Role of photoionization processes in propagation of cathode-directed streamer

Abstract

The effect of the electron distribution in front of thecathode-directed streamer head on the characteristics of the dischargeitself has been analysed in this paper. Both the process of gasphotoionization in front of the streamer head and the effect of spatiallyuniform `background' pre-ionization have been taken into consideration. Itis shown that the substitution of the actual photoelectron distribution infront of the streamer head for uniform `background' pre-ionization makesit possible, by the variation of this parameter, to attain the coincidenceof some characteristics of the streamer discharge (streamer velocity,conduction current, electron distribution in the streamer head andchannel), not allowing for coincidence of all the characteristicssimultaneously in this case. The analytical model that allows us, with theuse of the known streamer head potential, to obtain associated values ofthe head radius and peak electric field strength has been proposed andverified.