Transport of the magnetic flux away from a decaying sunspot via convective motions

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Hauptverfasser: Zheng, Chenxi, Roudier, Thierry, Schmieder, Brigitte, Ruan, Guiping, Malherbe, Jean-Marie, Liu, Yang, Chen, Yao, Cao, Wenda
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Veröffentlicht: 2024
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author Zheng, Chenxi
Roudier, Thierry
Schmieder, Brigitte
Ruan, Guiping
Malherbe, Jean-Marie
Liu, Yang
Chen, Yao
Cao, Wenda
author_facet Zheng, Chenxi
Roudier, Thierry
Schmieder, Brigitte
Ruan, Guiping
Malherbe, Jean-Marie
Liu, Yang
Chen, Yao
Cao, Wenda
contents Aims. The aim of this paper is to consider relationship between the decay of sunspots and convection via the motion of the family of granules and how the diffusion mechanism of magnetic field operates in a decaying sunspot. Methods. We report the decay of a sunspot observed by the 1.6m Goode Solar Telescope (GST) with the TiO Broadband Filter Imager (BFI) and the Near-InfraRed Imaging Spectropolarimeter (NIRIS). The analysis was aided by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory (SDO). In the first step, we followed the decay of the sunspot with HMI data over three days by constructing its evolving area and total magnetic flux. In the second step, the high spatial and temporal resolution of the GST instruments allowed us to analyze the causes of the decay of the sunspot. Afterward, we followed the emergence of granules in the moat region around the sunspot over six hours. The evolution of the trees of fragmenting granules (TFGs) was derived based on their relationship with the horizontal surface flows. Results. We find that the area and total magnetic flux display an exponential decrease over the course of the sunspot decay. We identified 22 moving magnetic features (MMFs) in the moats of pores, which is a signature of sunspot decay through diffusion. We note that the MMFs were constrained to follow the borders of TFGs during their journey away from the sunspot. Conclusions. The TFGs and their development contribute to the diffusion of the magnetic field outside the sunspot. The conclusion of our analysis shows the important role of the TFGs in sunspot decay. Finally, the the family of granules evacuates the magnetic field.
format Preprint
id arxiv_https___arxiv_org_abs_2404_00889
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Transport of the magnetic flux away from a decaying sunspot via convective motions
Zheng, Chenxi
Roudier, Thierry
Schmieder, Brigitte
Ruan, Guiping
Malherbe, Jean-Marie
Liu, Yang
Chen, Yao
Cao, Wenda
Solar and Stellar Astrophysics
Aims. The aim of this paper is to consider relationship between the decay of sunspots and convection via the motion of the family of granules and how the diffusion mechanism of magnetic field operates in a decaying sunspot. Methods. We report the decay of a sunspot observed by the 1.6m Goode Solar Telescope (GST) with the TiO Broadband Filter Imager (BFI) and the Near-InfraRed Imaging Spectropolarimeter (NIRIS). The analysis was aided by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory (SDO). In the first step, we followed the decay of the sunspot with HMI data over three days by constructing its evolving area and total magnetic flux. In the second step, the high spatial and temporal resolution of the GST instruments allowed us to analyze the causes of the decay of the sunspot. Afterward, we followed the emergence of granules in the moat region around the sunspot over six hours. The evolution of the trees of fragmenting granules (TFGs) was derived based on their relationship with the horizontal surface flows. Results. We find that the area and total magnetic flux display an exponential decrease over the course of the sunspot decay. We identified 22 moving magnetic features (MMFs) in the moats of pores, which is a signature of sunspot decay through diffusion. We note that the MMFs were constrained to follow the borders of TFGs during their journey away from the sunspot. Conclusions. The TFGs and their development contribute to the diffusion of the magnetic field outside the sunspot. The conclusion of our analysis shows the important role of the TFGs in sunspot decay. Finally, the the family of granules evacuates the magnetic field.
title Transport of the magnetic flux away from a decaying sunspot via convective motions
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2404.00889