Numerical simulation of the magnetron operation with resonance load

Abstract

The results of numerical simulations and a comparison with experimental data obtained in recent experiments with the relativistic S-band magnetron by Sayapin et al. [Appl. Phys. Lett. 95, 074101 (2009)], having a resonance load and without special measures being taken to suppress the microwaves reflected from the load, are presented. The numerical simulations were based on the model which considers a magnetron as a traveling wave resonator coupled with external resonator. In these simulations, experimentally determined parameters of the magnetron and resonator and their coupling coefficient were used. It was found that, under certain conditions, the electromagnetic wave reflected from the resonator leads to an increase in the efficiency of the magnetron operation. Taking into account microwave energy compression in the resonator, one obtains a microwave power comparable with the power of the electron beam in the magnetron. Also, it was shown that the magnetron traveling wave acquires a phase shift due to its interaction with the amplified wave of the resonator. This phase shift can be comparable with the phase of the electron spoke with respect to the maximum of the decelerating phase of the microwave electric field. The latter could be a reason for the quenching of the microwave generation and the fast decay of the microwave power in the resonator found in experiments.