COMPUTATIONAL MODELING IN THE STUDY OF GLOW DISCHARGE PHYSICAL PROCESSES IN THE AIR AT LOW PRESSURES

Simple numerical models of low-pressure air gas discharge have been developed based on modern concepts of nonlocal plasma methods of the computational simulation of multi-component discharge environments. Voltage drop at the discharge gap has been calculated as a sum of incidences in the cathode sheath and on the positive column of a glow discharge as part of the semi-empirical approach. Electron impact ionization of the ground state, the recombination of charged particles on the walls of the discharge tube, ion-electron emission from the cathode, and the energy loss of electrons in collisions with ground state molecules have been taken into account in the models. The calculated voltage drop, depending on the pressure, has been compared with the results of another numerical discharge model based on the solutions of hydrodynamic equations for the particle densities in a two-dimensional case. Within these approximations, both models give satisfactory agreement between their results, which are strongly underestimated against the experiment corresponding to the normal highpressure glow discharge. The resulting discrepancy can be explained by an incompleteness of elementary processes taken into account in the simulation. For example, an unaccounted presence of gases from triatomic molecules as an impurity can lead to an increase in the collision energy losses of electrons, which in turn should lead to an increased electric field in the positive column, as compared with the values obtained in the models.