Effect of the cathode material on the amplitude of the ultrashort avalanche electron beam in atmospheric-pressure air

Generation of ultrashort avalanche electron beam (UAEB) during subnanosecond breakdown in atmospheric-pressure air is investigated with a picosecond time resolution. The signals of incident and reflected voltage waves measured in the transmission line of the SLEP-150M generator have made it possible to reconstruct the voltage in the electrode gap. It is found that due to an increase in the gap voltage in the case of a stainless steel conical electrode, the UAEB amplitude is larger than for identical electrodes made of copper and aluminum. It is shown that the UAEB duration and amplitude increase when the conical electrode is replaced by a tubular electrode.