An Analytical Model of Turbulence in Parker Spiral Geometry and Associated Magnetic Field Line Lengths
Understanding the magnetic connections from the Sun to interplanetary space is crucial for linking in situ particle observations with the solar source regions of the particles. A simple connection along the large-scale Parker spiral magnetic field is made complex by the turbulent random walk of fiel...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/aca892 |
| _version_ | 1797701292234113024 |
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| author | T. Laitinen S. Dalla C. O. G. Waterfall A. Hutchinson |
| author_facet | T. Laitinen S. Dalla C. O. G. Waterfall A. Hutchinson |
| author_sort | T. Laitinen |
| collection | DOAJ |
| description | Understanding the magnetic connections from the Sun to interplanetary space is crucial for linking in situ particle observations with the solar source regions of the particles. A simple connection along the large-scale Parker spiral magnetic field is made complex by the turbulent random walk of field lines. In this paper, we present the first analytical model of heliospheric magnetic fields where the dominant 2D component of the turbulence is transverse to the Parker spiral. The 2D wave field is supplemented with a minor wave field component that has asymptotic slab geometry at small and large heliocentric distances. We show that turbulence spreads field lines from a small source region at the Sun to a 60° heliolongitudinal and heliolatitudinal range at 1 au, with a standard deviation of the angular spread of the field lines of 14°. Small source regions map to an intermittent range of longitudes and latitudes at 1 au, consistent with dropouts in solar energetic particle intensities. The lengths of the field lines are significantly extended from the nominal Parker spiral length of 1.17 au up to 1.6 au, with field lines from sources at and behind the west limb considerably longer than those closer to the solar disk center. We discuss the implications of our findings for understanding charged particle propagation and the importance of understanding the turbulence properties close to the Sun. |
| first_indexed | 2024-03-12T04:34:17Z |
| format | Article |
| id | doaj.art-e8ae078a16384d17b4f662d6083c97a7 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T04:34:17Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-e8ae078a16384d17b4f662d6083c97a72023-09-03T09:58:14ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01943210810.3847/1538-4357/aca892An Analytical Model of Turbulence in Parker Spiral Geometry and Associated Magnetic Field Line LengthsT. Laitinen0https://orcid.org/0000-0002-7719-7783S. Dalla1https://orcid.org/0000-0002-7837-5780C. O. G. Waterfall2https://orcid.org/0000-0003-4390-2920A. Hutchinson3https://orcid.org/0000-0002-9362-7165Jeremiah Horrocks Institute, University of Central Lancashire, UKJeremiah Horrocks Institute, University of Central Lancashire, UKJeremiah Horrocks Institute, University of Central Lancashire, UKJeremiah Horrocks Institute, University of Central Lancashire, UKUnderstanding the magnetic connections from the Sun to interplanetary space is crucial for linking in situ particle observations with the solar source regions of the particles. A simple connection along the large-scale Parker spiral magnetic field is made complex by the turbulent random walk of field lines. In this paper, we present the first analytical model of heliospheric magnetic fields where the dominant 2D component of the turbulence is transverse to the Parker spiral. The 2D wave field is supplemented with a minor wave field component that has asymptotic slab geometry at small and large heliocentric distances. We show that turbulence spreads field lines from a small source region at the Sun to a 60° heliolongitudinal and heliolatitudinal range at 1 au, with a standard deviation of the angular spread of the field lines of 14°. Small source regions map to an intermittent range of longitudes and latitudes at 1 au, consistent with dropouts in solar energetic particle intensities. The lengths of the field lines are significantly extended from the nominal Parker spiral length of 1.17 au up to 1.6 au, with field lines from sources at and behind the west limb considerably longer than those closer to the solar disk center. We discuss the implications of our findings for understanding charged particle propagation and the importance of understanding the turbulence properties close to the Sun.https://doi.org/10.3847/1538-4357/aca892Interplanetary turbulenceInterplanetary physicsHeliosphere |
| spellingShingle | T. Laitinen S. Dalla C. O. G. Waterfall A. Hutchinson An Analytical Model of Turbulence in Parker Spiral Geometry and Associated Magnetic Field Line Lengths The Astrophysical Journal Interplanetary turbulence Interplanetary physics Heliosphere |
| title | An Analytical Model of Turbulence in Parker Spiral Geometry and Associated Magnetic Field Line Lengths |
| title_full | An Analytical Model of Turbulence in Parker Spiral Geometry and Associated Magnetic Field Line Lengths |
| title_fullStr | An Analytical Model of Turbulence in Parker Spiral Geometry and Associated Magnetic Field Line Lengths |
| title_full_unstemmed | An Analytical Model of Turbulence in Parker Spiral Geometry and Associated Magnetic Field Line Lengths |
| title_short | An Analytical Model of Turbulence in Parker Spiral Geometry and Associated Magnetic Field Line Lengths |
| title_sort | analytical model of turbulence in parker spiral geometry and associated magnetic field line lengths |
| topic | Interplanetary turbulence Interplanetary physics Heliosphere |
| url | https://doi.org/10.3847/1538-4357/aca892 |
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