Tolerance of pulsed discharges to contamination by gas phase particulates

Summary form only given. The consequences of contamination of pulsed gas discharges by gas-phase particulates were studied theoretically. This study was performed with a multidimensional continuum model for a glow discharge sustained in rare gases in which a distribution of dust is specified. The continuum model integrates the conservation and transport equations for excited states and ions, while driving the plasma with an external circuit. Electron impact rate coefficients are obtained from a lookup table in which they are cataloged as a function of E/N and dust density, as well as other pertinent parameters such as fractional ionization. These rate coefficients were obtained by separately parameterizing a Monte Carlo simulation performed previously. Variations in dust density of less than tens of percents across the bore of the discharge tube (dust density ≈10⁵ cm^-3) were sufficient to cause constriction and arcing of the plasma. Wall-generated contamination leads to arcing along the axis; volumetrically generated contamination leads to constriction along the walls. Tolerances of rare gas discharges against instabilities caused by contamination were investigated