Scaling laws for positron production in laser--electron-beam collisions

TL;DR

This paper derives scaling laws for positron production in laser-electron-beam collisions, showing that current high-intensity lasers can generate thousands of positrons per shot in the non-linear regime.

Contribution

It introduces new scaling laws for electron energy loss, gamma-ray spectra, and positron yields in the radiation-reaction regime of laser-electron interactions.

Findings

Scaling laws are valid in the non-linear, radiation-reaction regime.

High-intensity lasers can produce around 10,000 positrons per shot.

Current facilities can achieve significant positron yields via light-by-light scattering.

Abstract

Showers of $\gamma$-rays and positrons are produced when a high-energy electron beam collides with a super-intense laser pulse. We present scaling laws for the electron beam energy loss, the $\gamma$-ray spectrum, and the positron yield and energy that are valid in the non-linear, radiation-reaction--dominated regime. As an application we demonstrate that by employing the collision of a $>$GeV electron beam with a laser pulse of intensity $>5\times10^{21}\,\text{Wcm}^{-2}$, today's high-intensity laser facilities are capable of producing $O(10^4)$ positrons per shot via light-by-light scattering.