Issue |
A&A
Volume 666, October 2022
|
|
---|---|---|
Article Number | L2 | |
Number of page(s) | 8 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202244403 | |
Published online | 27 September 2022 |
Letter to the Editor
What drives decayless kink oscillations in active-region coronal loops on the Sun?⋆
1
Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
e-mail: smandal.solar@gmail.com
2
Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle upon Tyne NE1 8ST, UK
3
School of Space Research, Kyung Hee University, Yongin, Gyeonggi 446-701, Republic of Korea
4
Institut d’Astrophysique Spatiale, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Bât. 121, 91405 Orsay, France
5
Royal Observatory of Belgium, Ringlaan -3- Av. Circulaire, 1180 Brussels, Belgium
6
Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119992 Moscow, Russia
7
Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, 7260 Davos Dorf, Switzerland
8
ETH-Zürich, Wolfgang-Pauli-Str. 27, 8093 Zürich, Switzerland
9
UCL-Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK
Received:
3
July
2022
Accepted:
8
September
2022
Here, we present a study of the phenomena of decayless kink oscillations in a system of active-region (AR) coronal loops. Using high-resolution observations from two different instruments, namely the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we follow these AR loops for an hour each on three consecutive days. Our results show significantly more resolved decayless waves in the higher resolution EUI data compared with the AIA data. Furthermore, the same system of loops exhibits many of these decayless oscillations on Day 2, while we detect very few oscillations on Day 3 , and find none at all on Day 1. Analysis of photospheric magnetic field data reveals that, most of the time, these loops were rooted in sunspots, where supergranular flows are generally absent. This suggests that supergranular flows, which are often invoked as drivers of decayless waves, are not necessarily driving such oscillations in our observations. Similarly, our findings also cast doubt on other possible drivers of these waves, such as a transient driver or mode conversion of longitudinal waves near the loop footpoints. In conclusion, our analysis suggests that none of the commonly suspected sources proposed to drive decayless oscillations in active-region loops seem to be operating in this event, and therefore the search for that elusive wave driver needs to continue.
Key words: Sun: corona / Sun: magnetic fields / Sun: UV radiation / Sun: oscillations / Sun: transition region
Movies associated to Figs. 1 and 2 are available at https://www.aanda.org
© S. Mandal et al. 2022
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article is published in open access under the Subscribe-to-Open model.
Open Access funding provided by Max Planck Society.
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