Development of ionization waves in argon at atmospheric pressure with inhomogeneous preliminary ionization

Experimental and theoretical investigations of the initial stage of the formation of a pulsed volume discharge between two plane electrodes in argon at atmospheric pressure under conditions of inhomogeneous preionization are reported. The experimental results of the propagation velocity of an ionization wave are compared with the obtained value from the numerical simulation. The features of the development of ionization waves in atmospheric-pressure argon are studied

Features of the cathode plasma formation at the initial stage of a nanosecond spark discharge in air

Nanosecond discharges at atmospheric pressure have a wide range of applications. The features of a nanosecond spark discharge formation strongly depend on the discharge gap geometry and the applied voltage. The present paper contains the results of near-electrode processes investigation at the initial stage of a spark discharge in air in the pin-to-plate geometry. Extra-high electron concentration in the range of $10^{19}\text{--}10^{20}\ \text{cm}^{-3}$ was obtained based on the Mach-Zehnder interferometer after breakdown near the surface of a flat cathode. It is confirmed that the discharge channel is a multitude of microchannels that close the discharge gap. Analysis of a flat electrode surface after breakdown shows that the channel binding region is a cluster of microcraters with diameter from 5 to $35\ \mu \text{m}$ . A model for the gas dynamics processes at the initial stage of a nanosecond spark discharge is proposed