Tripolar vortices in inhomogeneous magnetoplasmas in the presence of non-Maxwellian electron distributions

Abstract

Nonlinear equations governing the characteristics of tripolar vortices (TPVs) are investigated in an inhomogeneous magnetoplasma having inertialess non-Maxwellian electrons that obey the Cairns, kappa, and (r, q)-distributions. Analytical and numerical solutions of the nonlinear equations are presented for various possible cases. In this regard, the dispersion relation for the drift ion-acoustic waves (IAWs) is derived, and the condition describing the shear flow instability is discussed. It is realized that enhancing the impact of non-Maxwellian electrons in the aforementioned three distributions modifies the size and formation of TPVs. It is found that the increase in the electron concentration in the regions of low-phase space density leads to enhancement in the size of TPVs and the perturbation potential as compared to the effect of increasing concentration of electrons in the regions of high phase space density. The riveting interplay of low and high-energy electrons with spiky distribution and the resulting novel effects on the propagation of vortex structures are also discussed in detail. The present study is useful to understand the (non)linear propagation characteristics of the drift IAWs in space plasmas with special reference to the F-region of the ionosphere and also in laboratory experiments where the nonthermal distribution functions are usually found.