Quasiperiodic Slipping Motion of Flare Ribbon Fine Structures Anchored in a Sunspot Light Bridge

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Hauptverfasser: Chen, Tianyuan, Yan, Xiaoli, Xue, Zhike, Wang, Jincheng, Xu, Zhe, Yang, Liheng, Duan, Yadan, Zhou, Yian, Wu, Zongyin, Dong, Qifan, Wu, Guotang, Zhang, Xinsheng
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Veröffentlicht: 2026
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author Chen, Tianyuan
Yan, Xiaoli
Xue, Zhike
Wang, Jincheng
Xu, Zhe
Yang, Liheng
Duan, Yadan
Zhou, Yian
Wu, Zongyin
Dong, Qifan
Wu, Guotang
Zhang, Xinsheng
author_facet Chen, Tianyuan
Yan, Xiaoli
Xue, Zhike
Wang, Jincheng
Xu, Zhe
Yang, Liheng
Duan, Yadan
Zhou, Yian
Wu, Zongyin
Dong, Qifan
Wu, Guotang
Zhang, Xinsheng
contents We used high-resolution observations from the New Vacuum Solar Telescope and the Solar Dynamics Observatory to carry out a detailed multiwavelength analysis of the fine structures in the flare ribbon of a C3.9-class flare on 22 April 2021. A segment of the flare ribbon was rooted in a sunspot light bridge and exhibited discrete substructures, which we term "burrs", with equivalent diameters of 233-895 km and inter-core separations of 1129-1739 km. These structures are characterized by discrete redshifted cores accompanied by "tails" with lengths of 700-1370 km and widths of 310-600 km that show faint blueshifts. The burrs display systematic slipping motions along the ribbon, with apparent velocities decreasing from about 40 to 21 km/s, and show a distinct quasi-periodicity of about 6 minutes in H-alpha and EUV passbands. Differential emission measure analysis indicates that the emitting plasma is multi-thermal and dominated by temperatures of 1-2 MK. The observed morphology and kinematics are consistent with impulsive energy deposition by precipitating plasmoids, or oblique flux ropes, produced by tearing-mode fragmentation in the coronal current sheet. The close spatiotemporal association between the tails and blueshifts supports the interpretation that these features are related to untwisting magnetic flux ropes. The approximately 6-minute periodicity further suggests that the reconnection process may be modulated by photospheric p-mode oscillations coupled with tearing-mode instability. These results provide observational evidence that light-bridge-anchored fine structures can act as elementary units of flare energy release.
format Preprint
id arxiv_https___arxiv_org_abs_2603_22940
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Quasiperiodic Slipping Motion of Flare Ribbon Fine Structures Anchored in a Sunspot Light Bridge
Chen, Tianyuan
Yan, Xiaoli
Xue, Zhike
Wang, Jincheng
Xu, Zhe
Yang, Liheng
Duan, Yadan
Zhou, Yian
Wu, Zongyin
Dong, Qifan
Wu, Guotang
Zhang, Xinsheng
Solar and Stellar Astrophysics
We used high-resolution observations from the New Vacuum Solar Telescope and the Solar Dynamics Observatory to carry out a detailed multiwavelength analysis of the fine structures in the flare ribbon of a C3.9-class flare on 22 April 2021. A segment of the flare ribbon was rooted in a sunspot light bridge and exhibited discrete substructures, which we term "burrs", with equivalent diameters of 233-895 km and inter-core separations of 1129-1739 km. These structures are characterized by discrete redshifted cores accompanied by "tails" with lengths of 700-1370 km and widths of 310-600 km that show faint blueshifts. The burrs display systematic slipping motions along the ribbon, with apparent velocities decreasing from about 40 to 21 km/s, and show a distinct quasi-periodicity of about 6 minutes in H-alpha and EUV passbands. Differential emission measure analysis indicates that the emitting plasma is multi-thermal and dominated by temperatures of 1-2 MK. The observed morphology and kinematics are consistent with impulsive energy deposition by precipitating plasmoids, or oblique flux ropes, produced by tearing-mode fragmentation in the coronal current sheet. The close spatiotemporal association between the tails and blueshifts supports the interpretation that these features are related to untwisting magnetic flux ropes. The approximately 6-minute periodicity further suggests that the reconnection process may be modulated by photospheric p-mode oscillations coupled with tearing-mode instability. These results provide observational evidence that light-bridge-anchored fine structures can act as elementary units of flare energy release.
title Quasiperiodic Slipping Motion of Flare Ribbon Fine Structures Anchored in a Sunspot Light Bridge
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2603.22940