Stagnation of electron flow by a nonlinearly generated whistler wave

TL;DR

This paper investigates how a nonlinearly generated whistler wave can halt relativistic electron beams in a magnetized plasma, revealing a new mechanism of beam stagnation through wave coupling.

Contribution

It introduces a novel nonlinear coupling process involving whistler waves that leads to electron beam stagnation in magnetized plasma environments.

Findings

Whistler waves are excited by instabilities in the plasma.

A large amplitude parallel whistler wave can stop the electron beam.

Magnetic field strength influences the onset of the secondary instability.

Abstract

Relativistic electron beam transport through a high-density, magnetized plasma is studied numerically and theoretically. An electron beam injected into a cold plasma excites Weibel and two-stream instabilities that heat the beam and saturate. In the absence of an applied magnetic field, the heated beam continues to propagate. However, when a magnetic field of particular strength is applied along the direction of beam propagation, a secondary instability of off-angle whistler modes is excited. These modes then couple nonlinearly creating a large amplitude parallel propagating whistler that stops the beam. In this letter, we will show the phenomena in detail and explain the mechanism of whistler mediated beam stagnation.