DISSOCIATION OF OXYGEN AND WATER MOLECULES IN NEGATIVE CORONA

Numerical simulations of negative corona in the Trichel pulse mode with calculations of dissociation rates of oxygen molecules in air and oxygen and of water molecules in humid air are carried out. It is found that the yield of oxygen atoms and hydroxyl radicals from the first pulse is considerably greater than from each of subsequent pulses and the main part of dissociation acts occurs during the ionization wave propagation over the cathode surface in a small space of intensive impact ionization. The obtained differences in ratio of dissociation rates at the different stages of ionization wave propagation and for different subsequent pulses are explained by the difference in the characteristics of the ionization wave at these stages and pulses, determined by different dependences of the frequencies of electron processes on the field strength.