Physics and technique of plasma electron sources

This paper reviews the properties of electron emission from a gas discharge plasma. Interest in electron emission from plasma is due to the possibility of creating reliable and effective sources of high-current electron beams. The constricted arc discharge, vacuum arc and superdense glow discharge in crossed E x H fields are used for the creation of the plasma emission surface. Grid stabilization of the plasma emission surface is used to stabilize the plasma parameters. Electron current switching is used to increase plasma cathode efficiency. The plasma cathode emission current is controlled by variation of the plasma concentration, the emission electrode potential and the crossed magnetic field. The plasma cathode electron beam source, with 200 keV energy and microsecond pulse duration, provides electron beams with a cross section up to 10(4) cm(2), beam current from 10 to 1000 A and current density up to 1 A cm(-2). The annular electron beam source provides an electron beam with 10 cm diameter, 1 mm width, 15 mu s pulse, 600 A current and current density of 75 A cm(-2).