On the ordinary mode Weibel instability in space plasmas: a comparison of three-particle distributions

Abstract

Electromagnetic wave fluctuations driven by temperature anisotropy in plasmas are of interest for solar flare, solar corona, and solar wind studies. We investigate the dispersion characteristics of electromagnetic wave propagating perpendicular to the uniform magnetic field which is derived by using multiple particle distribution functions: Maxwellian, bi‐kappa, and product bi‐kappa. The presence of temperature anisotropy in which the parallel plasma kinetic energy density exceeding by a sufficient amount can lead to Weibel‐like electromagnetic instability. A general description is made to calculate the growth/damping rates of Weibel‐like modes when the temperature anisotropy and nonthermal features are associated with these distributions. We demonstrate that for the zeroth cyclotron harmonic, our results for bi‐Maxwellian and bi‐kappa overlap with each other, while the product bi‐kappa distribution shows some dependence on parallel kappa index. For higher harmonics, the growth rates vanish and the damping prevails.