Interpretation of planar shock ignition experiments at LULI

The capacity to launch a strong shock wave in a compressed target in presence of large pre-plasma has been investigated in a planar geometry, at 2$\omega $. Experiments were performed at the LULI facility. The target is a three-material target: CH on the laser side, Titanium and Quartz on the opposite side. Two beams are involved. A low-intensity beam launches a first shock and compresses the target. Then, an intensity spike launches a strong chock in the pre-shocked plasma. Shock chronometry and velocity in quartz are measured with a VISAR on the rear side of the target. Three events are observed in both experiments and calculations. We observed a good agreement on chronometry which, nevertheless, departs with time.