The ramp compression experiment with laser-driven reservoir target at Shenguang-III prototype facility

The quasi-isentropic compression of material can be obtained by the ramp wave loading of plasma jet produced by laser-driven reservoir target. The experiments were carried out on the high power laser facility of SG-III prototype using Al with direct-driven and indirect-driven method. The smooth and continuous speed history of free surface of specimen was recorded with a line-imaging velocity interferometer(VISAR). 16/26/36$\mu $m Al foil were compressed to more than 40 GPa with good planarity. The back-integrating method gave almost the same loading history for the three steps. 7$\mu $m Al backed by 500$\mu $m LiF were compressed to near 200GPa. The rise time of the load was about 10ns and the strain was about 10$^{8}$s$^{-1}$.