On December 5th, 2022, controlled fusion ignition was demonstrated for the first time at the National Ignition Facility (NIF), a major achievement in the field of Inertial Confinement Fusion (ICF) requiring a multi-decadal effort involving broad national and international collaborations. To drive the fusion ignition reaction with the compressed fuel capsule, that yielded 3.15 MJ of nuclear energy [1], the NIF laser delivered a high-precision pulse shape with 2.05 MJ of ultra-violet (UV) laser energy and a peak power of 440 TW. This laser energy was an increase of similar to 8 % compared to that delivered on the previous "threshold of ignition" record yield experiment (1.37 MJ of yield for 1.89 MJ of laser energy) on August 8th, 2021 [2]. We explain how the results of our extensive research in laser technology and UV optics damage mitigation led to major improvements in the NIF laser, enabling this energy increase along with additional accuracy, precision, and power balance enhancements. Furthermore, we will discuss on-going efforts that have enabled operations at 2.2 MJ of UV energy as well as potential new initiatives to push the laser performance -accuracy and delivered energy- to even higher levels in the future as previously demonstrated on a small subset of NIF beams [3].

In this work we present the design of the first controlled fusion laboratory experiment to reach target gain G>1 N221204 (5 December 2022) [Phys. Rev. Lett. 132, 065102 (2024)10.1103/PhysRevLett.132.065102], performed at the National Ignition Facility, where the fusion energy produced (3.15 MJ) exceeded the amount of laser energy required to drive the target (2.05 MJ). Following the demonstration of ignition according to the Lawson criterion N210808, experiments were impacted by nonideal experimental fielding conditions, such as increased (known) target defects that seeded hydrodynamic instabilities or unintentional low-mode asymmetries from nonuniformities in the target or laser delivery, which led to reduced fusion yields less than 1 MJ. This Letter details design changes, including using an extended higher-energy laser pulse to drive a thicker high-density carbon (also known as diamond) capsule, that led to increased fusion energy output compared to N210808 as well as improved robustness for achieving high fusion energies (greater than 1 MJ) in the presence of significant low-mode asymmetries. For this design, the burnup fraction of the deuterium and tritium (DT) fuel was increased (approximately 4% fuel burnup and a target gain of approximately 1.5 compared to approximately 2% fuel burnup and target gain approximately 0.7 for N210808) as a result of increased total (DT plus capsule) areal density at maximum compression compared to N210808. Radiation-hydrodynamic simulations of this design predicted achieving target gain greater than 1 and also the magnitude of increase in fusion energy produced compared to N210808. The plasma conditions and hotspot power balance (fusion power produced vs input power and power losses) using these simulations are presented. Since the drafting of this manuscript, the results of this paper have been replicated and exceeded (N230729) in this design, together with a higher-quality diamond capsule, setting a new record of approximately 3.88MJ of fusion energy and fusion energy target gain of approximately 1.9.

Introduction The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is the National Nuclear Security Administration (NNSA) Stockpile Stewardship Program’s (SSP) premier tool for High Energy Density (HED) Physics science, delivering data at levels of precision, pressure and temperature unparalleled in the world [1,2] and recently fusion experiments on the threshold of ignition [3]. With continued upgrades and plans for modest changes that would produce significant performance enhancements, the NIF will likely be the leading ICF facility for studying fusion ignition at full scale for at least another decade. Additionally, there are multiple areas of Inertial Fusion Energy (IFE) development where NIF can play an important role, ranging from testing of high gain advanced ignition schemes, to target chamber dynamics experiments, to materials damage, to Equation of State (EOS) studies of IFE-relevant materials (for target ablators or chamber walls) at extreme conditions, to data for the further development of code predictive capability. Furthermore, lessons from NIF in construction, operations, systems integration, and large facility architecture will provide a very useful steppingstone to any follow-on dedicated IFE facility.

The National Ignition Facility (NIF) is one of the highest fluence neutron sources provided by the nuclear fusion of deuterium and tritium nuclei. One of the resultant products is 14.1 MeV neutrons which provide key information to the conditions in which they were formed. The degree of polar and azimuthal symmetry of the neutron flux is a key metric for the performance of the capsule, thus a spatially-resolved measurement of the neutron distribution is critical. Implementing a suite of 48 lanthanum bromide detectors with zirconium activation samples around the target chamber has been developed to measure the neutron distribution. The system provides near real-time time estimates of the neutron fluence distribution. It is designed to operate over six orders of magnitude of neutron yield, providing overall yield estimates precise to 2%. The system is designed to operate continuously through the NIF shot cycles, accommodating high data rates. We will describe the nuclear counting system, data acquisition and archiving, analysis, and yield distribution results for some NIF high yield shots. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-CONF-736439

The National Ignition Facility (NIF) is the world’s largest and most energetic laser experimental facility, with 192 beams capable of delivering 1.8 megajoules (MJ) and 500-terawatts of ultraviolet light to a target. To aid in NIF control system troubleshooting, the commercial product Splunk was introduced to collate and view system log files collected from 2,600 processes running on 1,800 servers, front-end processors, and embedded controllers [1]. We have since extended Splunk’s access into current and historical control system configuration data, as well as experiment setup and results. Leveraging Splunk’s built-in data visualization and analytical features, we have built custom tools to gain insight into the operation of the control system and to increase its reliability and integrity [3]. Use cases include predictive analytics for alerting on pending failures, analyzing shot operation critical paths to improve operational efficiency, performance monitoring, project management, and analyzing and monitoring system availability. This talk will cover the numerous ways we have leveraged Splunk to improve and maintain NIF’s integrated control system.

The Advanced Radiographic Capability (ARC) laser system at the National Ignition Facility (NIF) is designed to ultimately provide eight beamlets with a pulse duration adjustable from 1 to 30 ps, and energies up to 1.5 kJ per beamlet. Currently, four beamlets have been commissioned. In the first set of 6 commissioning target experiments, the individual beamlets were fired onto gold foil targets with energy up to 1 kJ per beamlet at 20–30 ps pulse length. The x-ray energy distribution and pulse duration were measured, yielding energy conversion efficiencies of 4–9 × 10−4 for x-rays with energies greater than 70 keV. With greater than 3 J of such x-rays, ARC provides a high-precision x-ray backlighting capability for upcoming inertial confinement fusion and high-energy-density physics experiments on NIF.

Orchestration of every National Ignition Facility (NIF) shot cycle is managed by the Integrated Computer Control System (ICCS), which uses a scalable software architecture running code on more than 1950 front-end processors, embedded controllers, and supervisory servers. The ICCS operates laser and industrial control hardware containing 66 000 control and monitor points to ensure that all of NIF's laser beams arrive at the target within 30 ps of each other and are aligned to a pointing accuracy of less than 50 mu m root-mean-square, while ensuring that a host of diagnostic instruments record data in a few billionths of a second. NIF's automated control subsystems are built from a common object-oriented software framework that distributes the software across the computer network and achieves interoperation between different software languages and target architectures. A large suite of business and scientific software tools supports experimental planning, experimental setup, facility configuration, and post-shot analysis. Standard business services using open-source software, commercial workflow tools, and database and messaging technologies have been developed. An information technology infrastructure consisting of servers, network devices, and storage provides the foundation for these systems. This paper is an overview of the control and information systems used to support a wide variety of experiments during the National Ignition Campaign.

Network packet inspection using port mirroring provides the ultimate tool for understanding complex behaviors in large distributed control systems. The timestamped captures of network packets embody the full spectrum of protocol layers and uncover intricate and surprising interactions. No other tool is capable of penetrating through the layers of software and hardware abstractions to allow the researcher to analyze an integrated system composed of various operating systems, closed-source embedded controllers, software libraries and middleware. Being completely passive, the packet inspection does not modify the timings or behaviors. The completeness and fine resolution of the network captures present an analysis challenge, due to huge data volumes and difficulty of determining what constitutes the signal and noise in each situation. We discuss the development of a deep packet inspection toolchain and application of the R language for data mining and visualization. We present case studies demonstrating off-normal analysis in a distributed real-time control system. In each case, the toolkit pinpointed the problem root cause which had escaped traditional software debugging techniques.

Indirect drive experiments have now been carried out with laser powers and energies up to 520 TW and 1.9 MJ. These experiments show that the energy coupling to the target is nearly constant at 84% ± 3% over a wide range of laser parameters from 350 to 520 TW and 1.2 to 1.9 MJ. Experiments at 520 TW with depleted uranium hohlraums achieve radiation temperatures of ∼330 ± 4 eV, enough to drive capsules 20 μm thicker than the ignition point design to velocities near the ignition goal of 370 km/s. A series of three symcap implosion experiments with nearly identical target, laser, and diagnostics configurations show the symmetry and drive are reproducible at the level of ±8.5% absolute and ±2% relative, respectively.

The Advanced Radiographic Capability (ARC) currently under development for the National Ignition Facility (NIF) will provide short (1-50 picoseconds) ultra high power (>1 Petawatt) laser pulses used for a variety of diagnostic purposes on NIF ranging from a high energy xray pulse source for backlighter imaging to an experimental platform for fast-ignition. A single NIF Quad (4 beams) is being upgraded to support experimentally driven, autonomous operations using either ARC or existing NIF pulses. Using its own seed oscillator, ARC generates short, wide bandwidth pulses that propagate down the existing NIF beamlines for amplification before being redirected through large aperture gratings that perform chirped pulse compression, generating a series of high-intensity pulses within the target chamber. This significant effort to integrate the ARC adds 70% additional control points to the existing NIF Quad and will be deployed in several phases over the coming year. This talk discusses some new unique ARC software controls used for short pulse operation on NIF and integration techniques being used to expedite deployment of this new diagnostic.

First results from the analysis of neutron image data collected on implosions of cryogenically layered deuterium-tritium capsules during the 2011-2012 National Ignition Campaign are reported. The data span a variety of experimental designs aimed at increasing the stagnation pressure of the central hotspot and areal density of the surrounding fuel assembly. Images of neutrons produced by deuterium–tritium fusion reactions in the hotspot are presented, as well as images of neutrons that scatter in the surrounding dense fuel assembly. The image data are compared with 1D and 2D model predictions, and consistency checked using other diagnostic data. The results indicate that the size of the fusing hotspot is consistent with the model predictions, as well as other imaging data, while the overall size of the fuel assembly, inferred from the scattered neutron images, is systematically smaller than models' prediction. Preliminary studies indicate these differences are consistent with a significant fraction (20%–25%) of the initial deuterium-tritium fuel mass outside the compact fuel assembly, due either to low mode mass asymmetry or high mode 3D mix effects at the ablator-ice interface.

Programmable spatial shapers using liquid-crystal-based spatial-light-modulators in the National Ignition Facility lasers enable spatial shaping of the beam profile so that power delivered to the target can be maximized while maintaining system longevity. Programmable spatial shapers achieve three objectives: Introduce obscurations shadowing isolated flaws on downstream optical elements that could otherwise be affected by high fluence laser illumination; Spatial shaping to reduce beam peak-to-mean fluence variations to allow the laser to operate at higher powers so that maximum power can be delivered to the target; And finally gradually exposing the optical regions that have never seen laser light because they have always had shadowing from a blocker that is no longer needed. In this paper, we describe the control and image processing algorithms that determine beam shaping and verification of the beam profile. Calibration and transmittance mapping essential elements of controlling the PSS are described along with spatially nonlinear response of the device such as scale and rotation.

The National Ignition Facility has been used to compress deuterium-tritium to an average areal density of ~1.0±0.1 g cm(-2), which is 67% of the ignition requirement. These conditions were obtained using 192 laser beams with total energy of 1-1.6 MJ and peak power up to 420 TW to create a hohlraum drive with a shaped power profile, peaking at a soft x-ray radiation temperature of 275-300 eV. This pulse delivered a series of shocks that compressed a capsule containing cryogenic deuterium-tritium to a radius of 25-35 μm. Neutron images of the implosion were used to estimate a fuel density of 500-800 g cm(-3).

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is a stadium-sized facility containing a 192 beam, 1.8MJ, 500TW ultraviolet laser system used for inertial confinement fusion research. For each experimental shot, NIF must deliver a precise amount of laser power on the target for successful and efficient target ignition, and these characteristics vary depending on the physics of the particular campaign. The precise temporal shape, energy and timing characteristics of a pulsed waveform target interaction are key components in meeting the experimental goals. Each NIF pulse is generated in the Master Oscillator Room (MOR) using an electro-optic modulator to vary the intensity of light in response to an electrical input. The electrical drive signal to the modulator is produced using a unique, high-performance arbitrary waveform generator (AWG). This AWG sums the output of 140 electrical impulse generators, each producing a 300ps pulse width Gaussian signal separated in time by 250ps. By adjusting the amplitudes and summing the 140 impulses, a pulsed waveform can be sculpted from a seed 45ns square pulse. Using software algorithms written for NIF's Integrated Computer Control System (ICCS), the system is capable of autonomously shaping 48 unique experimental pulsed waveforms for each shot that have demonstrated up to 275:1 contrast ratio with ±3% absolute error averaged over any 2ns interval, meeting the stringent pulse requirements needed to achieve ignition. In this paper, we provide an overview of the pulse shaping system, software algorithms and associated challenges that have been overcome throughout the evolution of the controls.