Explanipedia

Author Correction: Helioseismic inference of the solar radiative opacity Open

G. Buldgen, Jean‐Christophe Pain, Ph. Cossé, C. Blancard, F. Gilleron , et al. · 2025

Helioseismic inference of the solar radiative opacity Open

G. Buldgen, Jean‐Christophe Pain, Ph. Cossé, C. Blancard, F. Gilleron , et al. · 2025

The Sun is the most studied of all stars, and thus constitutes a benchmark for stellar models. However, our vision of the Sun is still incomplete, as illustrated by the current debate on its chemical composition. The problem reaches far be…

FY2024 Q4 L2 Milestone 8237 for Opacity-on-NIF Open

Paul A. Bradley, Ethan Smith, Ahmed Elshafiey, A. S. Moore, Nomita Vazirani , et al. · 2024

This document addresses parts 2 and 3 of the original milestone request. In the following writeup, the development of OpSpecTR at LLNL by LLNL and NNSS personnel will be detailed first, followed by a write-up of the development of Vme-reso…

An Expanded Set of Los Alamos OPLIB Tables in MESA: Type-1 Rosseland-mean Opacities and Solar Models Open

Ebraheem Farag, Christopher J. Fontes, F. X. Timmes, Earl P. Bellinger, Joyce Ann Guzik , et al. · 2024

We present a set of 1194 Type-1 Rosseland-mean opacity tables for four different metallicity mixtures. These new Los Alamos OPLIB atomic radiative opacity tables are an order of magnitude larger in number than any previous opacity table re…

In-depth analysis of solar models with high-metallicity abundances and updated opacity tables Open

G. Buldgen, A. Noels, R. Scuflaire, A. M. Amarsi, N. Grevesse , et al. · 2024

Due to the high quality constraints available for the Sun, we can carry out combined analyses using neutrino, spectroscopic and helioseismic observations. Such studies lay the ground for future improvements of key physical components of so…

In-depth analysis of solar models with high-metallicity abundances and updated opacity tables Open

G. Buldgen, A. Noels, R. Scuflaire, A. M. Amarsi, N. Grevesse , et al. · 2024

Context. As a result of the high-quality constraints available for the Sun, we are able to carry out detailed combined analyses using neutrino, spectroscopic, and helioseismic observations. These studies lay the ground for future improveme…

Development of FESTR: a new spectroscopic modeling and analysis code Open

P. Hakel · 2024

The FESTR code solves the radiation transport equation to model LTE and NLTE plasmas. Motivation, implementation, examples, and future work regarding the code are presented in a series of slides.

Symmetry Tuning of Polar-Direct-Drive Implosions on OMEGA Open

S.-C. Hsu, J. Cobble, T. J. Murphy, N. Krasheninnikova, J. A. Baumgaertel , et al. · 2024

Polar Direct-Drive Plastic Capsule Implosions for Studying Mix on the National Ignition Facility Open

T. J. Murphy, G. A. Kyrala, Paul A. Bradley, J. A. Cobble, I. L. Tregillis , et al. · 2024

The Defect Induced Mix Experiment (DIME) for NIF Open

Mark Schmitt, Paul A. Bradley, J. A. Cobble, P. Hakel, Scott Hsu , et al. · 2024

LANL will perform two Defect Induced Mix Experiment (DIME) implosion campaigns on NIF in July and September, 2012. This presentation describes the goals for these shots and the experimental configuration and diagnostic set up to collect th…

Transition from LEDCOP to ATOMIC Open

N. H. Magee, J Abdallah, J. Colgan, P. Hakel, D. P. Kilcrease , et al. · 2024

This paper discusses the development of the ATOMIC code, a new low to mid Z opacity code, which will replace the current Los Alamos low Z opacity code LEDCOP. The ATOMIC code is based on the FINE code, long used by the Los Alamos group for…

Magnetic-sublevel atomic kinetics modeling for line polarization spectroscopy Open

P. Hakel, R. C. Mancini · 2024

We discuss the mechanism of polarized X-ray line emission in plasmas, its connection to plasma anisotropy, and introduce an atomic kinetics model and code (POLAR) based on the population kinetics of magnetic sublevels. POLAR represents a m…

X-ray line polarization spectroscopy of Li-like satellite line spectra Open

Manolo Sherrill, Joseph Abdallah, Honglin Zhang, P. Hakel, Roberto Mancini · 2024

We apply the magnetic-sublevel atomic kinetics model POLAR to the calculation of polarization properties of satellite lines in Li-like Si driven by subpicosecond-duration laser pulses. We identify spectral lines whose polarization can serv…

Virtreg Open

P. Hakel · 2024

Virtual register for performing addition and subtraction of floating-point numbers without loss of precision

Checkpoint Open

P. Hakel · 2024

Checkpoint-restart

Target Design for XFEL Experiments Open

Alexandria Strickland, P. Hakel, N. M. Hoffman, S. H. Batha · 2023

High-energy-density (HED) experiments utilizing X-ray free electron lasers (XFELs) must take a different approach to fielding these experiments than the current methodology used for the large HED facilities in the United States. The XFELs …

Milestone 7714 National Opacity Program: High-Fidelity Iron Data on NIF Open

J. Colgan, J. Cowan, T. H. Day, E. S. Dodd, Christopher J. Fontes , et al. · 2022

Establish the level of reproducibility of NIF iron opacity shots, quantify to-date improvements in data quality through, e.g. background reduction, improved signal, and improved analysis methods, and formalize the approach that will be tak…

Enabling High-Energy-Density Physics Using X-Ray Free Electron Lasers Open

S. H. Batha, P. Hakel, N. M. Hoffman, Alexandria Strickland · 2022

New High-Energy-Density (HED) Physics research facilities, such as x-ray free electron lasers (XFEL) are becoming available to the research community. These new tools can be used to address stockpile stewardship science questions in the HE…

A temperature profile diagnostic for radiation waves on OMEGA-60 Open

Heather Johns, Chris L. Fryer, Suzannah R. Wood, Christopher J. Fontes, Pawel Kozłowski , et al. · 2021

Sodium tracer measurements of an expanded dense aluminum plasma from e-beam isochoric heating Open

Nicholas Ramey, J. E. Coleman, P. Hakel, Heidi Morris, J. Colgan , et al. · 2021

Spatially and temporally resolved visible absorption spectroscopy is performed on sodium D-lines present as surface contaminants on an expanded dense aluminum plasma plume. An 80-ns FWHM, intense, relativistic electron beam deposits 5.4 J …

Experiments and simulations of isochorically heated warm dense carbon foam at the Texas Petawatt Laser Open

R. Roycroft, Paul A. Bradley, E. McCary, Brant Bowers, H. Smith , et al. · 2020

An experimental and simulation study of warm dense carbon foams at ambient density (ne ∼ 1021 cm−3) is presented. This study of isochorically heated foams is motivated by their potential application in carbon-atmosphere white-dwarf envelop…

Laser-driven production of the antihydrogen molecular ion Open

Mark C. Zammit, M. Charlton, S. Jonsell, J. Colgan, Jeremy Savage , et al. · 2019

The feasibility of producing the molecular antihydrogen anion H₂^– in the laboratory is investigated here. Utilizing reaction rates calculated here involving the interaction of laser excited-state antihydrogen atoms he…

Design-by-contract and test-driven software development [Slides] Open

P. Hakel · 2019

addition of fixed components not represented in systems such as buttons. The conversion process utilizes the critical features of JDOM, a Java based XML parser, and Core Java Reflection, an advanced Java feature that generates objects at r…

Progress on observations of interspecies ion separation in inertial-confinement-fusion implosions via imaging x-ray spectroscopy Open

T. R. Joshi, Scott Hsu, P. Hakel, N. M. Hoffman, H. Sio , et al. · 2019

We report on the analyses of x-ray-imaging spectroscopy data from experiments to study interspecies ion separation in direct-drive inertial-confinement-fusion experiments on the Omega laser facility. This is a continuation of recent, relat…

FESTR: Finite-Element Spectral Transfer of Radiation spectroscopic modeling and analysis code (New Version Announcement) Open

P. Hakel · 2019

Opacity: A window into High Energy Density Plasma Physics Open

Heather Johns, Paul Keiter, J. Colgan, Pawel Kozłowski, T. S. Perry , et al. · 2019

Opacity is a fundamental property of matter and knowledge of it is required to understand the transport of radiation through a material. Exact knowledge of opacity is crucial in many fields such as astrophysics, which recently produced a w…

Inference of the electron temperature in inertial confinement fusion implosions from the hard X‐ray spectral continuum Open

Grigory Kagan, O. L. Landen, D. Svyatskiy, H. Sio, N. V. Kabadi , et al. · 2018

Using the free‐free continuum self‐emission spectrum at photon energies above 15 keV is one of the most promising concepts for assessing the electron temperature in inertial confinement fusion (ICF) experiments. However, these photons are …

Toward X-ray diagnostics for WDM on DARHT Axis-I: a PhD roadmap Open

Nicholas Ramey, T. N. Archuleta, J. Colgan, V. E. Fatherley, Christopher J. Fontes , et al. · 2018

beam energy of 19.8 MeV. The principal goal of this project is to characterize these angular distributions to determine the optimal location to deploy the soft X-ray spectrometer. In addition, a proof-of-principle design will be presented.…

New Los Alamos Opacity Calculations Open

J. Colgan, D. P. Kilcrease, N. H. Magee, Manolo Sherrill, Christopher J. Fontes , et al. · 2018

In 2015 Los Alamos National Laboratory (LANL) released a new set of OPLIB opacity tables for the elements hydrogen through zinc. The new LANL opacities are publicly available via our website and are already in use by the astrophysics commu…

State-resolved Photodissociation and Radiative Association Data for the Molecular Hydrogen Ion Open

Mark C. Zammit, Jeremy Savage, J. Colgan, Dmitry V. Fursa, D. P. Kilcrease , et al. · 2017

We present state-resolved (electronic, vibrational, and rotational) cross sections and rate coefficients for the photodissociation (PD) of and radiative association (RA) of H–H + . We developed a fully quantum mechanical approach within th…

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