Experimental Research Of Different Plasma Cathodes For Generation Of High-Current Electron Beams

The results of experimental studies of different types of cathodes-carbon-epoxy rods, carbon-epoxy capillary, edged graphite, and metal-dielectric-under the application of high-voltage pulses with an amplitude of several hundreds of kV and pulse duration of several nanoseconds are presented. The best diode performance was achieved with the edged graphite and carbon-epoxy-based cathodes characterized by uniform and fast (< 1 ns) formation of explosive emission plasma spots and quasi-constant diode impedance. This result was achieved for both annular cathodes in a strong magnetic field and planar cathodes of a similar diameter (similar to 2 cm) with no external magnetic field. The cathodes based on carbon-epoxy rods and carbon-epoxy capillaries operating with an average current density up to 1 kA/cm(2) showed insignificant erosion along 10(6) pulses of the generator and the generated electron beam current showed excellent reproducibility in terms of the amplitude and waveform. (C) 2015 AIP Publishing LLC.