ELECTROMAGNETIC ION CYCLOTRON INSTABILITY IN SPACE PLASMAS

This study presents observations of ion waves having low-frequencies and their associated ion velocity distribution functions (VDFs) from the Earth’s magnetosphere and solar wind, using the data from Cluster mission. The ion VDFs observed are characterized as non-Maxwellian, comprising a predominant cold component alongside hot tenuous components. We derive the dispersion relation of low-frequency ion waves, by fitting the parameters of observed VDFs, and numerically obtained the instabilitygrowth rate. We further investigate the influence of superthermal particles on the instability.