Insights From Optical Emissions into Physics of High Power Radio Wave Interactions With Plasmas

摘要

The fact is noted that sufficiently high power density HF radio waves incident on the bottom side ionosphere will produce optical emissions. It was previously suggested that the mechanism for such excitation will switch from thermal electron collision excitation to supra-thermal electron collision excitation, as the ionospheric plasma density at the reflection height switches from much below 5 MHz to much above 6 Mhz. Experimental data more directly supporting the assertion is presented. The physical basis for the assertion, including more recent theoretical work, is presented.