Transport in Auxiliary Heated NSTX Discharges
Authors: B.P. LeBlanc, M.G. Bell, R.E. Bell, M.L. Bitter, C. Bourdelle, D.A. Gates, S.M. Kaye, R. Maingi, J.E. Menard, D. Mueller, M. Ono, S.F. Paul, M.H. Redi, A.L. Roquemore, A. Rosenberg, S.A. Sabbagh, D. Stutman, E.J. Synakowski, V.A. Soukhanovskii, and J.R.Wilson
Date of PPPL Report: July 2003
Presented at: the 30th EPS Conference on Controlled Fusion and Plasma Physics, July 7-11, 2003, Saint Petersburg, Russia Federation, Russia. Published as "Confinement Studies of Auxiliary Heated NSTX Plasmas" Nucl Fus 44:4 (2004) 513-523.
The NSTX spherical torus (ST) provides a unique platform to investigate magnetic confinement in auxiliary-heated plasmas at low aspect ratio. Auxiliary power is routinely coupled to ohmically heated plasmas by deuterium neutral-beam injection (NBI) and by high-harmonic fast waves (HHFW) launch. While theory predicts both techniques to preferentially heat electrons, experiment reveals the electron temperature is greater than the ion temperature during HHFW, but the electron temperature is less than the ion temperature during NBI. In the following we present the experimental data and the results of transport analyses.