Modelling of low-current discharges in atmospheric-pressure air taking account of non-equilibrium effects

A model of stationary direct current discharges in atmospheric-pressure air is developed that accounts for deviation of plasma state from the local thermodynamic equilibrium. It is shown that at the current range 0.01–0.1 A a change in the dominant ionization mechanism takes place, from ionization by electron impact at low currents to associative ionization in atomic collisions at high currents. Results of the calculation of discharge parameters over a wide current range are presented. Calculated plasma parameters agree with the available experimental data.