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Titel |
Effect of the solar wind conditions on the ionospheric equivalent current systems |
VerfasserIn |
J. J. Zhang, C. Wang, B. B. Tang, H. Li |
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 ; 31, no. 3 ; Nr. 31, no. 3 (2013-03-14), S.489-501 |
Datensatznummer |
250019009
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Publikation (Nr.) |
copernicus.org/angeo-31-489-2013.pdf |
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Zusammenfassung |
We employ a global magnetohydrodynamics (MHD) model, namely the PPMLR-MHD model,
to investigate the effect of the solar wind conditions, such as the
interplanetary magnetic field (IMF) clock angle, southward IMF magnitude and
solar wind speed, on the average pattern of the ionospheric equivalent
current systems (ECS). A new method to derive ECS from the MHD model is
proposed and applied, which takes account of the oblique magnetic field line
effects. The model results indicate that when the IMF is due northward, the
ECS are very weak while the current over polar region is stronger than the
lower latitude; when the IMF rotates southward, the two-cell current
system dominates, the eastward electrojet on the afternoon sector and the
westward electrojet on the dawn sector increase rapidly while the westward
electrojet is stronger than the eastward electrojet. Under southward IMF, the
intensity of the westward electrojet and eastward electrojet both increase
with the increase of the southward IMF magnitude and solar wind speed, and
the increase is very sharp for the westward electrojet. Furthermore, we
compare the geomagnetic perturbations on the ground represented by the
simulated average ECS with the observation-based statistical results under
similar solar wind conditions. It is found that the model results generally match with
the observations, but the underestimation of the eastward
equivalent current on the dusk sector is the main limitation of the present
model. |
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