Theory and Observations of High Frequency Alfven Eigenmodes in Low Aspect Ratio Plasma

Gorelenkov, N.N. ; Fredrickson, E. ; Belova, E. ; Cheng, C.Z. ; Gates, D. ; Kaye, S. ; White, R.

Princeton University. Plasma Physics Laboratory.

关键词: Spherical Tokamak;    Cyclotron Resonance;    70 Plasma Physics And Fusion Technology;    43 Particle Accelerators;    Cyclotrons;   

DOI  :  10.2172/814692
RP-ID  :  PPPL-3828
RP-ID  :  AC02-76CH03073
RP-ID  :  814692

美国|英语

来源: UNT Digital Library

【 摘 要 】

New observations of sub-cyclotron frequency instability in low aspect ratio plasma in National Spherical Torus Experiments (NSTX) are reported. The frequencies of observed instabilities correlate with the characteristic Alfven velocity of the plasma. A theory of localized Compressional Alfven Eigenmodes (CAE) and Global shear Alfven Eigenmodes (GAE) in low aspect ratio plasma is presented to explain the observed high frequency instabilities. CAE's/GAE's are driven by the velocity space gradient of energetic super-Alfvenic beam ions via Doppler shifted cyclotron resonances. One of the main damping mechanisms of GAE's, the continuum damping, is treated perturbatively within the framework of ideal MHD. Properties of these cyclotron instabilities ions are presented.