Nonlinear solitary kinetic Alfvén waves in multi component plasmas

Abstract

Nonlinear solitary kinetic Alfvén waves (SKAWs) have received much attention in space plasmas since the observations of strong electromagnetic spikes having a solitary structure by Freja and FAST satellites. A possible interpretation for these observations has been put forward in terms of SKAWs. Many theoretical studies have been carried out for SKAWs in a two component electron-ion plasma. However, the realistic space plasma environment in Earth's magnetosphere is composed of multi-species. The already existing theoretical models for SKAWs are without any free energy sources. Also, ion beams are frequently observed in polar cusp and auroral regions as well as other regions of Earth's magnetosphere. Here, the generation of SKAWs will be discussed through a three-component theoretical model composed of Kappa-electrons, background ions and beam ions using Sagdeev potential approach. The properties of solitary structures and role of ion beams in exciting the SKAWs will be presented. The effect of non-Maxwellian parameter κ (kappa) and other plasma parameters, such as number density, plasma beta etc. on the SKAWs will be discussed in great details. The application of the model will be shown for the plasma parameters relevant to different magnetospheric regions of the Earth.