Radiation damping in pulsed Gaussian beams

TL;DR

This paper investigates how radiation damping influences electron behavior in Gaussian laser beams, revealing regimes of negligible damping, energy modification, and electron capture at high intensities, with implications for different laser field models.

Contribution

It introduces a detailed analysis of radiation damping effects across various intensity regimes in Gaussian beams, including the stable electron capture phenomenon.

Findings

Radiation damping effects are negligible at low electron energies.

At high energies, damping alters electron displacement and energy.

Electron capture due to radiation reaction occurs at very high intensities.

Abstract

We consider the effects of radiation damping on the electron dynamics in a Gaussian beam model of a laser field. For high intensities, i.e. with dimensionless intensity a0 \gg 1, it is found that the dynamics divide into three regimes. For low energy electrons (low initial {\gamma}-factor, {\gamma}0) the radiation damping effects are negligible. At higher energies, but still at 2{\gamma}0 < a0, the damping alters the final displacement and the net energy change of the electron. For 2{\gamma}0 > a0 one is in a regime of radiation reaction induced electron capture. This capture is found to be stable with respect to the spatial properties of the electron beam and results in a significant energy loss of the electrons. In this regime the plane wave model of the laser field provides a good description of the dynamics, whereas for lower energies the Gaussian beam and plane wave models differ significantly. Finally the dynamics are considered for the case of an XFEL field. It is found that the significantly lower intensities of such fields inhibits the damping effects.