Issue |
A&A
Volume 664, August 2022
|
|
---|---|---|
Article Number | A48 | |
Number of page(s) | 11 | |
Section | The Sun and the Heliosphere | |
DOI | https://doi.org/10.1051/0004-6361/202142711 | |
Published online | 04 August 2022 |
Coronal loop kink oscillation periods derived from the information of density, magnetic field, and loop geometry
1
School of Astronomy and Space Science and Key Laboratory for Modern Astronomy and Astrophysics, Nanjing University, Nanjing 210023, PR China
e-mail: guoyang@nju.edu.cn
2
Solar Physics and Space Plasma Research Center (SP2RC), School of Mathematics and Statistics, University of Sheffield, Sheffield S3 7RH, UK
3
Department of Astronomy, Eötvös Lorand University, Pázmány Péter sétány 1/A, Budapest 1117, Hungary
4
Gyula Bay Zoltan Solar Observatory (GSO), Hungarian Solar Physics Foundation (HSPF), Petőfi tér 3., Gyula 5700, Hungary
Received:
21
November
2021
Accepted:
9
May
2022
Context. Coronal loop oscillations can be triggered by solar eruptions, for example, and are observed frequently by the Atmospheric Imaging Assembly (AIA) on board Solar Dynamics Observatory (SDO). The Helioseismic and Magnetic Imager (HMI) on board SDO offers us the opportunity to measure the photospheric vector magnetic field and carry out solar magneto-seismology (SMS).
Aims. By applying SMS, we aim to verify the consistency between the observed period and the one derived from the information of coronal density, magnetic field, and loop geometry, that is, the shape of the loop axis.
Methods. We analysed the data of three coronal loop oscillation events detected by SDO/AIA and SDO/HMI. First, we obtained oscillation parameters by fitting the observational data. Second, we used a differential emission measure (DEM) analysis to diagnose the temperature and density distribution along the coronal loop. Subsequently, we applied magnetic field extrapolation to reconstruct the three-dimensional magnetic field and then, finally, used the shooting method to compute the oscillation periods from the governing equation.
Results. The average magnetic field determined by magnetic field extrapolation is consistent with that derived by SMS. A new analytical solution is found under the assumption of exponential density profile and uniform magnetic field. The periods estimated by combining the coronal density and magnetic field distribution and the associated loop geometry are closest to the observed ones, and are more realistic than when the loop geometry is regarded as being semi-circular or having a linear shape.
Conclusions. The period of a coronal loop is sensitive to not only the density and magnetic field distribution but also the loop geometry.
Key words: Sun: corona / Sun: oscillations / Sun: magnetic fields
© G. Y. Chen 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. Subscribe to A&A to support open access publication.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.