The Sun’s Open–Closed Flux Boundary and the Origin of the Slow Solar Wind
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...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adcd65 |
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| author | Chloe P. Wilkins David I. Pontin Anthony R. Yeates Spiro K. Antiochos Hannah Schunker Bishnu Lamichhane |
| author_facet | Chloe P. Wilkins David I. Pontin Anthony R. Yeates Spiro K. Antiochos Hannah Schunker Bishnu Lamichhane |
| author_sort | Chloe P. Wilkins |
| collection | DOAJ |
| description | 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 | Article |
| id | doaj-art-d8bf949df4324625b77c784b0931ff7c |
| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-d8bf949df4324625b77c784b0931ff7c2025-08-20T03:13:36ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01985219010.3847/1538-4357/adcd65The Sun’s Open–Closed Flux Boundary and the Origin of the Slow Solar WindChloe P. Wilkins0https://orcid.org/0000-0002-0154-8380David I. Pontin1https://orcid.org/0000-0002-1089-9270Anthony R. Yeates2https://orcid.org/0000-0002-2728-4053Spiro K. Antiochos3https://orcid.org/0000-0003-0176-4312Hannah Schunker4https://orcid.org/0000-0001-9932-9559Bishnu Lamichhane5School of Information and Physical Sciences, University of Newcastle , University Drive, Callaghan, NSW 2308, AustraliaSchool of Information and Physical Sciences, University of Newcastle , University Drive, Callaghan, NSW 2308, AustraliaDepartment of Mathematical Sciences, Durham University , Durham, DH1 3LE, UKDepartment of Climate and Space Sciences and Engineering, University of Michigan , Ann Arbor, MI 48109, USASchool of Information and Physical Sciences, University of Newcastle , University Drive, Callaghan, NSW 2308, AustraliaSchool of Information and Physical Sciences, University of Newcastle , University Drive, Callaghan, NSW 2308, AustraliaThe 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.https://doi.org/10.3847/1538-4357/adcd65Slow solar windSolar coronaSolar coronal holesSolar magnetic fields |
| spellingShingle | Chloe P. Wilkins David I. Pontin Anthony R. Yeates Spiro K. Antiochos Hannah Schunker Bishnu Lamichhane The Sun’s Open–Closed Flux Boundary and the Origin of the Slow Solar Wind The Astrophysical Journal Slow solar wind Solar corona Solar coronal holes Solar magnetic fields |
| title | The Sun’s Open–Closed Flux Boundary and the Origin of the Slow Solar Wind |
| title_full | The Sun’s Open–Closed Flux Boundary and the Origin of the Slow Solar Wind |
| title_fullStr | The Sun’s Open–Closed Flux Boundary and the Origin of the Slow Solar Wind |
| title_full_unstemmed | The Sun’s Open–Closed Flux Boundary and the Origin of the Slow Solar Wind |
| title_short | The Sun’s Open–Closed Flux Boundary and the Origin of the Slow Solar Wind |
| title_sort | sun s open closed flux boundary and the origin of the slow solar wind |
| topic | Slow solar wind Solar corona Solar coronal holes Solar magnetic fields |
| url | https://doi.org/10.3847/1538-4357/adcd65 |
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