Issue |
A&A
Volume 681, January 2024
|
|
---|---|---|
Article Number | L4 | |
Number of page(s) | 6 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202348702 | |
Published online | 22 December 2023 |
Letter to the Editor
Detection of decayless oscillations in solar transition region loops
1
School of Earth and Space Sciences, Peking University, Beijing 100871, PR China
e-mail: zhenyonghou@pku.edu.cn
2
Centre for mathematical Plasma-Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B bus 2400, 3001 Leuven, Belgium
3
Institute of Space Sciences, Shandong University, Weihai, Shandong 264209, PR China
Received:
22
November
2023
Accepted:
12
December
2023
Context. Decayless kink oscillations have been frequently observed in coronal loops, serving as a valuable diagnostic tool for the coronal magnetic field. Such oscillations have never before been reported in low-lying loops of the transition region (TR).
Aims. The aim of this study is to detect decayless kink oscillations in TR loops for the first time.
Methods. We used the SI IV 1400 Å imaging data obtained from the Interface Region Imaging Spectrograph. We applied the Multiscale Gaussian Normalization method to highlight the TR loops, and generated time–distance maps to analyse the oscillation signals.
Results. Seven oscillation events detected here exhibit a small but sustained displacement amplitude (0.04–0.10 Mm) for more than three cycles. Their periods range from 3 to 5 min. The phase speed is found to increase with loop length, which is consistent with the decrease in Alfvén speed with height. With these newly detected oscillations, we obtain a rough estimate of the magnetic field in the transition region, which is about 5–10 G.
Conclusions. Our results further reveal the ubiquity of decayless kink oscillations in the solar atmosphere. These oscillations in TR loops have the potential to be a diagnostic tool for the TR magnetic field.
Key words: Sun: atmosphere / Sun: magnetic fields / Sun: oscillations / Sun: transition region
© The Authors 2023
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.
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