Trajectory Analysis in a Collector with Multistage Energy Recovery for a DEMO Prototype Gyrotron. Part I. Idealized Magnetic Field Distribution

Abstract

This paper presents the results of simulation of the collector of a prototype gyrotron designed for the DEMO project. Trajectory analysis in a collector with four-stage recovery of the residual beam energy based on the method of spatial separation of electrons in crossed azimuthal magnetic and axial electric fields was carried out. In this part of the research, the azimuthal magnetic field was formed using a conductor located on the axis of the device. The study was carried out for a spent electron beam with a particle velocity and coordinate distribution close to those obtained in experiments with high-power gyrotrons. As a result of optimizing the geometry and potentials of the collector sections, an overall efficiency of the gyrotron higher than 80% was achieved, which is close to the maximum efficiency with ideal separation of electron beam fractions with different energies. The data obtained will be used to design a toroidal solenoid for creating an azimuthal magnetic field.