Potential and rotational Space-charge fields In a free electron maser

Abstract

Simulation of periodic signal amplification regime in a free-electron maser (FEM) is carried out taking into account the space-charge field. We study influence both of the potential and rotational space-charge fields. An approximate method of calculation of the rotational part of the space-charge field is proposed. Its idea lies in approximation of an infinite set of rotational cutoff modes by some quasi-static electric and magnetic fields. We determine that the rotational part of the space-charge field suppresses the defocusing influence of the potential part on electron beam bunching.