Plasma Generation in a High-Current Glow Discharge with a Hollow Cylindrical Cathode Using Two Electron Sources

Experimental distributions of plasma parameters in the volume of a hollow cathode of a high-current non-selfsustained low-pressure glow discharge supported by electron injection from one and two electron sources located on the upper and lower bases of the cylindrical hollow cathode are obtained. A plasma source based on an arc discharge with an integrally cold hollow cathode is used as an electron source. The possibility of applying the superposition principle to predict the distribution of plasma concentration in the hollow cathode of a high-current low-pressure glow discharge with two electron sources is investigated. The distributions of the plasma parameters were measured at arc discharge currents of 20 and 45 A and glow discharge currents up to 200 A. With an increase in arc discharge currents by about 2 times, from 20 to 45 A, the accuracy of the superposition principle decreases. The maximum degree of inhomogeneity of the plasma concentration when two sources of electrons with currents of 20 A were turned on in the longitudinal direction was 25%. In the radial direction, it was 52%. The maximum discrepancy between the inhomogeneity coefficients for the experimental distribution and the distribution obtained as a result of summing the data obtained with separate operation of electron sources amounted to 8%. When two sources of electrons with currents of 45 A were switched on, the maximum inhomogeneity in the longitudinal direction was 8%, in the radial direction, it was 34%, and the maximum mismatch of the inhomogeneity coefficients was 25%.