Strong electromagnetic pulses generated in high-intensity laser-matter interactions

TL;DR

This study investigates the generation of strong electromagnetic pulses during high-intensity laser-matter interactions, revealing dependencies on target material, laser contrast, and pulse duration, with results consistent with previous findings.

Contribution

It provides new experimental data on electromagnetic pulse generation with varied target materials and laser parameters, highlighting the influence of preplasma and laser contrast.

Findings

Higher electromagnetic signals in thick Cu targets compared to previous studies.

Enhanced signals in thin Al foils for longer pulse durations.

Strong correlation between target charge, neutralization current, and magnetic field.

Abstract

Results are reported of an experiment performed at the Eclipse laser facility in CELIA, Bordeaux, on the generation of strong electromagnetic pulses. Measurements were performed of the target neutralization current, the total target charge and the tangential component of the magnetic field for the laser energies ranging from 45 mJ to 92 mJ with the pulse duration approximately 40 fs, and for the pulse durations ranging from 39 fs to 1000 fs, with the laser energy approximately 90 mJ. It was found that the values obtained for thick (mm scale) Cu targets are visibly higher than values reported in previous experiments, which is argued to be a manifestation of a strong dependence of the target electric polarization process on the laser contrast and hence on the amount of preplasma. It was also found that values obtained for thin (micrometer scale) Al foils were visibly higher than values for thick Cu targets, especially for pulse durations longer than 100 fs. The correlations between the total target charge versus the maximum value of the target neutralization current, and the maximum value of the tangential component of the magnetic field versus the total target charge were analysed. They were found to be in very good agreement with correlations seen in data from previous experiments, which provides a good consistency check on our experimental procedures.