ICRF Mode Conversion Flow Drive Experiments on Alcator C-Mod

摘要

We have carried out a detailed study of the dependence of ICRF mode conversion flow drive (MCFD) on plasma and RF parameters. The flow drive efficiency is found to depend strongly on the ~(3)He concentration in D(~(3)He) plasmas, a key parameter separating the ICRF minority heating regime and mode conversion regime. At +90 deg antenna phasing (waves in the co-I_(p) direction) and dipole phasing, the driven flow is in the co-I_(p) direction, and the change of the rotation velocity increases with both P_(RF) and I_(p), and scales unfavorably vs. plasma density and antenna frequency. When MCFD is applied to I-mode plasmas, the plasma rotation increases until the onset of MHD modes triggered by large sawtooth crashes. Very high performance I-mode plasmas with H_(ITER98,y2) approx1.4 and T_(e0) approx 8 keV have been obtained in these experiments.