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Title: X-Ray-Spectroscopy of Astrophysically-Relevant Photoionized Iron Plasmas at Z

Abstract

In order to provide benchmark data for models used to interpret X-ray astronomy data from newly-launched orbital telescopes such as Chandra, they have used 120 TW, 180 eV pinch plasmas on the Sandia Z facility to drive iron foils into X-ray photoionized equilibrium. The experiment was designed to achieve photoionization parameters characteristic of accretion-powered objects such as X-ray binaries (neutron stars) and active galactic nuclei (black holes). These objects comprise roughly half of observed X-ray sources, but the interpretation of their spectra is difficult: state-of-the-art models for photoionized iron plasmas do not yet agree on the expected ionization balance. In the initial experiments the foil samples consisted of 200 {angstrom} of iron codeposited with 300 {angstrom} of sodium fluoride and sandwiched between two 1000 {angstrom} layers of Lexan (CH and O). They characterized the pinch spectrum, temperature, power and uniformity and qualified it as a photoionization driver. They obtained time-integrated absorption spectra for the foil from 8 to 18 {angstrom} and identified spectral lines from O VIII, F IX, Na X and XI, and Fe XVII and XVIII, i.e. neon-line and fluorine-like iron. Time-resolved absorption and emission spectra for the foils were also obtained from 12.5 to 16 {angstrom}, andmore » hydrogen-like F and neon-like and fluorine-like Fe were again observed in the 2 ns time window of interest. In subsequent ride along experiments they have developed a density diagnostic and measured the density via foil-expansion imaging at two locations. They conclude by discussing upcoming experiments at Z in which they plan to obtain a full data set of plasma density, temperature, and absorption and emission spectra for multiple photoionization equilibria.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (US)
Sponsoring Org.:
USDOE Office of Defense Programs (DP) (US)
OSTI Identifier:
792756
Report Number(s):
UCRl-JC-137660
Journal ID: ISSN 0094-243X; TRN: US200223%%717
DOE Contract Number:  
W-7405-Eng-48
Resource Type:
Conference
Resource Relation:
Journal Volume: 547; Conference: 12th APS Topical Conference on Atomic Processes in Plasmas, Reno, NV (US), 03/19/2000--03/23/2000; Other Information: PBD: 12 Jun 2000
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION SPECTRA; ASTRONOMY; BENCHMARKS; EMISSION SPECTRA; IRON; NUCLEI; PHOTOIONIZATION; PLASMA DENSITY; SODIUM FLUORIDES; SPECTRA; STARS; TELESCOPES; X-RAY SOURCES

Citation Formats

Heeter, R F, Bailey, J E, Cuneo, M E, Emig, J, Foord, M E, Springer, P T, and Thoe, R S. X-Ray-Spectroscopy of Astrophysically-Relevant Photoionized Iron Plasmas at Z. United States: N. p., 2000. Web. doi:10.1063/1.1361782.
Heeter, R F, Bailey, J E, Cuneo, M E, Emig, J, Foord, M E, Springer, P T, & Thoe, R S. X-Ray-Spectroscopy of Astrophysically-Relevant Photoionized Iron Plasmas at Z. United States. doi:10.1063/1.1361782.
Heeter, R F, Bailey, J E, Cuneo, M E, Emig, J, Foord, M E, Springer, P T, and Thoe, R S. Mon . "X-Ray-Spectroscopy of Astrophysically-Relevant Photoionized Iron Plasmas at Z". United States. doi:10.1063/1.1361782. https://www.osti.gov/servlets/purl/792756.
@article{osti_792756,
title = {X-Ray-Spectroscopy of Astrophysically-Relevant Photoionized Iron Plasmas at Z},
author = {Heeter, R F and Bailey, J E and Cuneo, M E and Emig, J and Foord, M E and Springer, P T and Thoe, R S},
abstractNote = {In order to provide benchmark data for models used to interpret X-ray astronomy data from newly-launched orbital telescopes such as Chandra, they have used 120 TW, 180 eV pinch plasmas on the Sandia Z facility to drive iron foils into X-ray photoionized equilibrium. The experiment was designed to achieve photoionization parameters characteristic of accretion-powered objects such as X-ray binaries (neutron stars) and active galactic nuclei (black holes). These objects comprise roughly half of observed X-ray sources, but the interpretation of their spectra is difficult: state-of-the-art models for photoionized iron plasmas do not yet agree on the expected ionization balance. In the initial experiments the foil samples consisted of 200 {angstrom} of iron codeposited with 300 {angstrom} of sodium fluoride and sandwiched between two 1000 {angstrom} layers of Lexan (CH and O). They characterized the pinch spectrum, temperature, power and uniformity and qualified it as a photoionization driver. They obtained time-integrated absorption spectra for the foil from 8 to 18 {angstrom} and identified spectral lines from O VIII, F IX, Na X and XI, and Fe XVII and XVIII, i.e. neon-line and fluorine-like iron. Time-resolved absorption and emission spectra for the foils were also obtained from 12.5 to 16 {angstrom}, and hydrogen-like F and neon-like and fluorine-like Fe were again observed in the 2 ns time window of interest. In subsequent ride along experiments they have developed a density diagnostic and measured the density via foil-expansion imaging at two locations. They conclude by discussing upcoming experiments at Z in which they plan to obtain a full data set of plasma density, temperature, and absorption and emission spectra for multiple photoionization equilibria.},
doi = {10.1063/1.1361782},
journal = {},
issn = {0094-243X},
number = ,
volume = 547,
place = {United States},
year = {2000},
month = {6}
}

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