Bremsstrahlung emission and plasma characterization driven by moderately relativistic laser-plasma interactions

TL;DR

This paper investigates how petawatt-class laser pulses interact with solid targets to produce bremsstrahlung X-rays, analyzing electron spectra and plasma conditions to understand energy transfer efficiency.

Contribution

It provides experimental insights into laser absorption, pre-plasma effects, and electron/bremsstrahlung spectra at high intensities, advancing plasma characterization methods.

Findings

Measured electron and bremsstrahlung spectra reveal energy transfer efficiency.

In-situ reflection measurements characterize laser focus and pre-plasma conditions.

Results inform optimization of laser-driven X-ray sources.

Abstract

Relativistic electrons generated by the interaction of petawatt-class short laser pulses with solid targets can be used to generate bright X-rays via bremsstrahlung. The efficiency of laser energy transfer into these electrons depends on multiple parameters including the focused intensity and pre-plasma level. This paper reports experimental results from the interaction of a high intensity petawatt-class glass laser pulses with solid targets at a maximum intensity of $10^{19}$ W/cm$^2$. In-situ measurements of specularly reflected light are used to provide an upper bound of laser absorption and to characterize focused laser intensity, the pre-plasma level and the generation mechanism of second harmonic light. The measured spectrum of electrons and bremsstrahlung radiation provide information about the efficiency of laser energy transfer.