ATOMIC-LEVEL PSEUDO-DEGENERACY of ATOMIC LEVELS GIVING TRANSITIONS INDUCED by MAGNETIC FIELDS, of IMPORTANCE for DETERMINING the FIELD STRENGTHS in the SOLAR CORONA
(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)
- author
- Li, Wenxian ; Yang, Yang ; Tu, Bingsheng ; Xiao, Jun ; Grumer, Jon LU ; Brage, Tomas LU ; Watanabe, Tetsuya ; Hutton, Roger LU and Zou, Yaming
- organization
- publishing date
- 2016-08-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- atomic processes, magnetic fields, Sun: corona, techniques: spectroscopic, UV radiation
- in
- Astrophysical Journal
- volume
- 826
- issue
- 2
- article number
- 219
- publisher
- American Astronomical Society
- external identifiers
-
- wos:000381977900119
- scopus:84982199292
- ISSN
- 0004-637X
- DOI
- 10.3847/0004-637X/826/2/219
- language
- English
- LU publication?
- yes
- id
- 485f3203-f07e-41f6-8df8-276420ce768a
- date added to LUP
- 2016-09-20 22:57:02
- date last changed
- 2024-06-28 15:21:00
@article{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}}, keywords = {{atomic processes; magnetic fields; Sun: corona; techniques: spectroscopic; UV radiation}}, language = {{eng}}, month = {{08}}, number = {{2}}, publisher = {{American Astronomical Society}}, 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}}, doi = {{10.3847/0004-637X/826/2/219}}, volume = {{826}}, year = {{2016}}, }