Generation of narrow focused beams in a plasma-cathode electron gun

The possibility of generating a narrow focused electron beam in a plasma-cathode electron gun has been studied. An operating mode in which the emitting plasma surface is deep in the emitting channel is optimal for obtaining the highest emission-current density. The beam diameter is reduced by a factor of 1.5–2.0 by choosing the operating mode of the plasma emitter. A two-lens focusing system is used to focus the electron beam. Studies have shown the possibility of generating beams with a power density five to seven times higher than that attained earlier in plasma-cathode guns. As a result of these studies, a plasma-cathode electron gun that allows generation of an electron beam with a diameter of ～260 μm and a power of 3 kW at an accelerating voltage of 30 kV has been developed.