The theory of radio windows in planetary magnetospheres

The theory of radio windows given in two previous papers for a stratified cold plasma is extended to apply in a warm plasma. It is used to investigate one suggested mechanism for the production of non-thermal continuum radiation in magnetospheric cavities. The source is a plasma wave that enters a region where there is a gradient of electron concentration and there undergoes partial linear mode conversion to give ordinary and extraordinary electromagnetic waves and a reflected plasma wave. This theory is needed particularly for the plasmapause and magnetopause where the concentration gradients may be large. Some typical results for plasma waves are presented and discussed. (author)