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| Titel |
Fluid and particle signatures of dayside reconnection |
| VerfasserIn |
T. M. Bauer, G. Paschmann, N. Sckopke, R. A. Treumann, W. Baumjohann, T.-D. Phan |
| 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 ; 19, no. 9 ; Nr. 19, no. 9, S.1045-1063 |
| Datensatznummer |
250014316
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| Publikation (Nr.) |
 copernicus.org/angeo-19-1045-2001.pdf |
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| Zusammenfassung |
Using measurements of the
AMPTE/IRM spacecraft, we study reconnection signatures at the dayside
magnetopause. If the magnetopause is open, it should have the properties of a
rotational discontinuity. Applying the fluid concept of a rotational
discontinuity, we check for the existence of a de Hoffmann-Teller frame and the
tangential stress balance (Walén relation). For 13 out of 40 magnetopause
crossings in a statistical survey we find a reasonable agreement between
observed plasma flows and those predicted by the Walén relation. In addition,
we check if the measured distribution functions show single particle signatures
which are expected on open field lines. We find the following types of
signatures: field-aligned streaming of ring current particles,
"D-shaped" distributions of solar wind particles, counterstreaming of
solar wind and cold ionospheric ions, two-beam distributions of solar wind
ions, and distributions of solar wind particles associated with field-aligned
heat flux. While a particular type of particle signature is observed only for
the minority of magnetopause crossings, 24 of the 40 crossings show at least
one type of signature. Both the particle signatures and the fit to the Walén
relation can be used to infer the sign of the normal magnetic field, Bn.
We find that the two ways of inferring the sign of Bn lead
primarily to the same result. Thus, both the particle signatures and a
reasonable agreement with the Walén relation can, in a statistical
sense, be considered as a useful indicator of open field lines. On the other
hand, many crossings do not show any reconnection signatures. We discuss the
possible reasons for their absence.
Key words. Magnetopause, cusp and
boundary layers; magnetosheath; solar wind – magnetosphere interactions |
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