Dust-cyclotron and dust-lower-hybrid modes in self-gravitating magnetized dusty plasmas

Abstract

A theoretical investigation has been made of two new ultra-low-frequency electrostatic modes, namely, dust-cyclotron mode and dust-lower-hybrid mode, propagating perpendicular to the external magnetic eld, in a self-gravitating magnetized two uid dusty plasma system. It has been shown that the e ect of the self-gravitational force, acting on both dust grains and ions, signi cantly modi es the dispersion properties of both of these two electrostatic modes. It is also found that under certain conditions, this self-gravitational e ect can destabilize these ultra-low-frequency electrostatic modes. The implications of these results to some space and astrophysical dusty plasma systems, especially to planetary ring-systems and cometary tails, are brie y mentioned. MIRAMARE TRIESTE