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Your search keyword '"null D. Stutman"' showing total 2 results
Start Over Author "null D. Stutman" Topic atomic physics
2 results on '"null D. Stutman"'

1. Exploration of High Harmonic Fast Wave Heating on the National Spherical Torus Experiment

Author

null J.R. Wilson, null R.E. Bell, null S. Bernabei, null M. Bitter, null P. Bonoli, null D. Gates, null J. Hosea, null B. LeBlanc, null T.K. Mau, null S. Medley, null J. Menard, null D. Mueller, null M. Ono, null C.K. Phillips, null R.I. Pinsker, null R. Raman, null A. Rosenberg, null P. Ryan, null S. Sabbagh, null D. Stutman, null D. Swain, null Y. Takase, null J. Wilgen, and null the NSTX Team

Subjects
Physics, Heating system, Physics::Plasma Physics, Plasma parameters, Harmonics, Dielectric heating, Harmonic, Torus, Plasma, Atomic physics, Computational physics, Bootstrap current
Abstract

High Harmonic Fast Wave (HHFW) heating has been proposed as a particularly attractive means for plasma heating and current drive in the high-beta plasmas that are achievable in spherical torus (ST) devices. The National Spherical Torus Experiment (NSTX) [Ono, M., Kaye, S.M., Neumeyer, S., et al., Proceedings, 18th IEEE/NPSS Symposium on Fusion Engineering, Albuquerque, 1999, (IEEE, Piscataway, NJ (1999), p. 53.)] is such a device. An radio-frequency (rf) heating system has been installed on NSTX to explore the physics of HHFW heating, current drive via rf waves and for use as a tool to demonstrate the attractiveness of the ST concept as a fusion device. To date, experiments have demonstrated many of the theoretical predictions for HHFW. In particular, strong wave absorption on electrons over a wide range of plasma parameters and wave parallel phase velocities, wave acceleration of energetic ions, and indications of current drive for directed wave spectra have been observed. In addition HHFW heating has been used to explore the energy transport properties of NSTX plasmas, to create H-mode (high-confinement mode) discharges with a large fraction of bootstrap current and to control the plasma current profile during the early stages of the discharge.

Published
2003
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2. Stability and Confinement Properties of Auxiliary Heated NSTX Discharges

Author

null J.E. Menard, null R.E.Bell, null C. Bourdelle, null D.S. Darrow, null E.D. Fredrickson, null D.A. Gates, null L.R. Grisham, null S.M. Kaye, null B.P. LeBlanc, null R. Maingi, null S.S. Medley, null D. Mueller, null F. Paoletti, null S.A. Sabbagh, null D. Stutman, null D.W. Swain, null J.R. Wilson, null M.G. Bell, null J.M. Bialek, null C.E.Bush, null J.C. Hosea, null D.W. Johnson, null R. Kaita, null H.W. Kugel, null R.J. Maqueda, null M. Ono, null Y-K.M. Peng, null C.H. Skinner, null V.A. Soukhanovskii, null E.J. Synakowski, null G. Taylor, null G.A. Wurden, and null and S.J. Zweben

Subjects
Electron density, Chemistry, Thomson scattering, Electron temperature, Radius, Plasma, Atomic physics, Spherical tokamak, Energy source, Dimensionless quantity
Abstract

The National Spherical Torus Experiment (NSTX) is a spherical tokamak with nominal plasma major radius R(subscript ''0'') = 0.85 m, minor radius a = 0.66 m, and aspect ratio A > 1.28. Typical discharge parameters are plasma current I (subscript ''p'') = 0.7-1.4 MA, toroidal magnetic field B(subscript ''t0'') = 0.25-0.45 Tesla at major radius R(subscript ''0''), elongation = 1.7-2.2, triangularity 0.3-0.5, line-average electron density = 2-5 x 10(superscript ''19'') m(superscript ''-3''), electron temperature T(subscript ''e'')(0) = 0.5-1.5 keV, and ion temperature T(subscript ''i'')(0) = 0.5-2 keV. The NSTX auxiliary heating systems can routinely deliver 4.5 MW of 80-keV deuterium neutral beams and 3 MW of 30-MHz high-harmonic fast-wave power. Kinetic profile diagnostics presently include a 10-channel, 30-Hz multipulse Thomson scattering system (MPTS), a 17-channel charge-exchange recombination spectroscopy (CHERS) system, a 48-chord ultra-soft X-ray (USXR) array, and a 15-chord bolometry array. Initial experiments utilizing auxiliary heating on NSTX have focused on MHD stability limits, confinement trends, studying H-mode characteristics, and performing initial power balance calculations.

Published
2001
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