Finite Temperature Effect on Ray Tracing near the Electron Cyclotron Resonance

Propagation and absorption of electromagnetic waves near the electron cyclotron resonance frequency are numerically investigated in inhomogeneous plasmas. Geometrical optics is used for both warm and cold plasmas to study the finite temperature effect on ray tracing, and it is found that the geometrical optics cannot be applied in the region of electron cyclotron resonance, where the group velocity does not coincide with the velocity of energy flow. The singular behavior of the group velocity near the cyclotron resonance zone agrees with that reported by Brillouin in an absorbing dielectric mediun.