Experimental Examination of Diode Features in a High-Power Magnetron with a Transparent Cathode

Abstract

A Magnetron is a high efficiency microwave source, although the energy conversion efficiency of a pulsedpower magnetron with a relativistic electron beam is less than that of a non-relativistic magnetron. We studied the possibility of increasing the energy conversion efficiency of a high-power magnetron using a transparent cathode. The conversion efficiency is controlled by the resonance efficiency between the electron beam and microwave oscillation, and initial rise time of the oscillation. In particular, the initial rise time of interaction with the pulsed-power generator is important. The transparent cathode can lower start-up times and enhance the oscillation efficiency. It consists of independent cathode strips, each of which produces an azimuthal magnetic field. The radial drift velocity of electrons emitted from this cathode is accelerated more than that of electrons emitted from a normal cathode. In particle-in-cell electron simulation, the availability of the transparent cathode was indicated. We investigated the experimental effect of the transparent cathode. The experimental setup of the relativistic magnetron is operated with “ETIGO IV,” which is a 400-kV-class repetitive pulsed-power generator. The start-up time of magnetron with the transparent cathode is shorter than that with a traditional cathode. We expect that the transparent cathode method will be advantageous over the current method. c