High-Current Carbon-Epoxy Capillary Cathode

The experimental results of a promising pulsed plasma source, producing electron beams with a current density of up to 10 kA/cm2 are presented. The beam duration was up to ~1 μs, in an accelerating voltage of up to ~350 kV, without shorting of the cathode-anode gap by the cathode plasma. This plasma electron source is proven to sustain hundreds of pulses without degradation in its emission properties. The cathode plasma electron density ne ≤ 1015 cm-3, electron Te ≤ 13 eV and ion Ti ≤ 4 eV temperatures, and expansion velocity Vpl 1.6 × 106 cm/s were determined using time- and space-resolved spectroscopy and light emission.