Coronal Field Geometry and Solar Wind Speed
The Wang–Sheeley–Arge (WSA) solar wind (SW) model is based on the idea that weakly expanding coronal magnetic field tubes are associated with sources of fast SWs and vice versa. A parameter called the “flux tube expansion” (FTE) is used to determine the degree of expansion of magnetic tubes. The FTE...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-12-01
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| Series: | Universe |
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| Online Access: | https://www.mdpi.com/2218-1997/8/12/646 |
| _version_ | 1797455016569602048 |
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| author | Ivan Berezin Andrey Tlatov |
| author_facet | Ivan Berezin Andrey Tlatov |
| author_sort | Ivan Berezin |
| collection | DOAJ |
| description | The Wang–Sheeley–Arge (WSA) solar wind (SW) model is based on the idea that weakly expanding coronal magnetic field tubes are associated with sources of fast SWs and vice versa. A parameter called the “flux tube expansion” (FTE) is used to determine the degree of expansion of magnetic tubes. The FTE is calculated based on the coronal magnetic field model, usually in the potential approximation. The second input parameter for the WSA model is the great circle distance from the base of the open magnetic field line in the photosphere to the boundary of the corresponding coronal hole (DCHB). These two coronal magnetic field parameters are related by an empirical relationship with the solar wind velocity near the Sun. The WSA model has shortcomings and does not fully explain the solar wind formation mechanisms. In the present work, we model various coronal magnetic field parameters in the potential-field source-surface (PFSS) approximation from a long series of magnetographic observations: the Solar Telescope-magnetograph for Operative Prognoses (STOP) (Kislovodsk Mountain Astronomical Station), the Helioseismic and magnetic imager (SDO/HMI), and data from the Wilcox Solar Observatory (WSO). Our main goal is to identify correlations between the coronal magnetic field parameters and the observed SW velocity in order to use them for modeling SW. We found that the SW velocity correlates relatively well with some geometric properties of the magnetic tubes, including the force line length, the latitude of the force line footpoints, and the DCHB. We propose a formula for calculating the SW velocity based on these parameters. The presented relationship does not use FTE and showed a better correlation with observations compared to the WSA model. |
| first_indexed | 2024-03-09T15:46:28Z |
| format | Article |
| id | doaj.art-24cb20719142420a8bac479acef5bfeb |
| institution | Directory Open Access Journal |
| issn | 2218-1997 |
| language | English |
| last_indexed | 2024-03-09T15:46:28Z |
| publishDate | 2022-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Universe |
| spelling | doaj.art-24cb20719142420a8bac479acef5bfeb2023-11-24T18:29:28ZengMDPI AGUniverse2218-19972022-12-0181264610.3390/universe8120646Coronal Field Geometry and Solar Wind SpeedIvan Berezin0Andrey Tlatov1Kislovodsk Mountain Astronomical Station of the Pulkovo Observatory, Gagarina Str. 100, 357700 Kislovodsk, RussiaKislovodsk Mountain Astronomical Station of the Pulkovo Observatory, Gagarina Str. 100, 357700 Kislovodsk, RussiaThe Wang–Sheeley–Arge (WSA) solar wind (SW) model is based on the idea that weakly expanding coronal magnetic field tubes are associated with sources of fast SWs and vice versa. A parameter called the “flux tube expansion” (FTE) is used to determine the degree of expansion of magnetic tubes. The FTE is calculated based on the coronal magnetic field model, usually in the potential approximation. The second input parameter for the WSA model is the great circle distance from the base of the open magnetic field line in the photosphere to the boundary of the corresponding coronal hole (DCHB). These two coronal magnetic field parameters are related by an empirical relationship with the solar wind velocity near the Sun. The WSA model has shortcomings and does not fully explain the solar wind formation mechanisms. In the present work, we model various coronal magnetic field parameters in the potential-field source-surface (PFSS) approximation from a long series of magnetographic observations: the Solar Telescope-magnetograph for Operative Prognoses (STOP) (Kislovodsk Mountain Astronomical Station), the Helioseismic and magnetic imager (SDO/HMI), and data from the Wilcox Solar Observatory (WSO). Our main goal is to identify correlations between the coronal magnetic field parameters and the observed SW velocity in order to use them for modeling SW. We found that the SW velocity correlates relatively well with some geometric properties of the magnetic tubes, including the force line length, the latitude of the force line footpoints, and the DCHB. We propose a formula for calculating the SW velocity based on these parameters. The presented relationship does not use FTE and showed a better correlation with observations compared to the WSA model.https://www.mdpi.com/2218-1997/8/12/646solar windsolar coronasolar magnetic fields |
| spellingShingle | Ivan Berezin Andrey Tlatov Coronal Field Geometry and Solar Wind Speed Universe solar wind solar corona solar magnetic fields |
| title | Coronal Field Geometry and Solar Wind Speed |
| title_full | Coronal Field Geometry and Solar Wind Speed |
| title_fullStr | Coronal Field Geometry and Solar Wind Speed |
| title_full_unstemmed | Coronal Field Geometry and Solar Wind Speed |
| title_short | Coronal Field Geometry and Solar Wind Speed |
| title_sort | coronal field geometry and solar wind speed |
| topic | solar wind solar corona solar magnetic fields |
| url | https://www.mdpi.com/2218-1997/8/12/646 |
| work_keys_str_mv | AT ivanberezin coronalfieldgeometryandsolarwindspeed AT andreytlatov coronalfieldgeometryandsolarwindspeed |