Empirical scaling laws for self-focused laser pulses in nitrogen plasmas

TL;DR

This paper derives scaling laws for laser self-focusing in high-density nitrogen plasmas, aiding the understanding of laser-plasma interactions for high-charge electron beam generation.

Contribution

It introduces new empirical scaling laws for laser self-focusing, wakefield amplitude, and plasma structures in nitrogen plasmas at high densities.

Findings

Scaling laws for laser diffraction and wakefield amplitude

Insights into plasma structure evolution under self-focusing

Enhanced understanding of laser-plasma interaction regimes

Abstract

We investigate the interaction between a superintense laser pulse and a nitrogen plasma with densities exceeding $10^{19}\,$cm$^{-3}$, using particle-in-cell simulations. Such configurations have recently demonstrated the capability to produce highly charged electron beams (i.e., $>10\,$nC) with $1\,$J-class lasers, a significant step toward high-average-current laser-plasma accelerators. Our study focuses on analyzing the impact of laser self-focusing on laser dynamics, leading to scaling laws that characterize beam diffraction, wakefield amplitude and plasma structures, providing important insights of this interaction regime.