Radiation of a Bunch Crossing a Boundary between a Vacuum and Cold Magnetized Plasma in a Waveguide

TL;DR

This paper analytically investigates the electromagnetic radiation emitted by a small charged bunch crossing a boundary between vacuum and cold magnetized plasma within a waveguide, revealing key radiation characteristics.

Contribution

It introduces an analytical approach to study bunch radiation at vacuum-plasma boundaries in waveguides, considering finite magnetic fields and boundary crossing scenarios.

Findings

Identifies unique radiation features at plasma-vacuum boundary.

Provides analytical expressions for waveguide mode components.

Analyzes two crossing scenarios: plasma to vacuum and vacuum to plasma.

Abstract

We analyze the electromagnetic field of a small bunch that uniformly moves in a circular waveguide and transverses a boundary between an area filled up with cold magnetized electron plasma and a vacuum area. The magnetic field is supposed to be strong but finite so the perturbation technique can be applied. Two cases are studied in detail: the bunch is flying out of the plasma into a vacuum, and, inversely, the bunch is flying into the plasma out of the vacuum area of waveguide. The investigation of the waveguide mode components is performed analytically with methods of the complex variable function theory. The main peculiarities of the bunch radiation in such situations are revealed.