Radiation reaction as an energy enhancement mechanism for laser-irradiated electrons in a strong plasma magnetic field

Z Gong,A V Arefiev,F Mackenroth,X Q Yan

doi:10.1038/s41598-019-53644-x

Abstract

Conventionally, friction is understood as a mechanism depleting a physical system of energy and as an unavoidable feature of any realistic device involving moving parts. In this work, we demonstrate that this intuitive picture loses validity in nonlinear quantum electrodynamics, exemplified in a scenario where spatially random friction counter-intuitively results in a highly directional energy flow. This peculiar behavior is caused by radiation friction, i.e., the energy loss of an accelerated charge due to the emission of radiation. We demonstrate analytically and numerically how radiation friction can dramatically enhance the energy gain by electrons from a laser pulse in a strong magnetic field that naturally arises in dense laser-irradiated plasma. We find the directional energy boost to be due to the transverse electron momentum being reduced through friction whence the driving laser can accelerate the electron more efficiently. In the considered example, the energy of the laser-accelerated electrons is enhanced by orders of magnitude, which then leads to highly directional emission of gamma-rays induced by the plasma magnetic field.

Highlights

In the corresponding time step, the electron emits a photon with its specific value χ f γ found from the relation η
− ω γ,ωiγs/(dcept)e]r→pm.iFniendalblyy, since εe the gamma-rays are primarily emitted within a cone mec[2], we assume them to be emitted along the electron’s of opening angle Δθ mec2/εe and instantaneous direction of motion
All relevant numerical data supporting our findings are available from the corresponding author upon reasonable request

Summary

Introduction

Www.nature.com/scientificreports where s = 4χγ/[3χ(χ − 2χγ)] and Kn(s) are modified second order Bessel functions. Each electron is initially assigned a final optical depth τf = log [1/(1 − P)], with a random number P ∈ [0, 1] modeling stochastic emission and straggling.

Results

Conclusion