Hugoniot EOS measurements at Mbar pressures

Abstract

The AWE HELEN laser is being used to measure high-pressure Hugoniot data by the impedance match method. Indirect drive is used to generate pressures of up to 10 Mbar in the aluminum reference material. We are aiming to measure shock velocities in our targets to ±1%, leading to errors in pressure and particle velocity of the order of ±2%. This requires improvements in target fabrication and characterization, streak camera calibration and data analysis, coupled with investigations into shock planarity and attenuation. Our latest results have accuracies of 2-4% in shock velocity but have identified work that should allow us to achieve our intended level of accuracy. Experiments have been done with copper and chlorinated plastic; our results are compared with theory, and, for copper, with U.S. and Russian gas-gun, explosively or nuclear-driven experiments.