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Results for “Opacity”
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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Helioseismic inference of the solar radiative opacity
Not provided.
Deep learning for NLTE spectral opacities
Computer simulations of high energy density science experiments are computationally challenging, consisting of multiple physics calculations including radiation transport, hydrodynamics, atomic physics, nuclear reactions, laser–plasma interactions, and more. To simulate inertial confinement fusion (ICF) experiments at high fidelity, each of these physics calculations should be as detailed as possible. However, this quickly becomes too computationally expensive even for modern supercomputers, and thus many simplifying assumptions are made to reduce the required computational time. Much of the research has focused on acceleration techniques for the various packages in multiphysics codes. In this work, we explore a novel method for accelerating physics packages via machine learning. The non-local thermodynamic equilibrium (NLTE) package is one of the most expensive calculations in the simulations of indirect drive inertial confinement fusion, taking several tens of percent of the total wall clock time. We explore the use of machine learning to accelerate this package, by essentially replacing the physics calculation with a deep neural network that has been trained to emulate the physics code. Overall, we demonstrate the feasibility of this approach on a simple problem and perform a side-by-side comparison of the physics calculation and the neural network inline in an ICF Hohlraum simulation. We show that the neural network achieves a 10× speed up in NLTE computational time while achieving good agreement with the physics code for several quantities of interest.
Ab initio coupling of jets to collective flow in the opacity expansion approach
Not Available
Dense plasma opacity from excited states method
Not Available
The National Ignition Facility's Soft X-ray Opacity Spectrometer Design Upgrades
Explore the source record for details and available documents.
Z opacity sample evolution using time-resolved spectroscopy with a gated hybrid CMOS detector.
Abstract not provided.
Revisiting iron opacity discrepancies at stellar interior conditions.
Abstract not provided.
Increasing the accuracy of cold Fe opacity measurements to help resolve the Fe solar.
Abstract not provided.
2nd and 3rd order spectral energy corrections with penumbral de-blurring methodology for Opacity platform used on NIF
High-Temperature Plasma Diagnostics Conference May 15 to 19th, 2022 https://htpd.lle.rochester.edu/
Sub keV design for the National Ignition Facility’s Soft X ray Opacity Spectrometer (OpSpec) and expansion into time resolved measurements
Slide form of poster with 5 minute voice over for online submission to the conference
Solar convection-zone-base problem and laboratory stellar-opacity measurements.
Abstract not provided.
Re-analysis of plasma temperature and density for stellar iron opacity experiments.
Abstract not provided.