Effect of radiation-reaction on charged particle dynamics in a focused electromagnetic wave

TL;DR

This paper investigates how radiation-reaction forces influence charged particle dynamics in intense focused electromagnetic waves, revealing that such forces enable particles to cross the focal region and gain more energy, contrasting with previous models without radiation reaction.

Contribution

It demonstrates that radiation-reaction forces cause particles to cross the focal region and gain energy, a novel insight confirmed using the Hartemann-Luhmann and Landau-Lifshitz equations.

Findings

Radiation reaction causes particles to cross the focal region.

Particles gain more energy due to radiation reaction.

Results align with Landau-Lifshitz equation predictions.

Abstract

Effect of radiation-reaction force on the dynamics of a charged particle in an intense focused light wave is investigated using the physically appealing Hartemann-Luhmann equation of motion. It is found that, irrespective of the choice of initial conditions, radiation reaction force causes the charge particle to cross the focal region, thereby enhancing the forward energy gained by the particle from the intense light wave. This result is in sharp contrast to the well known result, derived in the absence of radiation reaction forces, where for certain initial conditions the particle reflects from the high intensity region of the focused light wave, thereby losing forward energy. These results, which are of relevance to the present day direct laser acceleration schemes of charge particle, also agrees with that obtained using the well known Landau-Lifshitz equation of motion.