THE PARAMETERS OF A CATHODE-DIRECTED STREAMER PLASMA IN AIR - THE EFFECT ON CURRENT AND PROPAGATION VELOCITY

A numerical quasi-two-dimensional model of a long streamer is used to analyze a streamer plasma. The gas temperature and vibrational tempera ture are determined. The dynamics of variation of the electron concent ration along the long streamer are traced under the effect of voltage pulses with a nanosecond pulse duration. It is established that the ra dius of the region of streamer-current transport is approximately two orders greater than the characteristic radius of the initial avalanche . The hypothesis on the expansion of the channel radius due to the pro pagation of a cylindrical wave of ionization is developed. Direct prop ortionality is revealed between the streamer velocity and the electron concentration immediately behind die ionization wave front. It is sho wn that the mobility of the particles baring the volumetric charge has little effect on the maximum velocity of the streamer.