D. N. Fittinghoff
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Development and scaling of MeV x-ray radiography at NIF-ARC Open
We investigate the generation of MeV x-rays using the Advanced Radiography Capability laser system at the National Ignition Facility using 1, 10, and 38 ps pulse durations, with laser energies reaching up to 4 kJ and using compound parabol…
View article: Present understanding of ignition and gain using indirect-drive inertial confinement fusion target designs on the U.S. National Ignition Facility
Present understanding of ignition and gain using indirect-drive inertial confinement fusion target designs on the U.S. National Ignition Facility Open
For many decades, the running joke in fusion research has been that ‘fusion’ is thirty years away and always will be. Yet, these past few years we find ourselves in a position where we can now talk about the milestones of burning plasmas, …
View article: Thermonuclear performance variability near ignition at the National Ignition Facility
Thermonuclear performance variability near ignition at the National Ignition Facility Open
We describe our current understanding of the variability and degradation mechanisms observed through a series of five indirectly driven inertial fusion implosions fielded at the National Ignition Facility in the fall of 2021, four of which…
View article: On the theory of multi-target coded sources for high-energy, high-resolution, and high-brightness x-ray radiography
On the theory of multi-target coded sources for high-energy, high-resolution, and high-brightness x-ray radiography Open
X-ray radiography is a ubiquitous diagnostic technique in high energy density (HED) physics, with point projection backlighting commonly used for characterizing static and dynamic objects at high spatial and temporal resolutions. These are…
View article: First look at neutron emission shape characteristics of ignition hotspots at the National Ignition Facility (invited)
First look at neutron emission shape characteristics of ignition hotspots at the National Ignition Facility (invited) Open
The nuclear imaging system has been capturing neutron images of inertial confinement fusion (ICF) driven implosions for over a decade at the National Ignition Facility. This imaging system has evolved from one to three nearly orthogonal li…
View article: Diagnosing inertial confinement fusion ignition
Diagnosing inertial confinement fusion ignition Open
Fusion ignition by inertial confinement requires compression and heating of the fusion fuel to temperatures in excess of 5 keV and densities exceeding hundreds of g/cc. In August 2021, this scientific milestone was surpassed at the Nationa…
View article: Source shape estimation for neutron imaging systems using convolutional neural networks
Source shape estimation for neutron imaging systems using convolutional neural networks Open
Neutron imaging systems are important diagnostic tools for characterizing the physics of inertial confinement fusion reactions at the National Ignition Facility (NIF). In particular, neutron images give diagnostic information on the size, …
View article: 3D reconstruction of an inertial-confinement fusion implosion with neural networks using multiple heterogeneous data sources
3D reconstruction of an inertial-confinement fusion implosion with neural networks using multiple heterogeneous data sources Open
3D asymmetries are major degradation mechanisms in inertial-confinement fusion implosions at the National Ignition Facility (NIF). These asymmetries can be diagnosed and reconstructed with the neutron imaging system (NIS) on three lines of…
View article: Source localization for neutron imaging systems using convolutional neural networks
Source localization for neutron imaging systems using convolutional neural networks Open
The nuclear imaging system at the National Ignition Facility (NIF) is a crucial diagnostic for determining the geometry of inertial confinement fusion implosions. The geometry is reconstructed from a neutron aperture image via a set of rec…
View article: Source localization for neutron imaging systems using convolutional neural networks
Source localization for neutron imaging systems using convolutional neural networks Open
The nuclear imaging system at the National Ignition Facility (NIF) is a crucial diagnostic for determining the geometry of inertial confinement fusion implosions. The geometry is reconstructed from a neutron aperture image via a set of rec…
View article: The impact of low-mode symmetry on inertial fusion energy output in the burning plasma state
The impact of low-mode symmetry on inertial fusion energy output in the burning plasma state Open
Indirect Drive Inertial Confinement Fusion Experiments on the National Ignition Facility (NIF) have achieved a burning plasma state with neutron yields exceeding 170 kJ, roughly 3 times the prior record and a necessary stage for igniting p…
View article: Neutron source reconstruction using a generalized expectation–maximization algorithm on one-dimensional neutron images from the Z facility
Neutron source reconstruction using a generalized expectation–maximization algorithm on one-dimensional neutron images from the Z facility Open
Magnetized Liner Inertial Fusion experiments have been performed at the Z facility at Sandia National Laboratories. These experiments use deuterium fuel, which produces 2.45 MeV neutrons on reaching thermonuclear conditions. To study the s…
View article: Three-Dimensional Gamma Imaging of Inertial Confinement Fusion [Slides]
Three-Dimensional Gamma Imaging of Inertial Confinement Fusion [Slides] Open
the remaining ablator and potential contamination of the hot spot—a powerful diagnostic window into the capsule assembly during burn.
View article: Modeling gated neutron images of THD capsules
Modeling gated neutron images of THD capsules Open
Time gating a neutron detector 28m from a NIF implosion can produce images at different energies. The brighter image near 14 MeV reflects the size and symmetry of the capsule 'hot spot'. Scattered neutrons, {approx}9.5-13 MeV, reflect the …
View article: Observations and properties of the first laboratory fusion experiment to exceed a target gain of unity
Observations and properties of the first laboratory fusion experiment to exceed a target gain of unity Open
An indirect-drive inertial fusion experiment on the National Ignition Facility was driven using 2.05 MJ of laser light at a wavelength of 351 nm and produced 3.1±0.16 MJ of total fusion yield, producing a target gain G=1.5±0.1 exceeding un…
View article: The impact of low-mode symmetry on inertial fusion energy output in the burning plasma state
The impact of low-mode symmetry on inertial fusion energy output in the burning plasma state Open
Indirect Drive Inertial Confinement Fusion Experiments on the National Ignition Facility (NIF) have achieved a burning plasma state with neutron yields exceeding 170 kJ 1, 2 , roughly 3 times the prior record and a necessary stage for igni…
View article: Nuclear imaging to diagnose and correct target-driver registration at high-repetition-rate for improved reactor efficiency
Nuclear imaging to diagnose and correct target-driver registration at high-repetition-rate for improved reactor efficiency Open
Inertial Confinement Fusion produces energy from a burning plasma lasting a fraction of a nanosecond. Power plant designs based on Inertial Fusion Energy (IFE) will need to ignite targets 1-10 times a second, fired as projectiles into a ch…
View article: Assembly of high-Areal-Density Deuterium-Tritium fuel from indirectly driven cryogenic implosions
Assembly of high-Areal-Density Deuterium-Tritium fuel from indirectly driven cryogenic implosions Open
The National Ignition Facility has been used to compress deuterium-tritium to an average areal density of ∼1.0±0.1gcm -2, which is 67% of the ignition requirement. These conditions were obtained using 192 laser beams with total energy of 1…
View article: A coded aperture with sub-mean free-path thickness for neutron implosion geometry imaging on inertial confinement fusion and inertial fusion energy experiments
A coded aperture with sub-mean free-path thickness for neutron implosion geometry imaging on inertial confinement fusion and inertial fusion energy experiments Open
Inertial confinement fusion and inertial fusion energy experiments diagnose the geometry of the fusion region through imaging of the neutrons released through fusion reactions. Pinhole arrays typically used for such imaging require thick s…
View article: Correlations between asymmetric compression, burn amplification, and hot-spot velocities in inertial confinement fusion implosions
Correlations between asymmetric compression, burn amplification, and hot-spot velocities in inertial confinement fusion implosions Open
This manuscript examines the correlations between the hot-spot velocity (an observable signature of residual kinetic energy), low-mode implosion asymmetries, and burn amplification in inertial confinement fusion implosions on the National …
View article: First large capsule implosions in a frustum-shaped <i>hohlraum</i>
First large capsule implosions in a frustum-shaped <i>hohlraum</i> Open
We report on the first indirect-drive implosions driven by a dual conical frustum-shaped hohlraum denoted “frustraum” and the experimental tuning campaigns leading up to two layered implosions. The campaign used 1.2 and 1.4 mm inner radius…
View article: Dynamics and Power Balance of Near Unity Target Gain Inertial Confinement Fusion Implosions
Dynamics and Power Balance of Near Unity Target Gain Inertial Confinement Fusion Implosions Open
The change in the power balance, temporal dynamics, emission weighted size, temperature, mass, and areal density of inertially confined fusion plasmas have been quantified for experiments that reach target gains up to 0.72. It is observed …
View article: Measuring and simulating ice–ablator mix in inertial confinement fusion
Measuring and simulating ice–ablator mix in inertial confinement fusion Open
Fuel–ablator mix has been established as a major performance degrading effect in the burning plasma regime of recent inertial confinement fusion (ICF) experiments. As such, the study of fuel–ablator mix with experiments and simulations can…