Plasma-cathode electron source based on a low-pressure arc discharge in the mode of the emission current enhancement

In the electron beam source based on a plasma cathode with a grid-stabilized plasma emission boundary, the anode plasma significantly affects the limited parameters of the source and widely determines the main characteristics of the source. This paper describes a theoretical and experimental investigation of the discharge plasma generation and the significant increasing mode of the electron emission current in the plasma electron source based on a low-pressure arc discharge. The source works at a pressure of 0.02–0.05 Pa, an accelerating voltage of 10 kV, and a longitudinal magnetic field of 0.1 T. According to experiment and theory, plasma potential depends on the electric field that penetrates from the accelerating gap of anode plasma through the grid meshes, on the discharge current, gas pressure, grid geometric transparency, and on the gas type. It is shown that the basic mechanisms corresponding to the discharge current enhancement and emission current are associated with the secondary ion-electron emission of electrons in the plasma cathode and transport channel on the grid electrode, the presence of positive feedback between the plasma cathode generation area and electron beam transport channel. © 2015 by Begell House, Inc.