A 22 yr Cycle of the Network Topology of Solar Active Regions

In this paper, solar cycles 21–24 were compared using complex network analysis. A network was constructed for these four solar cycles to facilitate the comparison. In these networks, the nodes represent the active regions of the Sun that emit flares, and the connections correspond to the sequence of...

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Main Authors: Eduardo Flández, Alejandro Zamorano, Víctor Muñoz
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ada60e
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author Eduardo Flández
Alejandro Zamorano
Víctor Muñoz
author_facet Eduardo Flández
Alejandro Zamorano
Víctor Muñoz
author_sort Eduardo Flández
collection DOAJ
description In this paper, solar cycles 21–24 were compared using complex network analysis. A network was constructed for these four solar cycles to facilitate the comparison. In these networks, the nodes represent the active regions of the Sun that emit flares, and the connections correspond to the sequence of solar flares over time. This resulted in a directed network with self-connections allowed. The model proposed by Abe and Suzuki for earthquake networks was followed. The incoming degree for each node was calculated, and the degree distribution was analyzed. It was found that for each solar cycle, the degree distribution follows a power law, indicating that solar flares tend to appear in correlated active zones rather than being evenly distributed. Additionally, a variation in the characteristic exponent γ for each cycle was observed, with higher values in even cycles compared to odd cycles. A more detailed analysis was performed by constructing 11 yr networks and shifting them in 1 yr intervals. This revealed that the characteristic exponent shows a period of approximately 22 yr coincident with the Hale cycle, suggesting that the complex networks provide information about the solar magnetic activity.
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spelling doaj-art-4edd3354e1744dd78e3f59079fa4dc5d2025-01-30T09:40:37ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-019801410.3847/1538-4357/ada60eA 22 yr Cycle of the Network Topology of Solar Active RegionsEduardo Flández0https://orcid.org/0000-0002-0472-2241Alejandro Zamorano1https://orcid.org/0000-0002-0211-3151Víctor Muñoz2https://orcid.org/0000-0003-1746-4875Departamento de Física, Facultad de Ciencias, Universidad de Chile , Santiago, Chile ; eduardo.flandez@ug.uchile.cl; Physics Department, Catholic University of America , Washington, DC, USADepartamento de Física, Facultad de Ciencias, Universidad de Chile , Santiago, Chile ; eduardo.flandez@ug.uchile.clDepartamento de Física, Facultad de Ciencias, Universidad de Chile , Santiago, Chile ; eduardo.flandez@ug.uchile.clIn this paper, solar cycles 21–24 were compared using complex network analysis. A network was constructed for these four solar cycles to facilitate the comparison. In these networks, the nodes represent the active regions of the Sun that emit flares, and the connections correspond to the sequence of solar flares over time. This resulted in a directed network with self-connections allowed. The model proposed by Abe and Suzuki for earthquake networks was followed. The incoming degree for each node was calculated, and the degree distribution was analyzed. It was found that for each solar cycle, the degree distribution follows a power law, indicating that solar flares tend to appear in correlated active zones rather than being evenly distributed. Additionally, a variation in the characteristic exponent γ for each cycle was observed, with higher values in even cycles compared to odd cycles. A more detailed analysis was performed by constructing 11 yr networks and shifting them in 1 yr intervals. This revealed that the characteristic exponent shows a period of approximately 22 yr coincident with the Hale cycle, suggesting that the complex networks provide information about the solar magnetic activity.https://doi.org/10.3847/1538-4357/ada60eSolar active regionsSolar activitySolar cycleSolar dynamoSolar flaresSolar magnetic fields
spellingShingle Eduardo Flández
Alejandro Zamorano
Víctor Muñoz
A 22 yr Cycle of the Network Topology of Solar Active Regions
The Astrophysical Journal
Solar active regions
Solar activity
Solar cycle
Solar dynamo
Solar flares
Solar magnetic fields
title A 22 yr Cycle of the Network Topology of Solar Active Regions
title_full A 22 yr Cycle of the Network Topology of Solar Active Regions
title_fullStr A 22 yr Cycle of the Network Topology of Solar Active Regions
title_full_unstemmed A 22 yr Cycle of the Network Topology of Solar Active Regions
title_short A 22 yr Cycle of the Network Topology of Solar Active Regions
title_sort 22 yr cycle of the network topology of solar active regions
topic Solar active regions
Solar activity
Solar cycle
Solar dynamo
Solar flares
Solar magnetic fields
url https://doi.org/10.3847/1538-4357/ada60e
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