Electron - positron cascades in multiple-laser optical traps

TL;DR

This paper investigates how multiple linearly polarized laser pulses can induce QED cascades, optimizing configurations to maximize gamma-ray production and laser energy conversion efficiency at ultra-high intensities.

Contribution

It extends analytical models of QED cascade growth to multiple laser interactions and verifies them through comprehensive numerical simulations with four laser pulses.

Findings

Over 50% energy conversion to gamma-rays at $10^{24} ext{ W/cm}^2$

Four laser pulses outperform two in cascade efficiency

Optimized polarization enhances cascade multiplicity and laser absorption

Abstract

We present an analytical and numerical study of multiple-laser QED cascades induced with linearly polarised laser pulses. We analyse different polarisation orientations and propose a configuration that maximises the cascade multiplicity and favours the laser absorption. We generalise the analytical estimate for the cascade growth rate previously calculated in the field of two colliding linearly polarised laser pulses and account for multiple laser interaction. The estimate is verified by a comprehensive numerical study of four-laser QED cascades across a range of different laser intensities with QED PIC module of OSIRIS. We show that by using four linearly polarised 30 fs laser pulses, one can convert more than 50 % of the total energy to gamma-rays already at laser intensity $I\simeq10^{24}\ \mathrm{W/cm^2}$. In this configuration, the laser conversion efficiency is higher compared with the case with two colliding lasers.