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| Titel |
Magnetosheath dynamic pressure enhancements: occurrence and typical properties |
| VerfasserIn |
M. O. Archer, T. S. Horbury |
| 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 ; 31, no. 2 ; Nr. 31, no. 2 (2013-02-26), S.319-331 |
| Datensatznummer |
250018995
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| Publikation (Nr.) |
 copernicus.org/angeo-31-319-2013.pdf |
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| Zusammenfassung |
| The first comprehensive statistical study of large-amplitude (> 100%)
transient enhancements of the magnetosheath dynamic pressure reveals
events of up to ~ 15 times the ambient dynamic pressure with
durations up to 3 min and an average duration of around 30 s, predominantly
downstream of the quasi-parallel shock. The dynamic pressure transients
are most often dominated by velocity increases along with a small
fractional increase in the density, though the velocity is generally
only deflected by a few degrees. Superposed wavelet transforms of
the magnetic field show that, whilst most enhancements exhibit changes
in the magnetosheath magnetic field, the majority are not associated
with changes in the Interplanetary Magnetic Field (IMF). However,
there is a minority of enhancements that do appear to be associated
with solar wind discontinuities which cannot be explained simply by
random events. In general, it is found that during periods of magnetosheath
dynamic pressure enhancements the IMF is steadier than usual. This
suggests that a stable foreshock and hence foreshock structures or
processes may be important in the generation of the majority of magnetosheath
dynamic pressure enhancements. |
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