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| Titel |
Multispacecraft observations of the terrestrial bow shock and magnetopause during extreme solar wind disturbances |
| VerfasserIn |
M. Tátrallyay, G. Erdős, Z. Nemeth, M. I. Verigin, S. Vennerstrøm |
| 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 ; 30, no. 12 ; Nr. 30, no. 12 (2012-12-12), S.1675-1692 |
| Datensatznummer |
250017294
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| Publikation (Nr.) |
 copernicus.org/angeo-30-1675-2012.pdf |
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| Zusammenfassung |
| Three events are discussed from the declining phase of the last solar cycle when the magnetopause
and/or the bow shock were observed unusually close to the Earth due to major interplanetary
disturbances. The observed extreme locations of the
discontinuities are compared with the predictions of three magnetopause and four bow shock models which describe
them in considerably different ways using statistical methods based on observations. A new 2-D magnetopause model
is introduced (based on Verigin et al., 2009) which takes into account the pressure of the compressed
magnetosheath field raised by the interplanetary magnetic field (IMF) component transverse to the solar
wind flow. The observed magnetopause crossings could be predicted with a reasonable accuracy (0.1–0.2 RE)
by one of the presented models at least.
For geosynchronous magnetopause crossings observed by the GOES satellites, (1) the new model provided the best predictions
when the IMF was extremely large having a large negative Bz component, and (2) the predictions of the model of
Shue et al. (1998) agreed best with the observations when the solar wind dynamic pressure was extremely large.
The magnetopause crossings close to the cusp observed by the Cluster spacecraft were best predicted by the
3-D model of Lin et al. (2010). The applied empirical bow shock models and the 3-D semi-empiric bow shock model
combined with magnetohydrodynamic (MHD) solution proved to be insufficient for predicting the observed unusual bow shock locations
during large interplanetary disturbances.
The results of a global 3-D MHD model were in good agreement with the Cluster observations on 17 January 2005,
but they did not predict the bow shock crossings on 31 October 2003. |
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