EQUILIBRIA AND PROCESSES IN DISSOCIATED AIR

For atmospheric air as a mixture of molecular gases in thermodynamic equilibrium, an algorithm is presented for calculating the density of atoms and molecules in the case of separation of dissociative transition regions for each component. The result is compared with an approximation where the partial pressures of nitrogen and oxygen are temperature-independent. Ionization equilibrium at temperatures below 7000 K occurs through the formation of molecular ion NO⁺, and at higher temperatures, the formation of atomic ions of oxygen and nitrogen dominates. It is shown that at pressures around atmospheric, with accuracy higher than 10%, electron-excited states of atoms can be neglected in the analysis of ionization equilibrium up to complete ionization of air. For the analysis of air plasma in the lightning conducting channel, the use of results and experimental data shows that the passage of the main electric current during the return stroke phase is temporally separated from the subsequent expansion of the heated channel. It is shown that the plasma temperature of the conducting channel between adjacent flashes, as well as before the passage of the main electric current, is approximately 4 kK. This temperature is maintained by small external electric fields.