PPPL-3587 is available in pdf or postscript formats.

Stability and Confinement Properties of Auxiliary Heated NSTX Discharges

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

Date of PPPL Report: July 2001

Presented at: the 28th EPS Conference on Controlled Fusion and Plasma Physics, Madeira, Portugal, June 18-22, 2001.

The National Spherical Torus Experiment (NSTX) is a spherical tokamak with nominal plasma major radius R0 = 0.85 m, minor radius a = 0.66 m, and aspect ratio A > 1.28. Typical discharge parameters are Ip = 0.7-1.4 MA, Bt0 = 0.25-0.45 Tesla at R0, elongation = 1.7-2.2, triangularity 0.3-0.5, line-average electron density ne = 2-5 x 1019 m-3, Te(0) = 0.5-1.5 keV, and Ti(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.