Thermonuclear neutron yield of 10¹² achieved with Gekko XII green laser

Abstract

One of the means by which hydrogen nuclei can be fused, liberating energy in a controllable fashion, involves the implosion of small hydrogen-filled pellets driven by laser radiation. Here we report a world record for thermonuclear neutron yield 1.25 ×10¹² per shot, achieved by the Gekko XII green laser system. As the green laser can suppress hot electrons to prevent the preheating of a pellet, high-aspect ratio targets are ablatively imploded with 12 green beams. The multiplexing of shock waves is generated at the centre of a pellet with an accelerating pusher by a quasi-tailored laser pulse. By this scheme the target pusher is uniformly accelerated up to a velocity of almost 10⁸ cm s⁻¹ without suffering breakup of the target. The temperature of a core is 7 keV, which supports a thermonuclear origin of the neutron yield.