Ignition on The National Ignition Facility

Indirect-drive Inertial Confinement Fusion (ICF) experiments on the National Ignition Facility (NIF) have, for the first time, demonstrated fusion ignition in the laboratory with a target gain

of ~1.5. This milestone occurred in an experiment conducted on December 5 th , 2022, releasing 3.15 MJ of energy from the deuterium-tritium (DT) fusion reaction using 2.05 MJ of laser energy. The goal of these experiments on the NIF is to create temperatures and densities such that the DT fusion reaction rate is sufficient to generate self-heating by alpha -particles, resulting in propagating fusion burn. The NIF, designed specifically for this purpose, uses a hohlraum to first convert the laser energy to x-ray energy. The x-rays then drive a DT filled spherical capsule implosion to these extreme conditions at stagnation. The conditions exist for about 100 ps. Recent major milestones occurred when energy from self heating exceeded the energy required to compress the capsule (burning plasma 1 ) and when self-heating exceeded all losses in the system (Lawson Criteria 2 ), and finally when the fusion output energy exceeded the energy used to create the reaction (target gain). This talk will describe these experiments and chronicle some of the important scientific and technological developments that contributed to the increase in experimental fusion energy output that occurred between 2011 and today.

1 Zylstra, Hurricane et. al Nature volume 601, pages 542–548 (2022)

2 Abu-Shawareb et al. Phys. Rev. Lett. 129, 075001 (2022)