Star formation through thermal instability of radiative plasma with finite electron inertia and finite Larmor radius corrections

Sachin Kaothekar

doi:10.1063/1.4961991

Abstract

I have studied the effects of finite electron inertia, finite ion Larmor radius (FLR) corrections, and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effect of thermal conductivity for star formation in interstellar medium (ISM). A general dispersion relation is derived using the normal mode analysis method with the help of relevant linearized perturbation equations of the problem. The wave propagation is discussed for longitudinal and transverse directions to the external magnetic field and the conditions of modified thermal instabilities and stabilities are discussed in different cases. We find that the thermal instability criterion is get modified into radiative instability criterion by inclusion of radiative heat-loss functions with thermal conductivity. The viscosity of medium removes the effect of FLR corrections from the condition of radiative instability. Numerical calculation shows stabilizing effect of heat-loss function, viscosity and FLR corrections, and destabilizing effect of finite electron inertia on the thermal instability. Results carried out in this paper shows that stars are formed in interstellar medium mainly due to thermal instability.

Highlights

Interstellar medium is the most concerned place for formation of large scale structures and small objects as well as molecular clouds and stars
I have studied the effects of finite electron inertia, finite ion Larmor radius (FLR) corrections, and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effect of thermal conductivity for star formation in interstellar medium (ISM)
We find that the thermal instability criterion is get modified into radiative instability criterion by inclusion of radiative heat-loss functions with thermal conductivity

Summary

INTRODUCTION

Prajapati et al.[14] have investigated the self-gravitational instability of rotating viscous Hall plasma with arbitrary radiative heat-loss function and electron inertia. Kaothekar and Chhajlani[15] have carried out the effect of radiative heat-loss function and finite Larmor radius corrections on Jeans instability of viscous thermally conducting self-gravitating astrophysical plasma. In the light of above work, we find that in these studies (Bora and Talwar,[8] Prajapati et al.,[14] Kaothekar et al.,[17] Chhajlani and Parihar,[23] Vyas and Chhajlani36) the joint influence of FLR corrections, electron inertia, radiative heat-loss functions, viscosity, thermal conductivity and magnetic field on the thermal instability is not investigated. In present work thermal instability of viscous magnetized plasma with electron inertia, FLR corrections, radiative heat-loss functions and thermal conductivity is studied.

BASIC SET OF EQUATIONS OF THE PROBLEM

PERTURBATION EQUATIONS

DISPERSION RELATION

DISCUSSION

CONCLUSIONS