Influence of dust particles on glow discharge

Abstract

The gas discharge–dust particle interaction for a dc discharge in air with micron-sized particles is investigated. The plasma of the dc column is described in the frame of diffusion approximation combined with the orbital motion limited approximation for ion and electron flow on the dust component surface. The problem is solved for dust particles of 2 μm radius, embedded in a uniform glow discharge column with a diameter of 16 mm at air pressure 0.5 torr, discharge current 0.5–3 mA and particle concentration up to 105 cm−3. The current–voltage characteristics as an easy-to-observe measure of the nonlocal dust influence on the total amount of charge carriers in the discharge, as well as the radial distributions of plasma components in the dc discharge, are calculated for different dust concentrations and discharge currents. The results are compared with recently published experimental data. The presence of dust particles leads to an increase of the longitudinal electric field due to additional loss of ions and electrons. A decrease of the radial electric field within the dust cloud under the action of dust particles results in an essential change of the electron concentration profile, down to the appearance of the local minimum at the axis of the discharge.