Collective effect of nonthermal and suprathermal particles on electrostatic waves and instabilities in Vasyliunas-Cairns distributed plasmas

Abstract

The combined effects of nonthermal and suprathermal particles on electrostatic modes of waves propagating in an electron-ion plasma are investigated. Vasyliunas-Cairns distribution with nonthermal and suprathermal spectral indices is used to describe the electron-ion plasma under consideration. The dispersion relation of Langmuir and ion-acoustic waves are examined using the kinetic theory approach. The population of nonthermal and suprathermal particles is found to have a considerable influence on the real wave frequency and damping rate of both Langmuir and ion-acoustic waves. The suprathermal particle population stabilizes the wave whereas the nonthermal particle population destabilizes the wave.