The role of photospheric magnetic flux diffusion in initiation of solar eruptions

Fuente: arXiv
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Main Authors: Bian, Xinkai, Jiang, Chaowei, Wang, Yang, Zou, Peng, Feng, Xueshang, Zuo, Pingbing, Wang, Yi
Format: Preprint
Published: 2025
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author Bian, Xinkai
Jiang, Chaowei
Wang, Yang
Zou, Peng
Feng, Xueshang
Zuo, Pingbing
Wang, Yi
author_facet Bian, Xinkai
Jiang, Chaowei
Wang, Yang
Zou, Peng
Feng, Xueshang
Zuo, Pingbing
Wang, Yi
contents Solar eruptions may occur at different evolutionary stages of active regions, during which the photospheric motions manifest in various forms, including flux emergence, sunspot rotation, shearing, converging, and magnetic flux diffusion. However, it remains unclear what are the specific roles played by these different motions in leading to eruptions. Here, we employ high resolution magnetohydrodynamic simulations to demonstrate how solar eruptions can be initiated in a single bipolar configuration, driven by first shearing and then flux diffusion at the bottom surface. Flux diffusion disperses the photospheric magnetic flux, driving portions of it toward the polarity inversion line (PIL). This process leads to the expansion of core field, enhancing the pinching effect to form the current sheet. When magnetic reconnection occurs within this current sheet, the eruption is initiated, characterized by a rapid release of magnetic energy and accompanied by the formation of a erupting flux rope. Additionally, flux diffusion contributes to magnetic cancellation near the PIL, leading to the formation of a weakly twisted magnetic flux rope prior to the eruption. However, this pre-exist flux rope plays a limited role in eruption initiation, as its spatial position remains largely unchanged throughout the eruption. These findings demonstrate that the primary role of flux diffusion is to facilitate current sheet formation, highlighting the critical role of current sheet formation in eruption initiation.
format Preprint
id arxiv_https___arxiv_org_abs_2509_20040
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The role of photospheric magnetic flux diffusion in initiation of solar eruptions
Bian, Xinkai
Jiang, Chaowei
Wang, Yang
Zou, Peng
Feng, Xueshang
Zuo, Pingbing
Wang, Yi
Solar and Stellar Astrophysics
Space Physics
Solar eruptions may occur at different evolutionary stages of active regions, during which the photospheric motions manifest in various forms, including flux emergence, sunspot rotation, shearing, converging, and magnetic flux diffusion. However, it remains unclear what are the specific roles played by these different motions in leading to eruptions. Here, we employ high resolution magnetohydrodynamic simulations to demonstrate how solar eruptions can be initiated in a single bipolar configuration, driven by first shearing and then flux diffusion at the bottom surface. Flux diffusion disperses the photospheric magnetic flux, driving portions of it toward the polarity inversion line (PIL). This process leads to the expansion of core field, enhancing the pinching effect to form the current sheet. When magnetic reconnection occurs within this current sheet, the eruption is initiated, characterized by a rapid release of magnetic energy and accompanied by the formation of a erupting flux rope. Additionally, flux diffusion contributes to magnetic cancellation near the PIL, leading to the formation of a weakly twisted magnetic flux rope prior to the eruption. However, this pre-exist flux rope plays a limited role in eruption initiation, as its spatial position remains largely unchanged throughout the eruption. These findings demonstrate that the primary role of flux diffusion is to facilitate current sheet formation, highlighting the critical role of current sheet formation in eruption initiation.
title The role of photospheric magnetic flux diffusion in initiation of solar eruptions
topic Solar and Stellar Astrophysics
Space Physics
url https://arxiv.org/abs/2509.20040