PDV MEASUREMENTS OF NS AND FS LASER DRIVEN SHOCK EXPERIMENTS ON SOLID TARGETS

We present a new heterodyne velocimeter setup embedding a second low-power frequency-tunable laser acting as a local oscillator. We thus double the overall bandwidth of the system and we make the tuning of the laser power levels easier, to achieve good matching between the electric signal matching and the dynamics of the detector. Recently, we used this velocimeter onto metallic target shock driven by high power laser. The aim is to test the ability of this means to reveal shock propagation and effects into materials under extremely high strain rate with fast variations into the loading evolution. Spallation and fragmentation experiments carried out on aluminum samples were performed on the LULbeta000 laser (800 J, 3 ns) and on the 100 TW laser (30 J, 300 fs) of the Ecole Polytechnique, with both VISAR and HV diagnostics. Comparisons reveal a very good consistency of experimental results.