Magnetosonic modes with dust mass distributions

Abstract

Previously it was shown that perpendicularly propagating magnetosonic waves in a self-gravitating dusty plasma can significantly increase the Jeans length characteristic of gravitational collapse. Whereas that work was based on the presence of a single dust species, an arbitrary number of charged dust species is now considered and a modified Jeans criterion is obtained, subject to neglect of the dust thermal speeds with respect to the magnetosonic speed. As an illustration, the case of two dust masses is considered and used to justify that assumption. It is found that, in general, the criterion derived for a single (average) dust species provides an adequate approximation to the physics.