The basic solar wind speed distribution and its sunspot cycle variations
In this paper, it is suggested that the latitudinal solar wind speed observed by the Ulysses spacecraft during the lowest solar activity (when both the ecliptic and magnetic equators coincide) may be identified as the basic speed distribution throughout the solar cycle. We demonstrate this suggestio...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-04-01
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| Series: | Frontiers in Astronomy and Space Sciences |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fspas.2023.1129596/full |
| _version_ | 1797847586513616896 |
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| author | Syun-Ichi Akasofu Lou-Chuang Lee |
| author_facet | Syun-Ichi Akasofu Lou-Chuang Lee |
| author_sort | Syun-Ichi Akasofu |
| collection | DOAJ |
| description | In this paper, it is suggested that the latitudinal solar wind speed observed by the Ulysses spacecraft during the lowest solar activity (when both the ecliptic and magnetic equators coincide) may be identified as the basic speed distribution throughout the solar cycle. We demonstrate this suggestion by rotating this particular Ulysses distribution counterclockwise up to 70° in accordance with the rotation of the equivalent dipole axis during active periods of the cycle. The corresponding magnetic equator in the Carrington map latitude-longitude (27 days) becomes quasi-sinusoidal with respect to the ecliptic equator. The quasi-sinusoidal magnetic equator on the Carrington map and its modification associated with the degree of sunspot activities can explain the two high speed peaks (750–800 km/s) and the two lowest speed (350 km/s) during 27-day solar rotation periods, most clearly recognizable after the sunspot peak period. Thus, it may be not necessary to consider coronal holes or open regions as the source of high speed streams. In fact, this particular (lowest solar activity) Ulysses distribution may represent the speed distribution pattern by the basic generation process of the solar wind itself. |
| first_indexed | 2024-04-09T18:13:51Z |
| format | Article |
| id | doaj.art-c35e464ea4b24cba8b7d70d65b8bde34 |
| institution | Directory Open Access Journal |
| issn | 2296-987X |
| language | English |
| last_indexed | 2024-04-09T18:13:51Z |
| publishDate | 2023-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Astronomy and Space Sciences |
| spelling | doaj.art-c35e464ea4b24cba8b7d70d65b8bde342023-04-13T09:35:10ZengFrontiers Media S.A.Frontiers in Astronomy and Space Sciences2296-987X2023-04-011010.3389/fspas.2023.11295961129596The basic solar wind speed distribution and its sunspot cycle variationsSyun-Ichi Akasofu0Lou-Chuang Lee1International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, AK, United StatesInstitute of Earth Science, Academia Sinica, Taipei, TaiwanIn this paper, it is suggested that the latitudinal solar wind speed observed by the Ulysses spacecraft during the lowest solar activity (when both the ecliptic and magnetic equators coincide) may be identified as the basic speed distribution throughout the solar cycle. We demonstrate this suggestion by rotating this particular Ulysses distribution counterclockwise up to 70° in accordance with the rotation of the equivalent dipole axis during active periods of the cycle. The corresponding magnetic equator in the Carrington map latitude-longitude (27 days) becomes quasi-sinusoidal with respect to the ecliptic equator. The quasi-sinusoidal magnetic equator on the Carrington map and its modification associated with the degree of sunspot activities can explain the two high speed peaks (750–800 km/s) and the two lowest speed (350 km/s) during 27-day solar rotation periods, most clearly recognizable after the sunspot peak period. Thus, it may be not necessary to consider coronal holes or open regions as the source of high speed streams. In fact, this particular (lowest solar activity) Ulysses distribution may represent the speed distribution pattern by the basic generation process of the solar wind itself.https://www.frontiersin.org/articles/10.3389/fspas.2023.1129596/fullsolar windUlyssessolar cyclegeomagnetic stormsolar magnetic field |
| spellingShingle | Syun-Ichi Akasofu Lou-Chuang Lee The basic solar wind speed distribution and its sunspot cycle variations Frontiers in Astronomy and Space Sciences solar wind Ulysses solar cycle geomagnetic storm solar magnetic field |
| title | The basic solar wind speed distribution and its sunspot cycle variations |
| title_full | The basic solar wind speed distribution and its sunspot cycle variations |
| title_fullStr | The basic solar wind speed distribution and its sunspot cycle variations |
| title_full_unstemmed | The basic solar wind speed distribution and its sunspot cycle variations |
| title_short | The basic solar wind speed distribution and its sunspot cycle variations |
| title_sort | basic solar wind speed distribution and its sunspot cycle variations |
| topic | solar wind Ulysses solar cycle geomagnetic storm solar magnetic field |
| url | https://www.frontiersin.org/articles/10.3389/fspas.2023.1129596/full |
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