A Bright Pulsed Fusion Neutron Source by the Laser-Driven Spherically Convergent Plasma Fusion

Abstract

For generation of a bright, robust pulsed fusion neutron source, a scheme of laser driven spherically convergent plasma fusion (SCPF) was proposed (Phys. Rev. Lett. 118, 165001). And it was demonstrated by the experiments on Shenguang-III prototype facility. A D-D neutron yield of $3\times 10^{9}$ was obtained with driven laser of 6kJ in 8 laser beams and 1ns pulse. Different with the ICF implosion, the SCPF scheme uses the laser beams of ns pulse duration to uniformly irradiate the inner surface of a CD wall spherical hohlraum. The high-speed deuteron involved plasma flows converge and merge in the center of the hohlraum. A high temperature (Ti~7keV) and large volume (several hundred $\mu \mathrm{m})$ plasma core is formed and can continue for more than 1ns. We proposed a predicted neutron yield scaling law as Yn $\propto(\mathrm{E}_{\mathrm{L}}/\mathrm{R}_{\mathrm{h}1.2}\tau^{0.2})^{2.5}$ , in which $\mathrm{E}_{\mathrm{L}}$ is the laser power, $\tau$ is the laser pulse duration and $\mathrm{R}_{\mathrm{h}}$ is the hohlraum radius.