Comparative studies on intense electron beams generated in transient hollow-cathode discharges

For a large range of pulsed power applications, intense pulsed electron beams with 0.1-2-mm diameter, power densities of about 10⁹ W/cm², peak currents in the 50 to 1000 A range, and electron energies up to several tens of kiloelectronvolts are generated in high voltage (5-30 kV) transient hollow cathode discharges (THCD). The most efficient THCD configurations for generating such electron beams are the pseudospark, the channel spark, and preionization-controlled open-ended hollow-cathode configurations, which differ from each other by the tube geometry and the typical working gas pressure (0.5-500 Pa). The beam parameters, such as current, pulse length, and electron energy are compared for all three configurations using the same diagnostics. The dependencies of these beam parameters on the discharge geometry, voltage, external capacitance, and gas pressure is discussed in these three configurations.