The National ignition facility: Status and performance of the world’s largest laser system for the high energy density and inertial confinement fusion

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory has been designed to support a wide variety of high energy density science (HEDS) experiments, including the demonstration of inertial fusion ignition and burn. To meet this goal, its 192-beam frequency-converted neodymium-glass laser must deliver up to 1.8-MJ total energy at 351nm, with peak power of 500 TW and precisely-controlled temporal pulse shapes spanning two orders of magnitude. Over the past two years, a series of detailed measurements have been performed on one beamline of the NIF laser at 1ω(1053nm), 2ω(526.5nm), and 3ω(351 nm). Results of these experiments lend confidence to the expectation that NIF will meet its laser performance design criteria and that it will be able to simultaneously deliver the temporal pulse shaping, focal spot conditioning, peak power, shot-to-shot reproducibility, and power balance required for indirect-drive fusion ignition campaigns. The NIF final optics system has also been demonstrated to be capable of operating at 2ω energies of up to 17.9kJ/beamline—3.4MJ for a similarly configured 192-beam NIF. We discuss the status of NIF commissioning, and the nature and results of these measurement campaigns.

The NIF laser build-out and commissioning have made substantial progress since last reported [1] and are on track to support the start of 192-beam operations in mid-2009 and to begin a full scale ignition campaign in 2010. As of November 2007, 120-beams have operated at at an average of more than 20kJlbeamline, bringing the current capability to 2.5MJ. We have propagated amplified light simultaneously through 168 beamlines at the joule level to the entrance of the switchyard, verifying proper operation of key laser systems including the entire oscillator and pre-amplifier, the integrated computer control, alignment, and diagnostic systems. Installation of the Final Optics Modules on the target chamber has begun, and operations will begin in early 2008. The current NIF laser status is shown in Fig. 1. Figure 1. NIF laser commissioning status as of November 2008