Emission characteristics of a forevacuum plasma-cathode source of wide-aperture pulsed electron beam with layer (mesh) stabilization of emission plasma

Research of emission characteristics of a pulsed forevacuum plasma electron source with layer (mesh) stabilization of emission plasma boundary has been carried out. Generation of a pulsed wide-aperture electron beam is provided by DC accelerating voltage (1–10 kV) and pulse-periodic formation of emission plasma by a cathodic arc with current 5–80 A, pulse duration 500–600 μs. Pressure (4–30 Pa) and the type of working gas (N2, O2, Ar, He, Kr) significantly influence on the emission characteristics of the forevacuum plasma electron source. An increase in the gas pressure and the use of gas with larger ionization cross-section provide an increase in the electron emission current. At low pressure (below a certain threshold value, which determined by the type of gas) an increase in the discharge current leads to an increase in the efficiency of electron emission. But at pressures more than the threshold value the emission efficiency decreases as the discharge current increases. The influence of pressure and type of gas on the emission characteristics are caused by the ion flux from the beam plasma which is formed due to ionization of gas by accelerated beam's electrons. •The electron emission depends on discharge current, pressure and type of gas.•An increase in the gas pressure leads to higher current of a pulsed electron beam.•Ion flux from beam plasma influences electron emission in a plasma electron source.•Ion-electron emission increases emission current if threshold pressure is reached.