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Titel |
Ring current and auroral electrojets in connection with interplanetary medium parameters during magnetic storm |
VerfasserIn |
Y. I. Feldstein, A. E. Levitin, S. A. Golyshev, L. A. Dremukhina, U. B. Vestchezerova, T. E. Valchuk, A. Grafe |
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. 7 ; Nr. 12, no. 7, S.602-611 |
Datensatznummer |
250010969
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Publikation (Nr.) |
copernicus.org/angeo-12-602-1994.pdf |
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Zusammenfassung |
The relationship between the auroral
electrojet indices (AE) and the ring current magnetic field (DR)
was investigated by observations obtained during the magnetic storm on 1-3 April
1973. During the storm main phase the DR development is accompanied by a
shift of the auroral electrojets toward the equator. As a result, the standard AE
indices calculated on the basis of data from auroral observatories was
substantially lower than the real values (AE'). To determine AE'
during the course of a storm main phase data from subauroral magnetic
observatories should be used. It is shown that the intensity of the indices (AE')
which take into account the shift of the electrojets is increased substantially
relative to the standard indices during the storm main phase. AE' values
are closely correlated with geoeffective solar wind parameters. A high
correlation was obtained between AE' and the energy flux into the ring
current during the storm main phase. Analysis of magnetic field variations
during intervals with intense southward IMF components demonstrates a decrease
of the saturation effect of auroral electrojet currents if subauroral stations
magnetic field variations are taken into account. This applies both to case
studies and statistical data. The dynamics of the electrojets in connection with
the development of the ring current and of magnetospheric substorms can be
described by the presence (absence) of saturation for minimum (maximum) AE
index values during a 1-h interval. The ring current magnetic field asymmetry (ASY)
was calculated as the difference between the maximum and minimum field values
along a parallel of latitude at low latitudes. The ASY value is closely
correlated with geoeffective solar wind parameters and simultaneously is a more
sensitive indicator of IMF Bz variations than the symmetric
ring current. ASY increases (decreases) faster during the main phase (the
recovery phase) than DR. The magnetic field decay at low latitudes in the
recovery phase occurs faster in the afternoon sector than at dusk. |
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