Using the method of shadow photographing, the formation of a spark discharge in the "tip (cathode) – plane" interval with a length of 1.5 mm is investigated. Two types of shock waves have been registered – cylindrical, created when the discharge channel expands, and cathode, presumably generated by cathode flares near the surface of the tip electrode. The computational and theoretical consideration of the proposed mechanism is carried out.

The results of studies of the dynamics of near-electrode processes in the initial phase of the spark are presented. discharge in air at atmospheric pressure in the tip – plane geometry. Near the surface of a flat After the breakdown of the cathode, regions with a size of about 50 μm and more were recorded with an increased electron concentration of (3–8)•10^19 cm^(– 3). Based on experimental data on erosion the effect of a discharge on the surface of a flat electrode and the associated gas-dynamic effects a physical model of near-electrode processes is proposed, based on which estimates are made gas dynamic parameters.