Computer simulation of the stimulation of electromagnetic vibrations of an open plasma resonator

Abstract

In calculating microwaves - amplifiers and generators based on the emission of highly relativistic electronic beams in limited plasma, you have to face a number of difficulties, one of
which is the correct setting of radiation conditions. Since there is no one-size-fits-all algorithm to overcome these challenges, you have to use a variety of simplistic assumptions and corresponding models. For example, plasma generators typically assumed that the width of the spectrum of vibrations generated was small and the central frequency corresponded to the frequency of accurate Cherenkov resonance. However, these assumptions were justified only for beams with currents of smaller maximum vacuum current. It was for such beams, using the method slowly- changing amplitude and introducing a constant ratio of plasma wave reflection from the radiating mouthpiece, it was possible to create a non-stationary theory of plasma microwave - a generator. However, the possibility of applying this approach is very limited, as it does not use
a strict form of radiation conditions. This is due to the fact that known boundary conditions of radiation were developed to describe only established vibrational processes. Currently, there are various options for generalizing these boundary conditions for a non-stationary case, but all of them are not without certain shortcomings. One of the most successful variants of the radiation boundary conditions for the complete non-stationary system of Maxwell - Vlasova is, in our view, the unsteady analogue of the partial radiation conditions. However, the practical implementation of these conditions also faces serious mathematical difficulties. The question of the feasibity and
effectiveness of these radiation conditions in relation to a specific electrodynamic system is being considered in this paper.