Expansion and Destruction of a Relativistic Electron Beam in a Uniform Magnetostatic Field under the Influence of a Symmetric TM Wave

Abstract

We solve the problem of the motion of a flow of relativistic electrons guided by a uniform magnetostatic field in the channel of interaction with a symmetric TM wave. The problem is related to the analysis of operation of powerful oscillators of Cherenkov microwave radiation and can also have other applications. This problem is of special interest for a possible reduction of the magnetostatic field within the permissible limits of the beam expansion. For synchronous interaction of electrons with a TM wave, we obtain a simple estimate of the possible expansion of the beam through the energy argument and consider the characteristic features of motion in some cases on the basis of more accurate calculations including those for the case of violation of the radial finiteness of motion (microwave “defocusing” of the beam). Attention is drawn to the inconsistency of the known models of expansion of the beam with a fixed maximum velocity of the radial drift of electrons.