Progress towards ignition on the National Ignition Facility

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory includes a precision laser system now capable of delivering 1.8 MJ at 500 TW of 0.35-mu m light to a target. NIF has been operational since March 2009. A variety of experiments have been completed in support of NIF's mission areas: national security, fundamental science, and inertial fusion energy. NIF capabilities and infrastructure are in place to support its missions with nearly 60 X-ray, optical, and nuclear diagnostic systems. A primary goal of the National Ignition Campaign (NIC) on the NIF was to implode a low-Z capsule filled with similar to 0.2 mg of deuterium-tritium (DT) fuel via laser indirect-drive inertial confinement fusion and demonstrate fusion ignition and propagating thermonuclear burn with a net energy gain of similar to 5-10 (fusion yield/input laser energy). This requires assembling the DT fuel into a dense shell of similar to 1000 g/cm(3) with an areal density (rho R) of similar to 1.5 g/cm(2), surrounding a lower density hot spot with a temperature of similar to 10 keV and a rho R similar to 0.3 g/cm(2), or approximately an a-particle range. Achieving these conditions demand precise control of laser and target parameters to allow a low adiabat, high convergence implosion with low ablator fuel mix. We have demonstrated implosion and compressed fuel conditions at similar to 80-90% for most point design values independently, but not at the same time. The nuclear yield is a factor of similar to 3-10x below the simulated values and a similar factor below the alpha dominated regime. This paper will discuss the experimental trends, the possible causes of the degraded performance (the off-set from the simulations), and the plan to understand and resolve the underlying physics issues. (C) 2013 AIP Publishing LLC.