Performance of NIF Ignition type implosions

Summary form only given. The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is conducting 192-beam implosion experiments with laser energies as high as 1.3 MJ, with the unprecedented energy and pulse shaping control required for ignition type experiments. The NIF ignition program is executed via the National Ignition Campaign (NIC), a partnership between Los Alamos National Laboratory, Lawrence Livermore National Laboratory, General Atomics, the University of Rochester Laboratory for Laser Energetics and Sandia National Laboratories, with other national and international partners notably MIT. The x-ray driven targets are either layered cryogenic tritium(T)-hydrogen(H)-deuterium(D) ice in doped plastic ablator shells or gas filled plastic shell emulants. Implosion tuning to achieve a high, generalized Lawson criterion and ignition has four phases. The first two phases involve tuning of the hohlraum and capsule to produce the correct x-ray radiation drive, symmetry, and shock timing conditions. This talk will focus on the measurements of the imploded core in the third phase. The layered targets for this phase have a cryogenic layered mixture of T, H and D, where the deuterium concentration is only several percent to keep the neutron yield low, and the T:H ratio is adjusted to keep the density that of equi-molar DT. The final step is DT ignition implosions with expected gains of 10-20. For this third phase many diagnostics are used. Yields and ion temperatures are measured to accuracies <;10% by several diagnostics. The shape of the imploded core, measured by time and spectrally resolved x-ray imaging and neutron imaging is used to tune the isotropy of the x-ray drive. Compressed areal densities, obtained from the number of neutrons down-scattered by the areal density of the compressed THD fuel, are measured by two different types of instruments. Areal density at measured particular times before full implosion time, are measured in emulant targets by the energy loss of the protons produced from the D-He
³
reaction. Implosion time and duration are measured by x-ray, neutron and gamma emissions. The talk will review results to date and compare them against the generalized Lawson criterion.