Role of Ordinary to Extraordinary Mode Wave Coupling in Ionospheric Heating Experiments

摘要

Electromagnetic wave propagation in a plane stratified ionospheric plasma and its possible applications to high power, high frequency (HF) experiments are investigated. A theoretical and computational examination of ordinary to extraordinary mode wave coupling is made. This coupling occurs when the propagation is in the magnetic meridian, near the critical angle of incidence. The importance of the mode coupling phenomenon in ionospheric heating experiments is discussed and demonstrated with numerical full wave solutions of the generalized differential equations governing radiowave propagation in a stratified ionosphere. Computational results indicate that mode coupling leads to intense absorption of radiowave energy near the plasma resonance level. The angular shape of the coupling window, in which the coupling is most effective, is found to be approximately circular with its width being a function of the gradient of the electron density.