Application of carbon/carbon composite cathode in relativistic klystron amplifier

A novel carbon/carbon composite cathode with carbon fibers perpendicular to the surface is developed and used in the relativistic klystron amplifier(RKA). The experimental results show that the field enhanced on the whisker is the main ignition of the explosive emission. RKA can steadily run at the frequency of 25 Hz with an output microwave power more than 1 GW, a pulse duration beyond 100 ns and a current density of 3.82 kA/cm2. The parameters of the carbon/carbon composite cathode such as start-up speed, current delay time and impedance characteristic still need to be studied in the future.