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Title: Numerical investigations of potential systematic uncertainties in iron opacity measurements at solar interior temperatures

Iron opacity calculations presently disagree with measurements at an electron temperature of ~180–195 eV and an electron density of (2–4)×10 22cm –3, conditions similar to those at the base of the solar convection zone. The measurements use x rays to volumetrically heat a thin iron sample that is tamped with low-Z materials. The opacity is inferred from spectrally resolved x-ray transmission measurements. Plasma self-emission, tamper attenuation, and temporal and spatial gradients can all potentially cause systematic errors in the measured opacity spectra. In this article we quantitatively evaluate these potential errors with numerical investigations. The analysis exploits computer simulations that were previously found to reproduce the experimentally measured plasma conditions. The simulations, combined with a spectral synthesis model, enable evaluations of individual and combined potential errors in order to estimate their potential effects on the opacity measurement. Lastly, the results show that the errors considered here do not account for the previously observed model-data discrepancies.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. Prism Computational Sciences, Madison, WI (United States)
Publication Date:
Report Number(s):
SAND-2017-3121J
Journal ID: ISSN 2470-0045; PLEEE8; 651987
Grant/Contract Number:
AC04-94AL85000; NA0003525
Type:
Accepted Manuscript
Journal Name:
Physical Review E
Additional Journal Information:
Journal Volume: 95; Journal Issue: 6; Journal ID: ISSN 2470-0045
Publisher:
American Physical Society (APS)
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1372356
Alternate Identifier(s):
OSTI ID: 1366583

Nagayama, T., Bailey, J. E., Loisel, G. P., Rochau, G. A., MacFarlane, J. J., and Golovkin, I. E.. Numerical investigations of potential systematic uncertainties in iron opacity measurements at solar interior temperatures. United States: N. p., Web. doi:10.1103/PhysRevE.95.063206.
Nagayama, T., Bailey, J. E., Loisel, G. P., Rochau, G. A., MacFarlane, J. J., & Golovkin, I. E.. Numerical investigations of potential systematic uncertainties in iron opacity measurements at solar interior temperatures. United States. doi:10.1103/PhysRevE.95.063206.
Nagayama, T., Bailey, J. E., Loisel, G. P., Rochau, G. A., MacFarlane, J. J., and Golovkin, I. E.. 2017. "Numerical investigations of potential systematic uncertainties in iron opacity measurements at solar interior temperatures". United States. doi:10.1103/PhysRevE.95.063206. https://www.osti.gov/servlets/purl/1372356.
@article{osti_1372356,
title = {Numerical investigations of potential systematic uncertainties in iron opacity measurements at solar interior temperatures},
author = {Nagayama, T. and Bailey, J. E. and Loisel, G. P. and Rochau, G. A. and MacFarlane, J. J. and Golovkin, I. E.},
abstractNote = {Iron opacity calculations presently disagree with measurements at an electron temperature of ~180–195 eV and an electron density of (2–4)×1022cm–3, conditions similar to those at the base of the solar convection zone. The measurements use x rays to volumetrically heat a thin iron sample that is tamped with low-Z materials. The opacity is inferred from spectrally resolved x-ray transmission measurements. Plasma self-emission, tamper attenuation, and temporal and spatial gradients can all potentially cause systematic errors in the measured opacity spectra. In this article we quantitatively evaluate these potential errors with numerical investigations. The analysis exploits computer simulations that were previously found to reproduce the experimentally measured plasma conditions. The simulations, combined with a spectral synthesis model, enable evaluations of individual and combined potential errors in order to estimate their potential effects on the opacity measurement. Lastly, the results show that the errors considered here do not account for the previously observed model-data discrepancies.},
doi = {10.1103/PhysRevE.95.063206},
journal = {Physical Review E},
number = 6,
volume = 95,
place = {United States},
year = {2017},
month = {6}
}