Numerical simulation of the reflex triode virtual cathode with an intense relativistic electron beam

A virtual cathode reflex triode is investigated by numerical simulation with a 3 dimensional particle-in-cell (PIC) code called MAGIC. The reflex triode virtual cathode oscillator has a disk cathode and a disk anode-mesh. Here anode-cathode (A-K) gap distance has been varied from 10 mm to 30 mm. Simulation results show that the output microwave frequency has a narrow bandwidth and its output microwave power depends sensitively AK gap distance. Output microwave mode is mixture of TE mode at A-K gap distance 10 mm, however, TE is to be dominant mode at A-K gap distance 30 mm.