Advanced

ATOMIC-LEVEL PSEUDO-DEGENERACY of ATOMIC LEVELS GIVING TRANSITIONS INDUCED by MAGNETIC FIELDS, of IMPORTANCE for DETERMINING the FIELD STRENGTHS in the SOLAR CORONA

Li, Wenxian; Yang, Yang LU ; Tu, Bingsheng; Xiao, Jun; Grumer, Jon LU ; Brage, Tomas LU ; Watanabe, Tetsuya; Hutton, Roger LU and Zou, Yaming (2016) In Astrophysical Journal 826(2).
Abstract

We present a measured value for the degree of pseudo-degeneracy between two fine-structure levels in Fe9+ from line intensity ratios involving a transition induced by an external magnetic field. The extracted fine-structure energy difference between 3p4 3d 4D7/2 the and 4D7/2 levels, where the latter is the upper state for the magnetic-field induced line, is needed in our recently proposed method to measure magnetic-field strengths in the solar corona. The intensity of the 3p4 3d 4D7/2 → 3p5 2 P3/2 line at 257.262 Å is sensitive to the magnetic field external to the ion. This sensitivity is in turn strongly... (More)

We present a measured value for the degree of pseudo-degeneracy between two fine-structure levels in Fe9+ from line intensity ratios involving a transition induced by an external magnetic field. The extracted fine-structure energy difference between 3p4 3d 4D7/2 the and 4D7/2 levels, where the latter is the upper state for the magnetic-field induced line, is needed in our recently proposed method to measure magnetic-field strengths in the solar corona. The intensity of the 3p4 3d 4D7/2 → 3p5 2 P3/2 line at 257.262 Å is sensitive to the magnetic field external to the ion. This sensitivity is in turn strongly dependent on the energy separation in the pseudo-degeneracy through the mixing induced by the external magnetic field. Our measurement, which uses an Electron Beam Ion Trap with a known magnetic-field strength, indicates that this energy difference is 3.5 cm-1. The high abundance of Fe9+ and the sensitivity of the line's transition probability to field strengths below 0.1 T opens up the possibility of diagnosing coronal magnetic fields. We propose a new method to measure the magnetic field in the solar corona, from similar intensity ratios in Fe9+. In addition, the proposed method to use the line ratio of the blended line 3p4 3d 4D7/2.5/2 → 3p5 2P3/2 with another line from Fe x as the density diagnostic should evaluate the effect of the magnetic-field-induced transition line.

(Less)
Please use this url to cite or link to this publication:
author
publishing date
type
Contribution to journal
publication status
published
keywords
atomic processes, magnetic fields, Sun: corona, techniques: spectroscopic, UV radiation
in
Astrophysical Journal
volume
826
issue
2
publisher
University of Chicago Press
external identifiers
  • Scopus:84982199292
ISSN
0004-637X
DOI
10.3847/0004-637X/826/2/219
language
English
LU publication?
no
id
485f3203-f07e-41f6-8df8-276420ce768a
date added to LUP
2016-09-20 22:57:02
date last changed
2016-10-02 12:38:02
@misc{485f3203-f07e-41f6-8df8-276420ce768a,
  abstract     = {<p>We present a measured value for the degree of pseudo-degeneracy between two fine-structure levels in Fe<sup>9+</sup> from line intensity ratios involving a transition induced by an external magnetic field. The extracted fine-structure energy difference between 3p<sup>4</sup> 3d <sup>4</sup>D<sub>7/2</sub> the and <sup>4</sup>D<sub>7/2</sub> levels, where the latter is the upper state for the magnetic-field induced line, is needed in our recently proposed method to measure magnetic-field strengths in the solar corona. The intensity of the 3p<sup>4</sup> 3d <sup>4</sup>D<sub>7/2</sub> → 3p<sup>5</sup> <sup>2</sup> P<sub>3/2</sub> line at 257.262 Å is sensitive to the magnetic field external to the ion. This sensitivity is in turn strongly dependent on the energy separation in the pseudo-degeneracy through the mixing induced by the external magnetic field. Our measurement, which uses an Electron Beam Ion Trap with a known magnetic-field strength, indicates that this energy difference is 3.5 cm<sup>-1</sup>. The high abundance of Fe<sup>9+</sup> and the sensitivity of the line's transition probability to field strengths below 0.1 T opens up the possibility of diagnosing coronal magnetic fields. We propose a new method to measure the magnetic field in the solar corona, from similar intensity ratios in Fe<sup>9+</sup>. In addition, the proposed method to use the line ratio of the blended line 3p<sup>4</sup> 3d <sup>4</sup>D<sub>7/2.5/2</sub> → 3p<sup>5</sup> <sup>2</sup>P<sub>3/2</sub> with another line from Fe x as the density diagnostic should evaluate the effect of the magnetic-field-induced transition line.</p>},
  author       = {Li, Wenxian and Yang, Yang and Tu, Bingsheng and Xiao, Jun and Grumer, Jon and Brage, Tomas and Watanabe, Tetsuya and Hutton, Roger and Zou, Yaming},
  issn         = {0004-637X},
  keyword      = {atomic processes,magnetic fields,Sun: corona,techniques: spectroscopic,UV radiation},
  language     = {eng},
  month        = {08},
  number       = {2},
  publisher    = {ARRAY(0xa3f4a18)},
  series       = {Astrophysical Journal},
  title        = {ATOMIC-LEVEL PSEUDO-DEGENERACY of ATOMIC LEVELS GIVING TRANSITIONS INDUCED by MAGNETIC FIELDS, of IMPORTANCE for DETERMINING the FIELD STRENGTHS in the SOLAR CORONA},
  url          = {http://dx.doi.org/10.3847/0004-637X/826/2/219},
  volume       = {826},
  year         = {2016},
}