Nonlinear theory for dust voids in plasmas

A nonlinear theory for dust voids in plasmas is presented. Specifically, it is shown that dust voids are caused by a large potential drop associated with the ion holes and double layers in plasmas. For this purpose, we solve cylindrically symmetric Poisson's equation with a Boltzmann electron density distribution, a modified Boltzmann dust density distribution, and an ion response consisting of trapped and untrapped ion velocity distributions in the self-consistent plasma potential. Numerical results exhibit significant holes in the ion distribution function, accompanied by a large electrostatic potential drop and charge density double layers. We discuss the underlying physics of dust voids in terms of our self-consistent steady state solutions of the Vlasov-Poisson system of equations. (C) 2003 Elsevier Science B.V. All rights reserved.