Design and analysis of indirect-drive cryogenic double-shell ignition targets

Due to the fuel surrounded by a high-Z pusher, the double-shell target differs from the cryogenic single-shell case, and it requires volume ignition of the whole fuel. In the paper, the ignition condition for the fuel surrounded by a high-Z pusher is analyzed, and an indirect-drive cryogenic double-shell ignition target is designed and analyzed, which releases a comparable energy to the hot-spot ignition target to be performed at National Ignition Facility (NIF). The collision between the outer and inner shell is the key in the energy transport. By adjusting the ratio of the mass between the two shells, the efficiency of the energy from the outer shell to the inner shell can be highly elevated, with a purpose of reducing the size of the target and the required energy to achieve ignition. For the double-shell ignition, a new preheating mechanism by the radiative shock is pointed out, which can help stabilize the Rayleigh-Taylor (RT) instability occurring at the outer surface of the inner shell. The preheat of radiative shock, as a potential effect in double-shell target, should be seriously realized and underlined.