Generation of Plasma with Increased Ionization Degree in a Pulsed High-Current Low-Pressure Hollow Cathode Discharge

The paper presents the results of research of the processes of generation of pulsed beam-plasma formations in a high-current non-self-sustained glow discharge with a hollow cathode at low (0.025–0.25 Pa) pressures. In the hollow cathode volume of 0.34 m³, the glow discharge pulsed currents up to 800 A were obtained at injected electron currents up to 150 A, discharge burning voltages up to 400 V, and a pulse duration of 1 ms. The plasma with a density of about 10¹² cm^-3 was formed with ionization degree up to 16%. It has been shown that the electron free path length λ_C between the Coulomb interactions in the pressure range 0.025–0.05 Pa is by a factor of about 3.5 less than the electron free path length λ_e when interacting with neutrals at high (10–15%) degree of plasma ionization. The measured saturation electron current density on the single electric probe was 3.7 (0.025 Pa), 5 (0.05 Pa), and 6.7 A/cm² (0.25 Pa). Relatively homogeneous beam-plasma formations generated in the glow discharge are promising for the formation of intensive pulsed electron beams of large cross section.