Electron cyclotron damping in thermal and nonthermal plasma

The relativistic dispersion relation including temperature anisotropy and a parallel drift has been derived for electron cyclotron waves of frequency up to third harmonics, and solved for a perpendicularly stratified plasma around the fundamental and second harmonic resonances. For quasiperpendicular propagation, damping of fundamental modes is much more sensitively affected by T∥ than by T⊥. This is also true for the ordinary mode of oblique propagation. The theory has been extended to a bulk thermal distribution with a two‐temperature or three‐temperature tail distribution by a simple summation of each contribution to the dispersion tensor. The effect of a tail distribution is relatively small if the tail is localized in the resonant layer for the bulk electrons. For a nonlocal tail distribution, the existence of a tail becomes important.