Photon emission by bremsstrahlung and nonlinear Compton scattering in the interaction of ultraintense laser and plasmas

TL;DR

This study uses a Monte Carlo-enhanced particle-in-cell simulation to compare bremsstrahlung and nonlinear Compton scattering during ultraintense laser-plasma interactions, revealing conditions where bremsstrahlung cannot be ignored.

Contribution

It introduces a method to simulate both photon emission processes simultaneously and compares their relative strengths across different laser intensities and target materials.

Findings

Nonlinear Compton scattering dominates at ultra-high laser intensities and high-Z targets.

Bremsstrahlung becomes significant at lower laser intensities ($<10^{22} ext{W/cm}^2$).

Reconsideration of bremsstrahlung's role in laser-plasma interactions at moderate intensities.

Abstract

By implementing the bremsstrahlung with Monte Carlo algorithm into the particle-in-cell code, the bremsstrahlung and nonlinear Compton scattering can be studied simultaneously in comparison way in the laser plasma interactions. The simulations are performed for the laser of different intensities interacting with either low-$Z$ or high-$Z$ target. The relative strength of the two photon emission from bremsstrahlung and nonlinear Compton scattering are compared. The result shows that when an ultrastrong intensity laser interacting with a thin and relative high $Z$ target the nonlinear Compton scattering is dominant, however, when the laser intensity $I < 10^{22} \mathrm{W/cm^2}$, the photon emission contributed by bremsstrahlung is comparable to that from nonlinear Compton scattering. In this case the usual ignorable of bremsstrahlung need to be reconsidered.