On the Influence of the Shape of Kappa Distributions of Ions and Electrons on the Ion Firehose Instability

Abstract

We consider a plasma with electrons and ions described by different combinations of different forms of Kappa distributions, and also by bi-Maxwellian distributions, for investigation of the ion firehose instability. The investigation considers Kappa distributions with small value of the kappa index, which enhance the differences between Kappa distributions and bi-Maxwellian distributions. The results obtained show that different forms of anisotropic Kappa distributions for the ions can have significantly different effect on the growth rates of the instability. The results obtained also show significant effect of the shape of the electron distribution, as well as effect of the anisotropy of electron temperatures, on the growth rates and on the unstable spectral range of the ion firehose instability.