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 n_e ≤ 10¹⁵ cm^-3, electron T_e ≤ 13 eV and ion T_i ≤ 4 eV temperatures, and expansion velocity V_pl 1.6 × 10⁶ cm/s were determined using time- and space-resolved spectroscopy and light emission.