Emission-line intensity ratios in Fe XVII observed with a microcalorimeter on an electron beam ion trap

J. M. Laming, I. Kink, E. Takács, J. V. Porto, J. D. Gillaspy, E. H. Silver, H. W. Schnopper, S. R. Bandler, N. S. Brickhouse, S. S. Murray, M. Barbera, A. K. Bhatia, G. A. Doschek, N. Madden, D. Landis, J. Beeman, E. E. Haller

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Abstract

We report new observations of emission line intensity ratios of Fe XVII under controlled experimental conditions, using the National Institute of Standards and Technology electron beam ion trap (EBIT) with a microcalorimeter detector. We compare our observations with collisional-radiative models using atomic data computed in distorted wave and R-matnx approximations, which follow the transfer of the polarization of level populations through radiative cascades. Our results for the intensity ratio of the 2p6 1S0-2p53d 1P1 15.014 Å line to the 2p61S0-2p53d3D 1 15.265 Å line are 2.94 ± 0.18 and 2.50 ± 0.13 at beam energies of 900 and 1250 eV, respectively. These results are not consistent with collisional-radiative models and support conclusions from earlier EBIT work at the Lawrence Livermore National Laboratory that the degree of resonance scattering in the solar 15.014 A line has been overestimated in previous analyses. Further observations assess the intensity ratio of the three lines between the 2p6-2p53s configurations to the three lines between the 2p6-2p523d configurations. Both R-matrix and distorted wave approximations agree with each other and our experimental results much better than most solar and stellar observations, suggesting that other processes not present in our experiment must play a role in forming the Fe XVII spectrum in solar and astrophysical plasmas.

Original languageEnglish
JournalAstrophysical Journal
Volume545
Issue number2 PART 2
Publication statusPublished - Dec 20 2000

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calorimeters
electron beams
electron
ion
polarization
scattering
plasma
matrix
resonance scattering
configurations
approximation
solar wind
energy
astrophysics
cascades
experiment
detectors
laboratory
detector

Keywords

  • Atomic data
  • Methods: laboratory
  • Stars: individual (Capella)
  • Sun: corona
  • Techniques: spectroscopic
  • X-rays: general

ASJC Scopus subject areas

  • Space and Planetary Science
  • Nuclear and High Energy Physics

Cite this

Laming, J. M., Kink, I., Takács, E., Porto, J. V., Gillaspy, J. D., Silver, E. H., ... Haller, E. E. (2000). Emission-line intensity ratios in Fe XVII observed with a microcalorimeter on an electron beam ion trap. Astrophysical Journal, 545(2 PART 2).

Emission-line intensity ratios in Fe XVII observed with a microcalorimeter on an electron beam ion trap. / Laming, J. M.; Kink, I.; Takács, E.; Porto, J. V.; Gillaspy, J. D.; Silver, E. H.; Schnopper, H. W.; Bandler, S. R.; Brickhouse, N. S.; Murray, S. S.; Barbera, M.; Bhatia, A. K.; Doschek, G. A.; Madden, N.; Landis, D.; Beeman, J.; Haller, E. E.

In: Astrophysical Journal, Vol. 545, No. 2 PART 2, 20.12.2000.

Research output: Contribution to journalArticle

Laming, JM, Kink, I, Takács, E, Porto, JV, Gillaspy, JD, Silver, EH, Schnopper, HW, Bandler, SR, Brickhouse, NS, Murray, SS, Barbera, M, Bhatia, AK, Doschek, GA, Madden, N, Landis, D, Beeman, J & Haller, EE 2000, 'Emission-line intensity ratios in Fe XVII observed with a microcalorimeter on an electron beam ion trap', Astrophysical Journal, vol. 545, no. 2 PART 2.
Laming, J. M. ; Kink, I. ; Takács, E. ; Porto, J. V. ; Gillaspy, J. D. ; Silver, E. H. ; Schnopper, H. W. ; Bandler, S. R. ; Brickhouse, N. S. ; Murray, S. S. ; Barbera, M. ; Bhatia, A. K. ; Doschek, G. A. ; Madden, N. ; Landis, D. ; Beeman, J. ; Haller, E. E. / Emission-line intensity ratios in Fe XVII observed with a microcalorimeter on an electron beam ion trap. In: Astrophysical Journal. 2000 ; Vol. 545, No. 2 PART 2.
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abstract = "We report new observations of emission line intensity ratios of Fe XVII under controlled experimental conditions, using the National Institute of Standards and Technology electron beam ion trap (EBIT) with a microcalorimeter detector. We compare our observations with collisional-radiative models using atomic data computed in distorted wave and R-matnx approximations, which follow the transfer of the polarization of level populations through radiative cascades. Our results for the intensity ratio of the 2p6 1S0-2p53d 1P1 15.014 {\AA} line to the 2p61S0-2p53d3D 1 15.265 {\AA} line are 2.94 ± 0.18 and 2.50 ± 0.13 at beam energies of 900 and 1250 eV, respectively. These results are not consistent with collisional-radiative models and support conclusions from earlier EBIT work at the Lawrence Livermore National Laboratory that the degree of resonance scattering in the solar 15.014 A line has been overestimated in previous analyses. Further observations assess the intensity ratio of the three lines between the 2p6-2p53s configurations to the three lines between the 2p6-2p523d configurations. Both R-matrix and distorted wave approximations agree with each other and our experimental results much better than most solar and stellar observations, suggesting that other processes not present in our experiment must play a role in forming the Fe XVII spectrum in solar and astrophysical plasmas.",
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T1 - Emission-line intensity ratios in Fe XVII observed with a microcalorimeter on an electron beam ion trap

AU - Laming, J. M.

AU - Kink, I.

AU - Takács, E.

AU - Porto, J. V.

AU - Gillaspy, J. D.

AU - Silver, E. H.

AU - Schnopper, H. W.

AU - Bandler, S. R.

AU - Brickhouse, N. S.

AU - Murray, S. S.

AU - Barbera, M.

AU - Bhatia, A. K.

AU - Doschek, G. A.

AU - Madden, N.

AU - Landis, D.

AU - Beeman, J.

AU - Haller, E. E.

PY - 2000/12/20

Y1 - 2000/12/20

N2 - We report new observations of emission line intensity ratios of Fe XVII under controlled experimental conditions, using the National Institute of Standards and Technology electron beam ion trap (EBIT) with a microcalorimeter detector. We compare our observations with collisional-radiative models using atomic data computed in distorted wave and R-matnx approximations, which follow the transfer of the polarization of level populations through radiative cascades. Our results for the intensity ratio of the 2p6 1S0-2p53d 1P1 15.014 Å line to the 2p61S0-2p53d3D 1 15.265 Å line are 2.94 ± 0.18 and 2.50 ± 0.13 at beam energies of 900 and 1250 eV, respectively. These results are not consistent with collisional-radiative models and support conclusions from earlier EBIT work at the Lawrence Livermore National Laboratory that the degree of resonance scattering in the solar 15.014 A line has been overestimated in previous analyses. Further observations assess the intensity ratio of the three lines between the 2p6-2p53s configurations to the three lines between the 2p6-2p523d configurations. Both R-matrix and distorted wave approximations agree with each other and our experimental results much better than most solar and stellar observations, suggesting that other processes not present in our experiment must play a role in forming the Fe XVII spectrum in solar and astrophysical plasmas.

AB - We report new observations of emission line intensity ratios of Fe XVII under controlled experimental conditions, using the National Institute of Standards and Technology electron beam ion trap (EBIT) with a microcalorimeter detector. We compare our observations with collisional-radiative models using atomic data computed in distorted wave and R-matnx approximations, which follow the transfer of the polarization of level populations through radiative cascades. Our results for the intensity ratio of the 2p6 1S0-2p53d 1P1 15.014 Å line to the 2p61S0-2p53d3D 1 15.265 Å line are 2.94 ± 0.18 and 2.50 ± 0.13 at beam energies of 900 and 1250 eV, respectively. These results are not consistent with collisional-radiative models and support conclusions from earlier EBIT work at the Lawrence Livermore National Laboratory that the degree of resonance scattering in the solar 15.014 A line has been overestimated in previous analyses. Further observations assess the intensity ratio of the three lines between the 2p6-2p53s configurations to the three lines between the 2p6-2p523d configurations. Both R-matrix and distorted wave approximations agree with each other and our experimental results much better than most solar and stellar observations, suggesting that other processes not present in our experiment must play a role in forming the Fe XVII spectrum in solar and astrophysical plasmas.

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KW - Stars: individual (Capella)

KW - Sun: corona

KW - Techniques: spectroscopic

KW - X-rays: general

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