Vortex structures formation in ultrarelativistic electron beam with virtual cathode

This report is devoted to the numerical analysis of vortex structures formation in the ultrarelativistic electron beam with virtual cathode in the presence of external magnetic field. The non-stationary dynamics of ultrarelativistic electron beam with overcritical current and its changes with the variation of the main control parameters (the beam current, the induction of external magnetic field et al.) as well as physical processes of structures formation observed in the system have been analyzed by means of the 3D electromagnetic simulation in CST Particle Studio. We have considered the simple model of the vircator with propagating current [1]: a cylindrical perfect or finite conducting waveguide drift space with the grid electrodes at both ends and axially symmetrical at the entrance monoenergetic overcritical annular relativistic electron beam (REB) travelling through the drift chamber. The model under study has been investigated previously in Ref. [2] to discover the typical dependencies of the critical current on the external uniform magnetic field value.