Propagation features and polarization properties of ion cyclotron waves in multi-component plasma

Lightning strokes are the source of wide-band emissions which, upon propagation in the Earth-ionosphere wave guide, partly leak through and penetrate into the magnetosphere. The lower frequency part (below few hundred Hz) of this emissions corresponds to ion cyclotron waves (ICW). The most familiar wave phenomena related to these waves are proton whistlers. These emissions have been known since mid-sixties. Recent multicomponent ELF observations by the DEMETER satellite triggered an interest to further analysis of these wave events. This analysis relies upon the investigation of propagation features and polarization properties of ion cyclotron waves in multi-component plasma in the upper ionosphere, which are discussed in the present paper.