Beat frequency heating of a magnetized plasma by circularly polarized microwaves

The mixing of two parallel or antiparallel beams of circularly polarized microwaves propagating in the extraordinary mode along a uniform, static magnetic field is examined. Resonant excitation of longitudinal electron plasma waves at the beat frequency is found to enhance the microwave absorption. An analysis is based on Maxwell's equations and the continuity and momentum equations for the electron gas with both collision and temperature effects included. Formulae for the average power absorption density and the absorption efficiency are derived. The results of a numerical study of the coupling constant and the efficiency are presented.