Effect of Self-Magnetic Fields on the Nonlinear Dynamics of Relativistic Electron Beam with Virtual Cathode

TL;DR

This study numerically investigates how self-magnetic and external magnetic fields influence the formation of virtual cathodes and azimuthal instabilities in relativistic electron beams, revealing dependencies on magnetic field strength and beam thickness.

Contribution

It introduces a detailed numerical analysis of the effects of self-magnetic fields on virtual cathode formation and azimuthal instability in relativistic electron beams.

Findings

Self-magnetic fields induce azimuthal instability leading to vortex structures.

Critical current for virtual cathode formation decreases due to self-magnetic effects.

Critical current depends on external magnetic field strength and beam thickness.

Abstract

The report is devoted to the results of the numerical study of the virtual cathode formation conditions in the relativistic electron beam under the influence of the self-magnetic and external axial magnetic fields. The azimuthal instability of the relativistic electron beam leading to the formation of the vortex electron structure in the system was found out. This instability is determined by the influence of the self-magnetic fields of the relativistic electron beam and it leads to the decrease of the critical value of the electron beam current (current when the non-stationary virtual cathode is formed in the drift space). The typical dependencies of the critical current on the external uniform magnetic field value were discovered. The effect of the beam thickness on the virtual cathode formation conditions was also analyzed.