Absolute measurements of the equations of state of low-Z materials in the multi-Mbar regime using laser-driven shocks

Although high intensity lasers offer the opportunity to explore the equations of state (EOSs) of materials under high energy density conditions, experimental difficulties have limited the application of laser-driven shocks to EOS measurements. However, we have recently performed absolute EOS measurements on the principal Hugoniot of liquid deuterium near one Mbar and of polystyrene from 10 to 40 Mbar. The D2 measurements were made with direct drive; the polystyrene experiments were indirectly driven. The data were sufficiently accurate to differentiate between existing EOS models and were surprising, particularly for D2. The results demonstrate that laser driven shocks can be used effectively to investigate high pressure EOSs.