Effect of Gas Fueling Location on H-mode Access in NSTX

Maingi, R. ; Bell, M. ; Bell, R. ; Biewer, T. ; Bush, C. ; Chang, C.S. ; Gates, D. ; Kaye, S. ; Kugel, H. ; LeBlanc, B. ; Maqueda, R. ; Menard, J. ; Mueller, D. ; Raman, R. ; Sabbagh, S. ; Soukhanovskii, V. ; Team, the NSTX

Princeton University. Plasma Physics Laboratory.

关键词: Rotation;    70 Plasma Physics And Fusion Technology;    Tokamaks, Nstx;    Edge Plasma;    Sensitivity;   

DOI  :  10.2172/820105
RP-ID  :  PPPL-3883
RP-ID  :  AC02-76CH03073
RP-ID  :  820105

美国|英语

来源: UNT Digital Library

【 摘 要 】

The dependence of H-mode access on the poloidal location of the gas injection source has been investigated in the National Spherical Torus Experiment (NSTX). We find that gas fueling from the center stack midplane area produces the most reproducible H-mode access with generally the lowest L-H threshold power in lower single-null configuration. The edge toroidal rotation velocity is largest (in direction of the plasma current) just before the L-H transition with center stack midplane fueling, and then reverses direction after the L-H transition. Simulation of these results with a 2-D guiding-center Monte Carlo neoclassical transport code is qualitatively consistent with the trends in the measured velocities. Double-null discharges exhibit H-mode access with gas fueling from either the center stack midplane or center stack top locations, indicating a reduced sensitivity of H-mode access on fueling location in that shape.