Production and dynamics of positrons in ultrahigh intensity laser-foil interactions

TL;DR

This paper investigates electron-positron pair production in ultrahigh intensity laser-foil interactions, revealing quantum-electrodynamical cascading and standing wave effects at intensities above 10^{24} W/cm^2, supported by simulations.

Contribution

It introduces a model for pair production dynamics near magnetic nodes in laser-foil interactions at extreme intensities, validated by 3D PIC-MC simulations.

Findings

Electron-positron plasma is generated via QED cascading.

Standing wave patterns influence pair density distribution.

Model predictions align with simulation results.

Abstract

The electron-positron pair production accompanying interaction of a circularly polarized laser pulse with a foil is studied for laser intensities higher than $10^{24}$W cm$^{-2}$. The laser energy penetrates into the foil due to the effect of the relativistic hole-boring. It is demonstrated that the electron-positron plasma is produced as a result of quantum-electrodynamical cascading in the field of the incident and reflected laser light in front of the foil. The incident and reflected laser light makes up the circularly polarized standing wave in the reference frame of the hole-boring front and the pair density peaks near the nodes and antinodes of the wave. A model based on the particle dynamics with radiation reaction effect near the magnetic nodes is developed. The model predictions are verified by 3D PIC-MC simulations.