Particle‐in‐cell/Monte Carlo‐simulation of the discharge in helium initiated by a relativistic electron beam in the chamber with a magnetic mirror

Abstract

A gas discharge is simulated and numerically studied in the gaseous helium in the region of the squeezed state of a single tubular magnetized relativistic electron beam at its partial reflection from a magnetic mirror. The code based on the particle-in-cell/Monte Carlo method was used. The electron beam dynamics, time evolution of phase portraits of particles, physical parameters, and spatial-time characteristics of plasma were calculated. It is shown that dense plasma appears in the cavity under the action of an electron beam in the form of a thin-walled long cylinder of a large length; its electron concentration can be several units of 10 11 cm −3 . At the same time, it turned out that plasma is considerably inhomogeneous in length; its more dense part corresponds to the part of the squeezed state of a beam. The time dependence of the charge compensation of electrons on the helium atom concentration in the chamber was calculated. The dependence turned out to be decreasing since the rate of discharge development is increasing with the growth of the helium pressure in the cavity.