Abstract
A new method of repetitive operation of a virtual cathode oscillator was performed using a carbon plate anode with a hole in the center, a knife-edged annular cathode and an external axial magnetic field. Repetitive microwave radiations more than 450 were observed. Almost all microwave frequency of each operation was contained in 11.8 to 12.8 GHz, while the microwave emission was varied widely. The maximum microwave peak power and pulse duration were 14 MW and 16 ns, respectively, for the diode voltage of 460 kV, the electron beam current of 12.8 kA at the upstream. The dominant radiation pattern of microwave was found to be TE01 mode.
