Influence of Perturbations in the Axial Symmetry on Formation of Helical Electron Beams in a System with the Reversed Magnetic Field

Abstract

We perform three-dimensional numerical simulation of the electron-optical system (EOS) with the reversed magnetic field, which is designed for a large-orbit gyrotron (GBO) operated in a wide frequency range of 0.26–0.65 GHz, within the framework of a static model and analyze the influence of perturbations in the axial symmetry of electrodes and the magnetic field on the parameters of the axis-encircling electron beam. It is shown that the most significant perturbation of the parameters of the helical electron beam (HEB) is determined by the radial displacement of the cathode and the tilt of the cathode coil, which ensures the reversal of the magnetic field. Analytical estimations are presented, which allow determining the corresponding margins for the development of such systems.