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| Titel |
A possible origin of dayside Pc1 magnetic pulsations observed at high latitudes |
| VerfasserIn |
V. Safargaleev, A. Serebryanskaya, A. Koustov, Mark Lester, E. Pchelkina, A. Vasilyev |
| 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 ; 22, no. 8 ; Nr. 22, no. 8 (2004-09-07), S.2997-3008 |
| Datensatznummer |
250014981
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| Publikation (Nr.) |
 copernicus.org/angeo-22-2997-2004.pdf |
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| Zusammenfassung |
| Induction magnetometer observations of dayside Pc1 activity at Barentsburg
(BAB, Spitsbergen archipelago, 78.05°N, 14.12°E) are combined
with data from two magnetometers located in Scandinavia and the Kola
peninsula. Seven events with very large negative IMF Bz components were
considered. For all of the events, the cusp location was expected to be
significantly shifted equatorward from the statistical position such that
the BAB magnetometer was located well inside the polar cap. The DMSP
particle data indicated that the BAB magnetometer was indeed inside the
polar cap, whereas other magnetometers were collocated with the ionospheric
projections of the cusp, the low-latitude boundary layer or the boundary
plasma sheet. Pc1 magnetic pulsations were observed only at BAB. In three
cases, for which SuperDARN convection data were available, the Pc1 activity
correlated with intervals of large-scale convection reconfiguration, such
that the plasma flow crossing the BAB location was associated with newly-reconnected
magnetic flux tubes drifting tailward. The convection
reconfigurations were in response to a decrease in the IMF By component. We
argue that the source of the observed Pc1 pulsations is anisotropic plasma
of the depletion layer within the magnetosheath. The plasma anisotropy
supports the excitation of electromagnetic ion cyclotron waves that are
detectable with a ground-based magnetometer when the flux tubes containing
the unstable plasma become connected to the Earth's ionosphere in the course
of the dayside reconnection processes. |
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