Highly-efficient source of collimated multi-MeV photons driven by radiation reaction of an electron beam in a self-generated magnetic field

TL;DR

This paper demonstrates through simulations that highly efficient, collimated multi-MeV photon sources can be generated at lower laser intensities than next-generation facilities, using a novel mechanism involving self-generated magnetic fields.

Contribution

It introduces a new method to produce high-yield, collimated multi-MeV photons at accessible laser intensities by leveraging radiation reaction in a self-generated magnetic field.

Findings

Achieves high conversion efficiency of multi-MeV photons at lower intensities.

Uses a bulk solid-density target to induce relativistic transparency.

Generates tens of TW of directed MeV photons with a PW-class laser.

Abstract

The rapid development of high brilliance X-ray radiation sources is revolutionizing physics, chemistry, and biology research through their novel applications. Another breakthrough is anticipated with the construction of next-generation laser facilities which will operate at intensities beyond $10^{23}$ $\mathrm{W/cm^2}$, leading to higher yield, shorter wavelength radiation sources. We use numerical simulations to demonstrate that a source of collimated multi-MeV photons with conversion efficiency comparable to the one expected for these facilities is achievable at an order of magnitude lower in intensity, within reach of the existing facilities. In the optimal setup, the laser pulse irradiates a bulk solid-density target, heating the target electrons and inducing relativistic transparency. As the pulse then propagates, it generates a beam of energetic electrons which in turn drives a strong azimuthal magnetic field. This field significantly enhances the radiation reaction for the electrons, yielding tens of TW of directed MeV photons for a PW-class laser.