Repetitively Pulsed Relativistic Cherenkov Microwave Oscillator Without a Guiding Magnetic Field

Repetitively pulsed modes of operation of a Cherenkov microwave oscillator without an external magnetic field for the electron energies of 0.5 and 1.2 MeV were realized in the experiment. In a batch mode with a 1-Hz repetition frequency, the oscillator efficiencies (taking into account the total diode current) were 8% ±2% and 16% ±3 %, respectively (at 0.2 ±0.04-GW and 2.5 ±0.5-GW peak generation power, respectively). For a batch mode with a 10-Hz repetition frequency, the corresponding efficiencies were 7% ±1% and 15% ±3%, respectively (at 0.17 ±0.03-GW and 2.0 ±0.4-GW peak generation power, respectively). Investigations of the lifetime of velvet-covered cathodes and anode grids of oscillators were carried out in repetitively pulsed modes. The lifetime of the anode grid and velvet-covered cathode for the electron energy of 1.2 MeV was about 3000 pulses, and for the electron energy of 0.5 MeV, it can exceed 11 000 pulses.