Laser-assisted radiative recombination beyond the dipole approximation

TL;DR

This paper develops a relativistic theoretical framework for electron-ion radiative recombination under intense laser pulses, incorporating nondipole effects and exploring how laser parameters influence emitted radiation spectra.

Contribution

It introduces a systematic expansion of the Coulomb-Volkov solution to include nondipole corrections, revealing their impact on radiation spectra and angular distributions.

Findings

Nondipole effects cause significant spectral and angular asymmetries.

High-frequency pulses extend the radiation cutoff.

Chirping pulses can enhance high-energy radiation efficiency.

Abstract

A comprehensive theoretical approach to describe the electron-ion radiative recombination in the presence of intense, short laser pulses, which accounts for nondipole corrections is presented. It is based on the relativistic Coulomb-Volkov solution describing an electron in a combined Coulomb potential and a laser field, which is systematically expanded in powers of $1/c$. Thus, it allows us to trace the origin of nondipole effects observed in the spectrum of emitted radiation. Hence, as we demonstrate for high-frequency pulses assisting the process, a significant extension of the cutoff and asymmetry in angular distributions of the emitted radiation can be attributed to the electron recoil off the laser pulse. In addition, we investigate a possibility of enhancing the efficiency of the generated high-energy radiation by chirping the pulse.