ИСТИНА

A model of fast gas heating in nitrogen-oxygen gas-discharge plasmas in a broad range of reduced electric fields E/N is presented. It is shown that in air at E/N  300 Td the main contribution to gas heating occurs due to the electron impact dissociation of О2 molecules and due to the quenching of electronically excited states of nitrogen by oxygen and quenching of excited N(2D), O(1D) atoms by nitrogen molecules. An analysis of the experimental data on fast heating of air and nitrogen in nanosecond discharges at high reduced electric fields E/N is given. It was shown that, in nitrogen-oxygen mixtures in a broad range of reduced electric fields, a fixed fraction of discharge power ηE, spent on the excitation of electronic degrees of freedom, ionization and dissociation of mixture molecules, is converted to the fast gas heating. In air the value of ηE is about 30% and diminishes with decreasing the fraction of oxygen in a mixture. The features of the mechanism of gas heating in nanosecond discharges in nitrogen-oxygen mixtures at high dissociation degree of oxygen molecules and high specific delivered energy are discussed.