Particulate dynamics at the plasma-sheath boundary in DC glow discharges

The forces on and resulting dynamics of particulate contaminants near the plasma-sheath boundary in a one-dimensional, steady-state glow discharge are examined. Various expressions for the electric force, including the effects of nonneutrality and particulate spacing on the charge state, are considered, and several different ways to compute the ion drag force are compared. The properties of the particulate traps that result from the interplay of these forces are studied. The effects of the gravitational, neutral drag, and polarization forces are also considered. Time-dependent motion of the particulates, including the effects of a temporally varying, spatially localized particulate density, is also investigated. While some uncertainties exist in the individual expressions for the various forces and in the properties of the discharge, the particulate traps are fairly well defined and consistent with experiments and other analyses