Sources of solar wind over the solar activity cycle
Fast solar wind has been recognized, about 40 years ago, to originate in polar coronal holes (CHs), that, since then, have been identified with sources of recurrent high speed wind streams. As of today, however, there is no general consensus about whether there are, within CHs, preferential location...
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| Format: | Article |
| Language: | English |
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Elsevier
2013-05-01
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| Series: | Journal of Advanced Research |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2090123212000653 |
| _version_ | 1818269300341866496 |
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| author | Giannina Poletto |
| author_facet | Giannina Poletto |
| author_sort | Giannina Poletto |
| collection | DOAJ |
| description | Fast solar wind has been recognized, about 40 years ago, to originate in polar coronal holes (CHs), that, since then, have been identified with sources of recurrent high speed wind streams. As of today, however, there is no general consensus about whether there are, within CHs, preferential locations where the solar wind is accelerated. Knowledge of slow wind sources is far from complete as well. Slow wind observed in situ can be traced back to its solar source by backward extrapolation of magnetic fields whose field lines are streamlines of the outflowing plasma. However, this technique often has not the necessary precision for an indisputable identification of the region where wind originates. As the Sun progresses through its activity cycle, different wind sources prevail and contribute to filling the heliosphere. Our present knowledge of different wind sources is here summarized. Also, a Section addresses the problem of wind acceleration in the low corona, as inferred from an analysis of UV data, and illustrates changes between fast and slow wind profiles and possible signatures of changes along the solar cycle. A brief reference to recent work about the deep roots of solar wind and their changes over different solar cycles concludes the review. |
| first_indexed | 2024-12-12T20:52:12Z |
| format | Article |
| id | doaj.art-71c63bc0c2c64ff6bc4fc4e47f88c91b |
| institution | Directory Open Access Journal |
| issn | 2090-1232 2090-1224 |
| language | English |
| last_indexed | 2024-12-12T20:52:12Z |
| publishDate | 2013-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Advanced Research |
| spelling | doaj.art-71c63bc0c2c64ff6bc4fc4e47f88c91b2022-12-22T00:12:23ZengElsevierJournal of Advanced Research2090-12322090-12242013-05-014321522010.1016/j.jare.2012.08.007Sources of solar wind over the solar activity cycleGiannina PolettoFast solar wind has been recognized, about 40 years ago, to originate in polar coronal holes (CHs), that, since then, have been identified with sources of recurrent high speed wind streams. As of today, however, there is no general consensus about whether there are, within CHs, preferential locations where the solar wind is accelerated. Knowledge of slow wind sources is far from complete as well. Slow wind observed in situ can be traced back to its solar source by backward extrapolation of magnetic fields whose field lines are streamlines of the outflowing plasma. However, this technique often has not the necessary precision for an indisputable identification of the region where wind originates. As the Sun progresses through its activity cycle, different wind sources prevail and contribute to filling the heliosphere. Our present knowledge of different wind sources is here summarized. Also, a Section addresses the problem of wind acceleration in the low corona, as inferred from an analysis of UV data, and illustrates changes between fast and slow wind profiles and possible signatures of changes along the solar cycle. A brief reference to recent work about the deep roots of solar wind and their changes over different solar cycles concludes the review.http://www.sciencedirect.com/science/article/pii/S2090123212000653Solar windCoronal holesActive regionsStreamersDoppler dimming |
| spellingShingle | Giannina Poletto Sources of solar wind over the solar activity cycle Journal of Advanced Research Solar wind Coronal holes Active regions Streamers Doppler dimming |
| title | Sources of solar wind over the solar activity cycle |
| title_full | Sources of solar wind over the solar activity cycle |
| title_fullStr | Sources of solar wind over the solar activity cycle |
| title_full_unstemmed | Sources of solar wind over the solar activity cycle |
| title_short | Sources of solar wind over the solar activity cycle |
| title_sort | sources of solar wind over the solar activity cycle |
| topic | Solar wind Coronal holes Active regions Streamers Doppler dimming |
| url | http://www.sciencedirect.com/science/article/pii/S2090123212000653 |
| work_keys_str_mv | AT gianninapoletto sourcesofsolarwindoverthesolaractivitycycle |