Modeling of laser-driven water-confined shocks into porous graphite

This paper presents a laser-driven water-confined shock experiment into a commercial grade of porous graphite. An intensity of about 3 GW/cm2 led to a pressure above 2 GPa on the front surface of the 0.46 mm sample. The rear surface velocity, recorded by a Velocity Interferometer System (VISAR), reached 325 m/s. Two classical models for porous materials are discussed. The first one uses plates of dense graphite spaced out in order to obtain the correct average density. The second one models a continuous material and includes an experimental compaction curve of our porous graphite. They were implemented into hydrocodes and both gave quite correct maximum free surface velocities and shock break-out instants. Nevertheless, the continuous representation appeared to be more efficient to reproduce the experimental free surface velocity ramp. Discussions on the laser-matter interaction modeling are also provided. Finally, a protocol for the simulation of future laser experiments is proposed.