Present Status of Fusion Fuel Injection System and Neutron Generation

Abstract

Repetitive fusion fuel injection and laser engagement are key technologies for achieving laser inertial confinement fusion reactors. This paper reports the present status of fusion fuel injection system and neutron generation conducted at the Graduate School for the Creation of New Photonics Industries with collaborators. A 1-mm diameter bead-pellet injection system engaged by ultra-intense counter laser beams respectively demonstrated 1 Hz/28 minute and 10 Hz/2 minute operation with the laser-hit-ratios to the pellet of 70% and 40%, respectively. The maximum neutron yield was 4 × 105 n/shot. In addition, a testbed of a 0.5 mm diameter spherical shell pellet injection demonstrated that (i) repetitive implosion (maximum frequency: 0.5 Hz) of shell injection was possible for more than ten shells at a shell speed of 191 mm/s, and (ii) the distribution of the injected shells after a 18 cm free-fall was within a circular region, 6.4 mm in diameter circular region. The estimated laser-hit-ratio to the spherical shell pellets was 10%.