Anode region of a low-pressure gas discharge

Abstract

This paper considers the processes that occur in the anode region of a low-pressure gas discharge. Two modes of the longitudinal transport of charged particles in the anode region have been revealed: the free flight mode and the diffusion-drift mode. It has been shown that the anode potential drop in the free flight mode should be negative at any discharge current. For the diffusion-drift mode, the distributions of the electric field strength and potential, as well as the velocities of directed motion of electrons and ions in the anode region have been calculated. Analysis of the results obtained has made it possible to determine the conditions for a positive and a negative anode potential drop to occur. The calculated values of the anode potential drop are in satisfactory agreement with experimental data. A similarity criterion has been formulated to determine the sign of the anode potential drop.