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We describe the design, parameters, and characteristics of a modified wide-aperture, plasma-cathode electron beam source operating in the pressure range of 3 Pa–30 Pa and generating large-radius, low-energy (up to 10 keV) electron beams with a pulse width varying from 0.05 ms to 20 ms and a beam current up to several tens of amperes. A pulsed cathodic arc is used to generate the emission plasma, and a DC accelerating voltage is used to form the electron beam. Modernization of the design and optimization of the operating conditions of the electron source have provided a multiple increase in the pulse duration of the electron beam current and the corresponding increase in the beam energy per pulse, as compared to previously developed pulsed forevacuum electron sources.

We describe our experimental investigation of the effect of background gas pressure on the emission parameters of a pulsed cathodic-arc-based forevacuum-pressure plasma-cathode electron source. We find that increased gas pressure over the range 4–16 Pa significantly reduces the beam current rise-time and significantly increases the emission current amplitude. For example, at a discharge current of 20 A, increasing the working gas pressure from 4 Pa to 16 Pa increases the emission current from 8 A to 18 A and shortens the beam rise-time from 50 μs to 20 μs. This influence of gas pressure on the electron beam parameters can be explained by the effect of arc discharge current switching from the anode to emission. In our case, the current switching effect is caused by increased working gas pressure. In the forevacuum pressure range, the increase of the electron emission current with the growth of gas pressure is due to a rise in the emission plasma potential which is caused by ion back-streaming from the plasma formed in the electron beam transport region. A model describing the influence of gas pressure on the electron emission from the plasma is presented.

We describe properties and parameters of a pulsed cathodic arc discharge, as applied in forevacuum-pressure plasma-cathode electron sources for the generation of broad electron beams. It is shown that during a single arc current pulse, the arc can operate in either of two modes, differing in their discharge operating voltage and plasma constitution. The radial plasma density distribution approximates a Gaussian. The effect of gas pressure on the plasma density is pronounced only at a considerable distance from the cathode.Index Terms-Cathode spots, cathodic arc, forevacuum, plasma-cathode electron source. and a Senior Physicist and Leader of the Department of Plasma Sources with the High Current Electronics Institute, Siberian Branch of the Russian Academy of Sciences. He has authored or co-authored over 200 papers in the area of basic phenomena in low-pressure gaseous discharges and vacuum arc plasmas, charged particle, emission from low-temperature plasma, ion sources and plasma electron guns, and a range of plasma applications.

The research of plasma produced by a pulsed low-energy large-radius electron beam generated by the plasma-cathode electron source in the forevacuum pressure range 4-13 Pa is presented. The beam-produced plasma has been generated in nitrogen by the electron beam with energy of 8 keV and pulse duration of 1.5 ms. The emission spectrum analysis and probe measurements have been used to investigate plasma parameters. Density of beam-produced plasma increases linearly with increasing electron beam current. The probe measurements have demonstrated almost linear dependence of plasma density on gas pressure in the pressure range 4-13 Pa, while intensities of spectral lines came from exited plasma ions are linear dependent on beam current only in pressure range 6-13 Pa. These spectral lines have low intensities at gas pressure below 6 Pa.

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