Analysis of laser shock experiments on precompressed samples using a quartz reference and application to warm dense hydrogen and helium

TL;DR

This paper presents a comprehensive analysis framework for laser shock experiments on precompressed samples, enabling more accurate measurements of pressure, density, and temperature in warm dense hydrogen and helium, and compares results with advanced EOS models.

Contribution

The paper introduces an improved analysis framework that corrects for precompression effects in laser shock experiments, enhancing the accuracy of thermodynamic measurements in warm dense matter.

Findings

Re-analysis of hydrogen and helium data with the new framework.

Updated pressure, density, and temperature measurements.

Comparison with advanced equation of state models.

Abstract

Megabar (1 Mbar = 100 GPa) laser shocks on precompressed samples allow reaching unprecedented high densities and moderately high 10000-100000K temperatures. We describe here a complete analysis framework for the velocimetry (VISAR) and pyrometry (SOP) data produced in these experiments. Since the precompression increases the initial density of both the sample of interest and the quartz reference for pressure-density, reflectivity and temperature measurements, we describe analytical corrections based on available experimental data on warm dense silica and density-functional-theory based molecular dynamics computer simulations. Using our improved analysis framework we report a re-analysis of previously published data on warm dense hydrogen and helium, compare the newly inferred pressure, density and temperature data with most advanced equation of state models and provide updated reflectivity values.