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| Titel |
Coronal mass ejections, type II radio bursts, and solar energetic particle events in the SOHO era |
| VerfasserIn |
N. Gopalswamy, S. Yashiro, S. Akiyama, P. Mäkelä, H. Xie, M. L. Kaiser, R. A. Howard, J. L. Bougeret |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 26, no. 10 ; Nr. 26, no. 10 (2008-10-15), S.3033-3047 |
| Datensatznummer |
250016251
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| Publikation (Nr.) |
 copernicus.org/angeo-26-3033-2008.pdf |
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| Zusammenfassung |
| Using the extensive and uniform data on coronal mass ejections (CMEs), solar
energetic particle (SEP) events, and type II radio bursts during the SOHO
era, we discuss how the CME properties such as speed, width and solar-source
longitude decide whether CMEs are associated with type II radio bursts and
SEP events. We discuss why some radio-quiet CMEs are associated with small
SEP events while some radio-loud CMEs are not associated with SEP events. We
conclude that either some fast and wide CMEs do not drive shocks or they
drive weak shocks that do not produce significant levels of particle
acceleration. We also infer that the Alfvén speed in the corona and
near-Sun interplanetary medium ranges from <200 km/s to ~1600 km/s.
Radio-quiet fast and wide CMEs are also poor SEP producers and the
association rate of type II bursts and SEP events steadily increases with
CME speed and width (i.e. energy). If we consider western hemispheric CMEs,
the SEP association rate increases linearly from ~30% for 800 km/s
CMEs to 100% for ≥1800 km/s. Essentially all type II bursts in the
decametre-hectometric (DH) wavelength range are associated with SEP events
once the source location on the Sun is taken into account. This is a
significant result for space weather applications, because if a CME
originating from the western hemisphere is accompanied by a DH type II
burst, there is a high probability that it will produce an SEP event. |
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