R. Patterson

National Ignition Facility laser performance status

The National Ignition Facility (NIF) is the worlds largest laser system. It contains a 192 beam neodymium glass laser that is designed to deliver 1.8 MJ at 500 TW at 351 nm in order to achieve energy gain (ignition) in a deuterium-tritium nuclear fusion target. To meet this goal, laser design criteria include the ability to generate pulses of up to 1.8 MJ total energy, with peak power of 500 TW and temporal pulse shapes spanning 2 orders of magnitude at the third harmonic (351 nm or 3omega) of the laser wavelength. The focal-spot fluence distribution of these pulses is carefully controlled, through a combination of special optics in the 1omega (1053 nm) portion of the laser (continuous phase plates), smoothing by spectral dispersion, and the overlapping of multiple beams with orthogonal polarization (polarization smoothing). We report performance qualification tests of the first eight beams of the NIF laser. Measurements are reported at both 1omega and 3omega, both with and without focal-spot conditioning. When scaled to full 192 beam operation, these results demonstrate, to the best of our knowledge for the first time, that the NIF will meet its laser performance design criteria, and that the NIF can simultaneously meet the temporal pulse shaping, focal-spot conditioning, and peak power requirements for two candidate indirect drive ignition designs.

Overview: Development of the National Ignition Facility and the Transition to a User Facility for the Ignition Campaign and High Energy Density Scientific Research

Abstract The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory has been operational since March 2009 and has been transitioning to a user facility supporting ignition science, high energy density stockpile science, national security applications, and fundamental science. The facility has achieved its design goal of 1.8 MJ and 500 TW of 3ω light on target, and has performed target experiments with 1.9 MJ at peak powers of 410 TW. The National Ignition Campaign (NIC), established by the U.S. National Nuclear Security Administration in 2005, was responsible for transitioning NIF from a construction project to a national user facility. Besides the operation and optimization of the use of the NIF laser, the NIC program was responsible for developing capabilities including target fabrication facilities; cryogenic layering capabilities; over 60 optical, X-ray, and nuclear diagnostic systems; experimental platforms; and a wide range of other NIF facility infrastructure. This paper provides a summary of some of the key experimental results for NIF to date, an overview of the NIF facility capabilities, and the challenges that were met in achieving these capabilities. They are covered in more detail in the papers that follow.

Demonstration of high-energy 2 ω (526.5 nm) operation on the National Ignition Facility Laser System

A single beamline of the National Ignition Facility (NIF) has been operated at a wavelength of 526.5 nm (2 omega) by frequency converting the fundamental 1053 nm (1 omega) wavelength with an 18.2 mm thick type-I potassium dihydrogen phosphate (KDP) second-harmonic generator (SHG) crystal. Second-harmonic energies of up to 17.9 kJ were measured at the final optics focal plane with a conversion efficiency of 82%. For a similarly configured 192-beam NIF, this scales to a total 2 omega energy of 3.4 MJ full NIF equivalent (FNE).

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 351 nm, 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 1omega(1053 nm), 2omega(526.5 nm), and 3omega(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 2omega energies of up to 17.9 kJ/beamline-3.4 MJ for a similarly configured 192-beam NIF. We discuss the status of NIF commissioning, and the nature and results of these measurement campaigns.

The National Ignition Facility: Transition to a User Facility

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) has been operational since March 2009 and has been transitioning to a user facility supporting ignition science, high energy density science (HEDS), national security applications, and fundamental science. The facility has achieved its design goal of 1.8 MJ and 500 TW of 3ω light on target, and has performed target experiments with 1.9 MJ at peak powers of 410 TW. The facility is on track to perform over 200 target shots this year in support of all of its user communities. The facility has nearly 60 diagnostic systems operational and has shown flexibility in laser pulse shape and performance to meet the requirements of its multiple users. Progress continues on its goal of demonstrating thermonuclear burn in the laboratory. It has performed over 40 indirect-drive experiments with cryogenic-layered capsules. New platforms are being developed for HEDS and fundamental science. Equation-of-state and material strength experiments have been done on a number of materials with pressures of over 50 MBars obtained in diamond, conditions never previously encountered in the laboratory and similar to those found in planetary interiors. Experiments are also in progress investigating radiation transport, hydrodynamic instabilities, and direct drive implosions. NIF continues to develop as an experimental facility. Advanced Radiographic Capability (ARC) is now being installed on NIF for producing high-energy radiographs of the imploded cores of ignition targets and for short pulse laser-plasma interaction experiments. One NIF beam is planned for conversion to two picosecond beams in 2014. Other new diagnostics such as x-ray Thomson scattering, low energy neutron spectrometer, and multi-layer reflecting x-ray optics are also planned. Incremental improvements in laser performance such as improved optics damage performance, beam balance, and back reflection control are being pursued.

Progress on the National Ignition Facility

The National Ignition Facility (NIF) is a 192 beam Nd-glass laser facility presently under construction at LLNL. When completed, NIF will produce 1.8 MJ, 500 TW of ultraviolet light making it the worlds largest and most powerful laser system. NIF will be the worlds preeminent facility for performing experiments for Inertial Confinement Fusion (ICF) and High Energy Density Science (HEDS). The Project, begun in 1995, is over 80% complete. The building and the beam path are essentially complete. Nearly all of the functionality of the laser subsystems has been demonstrated. NIF has demonstrated on a single beam basis that it meets its performance goals and shown the lasers precision and flexibility for pulse shaping, pointing, and timing. Beam conditioning techniques, important for target performance, were also demonstrated. The focal spot can be tailored to user specifications using phase plates. Temporal smoothing using smoothing by spectral dispersion (SSD) as well as polarization smoothing was demonstrated. The remaining work is mostly to complete the optics and install them in the beam path and complete the utilities. Presently, eight beams have been activated through the amplifiers and spatial filters to the switchyard wall. Over 150 kJ of 1ω light has been produced with just 4% of the NIF capacity activated. The Project is scheduled for completion in 2009 and plans have been developed to begin ignition experiments in 2010. This talk will provide NIF status, the plan to complete NIF, and the path to ignition.

The National Ignition Facility: the world's largest laser

The National Ignition Facility (NIF), currently under construction at the Lawrence Livermore National Laboratory, is a stadium-sized facility containing a 192-beam, 1.8-Megajoule, 500-Terawatt, ultraviolet laser system together with a 10-meter diameter target chamber with room for nearly 100 experimental diagnostics. When completed, NIF will be the worlds largest and most energetic laser experimental system, providing an international center to study inertial confinement fusion and the physics of matter at extreme energy densities and pressures. NIFs 192 energetic laser beams will compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. Other NIF experiments will allow the study of physical processes at temperatures approaching 10/sup 8/ K and 10/sup 11/ bars, conditions that exist naturally only in the interior of stars, planets and in nuclear weapons. NIF has now completed the first phases of its laser commissioning program. The first four beams of NIF have generated 106 kilojoules of infrared light, exceeding design requirements. Operation of single beams at the second harmonic (531 nm) and third harmonic (351 nm) at greater than 10 kilojoules have also exceeded the performance criteria. NlFs target experimental systems are being commissioned and experiments have begun. This paper provides a detailed look the NIF laser systems, laser and optical performance and results from recent laser commissioning shots, and plans for commissioning diagnostics for experiments on NIF.