Preliminary experiments on hohlraum-driven double-shell implosion at the ShenGuang-III laser facility

Double-shell implosion is proposed as a non-cryogenic target design for ignition, offering a robust implosion platform for inertial confinement fusion research. Hohlraum-driven double-shell implosions have been performed at the ShenGuang-III laser facility; a vacuum hohlraum with a high CCR value was employed. With 96kJ laser energy in a squared temporal profile, the implosion neutron yield was close to 1010, and the YOC1D was about 27%. A fuel areal density of 14 mg cm−2 was inferred from the measured yield ratio of secondary and primary neutrons. The implosion trajectory was diagnosed via the 4.75 keV x-ray backlight. The measured implosion velocity and hot-spot x-ray emission history indicate a predictable hydrodynamic process in the double-shell implosion. Two crucial factors which might detrimentally affect implosion performance are the implosion symmetry and pusher-gas mix. The loss of four driven laser beams in the backlight shot caused the YOC1D to decrease to 5% and fuel areal density to decrease to 4 mg cm−2. In future, optimization of the implosion symmetry and the capsule fabrication will be implemented to improve the double-shell implosion performance.