Influence of the rotational sense of two colliding laser beams on the radiation of an ultrarelativistic electron

TL;DR

This study analytically and numerically examines how the rotational sense of two colliding laser beams affects the dynamics and radiation of an ultrarelativistic electron, revealing qualitative differences in electron behavior but similar radiation spectra.

Contribution

It provides an analytical solution for electron dynamics in co-rotating and counter-rotating laser beams and compares their radiation spectra, highlighting qualitative differences in trajectories but similar spectral shapes.

Findings

Qualitative differences in electron energy and momentum based on laser rotation sense.

Radiation spectra are similar in shape despite differences in electron trajectories.

Quantitative differences in spectra are only a few percent.

Abstract

With analytical treatment, the classical dynamics of an ultrarelativistic electron in two counter-propagating circularly polarized strong laser beams with either co-rotating or counter-rotating direction are considered. Assuming that the particle energy is the dominant scale in the setup, an approximate solution is derived and the influence of the rotational sense on the dynamics is analyzed. Qualitative differences in both electron energy and momentum are found for the laser beams being co-rotating or counter-rotating and are confirmed by the exact numerical solution of the classical equation of motion. Despite of these differences in the electron trajectory, the radiation spectra of the electron do not deviate qualitatively from each other for configurations with varying rotational directions of the laser beams. Here, the radiation of an ultrarelativistic electron interacting with counterpropagating laser beams is given in the framework of the Baier-Katkov semi-classical approximation. Several parameter regimes are considered and the spectra resulting from the two scenarios all have the same shape and only differ quantitatively by a few percent.