Effects of Radiation-Reaction in Relativistic Laser Acceleration

TL;DR

This paper analytically investigates radiation-reaction effects on relativistic electrons in intense electromagnetic fields, identifying regimes where these effects are detectable and differentiating between various theoretical models of radiation reaction.

Contribution

It provides an analytical solution to the Landau-Lifshitz equation for arbitrary electromagnetic pulses and compares radiation emission predictions across different models, highlighting observable differences.

Findings

Radiation-reaction effects dominate in certain regimes.

Different models predict distinguishable radiation emissions at high accelerations.

Analytical solutions enable better understanding of electron dynamics in intense fields.

Abstract

The goal of this paper is twofold: to explore the response of classical charges to electromagnetic force at the level of unity in natural units and to establish a criterion that determines physical parameters for which the related radiation-reaction effects are detectable. In pursuit of this goal, the Landau-Lifshitz equation is solved analytically for an arbitrary (transverse) electromagnetic pulse. A comparative study of the radiation emission of an electron in a linearly polarized pulse for the Landau-Lifshitz equation and for the Lorentz force equation reveals the radiation-reaction dominated regime, in which radiation-reaction effects overcome the influence of the external fields. The case of a relativistic electron that is slowed down by a counter propagating electromagnetic pulse is studied in detail. We further show that when the electron experiences acceleration of order unity, the dynamics of the Lorentz force equation, the Landau-Lifshitz equation and the Lorentz-Abraham-Dirac equation all result in different radiation emission that could be distinguished in experiment. Finally, our analytic and numerical results are compared with those appearing in the literature.