Plasma and Gas-Dynamic Near-Electrode Processes in the Initial Phase of a Microstructured Spark Discharge in Air

The results of studies of the dynamics of near-electrode processes in the initial phase of a spark discharge in atmospheric-pressure air in the point-plane geometry are presented. After breakdown, regions of about 50 μm or more in size with an increased electron concentration of (3–8) × 1019 cm–3 near the surface of the flat cathode have been observed. With allowance for the experimental data on erosion effect of the discharge on the surface of a flat electrode and the associated gas-dynamic effects, a physical model of near-electrode processes has been proposed, based on which the gas-dynamic parameters are estimated.