| Issue |
A&A
Volume 634, February 2020
|
|
|---|---|---|
| Article Number | A131 | |
| Number of page(s) | 8 | |
| Section | The Sun | |
| DOI | https://doi.org/10.1051/0004-6361/201936941 | |
| Published online | 25 February 2020 | |
Evolution of Stokes V area asymmetry related to a quiet Sun cancellation observed with GRIS/IFU⋆
1
Leibniz Institute for Solar Physics, Schöneckstrasse 6, 79104 Freiburg, Germany
e-mail: kaithakkal@leibniz-kis.de
2
Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife, Spain
3
Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain
Received:
17
October
2019
Accepted:
15
January
2020
A quiet Sun magnetic flux cancellation event at the disk center was recorded using the Integral Field Unit (IFU) mounted on the GREGOR Infrared Spectrograph (GRIS). The GRIS instrument sampled the event in the photospheric Si I 10827 Å spectral line. The cancellation was preceded by a significant rise in line core intensity and excitation temperature, which is inferred from Stokes inversions under local thermodynamic equilibrium (LTE). The opposite polarity features seem to undergo reconnection above the photosphere. We also found that the border pixels neighboring the polarity inversion line of one of the polarities exhibit a systematic variation of area asymmetry. Area asymmetry peaks right after the line core intensity enhancement and gradually declines thereafter. Analyzing Stokes profiles recorded from either side of the polarity inversion line could therefore potentially provide additional information on the reconnection process related to magnetic flux cancellation. Further analysis without assuming LTE will be required to fully characterize this event.
Key words: Sun: magnetic fields / Sun: photosphere
Movie associated to Fig. 2 is available at https://www.aanda.org
© A. J. Kaithakkal et al. 2020
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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