Laser driven shock experiments at PALS

Abstract

We report on recent laser driven shock experiments performed at the PALS laboratory in Prague. In the first series of experiments, the ablation pressure at 0.44 μm has been measured at irradiance up to 2×10 14 W/cm 2 . The diagnostics consisted in the detection of shock breakout from stepped Al targets. By adopting large focal spots and smoothed laser beams, the lateral energy transport and "drilling effects" were avoided. The measured scaling shows a fair agreement with analytical models.Later, such shocks have been applied to the experimental study of carbon equation of state (EOS) at Megabar pressures. The rear side emissivity of "two materials -two steps" targets (Al-C) was recorded and, by applying the impedance mismatch method, allowed a direct determination of relative EOS points. Previously unreached pressures were obtained. Results are compared with previous experiments and with available theoretical models and seem to show high compressibility of carbon at Megabar pressures.