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| Titel |
Ion escape from the high latitude magnetopause: analysis of oxygen and proton dynamics in the presence of magnetic turbulence |
| VerfasserIn |
A. Taktakishvili, G. Zimbardo, E. Amata, S. Savin, A. Greco, P. Veltri, R. E. Lopez |
| 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 ; 25, no. 8 ; Nr. 25, no. 8 (2007-08-29), S.1877-1885 |
| Datensatznummer |
250015903
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| Publikation (Nr.) |
 copernicus.org/angeo-25-1877-2007.pdf |
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| Zusammenfassung |
| Recent Cluster observations of the vicinity of the high latitude
magnetopause indicate the presence
of beams of singly charged oxygen ions, which are of ionospheric origin.
In this paper we examine the role of magnetic
turbulence combined with a dc electric field across the magnetopause in
causing the cross field transport of protons and of
singly charged oxygen ions, by means of a
kinetic test particle simulation.
We find that the observed values of magnetosheath turbulence and electric
fields can produce a substantial escape of the oxygen
ions relative to protons.
By varying the magnetic turbulence level in the simulation, we find
that the number of O+ crossing the magnetopause grows
with δB/B0, and that very few ions can cross the
magnetopause for δB/B0=0. The ion temperature also grows
with δB/B0, showing that magnetic turbulence is effective
in thermalizing the kinetic energy gain due to the cross-magnetopause
potential drop. We suggest that this mechanism can help to explain Cluster
observations of energetic oxygen ions during a high-latitude
magnetopause crossing. |
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