Characteristics of ICRF heating near the second harmonic

Abstract

Analytical and numerical results of physical processes taking place around the second-harmonic resonance surface in ICRF heating are presented. It is shown that (1) symmetry of transmission coefficients follow from Onsager's reciprocity relation of the dielectric tensor, and (2) direct dissipation around the cyclotron harmonic layer is mostly due to the Bernstein branch and depends on k||, becoming low for low k||. The latter has the consequence that mode conversion and reflection are sensitively reduced by damping, but transmission is not.