Light Bridges and Solar Active Region Evolution Processes

Fuente: arXiv
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Main Authors: Li, Fuyu, Rao, Changhui, Zhao, Xinhua, Guo, Yang, Gong, Xiaoying, Chen, Yuhao, Xiang, Nanbin, Wang, Huaning
Format: Preprint
Published: 2024
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author Li, Fuyu
Rao, Changhui
Zhao, Xinhua
Guo, Yang
Gong, Xiaoying
Chen, Yuhao
Xiang, Nanbin
Wang, Huaning
author_facet Li, Fuyu
Rao, Changhui
Zhao, Xinhua
Guo, Yang
Gong, Xiaoying
Chen, Yuhao
Xiang, Nanbin
Wang, Huaning
contents The formation mechanism of light bridges (LBs) is strongly related to the dynamic evolution of solar active regions (ARs). To study the relationship between LB formation and AR evolution phases, we employ 109 LB samples from 69 ARs in 2014 using observational data from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory (HMI/SDO). LBs are well matched with the weak field lanes (WFLs), except that aligned on the polarity inversion line of δ sunspots. For penumbral intrusion (type-A) and umbral-dot emergence (type-C) LBs, the WFLs represent the splitting of magnetic flux systems. The sunspots tend to decay and split into several parts after type-A and type-C LBs formed. For sunspot/umbra merging (type-B) LBs, the WFLs declining are caused by collisions of flux systems. The sunspots merge and keep stable after type-B LBs formed. We conclude that type-B LBs are formed by collisions of flux systems, while type-A and type-C LBs are generated by splits. The time differences (δT) between LBs appearing and ARs peaking have average value of 1.06, -1.60, 1.82 for type-A, B, C LBs, with the standard deviation of 3.27, 2.17, 1.89, respectively. A positive value of δT means that the LB appear after AR peaking, whereas a minus δT before the peak. Type-A LBs trend to form in the decaying phase or around the peak time. Type-B LBs are more likely to be formed in the developing phase. Type-C LBs mostly take shape in the decaying phase of ARs.
format Preprint
id arxiv_https___arxiv_org_abs_2402_13455
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Light Bridges and Solar Active Region Evolution Processes
Li, Fuyu
Rao, Changhui
Zhao, Xinhua
Guo, Yang
Gong, Xiaoying
Chen, Yuhao
Xiang, Nanbin
Wang, Huaning
Solar and Stellar Astrophysics
The formation mechanism of light bridges (LBs) is strongly related to the dynamic evolution of solar active regions (ARs). To study the relationship between LB formation and AR evolution phases, we employ 109 LB samples from 69 ARs in 2014 using observational data from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory (HMI/SDO). LBs are well matched with the weak field lanes (WFLs), except that aligned on the polarity inversion line of δ sunspots. For penumbral intrusion (type-A) and umbral-dot emergence (type-C) LBs, the WFLs represent the splitting of magnetic flux systems. The sunspots tend to decay and split into several parts after type-A and type-C LBs formed. For sunspot/umbra merging (type-B) LBs, the WFLs declining are caused by collisions of flux systems. The sunspots merge and keep stable after type-B LBs formed. We conclude that type-B LBs are formed by collisions of flux systems, while type-A and type-C LBs are generated by splits. The time differences (δT) between LBs appearing and ARs peaking have average value of 1.06, -1.60, 1.82 for type-A, B, C LBs, with the standard deviation of 3.27, 2.17, 1.89, respectively. A positive value of δT means that the LB appear after AR peaking, whereas a minus δT before the peak. Type-A LBs trend to form in the decaying phase or around the peak time. Type-B LBs are more likely to be formed in the developing phase. Type-C LBs mostly take shape in the decaying phase of ARs.
title Light Bridges and Solar Active Region Evolution Processes
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2402.13455