Work continues at the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory in pursuit of fusion ignition and burn via inertial confinement fusion. This requires using the 1.8 MJ of energy in NIF’s 192 laser beams to implode a DT fuel capsule at nearly 400 kilometers per second, generating pressures of more than 200 billion atmospheres, hot spot temperatures greater than 4-5 keV and areal densities sufficiently large (rhoR > 0.3 gm/cm^2) to launch a burn wave while the surrounding colder and denser DT shell provides extra burn and tamping to obtain high neutron yields. To obtain these fuel conditions for ignition requires a high hot spot compression, high velocity, symmetric implosion without hydrodynamic mix polluting the hot spot.
While ignition is yet to be achieved, significant advancements have been made, including demonstrating the self-heating process for the first time in the laboratory, increasing the hohlraum efficiency, and the demonstration of a 1D-like DT implosion at a convergence ratio over 30x. Nonetheless, two major factors pose ongoing challenges in ignition-relevant platforms: implosion asymmetry and perturbations caused by engineering features in the capsule.
In this presentation, we will review the status of current understanding, and the continuing efforts to evaluate different capsule materials, to optimize hohlraum-capsule target configurations, and to search for and understand performance cliffs.