The absorption mechanism of the ordinary mode propagating perpendicularly to the magnetic field at the electron cyclotron frequency

Abstract

The nonrelativistic hot plasma resonances, which occur for the O mode propagating at right angles to the equilibrium magnetic field are explained in terms of a mode conversion mechanism. The hot plasma introduces additional wave branches—the transverse cyclotron harmonic waves. At an electron cyclotron resonance, an incident O mode is partially converted to a cyclotron harmonic wave and partially transmitted as an O wave. The energy converted to the cyclotron harmonic wave is shown to be identical to the energy absorbed when relativistic effects are included. A simple argument is given showing why earlier nonrelativistic calculations of the absorption gave the same result as the relativistic theory.