Instability of self-gravitating isotropic pressure plasma

Instability and wave propagation in an unbounded, self-gravitating, magnetized, one-component plasma is in--vestigated. The effect of self-gravitational attraction is discussed by taking complete pressure tensor equation instead of simple equation of state. The modified equations for collisionless plasma with the incorporation of the effect of self-gravitational attraction are used for the problem. The unperturbed pressure is assumed to be isotropic and the motion of plasma is supposed to be along a particular direction. The equations are linearized and dispersion relation for self-gravitating plasma is obtained. The dispersion relation is found to be a matrix form and is examined for the wave propagation along and perpendicular to the direction of magnetic field. It is found thath the effect of initial fluid motion is to produce Doppler shift in the frequency of wave propagation. It is also found that Jeans' criterion of gravitational instability remains unchanges and present in the system. (author)