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Titel |
The dynamic cusp at low altitudes: a case study utilizing Viking, DMSP-F7, and Sondrestrom incoherent scatter radar observations |
VerfasserIn |
J. Watermann, O. Beaujardiere, D. Lummerzheim, J. Woch, P. T. Newell, T. A. Potemra, F. J. Rich, M. Shapshak |
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 ; 12, no. 12 ; Nr. 12, no. 12, S.1144-1157 |
Datensatznummer |
250011245
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Publikation (Nr.) |
copernicus.org/angeo-12-1144-1994.pdf |
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Zusammenfassung |
Coincident multi-instrument magnetospheric
and ionospheric observations have made it possible to determine the position of
the ionospheric footprint of the magnetospheric cusp and to monitor its
evolution over time. The data used include charged particle and magnetic field
measurements from the Earth-orbiting Viking and DMSP-F7 satellites, electric
field measurements from Viking, interplanetary magnetic field and plasma data
from IMP-8, and Sondrestrom incoherent scatter radar observations of the
ionospheric plasma density, temperature, and convection. Viking detected cusp
precipitation poleward of 75.5° invariant latitude. The ionospheric response to
the observed electron precipitation was simulated using an auroral model. It
predicts enhanced plasma density and elevated electron temperature in the upper E-
and F-regions. Sondrestrom radar observations are in agreement with the
predictions. The radar detected a cusp signature on each of five consecutive
antenna elevation scans covering 1.2 h local time. The cusp appeared to be about
2° invariant latitude wide, and its ionospheric footprint shifted equatorward
by nearly 2° during this time, possibly influenced by an overall decrease in
the IMF Bz component. The radar plasma drift data and
the Viking magnetic and electric field data suggest that the cusp was associated
with a continuous, rather than a patchy, merging between the IMF and the
geomagnetic field. |
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