Two-dimensional numerical modelling of the cathode-directed streamer development in a long gap at high voltage

Two-dimensional hydrodynamic numerical modelling of a cathode-directed streamer discharge at a constant anode voltage of 100 kV in a 13 cm long gap filled with a nitrogen–oxygen mixture at atmospheric pressure is performed. The dynamics of main discharge parameters is analysed and quite good agreement with experimental measurements is obtained. It is shown that, when the electron loss processes in the streamer plasma are neglected, the discharge dynamics changes insignificantly: the electric field in the streamer head changes by less than 1% and the streamer propagation velocity changes by 7%, while the anode current and the electric field in the streamer channel change by a factor of about 2. The calculated anode current is found to coincide with the experimental one only when kinetic processes in the streamer channel are taken into account.