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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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61 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Complete time-resolved X-ray shape capability for a 10 MJ implosion: Milestone Report for MRT 8818

This report documents completion of MRT 8818, which established an upgraded equatorial time-resolved X-ray imaging capability for high-yield inertial confinement fusion experiments at the National Ignition Facility (NIF) using the equatorial Dilation X-ray Imager (DIXI). The need for this work arose from the sustained increase in fusion yield at NIF, which progressively intensified the neutron and gamma-ray environment experienced by target diagnostics. Although the existing polar imaging capability, particularly the Polar Dilation X-ray Imager (PDIXI), remained viable at high yields, the equatorial capability became inadequate because of radiation-induced failure of electronic readout hardware and increasing background levels that degraded image quality and ultimately caused saturation. The work performed under MRT 8818 addressed this limitation through a combination of hardware replacement, background characterization, and targeted mitigation. The DIXI backend was converted from CCD-based electronic readout to photographic film, and the principal sources of internally generated background were investigated using prior analyses, dedicated tests, and comparison with PDIXI performance on high-yield shots. This effort led to implementation of two principal improvements: a multilayer optical coating to suppress broadband radiation-induced background generated in the fiber-optic extension cylinder, and replacement of Kodak TMAX 400 film with Agfa Copex Rapid to reduce background generated directly in the film. These upgrades were completed in 2025 and performance assessment based on DT shot data since then, comparing with Polar DIXI and scaling of these experiments to 10 MJ indicates an expected signal-to-background ratio of approximately 34 for a single pinhole image, substantially exceeding the MRT 8818 completion criterion of SNR > 5.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2026

Multiphysics and Multiscale Simulation Methods for Electromagnetic Energy Assisted Fossil Fuel to Hydrogen Conversion (Final Scientific/Technical Report)

This report summarizes the technical accomplishments of the four-year research project “Multiphysics and Multiscale Simulation Methods for Electromagnetic Energy Assisted Fossil Fuel to Hydrogen Conversion” (Award No. DE-FE0032092), conducted at Howard University and the University of Houston (subawardee) from September 2021 to August 2025. The project successfully achieved all four major objectives: 1. 3D Structural Characterization – Developed 3D optical imaging and mechanical sectioning methods to characterize catalyst distribution and support morphology in nickel foam substrates. Successfully reconstructed 3D geometries and imported them into COMSOL Multiphysics for electromagnetic simulations. 2. EM Hotspot Simulation – Created all-frequency stable electromagnetic formulations and 3D nodal discontinuous Galerkin (NDG) methods for coupled electromagnetic-thermal-fluid problems in multiscale catalytic media. Demonstrated stable solutions from DC to microwave frequencies. 3. Multiphysics Coupling – Developed multiscale simulation methods coupling FEM electromagnetic solvers with thermal transport equations. Reactive molecular dynamics (ReaxFF MD) simulations were performed to investigate catalytic reaction mechanisms at the atomistic level. Demonstrated electromagnetic-thermal co-simulation capabilities for porous catalyst structures. 4. System Optimization – Designed and optimized EM-assisted catalytic systems using nickel foam and carbon foam structures, demonstrating significant temperature increases due to microwave heating. Observed and characterized plasma generation in carbon fiber catalysts. Investigated multiple reaction chamber geometries for improved microwave energy deposition. The project produced significant scientific contributions including 15+ peer-reviewed publications, trained multiple Ph.D. students and undergraduate researchers, and advanced the understanding of microwave-assisted hydrogen production from fossil fuels.

08 HYDROGEN↗
DOE OSTI2021

Icy Moon Project (Final Report)

For this Icy Moon project, we designed, procured, built, tested and used a compact ICI instrument. This instrument has several technical advances, including a compact form factor that uses fiber arrays to relay light to six APDs. This enables a single data acquisition to measure eleven unique baselines simultaneously. The DAQ is well-synchronized and provides a path forward to even more channels. The combination of a bright LED, a sinusoidal target and cylindrical optics enables high-SNR measurements based on a known formula: a 25-ms measurement should have an SNR of 188 on the baseline zero signal. This rapid measurement time should enable two-dimensional operation and obviate the impact of temperature drifts. However, the experiment did not detect a coherence signal on any baseline (see Section Single-shot measurement results).

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

A fiber-coupled dispersion interferometer for density measurements of pulsed power transmission line electron sheaths on Sandia’s Z machine

A fiber-coupled Dispersion Interferometer (DI) is being developed to measure the electron density of plasmas formed in power flow regions, such as magnetically insulated transmission lines, on Sandia National Laboratories (SNL’s) Z machine [D. B. Sinars et al., Phys. Plasmas 27, 070501 (2020)]. The diagnostic operates using a fiber-coupled 1550 nm CW laser with frequency-doubling to 775 nm. The DI is expected to be capable of line-average density measurements between ∼1013 and 1019 cm−2. Initial testing has been performed on a well-characterized RF lab plasma [A. G. Lynn et al., Rev. Sci. Instrum. 80, 103501 (2009)] at the University of New Mexico to quantify the density resolution lower limits of the DI. Initial testing of the DI has demonstrated line-average electron density measurements within 9% of results acquired via a 94 GHz mm wave interferometer for line densities of ∼1 × 1014 cm−2, despite significant differences in probe beam geometries. The instrument will next be utilized for measurements on a ∼1 MA-scale pulsed power driver {MYKONOS [N. Bennett et al., Phys. Rev. Accel. Beams 22, 120401 (2019)] at SNL} before finally being deployed on SNL’s Z machine. The close electrode spacing (mm scale) on Z requires probe beam sizes of ∼1 mm, which can only be obtained with visible or near infrared optical systems, as opposed to longer wavelength mm wave systems that would normally be chosen for this range of density.

Hines, N. R. (ORCID:0000000315316465)↗
DOE OSTI2021

Free space Thomson scattering to study high energy density shocks

A free space collective Thomson scattering system has been developed to study pulsed power produced plasmas. While most Thomson scattering diagnostics on pulsed power machines use a bundle of fibers to couple scattered light from the plasma to the spectrometer, this system used free space coupling of the light, which enabled a spatially continuous image of the plasma. Initial experiments with this diagnostic were performed on an inverse wire array generated by a 200 kA, 1100 ns rise time pulse power generator. The capabilities of this diagnostic were demonstrated by using the low frequency ion acoustic wave feature of the Thomson scattering spectra to measure the plasma flow velocity. The diagnostic was demonstrated to measure velocities between 20 and 40 km/s with an error of 4.7 km/s when fitting with a 600 μm spatial resolution or 8.9 km/s when fitting with a 150 μm spatial resolution. In some experiments, the diagnostic observed a bow shock in the plasma flow as the scattering intensity increased and flow velocity decreased.

47 OTHER INSTRUMENTATION↗
DOE OSTI2026

Upgrade and characterization of the fast-channels of Imaging Neutral Particle Analyzers in the DIII-D tokamak

This publication presents the characterization of the recently upgraded fast (MHz) channels of the DIII-D Imaging Neutral Particle Analyzers. The new system allows for a phase space resolution of < 10 keV and < 10 cm. The main source of noise is due to the background radiation (neutrons and gammas) present in the diagnostic lab during experiments, which can hit the photomultipliers and generate large spikes in signal. Good linear correlations (r 2 > 0.9) are found between the average rate of noise spikes in the fast channels and the average neutron rate. Additional noise is caused by the scintillation of the optical fibers used to guide the signal to the acquisition system, which is induced by neutron and gamma impacts. A correlation factor r 2 > 0.6 between the baseline noise caused by this scintillation and the signals in the neutron diagnostic was found. Possible mitigation strategies, such as the use of shielding and filters, are discussed. These allow to reduce the noise spike rate by an order of magnitude and the noise baseline by a factor 4. Despite the noise, it is shown that the upgraded fast channels provide enough signal-to-noise ratio to observe coherent fluctuations of the energetic particle population.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Instrument design for an inertial confinement fusion ion temperature imager

A mix of contaminant mass is a known, performance-limiting factor for laser-driven inertial confinement fusion (ICF). It has also recently been shown that the contaminant mass is not necessarily in thermal equilibrium with the deuterium–tritium plasma. Contaminant mass temperature is one of the dominant uncertainties in contaminant mass estimates. The MixIT diagnostic is a new and potentially transformative diagnostic, capable of spatially resolving ion temperature. The approach combines principles of neutron time-of-flight and neutron imaging diagnostics. The information from the MixIT diagnostic can be used to optimize ICF target and laser drive designs as well as provide key constraints on ICF radiation-hydrodynamic simulations that are critical to contaminant mass estimates. This work details the design and optimization of the major components of the MixIT diagnostic: the neutron aperture, the neutron detector (scintillator), and the recording system.

47 OTHER INSTRUMENTATION↗