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Title: X-ray line coincidence photopumping in a solar flare

Abstract

Line coincidence photopumping is a process where the electrons of an atomic or molecular species are radiatively excited through the absorption of line emission from another species at a coincident wavelength. There are many instances of line coincidence photopumping in astrophysical sources at optical and ultraviolet wavelengths, with the most famous example being Bowen fluorescence (pumping of O III 303.80 Å by He II), but none to our knowledge in X-rays. However, here we report on a scheme where a He-like line of Ne IX at 11.000 Å is photopumped by He-like Na X at 11.003 Å, which predicts significant intensity enhancement in the Ne IX 82.76 Å transition under physical conditions found in solar flare plasmas. A comparison of our theoretical models with published X-ray observations of a solar flare obtained during a rocket flight provides evidence for line enhancement, with the measured degree of enhancement being consistent with that expected from theory, a truly surprising result. Observations of this enhancement during flares on stars other than the Sun would provide a powerful new diagnostic tool for determining the sizes of flare loops in these distant, spatially unresolved, astronomical sources.

Authors:
 [1]; ORCiD logo [1];  [1];  [2];  [2];  [2];  [3];  [4];  [5]
  1. Queen’s Univ., Belfast (United Kingdom). Astrophysics Research Centre, School of Mathematics and Physics
  2. Imperial College, London (United Kingdom). Blackett Lab.
  3. California State Univ. (CalState), Northridge, CA (United States). Dept. of Physics and Astronomy
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  5. Univ. of Notre Dame, IN (United States). Dept. of Physics
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE; European Union (EU)
OSTI Identifier:
1438781
Report Number(s):
LLNL-JRNL-739147
Journal ID: ISSN 0035-8711
Grant/Contract Number:  
AC52-07NA27344; 606862
Resource Type:
Accepted Manuscript
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Volume: 474; Journal Issue: 3; Journal ID: ISSN 0035-8711
Publisher:
Royal Astronomical Society
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 79 ASTRONOMY AND ASTROPHYSICS; line: identification; radiative transfer; Sun: corona; Sun: flares; stars: coronae; stars: flare

Citation Formats

Keenan, F. P., Poppenhaeger, K., Mathioudakis, M., Rose, S. J., Flowerdew, J., Hynes, D., Christian, D. J., Nilsen, J., and Johnson, W. R. X-ray line coincidence photopumping in a solar flare. United States: N. p., 2017. Web. doi:10.1093/mnras/stx3035.
Keenan, F. P., Poppenhaeger, K., Mathioudakis, M., Rose, S. J., Flowerdew, J., Hynes, D., Christian, D. J., Nilsen, J., & Johnson, W. R. X-ray line coincidence photopumping in a solar flare. United States. doi:10.1093/mnras/stx3035.
Keenan, F. P., Poppenhaeger, K., Mathioudakis, M., Rose, S. J., Flowerdew, J., Hynes, D., Christian, D. J., Nilsen, J., and Johnson, W. R. Thu . "X-ray line coincidence photopumping in a solar flare". United States. doi:10.1093/mnras/stx3035. https://www.osti.gov/servlets/purl/1438781.
@article{osti_1438781,
title = {X-ray line coincidence photopumping in a solar flare},
author = {Keenan, F. P. and Poppenhaeger, K. and Mathioudakis, M. and Rose, S. J. and Flowerdew, J. and Hynes, D. and Christian, D. J. and Nilsen, J. and Johnson, W. R.},
abstractNote = {Line coincidence photopumping is a process where the electrons of an atomic or molecular species are radiatively excited through the absorption of line emission from another species at a coincident wavelength. There are many instances of line coincidence photopumping in astrophysical sources at optical and ultraviolet wavelengths, with the most famous example being Bowen fluorescence (pumping of O III 303.80 Å by He II), but none to our knowledge in X-rays. However, here we report on a scheme where a He-like line of Ne IX at 11.000 Å is photopumped by He-like Na X at 11.003 Å, which predicts significant intensity enhancement in the Ne IX 82.76 Å transition under physical conditions found in solar flare plasmas. A comparison of our theoretical models with published X-ray observations of a solar flare obtained during a rocket flight provides evidence for line enhancement, with the measured degree of enhancement being consistent with that expected from theory, a truly surprising result. Observations of this enhancement during flares on stars other than the Sun would provide a powerful new diagnostic tool for determining the sizes of flare loops in these distant, spatially unresolved, astronomical sources.},
doi = {10.1093/mnras/stx3035},
journal = {Monthly Notices of the Royal Astronomical Society},
number = 3,
volume = 474,
place = {United States},
year = {2017},
month = {11}
}

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Works referenced in this record:

The Fe XIV spectrum: Predicted line intensities and solar identifications
journal, May 1994

  • Bhatia, A. K.; Kastner, S. O.; Keenan, F. P.
  • The Astrophysical Journal, Vol. 427
  • DOI: 10.1086/174160

Solar Mn I 5432/5395 Åline formation explained
journal, April 2001


A Hertzsprung‐Russell–like Diagram for Solar/Stellar Flares and Corona: Emission Measure versus Temperature Diagram
journal, September 2002

  • Shibata, Kazunari; Yokoyama, Takaaki
  • The Astrophysical Journal, Vol. 577, Issue 1
  • DOI: 10.1086/342141

Formation of the CL I line at 1351 A in the solar chromosphere
journal, March 1983

  • Shine, R. A.
  • The Astrophysical Journal, Vol. 266
  • DOI: 10.1086/160835

Relativistic configuration-interaction calculations for the ground state and n =2 singlet states of heliumlike ions
journal, July 1994


Composition of the Solar Corona, Solar Wind, and Solar Energetic Particles
journal, July 2012


Analysis of the resonantly photopumped Na-Ne x-ray-laser scheme
journal, October 1991


A deep X-Ray view of the bare agn ark 120. i. Revealing the soft X-Ray line Emission
journal, September 2016


The X-ray Surveyor Mission: a concept study
conference, August 2015

  • Gaskin, Jessica A.; Weisskopf, Martin C.; Vikhlinin, Alexey
  • SPIE Optical Engineering + Applications, SPIE Proceedings
  • DOI: 10.1117/12.2190837

A Comparative Study of Flaring Loops in Active Stars
journal, May 2006

  • Mullan, D. J.; Mathioudakis, M.; Bloomfield, D. S.
  • The Astrophysical Journal Supplement Series, Vol. 164, Issue 1
  • DOI: 10.1086/502629

Formation of the O I resonance triplet and intercombination doublet in the solar chromosphere
journal, August 1982

  • Skelton, D. L.; Shine, R. A.
  • The Astrophysical Journal, Vol. 259
  • DOI: 10.1086/160221

CHIANTI - an atomic database for emission lines: I. Wavelengths greater than 50 Å
journal, October 1997

  • Dere, K. P.; Landi, E.; Mason, H. E.
  • Astronomy and Astrophysics Supplement Series, Vol. 125, Issue 1
  • DOI: 10.1051/aas:1997368

The effect of an ambient radiation field on the state of ionization in a laser-produced plasma
journal, July 1995


CHIANTI – An atomic database for emission lines. Version 8
journal, October 2015


The excitation of S I emission lines in chromospheres of late-type giant stars⋆
journal, March 1988


Modeling the Ne ix Triplet Spectral Region of Capella with the Chandra and XMM‐Newton Gratings
journal, December 2003

  • Ness, Jan‐Uwe; Brickhouse, Nancy S.; Drake, Jeremy J.
  • The Astrophysical Journal, Vol. 598, Issue 2
  • DOI: 10.1086/379059

Relativistic configuration-interaction calculations of n =2 triplet states of heliumlike ions
journal, May 1993


Escape factors in zero-dimensional radiation-transfer codes
journal, April 2008


The Excitation of the Permitted O III Nebular Lines
journal, February 1934

  • Bowen, I. S.
  • Publications of the Astronomical Society of the Pacific, Vol. 46
  • DOI: 10.1086/124435

Demonstration of population inversion by resonant photopumping in a neon gas cell irradiated by a sodium Z pinch
journal, February 1992


Rocket spectrogram of a solar flare in the 10-100 A region
journal, April 1985

  • Acton, L. W.; Bruner, M. E.; Brown, W. A.
  • The Astrophysical Journal, Vol. 291
  • DOI: 10.1086/163125

Electron density diagnostics in the 10-100 A interval for a solar flare
journal, February 1986

  • Brown, W. A.; Bruner, M. E.; Acton, L. W.
  • The Astrophysical Journal, Vol. 301
  • DOI: 10.1086/163961

The extreme-ultraviolet spectrum of a solar impulsive burst
journal, July 1982

  • Widing, K. G.
  • The Astrophysical Journal, Vol. 258
  • DOI: 10.1086/160130

First Light Measurements of Capella with the Low-Energy Transmission Grating Spectrometer aboard the [ITAL]Chandra X-Ray Observatory[/ITAL]
journal, February 2000

  • Brinkman, A. C.; Gunsing, C. J. T.; Kaastra, J. S.
  • The Astrophysical Journal, Vol. 530, Issue 2
  • DOI: 10.1086/312504