Experiments in pressure boost，plasma smoothing and LPI effect of Hybrid-drive ignition scheme on SG-III laser facility

The Hybrid-drive is a novel scheme for the lower compression ratio(~25) and robustly ignition. There are two significant advantages. The one is pressure boost based on “snow plow” effect. it can makes high ablation pressure over 500Mbar in ignition target design; the other one is plasma smoothing effect by long-scale length of ablated plasma. it can increase the uniformly of laser spot over 30 times.  

Hybrid-drive are studied in experiments that performed on SG-III laser facility.20 laser beams as indirect-drive and 4 laser beams as direct-drive were performed as hybrid-drive. The VISAR collected shock velocity in Quarte.The hybrid-drive makes high shock velocity(84.2km/s) compared with indirect-drive(43.6km/s).the Hybrid-drive proposed 3.5times ablation pressure than indirect-drive. According to the uniformity of shock by VISAR,The hybrid-drive proposed a wider shock signal than direct-drive. Furthermore, the LPI effect also studied in our experiments. the direct-drive laser with a laser intensity of 1.5*10¹⁵W/cm² proposed backscatter light fraction( SRS and SBS are considered) around 8% in direct-drive only shot, 3% in hybrid-drive shot. In hybrid-drive experiments, high pressure, better uniformity and lower LPI effect are proposed.