Electromagnetic and kinetic effects on the ion temperature gradient mode

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 (β MHD ). Trapped electrons are destabilizing and increase the upper limit of beta to a level comparable with β MHD . Ion Landau damping increases the critical temperature gradient typically by a factor of two (L T /L B ≲ 0.18), and the growth rate remains smaller than the ion transit frequency, ω Ti = k || v Ti