Dust voids associated with double layers in a magnetized dusty plasma

Using a gyrokinetic description for ions and a phase-transition model for the dust fluid, a nonlinear theory for stationary dust voids in a magnetized plasma is formulated. A self-consistent stationary solution of the Vlasov-Maxwell system is found in the form of a cylindrically symmetric double layer bordering a region from which all negatively charged dust grains are expelled. In the presence of an external magnetic field, the ions are drifting predominantly in the poloidal direction, and thus the ion drag force does not play a significant role in the creation of these nonlinear structures. Instead, they are supported by the population of resonant ions, whose guiding centers are trapped in the direction perpendicular to the magnetic field direction by the combined action of the grad-B, polarization and finite Larmor radius effects. We hope that forthcoming dusty plasma experiments in an external magnetic field will confirm our theoretical prediction of a dust void in association with a double layer in a magnetoplasma. (C) 2004 Published by Elsevier B.V.