injectors of the same type have been successfully tested and are ready for operation at tokamak in IPP, Prague.

  10. Tokamak Plasma Flows Induced by Local RF Forces

    NASA Astrophysics Data System (ADS)

    Chen, Jiale; Gao, Zhe

    2015-10-01

    The tokamak plasma flows induced by the local radio frequency (RF) forces in the core region are analyzed. The effective components of local RF forces are composed of the momentum absorption term and the resonant parallel momentum transport term (i.e. the parallel component of the resonant ponderomotive forces). Different momentum balance relations are employed to calculate the plasma flows depending on different assumptions of momentum transport. With the RF fields solved from RF simulation codes, the toroidal and poloidal flows by these forces under the lower hybrid current drive and the mode conversion ion cyclotron resonance heating on EAST-like plasmas are evaluated. supported by National Natural Science Foundation of China (Nos. 11405218, 11325524, 11375235 and 11261140327), in part by the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB111002, 2013GB112001 and 2013GB112010), and the Program of Fusion Reactor Physics and Digital Tokamak with the CAS “One-Three-Five” Strategic Planning

  11. What do the cited and citing environments reveal about Advances in Atmospheric Physics?

    NASA Astrophysics Data System (ADS)

    Shi, Aolan; Leydesdorff, Loet

    2011-01-01

    The networking status of journals reflects their academic influence among peer journals. This paper analyzes the cited and citing environments of this journal, Advances in Atmospheric Sciences ( Adv. Atmos. Sci.), using methods from social network analysis. Since its initial publication, Adv. Atmos. Sci. has been actively participating in the international journal environment and international journals are frequently cited in Adv. Atmos. Sci. Particularly, this journal is intensely interrelated with its international peer journals in terms of their similar citing patterns. The international influence of Adv. Atmos. Sci. is comparatively bigger than other Chinese SCI journals in atmospheric sciences as reflected by total cites to Adv. Atmos. Sci. and the total number of international journals citing it. The academic visibility of Adv. Atmos. Sci. is continuing to improve in the international research community as the number of reference citation it receives in its peer journals internationally increases over time.

  12. Engineering development of advanced physical fine coal cleaning technologies - froth flotation

    SciTech Connect

    Ferris, D.D.; Bencho, J.R.

    1995-11-01

    In 1988, ICF Kaiser Engineers was awarded DOE Contract No. DE-AC22-88PC88881 to research, develop, engineer and design a commercially acceptable advanced froth flotation coal cleaning technology. The DOE initiative is in support of the continued utilization of our most abundant energy resource. Besides the goal of commercialability, coal cleaning performance and product quality goals were established by the DOE for this and similar projects. primary among these were the goals of 85 percent energy recovery and 85 percent pyrite rejection. Three nationally important coal resources were used for this project: the Pittsburgh No. 8 coal, the Upper Freeport coal, and the Illinois No. 6 coal. Following is a summary of the key findings of this project.

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

    SciTech Connect

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

    2007-07-18

    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.

  14. Human-centered design of a cyber-physical system for advanced response to Ebola (CARE).

    PubMed

    Dimitrov, Velin; Jagtap, Vinayak; Skorinko, Jeanine; Chernova, Sonia; Gennert, Michael; Padir, Taşkin

    2015-08-01

    We describe the process towards the design of a safe, reliable, and intuitive emergency treatment unit to facilitate a higher degree of safety and situational awareness for medical staff, leading to an increased level of patient care during an epidemic outbreak in an unprepared, underdeveloped, or disaster stricken area. We start with a human-centered design process to understand the design challenge of working with Ebola treatment units in Western Africa in the latest Ebola outbreak, and show preliminary work towards cyber-physical technologies applicable to potentially helping during the next outbreak. PMID:26737868

  15. Recent advances in numerical simulation of space-plasma-physics problems

    NASA Technical Reports Server (NTRS)

    Birmingham, T. J.

    1983-01-01

    Computer simulations have become an increasingly popular, important and insightful tool for studying space plasmas. This review describes MHD and particle simulations, both of which treat the plasma and the electromagnetic field in which it moves in a self consistent fashion but on drastically different spatial and temporal scales. The complementary roles of simulation, observations and theory are stressed. Several examples of simulations being carried out in the area of magnetospheric plasma physics are described to illustrate the power, potential and limitations of the approach.

  16. Comprehensive numerical modelling of tokamaks

    SciTech Connect

    Cohen, R.H.; Cohen, B.I.; Dubois, P.F.

    1991-01-03

    We outline a plan for the development of a comprehensive numerical model of tokamaks. The model would consist of a suite of independent, communicating packages describing the various aspects of tokamak performance (core and edge transport coefficients and profiles, heating, fueling, magnetic configuration, etc.) as well as extensive diagnostics. These codes, which may run on different computers, would be flexibly linked by a user-friendly shell which would allow run-time specification of packages and generation of pre- and post-processing functions, including workstation-based visualization of output. One package in particular, the calculation of core transport coefficients via gyrokinetic particle simulation, will become practical on the scale required for comprehensive modelling only with the advent of teraFLOP computers. Incremental effort at LLNL would be focused on gyrokinetic simulation and development of the shell.

  17. Generation of plasma rotation by ion cyclotron resonance heating in tokamaks

    SciTech Connect

    Chang, C.S.; Phillips, C.K.; White, R.; Zweben, S.; Bonoli, P.T.; Rice, J.E.; Greenwald, M.J.; deGrassie, J.

    1999-05-01

    A physical mechanism for generation of a plasma rotation and radial electric field by ion cyclotron resonance heating (ICRH) is presented in a tokamak geometry. By breaking the omnigenity of resonant ion orbits, ICRH can induce a nonambipolar minor-radial transport of resonant ions. This yields a radial charge separation, a modification to radial electric field E{sub r}, and the generation of plasma rotation. It is estimated that the ICRH fast-wave power available in the present-day tokamak experiments can be large enough to give a significant modification to plasma rotation. {copyright} {ital 1999 American Institute of Physics.}

  18. Conditions for building a community of practice in an advanced physics laboratory

    NASA Astrophysics Data System (ADS)

    Irving, Paul W.; Sayre, Eleanor C.

    2014-06-01

    We use the theory of communities of practice and the concept of accountable disciplinary knowledge to describe how a learning community develops in the context of an upper-division physics laboratory course. The change in accountable disciplinary knowledge motivates students' enculturation into a community of practice. The enculturation process is facilitated by four specific structural features of the course and supported by a primary instructional choice. The four structural features are "paucity of instructor time," "all in a room together," "long and difficult experiments," and "same experiments at different times." The instructional choice is the encouragement of the sharing and development of knowledge and understanding by the instructor. The combination of the instructional choice and structural features promotes the development of the learning community in which students engage in authentic practices of a physicist. This results in a classroom community that can provide students with the opportunity to have an accelerated trajectory towards being a more central participant of the community of a practice of physicists. We support our claims with video-based observations of laboratory classroom interactions and individual, semistructured interviews with students about their laboratory experiences and physics identity.

  19. Magnetic island formation in tokamaks

    SciTech Connect

    Yoshikawa, S.

    1989-04-01

    The size of a magnetic island created by a perturbing helical field in a tokamak is estimated. A helical equilibrium of a current- carrying plasma is found in a helical coordinate and the helically flowing current in the cylinder that borders the plasma is calculated. From that solution, it is concluded that the helical perturbation of /approximately/10/sup /minus/4/ of the total plasma current is sufficient to cause an island width of approximately 5% of the plasma radius. 6 refs.

  20. Gyrosheath near the tokamak edge

    SciTech Connect

    Hazeltine, R.D.; Xiao, H.; Valanju, P.M.

    1993-03-01

    A new model for the structure of the radial electric field profile in the edge during the H-mode is proposed. Charge separation caused by the difference between electron and ion gyromotion, or more importantly in a tokamak, the banana motion (halo effect) can self-consistently produce an electric dipole moment that causes the sheared radial electric field. The calculated results based on the model are consistent with D-III D and TEXTOR experimental results.