The spherically convergent plasma fusion (SCPF) scheme is a robust approach to provide a high-brightness pulsed neutron source. The performance of the SCPF driven by the long-pulsed laser is investigated. The experiments, with the laser pulse duration in a range of 0.5 ns to 3 ns, were implemented on the ShenGuang-II Upgrade facility and a 100 kJ level laser facility. The intensity of the laser beam was about multiple 1014 W cm−2. The measured D–D reaction neutron yields were in a range of 7.3 × 108 to 1.01 × 1011, while the driven laser energies were in a range of 2.1 kJ to 100.5 kJ. The temporal self-emitted x-ray flux and image were measured. It showed that the plasma core could be maintained for a longer time in the long duration shots. The neutron reaction rate was measured on the 100 kJ level laser facility. The full width at half maximum reached about 1 ns in the shot with 2 ns duration laser. The scaling law of the measured yields with respect to the laser power and the pulse duration were presented. The neutron yield was able to be increased by increasing the power and extending the duration.
Neutron production from high-intensity laser–cluster induced fusion reactions