Stratification of the plasma column in transverse nanosecond gas discharges with a hollow cathode

Abstract

Electric and optical characteristics and the structure of spatial distribution of optical radiation from a transverse nanosecond discharge with a hollow cathode in inert gases are systematically studied experimentally. It is found that for moderate working gas pressures in nanosecond discharges with extended electrodes, a periodic plasma structure appears in the form of standing strata. The strata formation boundaries and the critical values of the discharge voltage and current are determined from the gas pressure in helium, neon, and argon under experimental conditions. It is found that the most probable mechanisms of strata formation are the direct ionization of atoms by an electron impact and electron drift in an electric field. The smearing of the plasma structure upon an increase in the voltage applied to electrodes is explained by the emergence of accelerated electrons in the discharge gap.