Preliminary target design for integrated direct-drive fast ignition experiments on Shenguang-II upgrade facility

Abstract

The laser energy will be increased substantially when the Shenguang-II laser facility upgrade is completed and the petawatt picosecond laser beam will be equipped at the same time. For the fast ignition approach, direct-drive implosions have some advantages over indirect-drive ones, such as higher energy efficiency and lower mixing of cone material into fuel. Based on Shenguang-II upgraded laser facility, integrated direct-drive fast ignition experiments will be carried out and it will contribute to the further understanding of the relevant physics such as integrated coupling efficiency. The radiation hydrodynamic code Multi1D is used to design fast-ignition targets, and the optimized target parameters are achieved. The optimized target has a relatively thick wall (35 μm) and 420 μm-outer-radius CH shell, which are consistent with the scaling laws in target design. The deposition in the optimization target of the hot electrons generated by the picosecond petawatt pulse is also calculated according to the hot electrons scaling relation. The results show that the achieved areal density is high enough to stop the hot electrons.