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| Titel |
Latitudinal profile of the ionospheric disturbance dynamo magnetic signature: comparison with the DP2 magnetic disturbance |
| VerfasserIn |
K. Z. Zaka, A. T. Kobea, P. Assamoi, O. K. Obrou, V. Doumbia, K. Boka, B. J.-P. Adohi, N. M. Mene |
| 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 ; 27, no. 9 ; Nr. 27, no. 9 (2009-09-24), S.3523-3536 |
| Datensatznummer |
250016647
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| Publikation (Nr.) |
 copernicus.org/angeo-27-3523-2009.pdf |
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| Zusammenfassung |
| During magnetic storms, the auroral electrojets intensification affects the
thermospheric circulation on a global scale. This process which leads to
electric field and current disturbance at middle and low latitudes, on the
quiet day after the end of a storm, has been attributed to the ionospheric
disturbance dynamo (Ddyn). The magnetic field disturbance observed as a
result of this process is the reduction of the H component amplitude in the
equatorial region which constitutes the main characteristic of the
ionospheric disturbance dynamo process, associated with a westward electric
current flow. The latitudinal profile of the Ddyn disturbance dynamo magnetic
signature exhibits an eastward current at mid latitudes and a westward one at
low latitudes with a substantial amplification at the magnetic equator. Such
current flow reveals an "anti-Sq" system established between the mid
latitudes and the equatorial region and opposes the normal Sq current vortex.
However, the localization of the eastward current and consequently the
position and the extent of the "anti-Sq" current vortex changes from one
storm to another. Indeed, for a strong magnetic storm, the eastward current
is well established at mid latitudes about 45° N and for a weak magnetic
storm, the eastward current is established toward the high latitudes (about
60° N), near the Joule heating region, resulting in a large
"anti-Sq"
current cell. The latitudinal profile of the Ddyn disturbance as well as the
magnetic disturbance DP2 generated by the mechanism of prompt penetration of
the magnetospheric convection electric field in general, show a weak
disturbance at the low latitudes with a substantial amplification at the
magnetic equator. Due to the intensity of the storm, the magnitude of the DP2
appears higher than the Ddyn over the American and Asian sector contrary to
the African sector. |
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