Laser Interactions with Gas Jets: EMP Emission and Nozzle Damage

TL;DR

This paper develops a theoretical model to understand electromagnetic pulse emission and nozzle damage caused by high-power lasers interacting with gas jets, providing insights for improving laser experiment stability.

Contribution

A novel theoretical model predicting EMP emission and nozzle damage from laser-gas interactions, validated with experimental data from multiple high-power laser facilities.

Findings

EMP fields of tens to hundreds of kV/m can be generated several meters away

Model predictions align with experimental measurements of EMP and damage

Understanding of plasma formation and electrostatic charging mechanisms

Abstract

Understanding the physics of electromagnetic pulse emission and nozzle damage is critical for the long-term operation of laser experiments with gas targets, particularly at facilities looking to produce stable sources of radiation at high repetition rate. We present a theoretical model of plasma formation and electrostatic charging when high-power lasers are focused inside gases. The model can be used to estimate the amplitude of gigahertz electromagnetic pulses (EMPs) produced by the laser and the extent of damage to the gas jet nozzle. Looking at a range of laser and target properties relevant to existing high-power laser systems, we find that EMP fields of tens to hundreds of kV/m can be generated several metres from the gas jet. Model predictions are compared with measurements of EMP, plasma formation and nozzle damage from two experiments on the VEGA-3 laser and one experiment on the Vulcan Petawatt laser.