Volume 633, January 2020
|Number of page(s)||8|
|Published online||21 January 2020|
A solar filament disconnected by magnetic reconnection⋆
Yunnan Observatories, Chinese Academy of Sciences, Kunming Yunnan 650216, PR China
2 Center for Astronomical Mega-Science, Chinese Academy of Sciences, Beijing 100012, PR China
3 CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Beijing 100012, PR China
4 University of Chinese Academy of Sciences, Beijing 100049, PR China
Accepted: 10 December 2019
Aims. We aim to study a high-resolution observation of an asymmetric inflow magnetic reconnection between a filament and its surrounding magnetic loops in active region NOAA 12436 on 2015 October 23.
Methods. We analyzed the multiband observations of the magnetic reconnection obtained by the New Vacuum Solar Telescope (NVST) and the Solar Dynamic Observatory. We calculated the NVST Hα Dopplergrams to determine the Doppler properties of the magnetic reconnection region and the rotation of a jet.
Results. The filament firstly becomes active and then approaches its southwestern surrounding magnetic loops (L1) with a velocity of 9.0 km s−1. During this period, the threads of the filament become loose in the reconnection region and then reconnect with L1 in turn. L1 is pressed backward by the filament with a velocity of 5.5 km s−1, and then the magnetic reconnection occurs between them. A set of newly formed loops are separated from the reconnection site with a mean velocity of 127.3 km s−1. In the middle stage, some threads of the filament return back first with a velocity of 20.1 km s−1, and others return with a velocity of 4.1 km s−1 after about 07:46 UT. Then, L1 also begins to return with a velocity of 3.5 km s−1 at about 07:47 UT. At the same time, magnetic reconnection continues to occur between them until 07:51 UT. During the reconnection, a linear typical current sheet forms with a length of 5.5 Mm and a width of 1.0 Mm, and a lot of hot plasma blobs are observed propagating from the typical current sheet. During the reconnection, the plasma in the reconnection region and the typical current sheet always shows redshifted feature. Furthermore, the material and twist of the filament are injected into the newly longer-formed magnetic loops by the magnetic reconnection, which leads to the formation of a jet, and its rotation.
Conclusions. The observational evidence for the asymmetric inflow magnetic reconnection is investigated. We conclude that the magnetic reconnection does occur in this event and results in the disconnection of the filament. The looseness of the filament may be due to the pressure imbalance between the inside and outside of the filament. The redshifted feature in the reconnection site can be explained by the expansion of the right flank of the filament to the lower atmosphere because of the complex magnetic configuration in this active region.
Key words: Sun: filaments, prominences / magnetic reconnection / Sun: activity / Sun: magnetic fields
Movies associated to Figs. 2–4 are available at https://www.aanda.org
© ESO 2020
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