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| Titel |
A multipoint study of a substorm occurring on 7 December, 1992, and its theoretical implications |
| VerfasserIn |
N. J. Fox, S. W. H. Cowley, V. N. Davda, G. Enno, E. Friis-Christensen, R. A. Greenwald, M. R. Hairston, Mark Lester, M. Lockwood, H. Lühr, D. K. Milling, J. S. Murphree, M. Pinnock, G. D. Reeves |
| 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 ; 17, no. 11 ; Nr. 17, no. 11, S.1369-1384 |
| Datensatznummer |
250013831
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| Publikation (Nr.) |
 copernicus.org/angeo-17-1369-1999.pdf |
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| Zusammenfassung |
On 7 December 1992, a moderate substorm was
observed by a variety of satellites and ground-based instruments. Ionospheric
flows were monitored near dusk by the Goose Bay HF radar and near midnight by
the EISCAT radar. The observed flows are compared here with magnetometer
observations by the IMAGE array in Scandinavia and the two Greenland chains, the
auroral distribution observed by Freja and the substorm cycle observations by
the SABRE radar, the SAMNET magnetometer array and LANL geosynchronous
satellites. Data from Galileo Earth-encounter II are used to estimate the IMF Bz
component. The data presented show that the substorm onset electrojet at
midnight was confined to closed field lines equatorward of the pre-existing
convection reversal boundaries observed in the dusk and midnight regions. No
evidence of substantial closure of open flux was detected following this
substorm onset. Indeed the convection reversal boundary on the duskside
continued to expand equatorward after onset due to the continued presence of
strong southward IMF, such that growth and expansion phase features were
simultaneously present. Clear indications of closure of open flux were not
observed until a subsequent substorm intensification 25 min after the initial
onset. After this time, the substorm auroral bulge in the nightside hours
propagated well poleward of the pre-existing convection reversal boundary, and
strong flow perturbations were observed by the Goose Bay radar, indicative of
flows driven by reconnection in the tail.
Key words. Ionosphere (auroral ionosphere; plasma
convection) · Magnetospheric physics (storms and substorms) |
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