Electromagnetic and kinetic effects on the ion temperature gradient mode

Abstract

Effects of finite beta , ion kinetic damping and trapped electrons on the toroidal ion temperature gradient (ITG) mode have been investigated by two methods-a fully toroidal fluid analysis corrected for ion Landau damping, and an electromagnetic local kinetic dispersion relation. When trapped electrons are ignored, the ITG mode is stabilized at a beta value well below the critical beta for the ideal MHD ballooning mode (βMHD). Trapped electrons are destabilizing and increase the upper limit of beta to a level comparable with βMHD. Ion Landau damping increases the critical temperature gradient typically by a factor of two (LT/LB ≲ 0.18), and the growth rate remains smaller than the ion transit frequency, ωTi = k||vTi