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| Titel |
Solar wind - magnetosphere coupling efficiency during ejecta and sheath region driven geomagnetic storms |
| VerfasserIn |
Minna Myllys, Emilia Kilpua, Benoit Lavraud |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250128923
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| Publikation (Nr.) |
 EGU/EGU2016-8969.pdf |
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| Zusammenfassung |
| We have investigated the effect of key solar wind driving parameters on solar wind-
magnetosphere coupling efficiency during sheath and magnetic cloud driven storms. The
particular focus of the study was on the coupling efficiency dependence with Alfven Mach
number (MA). The efficiency has been estimated using the dawn-dusk component of the
interplanetary electric field (EY ), Newell and Borovsky functions as a proxy for the energy
inflow and the polar cap potential (PCN), auroral electrojet (AE) and SYM-H indices as the
measure of the energy output. We have also performed a time delay analysis between the
input parameters and the geomagnetic indices.
We demonstrate that the PCN index distinctively shows both a MA dependent saturation
and a MA-independent saturation, pointing to the existence of at least two underlying
physical mechanisms for the saturation of the index. By contrast, we show that the AE index
saturates, but that the saturation of this index is independent of the solar wind MA. Finally
we find that the SYM-H index does not seem to saturate and that the absence of saturation is
independent of the MA regime. |
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