Influence of ionization and ion loss on radiative and gravitational instabilities of inhomogeneous plasma with dust polarization force

Abstract

In the present work, the radiative condensation and gravitational instabilities of inhomogeneous self-gravitating partially ionized dusty plasma have been studied with dust polarization force, ionization and recombination. The basic equations are constructed using four fluid model. The full dynamics of charged dust grains, ions and neutral species are employed considering the electrons as inertialess which have finite thermal conductivity and radiative cooling. The general dispersion relation is derived and discussed for different dusty plasma situations. It is found that the instability conditions are greatly affected due to the polarization force and recombination. Specifically, it is pointed out that the polarization force enhances the growth rate of both the radiative and gravitational instability while the recombination frequency decreases it. Both the parameters have influencing role in short wavelength regime. The e-folding times are calculated for maximum growth rates of gravitational and radiative condensation instabilities. The present work is applicable for study of interstellar molecular clouds and therefore the corresponding free fall time of molecular clouds is also presented.