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  Dark Structures in Sunspot Light Bridges

Zhang, J., Tian, H., Solanki, S. K., Wang, H., Peter, H., Ahn, K., et al. (2018). Dark Structures in Sunspot Light Bridges. The Astrophysical Journal, 865(1): 29. doi:10.3847/1538-4357/aada0a.

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Item Permalink: http://hdl.handle.net/21.11116/0000-0003-C3AE-D Version Permalink: http://hdl.handle.net/21.11116/0000-0004-B078-E
Genre: Journal Article


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Zhang, Jingwen, Author
Tian, Hui, Author
Solanki, Sami K.1, 2, Author              
Wang, Haimin, Author
Peter, Hardi1, Author              
Ahn, Kwangsu, Author
Xu, Yan, Author
Zhu, Yingjie, Author
Cao, Wenda, Author
He, Jiansen, Author
Wang, Linghua, Author
1Department Sun and Heliosphere, Max Planck Institute for Solar System Research, Max Planck Society, ou_1832289              
2ERC Advanced Grant: Solar magnetic field and its influence on solar variability and activity (SOLMAG), Max Planck Institute for Solar System Research, Max Planck Society, ou_3164813              


Free keywords: Sun: granulation; Sun: magnetic fields; Sun: photosphere; sunspots
 Abstract: We present unprecedented high-resolution TiO images and Fe i 1565 nm spectropolarimetric data of two light bridges taken by the 1.6 m Goode Solar Telescope at Big Bear Solar Observatory. In the first light bridge (LB1), we find striking knot-like dark structures within the central dark lane. Many dark knots show migration away from the penumbra along the light bridge. The sizes, intensity depressions, and apparent speeds of their proper motion along the light bridges of 33 dark knots identified from the TiO images are mainly in the ranges of 80 ~ 200 km, 30% ~ 50%, and 0.3 ~ 1.2 km s−1, respectively. In the second light bridge (LB2), a faint central dark lane and striking transverse intergranular lanes were observed. These intergranular lanes have sizes and intensity depressions comparable to those of the dark knots in LB1 and also migrate away from the penumbra at similar speeds. Our observations reveal that LB2 is made up of a chain of evolving convection cells, as indicated by patches of blueshift surrounded by narrow lanes of redshift. The central dark lane generally corresponds to blueshifts, supporting the previous suggestion of central dark lanes being the top parts of convection upflows. In contrast, the intergranular lanes are associated with redshifts and located at two sides of each convection cell. The magnetic fields are stronger in intergranular lanes than in the central dark lane. These results suggest that these intergranular lanes are manifestations of convergent convective downflows in the light bridge. We also provide evidence that the dark knots observed in LB1 may have a similar origin.


Language(s): eng - English
 Dates: 2018
 Publication Status: Published online
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.3847/1538-4357/aada0a
 Degree: -



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Project information

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Project name : ERC-2015-AdG - SOLMAG
Grant ID : 695075
Funding program : Horizon 2020 (H2020)
Funding organization : European Commission (EC)

Source 1

Title: The Astrophysical Journal
Source Genre: Journal
Publ. Info: Bristol; Vienna : IOP Publishing; IAEA
Pages: - Volume / Issue: 865 (1) Sequence Number: 29 Start / End Page: - Identifier: ISSN: 0004-637X
CoNE: https://pure.mpg.de/cone/journals/resource/954922828215_3