Cyclotron harmonic absorption via the Green’s function for the mode conversion-tunneling equation

Abstract

Cyclotron harmonic absorption is included in the analysis of the mode conversion-tunneling process by solving for the Green’s function of the fourth-order mode conversion-tunneling equation. For the first cyclotron harmonic where ω≈2ωci and the wave propagates exactly across the magnetic field, the solution is given in closed form in terms of the basic homogeneous solutions. For finite k∥, the solution is given by solving an integral equation where the kernel is not self-adjoint since the basic mode conversion-tunneling equation is not self-adjoint. For cavity modes, it appears that mode conversion losses are generally greater than harmonic cyclotron absorption losses although both are of the same order, and the result implies that electron heating may dominate ion heating for these processes.