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| Titel |
The location of the open-closed magnetic field line boundary in the dawn sector auroral ionosphere |
| VerfasserIn |
J. A. Wild, S. E. Milan, C. J. Owen, J. M. Bosqued, Mark Lester, D. M. Wright, H. Frey, C. W. Carlson, A. N. Fazakerley, H. Rème |
| 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. 10 ; Nr. 22, no. 10 (2004-11-03), S.3625-3639 |
| Datensatznummer |
250015036
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| Publikation (Nr.) |
 copernicus.org/angeo-22-3625-2004.pdf |
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| Zusammenfassung |
| As a measure of the degree of coupling between the solar
wind-magnetosphere-ionosphere systems, the rate at which the size of the
polar cap (the region corresponding to ionospheric termini of open magnetic
flux tubes) varies is of prime importance. However, a reliable technique by
which the extent of the polar cap might be routinely monitored has yet to be
developed. Current techniques provide particularly ambiguous indications of
the polar cap boundary in the dawn sector. We present a case study of space-
and ground-based observations of the dawn-sector auroral zone and attempt to
determine the location of the polar cap boundary using multi-wavelength
observations of the ultraviolet aurora (made by the IMAGE FUV imager),
precipitating particle measurements (recorded by the FAST, DMSP, and
Cluster 1 and 3 satellites), and SuperDARN HF radar observations of the ionospheric
Doppler spectral width boundary. We conclude that in the dawn sector, during
the interval presented, neither the poleward edge of the wideband auroral UV
emission (140-180nm) nor the Doppler spectral width boundary were
trustworthy indicators of the polar cap boundary location, while narrow band
UV emissions in the range 130-140nm appear to be much more reliable. |
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