Deviations from ionization equilibrium caused by diffusion in the near-cathode region of an atmospheric-pressure argon arc discharge are studied. The model comprises the continuity and transport equations for electrons, atoms, and singly-, doubly-and triply-charged ions. A numerical solution of these equations is obtained in a wide range of electron temperatures in the layer. Distributions of densities of the species across the layer and the ion currents to the cathode are presented. It is shown that in the whole range of the electron temperatures the major contribution to the total ion current to the cathode is due to singly-charged ions. A comparison is presented of the obtained numerical results with those given by a model with only singly-charged ions.

Influence of solution electrical conductivity and ionic composition on the performance of a gas-liquid pulsed spark discharge reactor for water treatment

A robust, fast, and accurate numerical method is proposed for finding the voltage of the ignition of DC self-sustaining gas discharges in a wide range of conditions. The method is based on physical grounds and builds up from the idea that the ignition of a self-sustaining gas discharge should be associated with a resonance that would occur in a non-self-sustained discharge in the same electrode configuration. Examples of the application of the method are shown for various configurations: parallel-plate discharge, coaxial and wire-to-plane corona discharges, and a discharge along a dielectric surface. The results conform to the conventional Townsend breakdown condition for the parallel-plate configuration and are in good agreement with existing experimental data for the other configurations. The method has the potential of providing a reference point for optimization of the hold-off capability of high-power switchgear operating in low-frequency fields.