Numerical Simulations of Laser-Driven Cratering Experiments into Porous Graphite

We present the results of an experimental campaign conducted on the LULI2000 laser facility. Semi-infinite targets of a commercial grade of porous graphite were submitted to high-power laser irradiation in order to generate craters. A 15 ns pulse duration was used along with a focal spot diameter of 900 pm to deliver energies up to 750 J. Numerical simulations of these shots have been performed following a specific methodology which can be divided in three steps. Firstly, the mechanical loading induced by the laser is calibrated by simulating the same shot on a thin aluminum target of which free surface velocity is measured by PDV and line-VISAR. Secondly, the same shot is performed on a thin graphite target to validate the material model of graphite. Thirdly, the craterization shot on semi-infinite target is simulated. Numerical results are compared to experimental measurements of craters obtained using an interferometric profilometer.