Larmor radius effects on the gravitational instability of a two-component plasma

Abstract

The gravitational instability of a two-component plasma has been studied here to include simultaneously the effects of neutral gas friction, finite ion Larmor radius, magnetic resistivity and Hall currents. The viscosities of the two components of the plasma have also been taken into account. The mode of the transverse as well as the longitudinal wave propagation have been discussed. The dispersion relations have been obtained for both these cases and numerical calculations have been performed to obtain the dependence of the growth rate of the gravitationally unstable mode on the various physical parameters involved. For the transverse mode of propagation, it is found that the growth rate of the unstable mode increases with magnetic resistivity and with the ratio of the densities of two components. The influence of the magnetic resistivity is, therefore, destabilizing on this mode of wave propagation. The viscosities of the two components are found to have a stabilizing influence on the growth rate in this case since it is found that the increase of hte viscosity effects reduces the growth rate. For the longitudinal mode also it is found that the effects of viscosities as well as that of neutral gas friction are stabilizing. The magnetic resistivity does not affect the growth rate since the equation determining the growth rate is found to be independent of this effect.