Pulse–periodic diffuse discharge with self-ionization in a gas flow

A pulse–periodic diffuse discharge self-initiated in an atmospheric-pressure air flow passing through an annular gap with a strongly nonuniform electric field has been studied. The discharge serves as a source of a weakly ionized nonequilibrium plasma in which effective synthesis of nitrogen oxide is provided. It has been found that diffuse current channels sequentially arise in the annular gap in the direction of the air flow in time with high-voltage pulses. Experimental data suggest that the self-ionization (self-initiation) effect is due to the shift of negative oxygen ions accumulated in current channels and the mechanism behind the appearance of “seed” electrons in breakdown areas is the detachment of electrons from oxygen ions.