Laser generated high-pressure shock wave experiments and their simulations

Laser driven shock wave experiments were performed to study the equation of state (EOS) of Cu material using impedance-matching technique with Al as reference material. An Nd:YAG laser chain (2 Joule, 1.06 μm wavelength, 200 ps pulse FWHM) was used for generating shocks in the planar Al foils and Al-Cu layered targets. EOS of materials at shock pressure up to 11 Mbar is obtained with pressure enhancement by a factor of 1.67 at Al-Cu interface. Numerical simulations performed using one-dimensional radiation hydrodynamic code MULTI show close agreement with the experimental value of shock pressure enhancement. Simulation reveals the fact that 5 - 6 μm thickness of Al foil as a reference material is sufficient to prevent the x-ray preheating effect as well as to attain planar and steady shock wave propagation for a given laser beam used in the experiment. The experimental Hugoniot data points obtained are in excellent agreement with the existing standard SESAME data and with other reported experimental results.