Larmor radius effect on Rayleigh-Taylor instability of a partially ionized plasma in composite medium

Abstract

The simultaneous effects of finite ion Larmor radius (FLR) and collisions with neutral atoms are investigated on the stability of an infinitely conducting plasma of variable density in the presence of a horizontal magnetic field. The perturbations propagating along the ambient magnetic field are considered. It is established that, real part ofn is negative, wheren is the growth rate of disturbance, so that instability does not arise in the form of increasing amplitude, i.e. overstability. A variational principle is used to obtain an approximate solution of the problem. Further the case of two semi-infinitely extending plasmas of constant densities separated by a horizontal interface is considered. It is found that the system is stable (for some wave numbers) for potentially stable configuration and unstable (for other wave numbers) for potentially unstable configuration even if there are collisions with dust particles. Also criteria determining stability and instability are independent of FLR effects.