MHD Induced Neutral Beam Ion Loss from NSTX Plasmas
Authors: D.S. Darrow, E.D. Fredrickson, N.N. Gorelenkov, A.L. Roquemore, and K. Shinohara
Abstract:
Bursts of ~60 kHz activity on Mirnov coils occur frequently in NSTX plasmas and these are accompanied by bursts of neutral beam ion loss over a range in pitch angles. These losses have been measured with a scintillator type loss probe imaged with a high speed (>10,000 frames/s) video camera, giving the evolution of the energy and pitch angle distributions of the lost neutral beam ions over the course of the events. The instability occurs below the TAE frequency in NSTX (~100 kHz) in high beta plasmas and may be a beta driven Alfvén acoustic (BAAE) mode.
____________________________________________________
Invited paper
Presented at Tenth IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems, 8–10 October 2007, Kloster Seeon, Germany.
Accepted for publication in Nuclear Fusion.
____________________________________________________
Download PPPL-4274 (pdf 864 KB)