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Main Authors: Wilkins, Chloe P., Pontin, David I., Yeates, Anthony R., Antiochos, Spiro K., Schunker, Hannah, Lamichhane, Bishnu
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2503.09744
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author Wilkins, Chloe P.
Pontin, David I.
Yeates, Anthony R.
Antiochos, Spiro K.
Schunker, Hannah
Lamichhane, Bishnu
author_facet Wilkins, Chloe P.
Pontin, David I.
Yeates, Anthony R.
Antiochos, Spiro K.
Schunker, Hannah
Lamichhane, Bishnu
contents The Sun's open-closed flux boundary (OCB) separates closed and open magnetic field lines, and is the site for interchange magnetic reconnection processes thought to be linked to the origin of the slow solar wind (SSW). We analyze the global magnetic field structure and OCB from 2010 December to 2019 December using three coronal magnetic field models: a potential-field source-surface (PFSS) model, a static equilibrium magnetofrictional model, and a time-dependent magnetofrictional model. We analyze the model and cycle dependence of the OCB length on the photosphere, as well as the magnetic flux in the vicinity of the OCB. Near solar maximum, the coronal magnetic field for each model consists predominantly of long, narrow coronal holes, and nearly all the open flux lies within 1 supergranule diameter (25 Mm) of the OCB. By comparing to interplanetary scintillation measurements of SSW speeds, we argue that the fraction of open flux within this 25 Mm band is a good predictor of the amount of SSW in the heliosphere. Importantly, despite its simplicity, we show that the PFSS model estimates this fraction as well as the time-dependent model. We discuss the implications of our results for understanding SSW origins and interchange reconnection at the OCB.
format Preprint
id arxiv_https___arxiv_org_abs_2503_09744
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Sun's open-closed flux boundary and the origin of the slow solar wind
Wilkins, Chloe P.
Pontin, David I.
Yeates, Anthony R.
Antiochos, Spiro K.
Schunker, Hannah
Lamichhane, Bishnu
Solar and Stellar Astrophysics
The Sun's open-closed flux boundary (OCB) separates closed and open magnetic field lines, and is the site for interchange magnetic reconnection processes thought to be linked to the origin of the slow solar wind (SSW). We analyze the global magnetic field structure and OCB from 2010 December to 2019 December using three coronal magnetic field models: a potential-field source-surface (PFSS) model, a static equilibrium magnetofrictional model, and a time-dependent magnetofrictional model. We analyze the model and cycle dependence of the OCB length on the photosphere, as well as the magnetic flux in the vicinity of the OCB. Near solar maximum, the coronal magnetic field for each model consists predominantly of long, narrow coronal holes, and nearly all the open flux lies within 1 supergranule diameter (25 Mm) of the OCB. By comparing to interplanetary scintillation measurements of SSW speeds, we argue that the fraction of open flux within this 25 Mm band is a good predictor of the amount of SSW in the heliosphere. Importantly, despite its simplicity, we show that the PFSS model estimates this fraction as well as the time-dependent model. We discuss the implications of our results for understanding SSW origins and interchange reconnection at the OCB.
title The Sun's open-closed flux boundary and the origin of the slow solar wind
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2503.09744