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| Titel |
The non-linearity of the cross-polar cap potential during high solar wind driving: GUMICS-4 results |
| VerfasserIn |
Antti Lakka, Tuija Pulkkinen, Andrew Dimmock, Ilja Honkonen, Minna Palmroth |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250151407
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| Publikation (Nr.) |
 EGU/EGU2017-15986.pdf |
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| Zusammenfassung |
| We study the influence of the solar wind driving on the cross-polar cap potential
(CPCP) using the Grand Unified Magnetosphere-Ionosphere Coupling Simulation
(GUMICS-4), the only European global MHD simulation developed by the Finnish
Meteorological Institute. The CPCP is a key parameter in describing the energy
input from the solar wind to the magnetosphere as it couples directly the solar wind
to the ionosphere. While it is generally accepted that the response of the CPCP to
the solar wind electric field Y component is nonlinear, the process associated with
the nonlinearity of the coupling remains an open issue.
We use artificial solar wind data in order to mimic weak and strong solar wind
driving in GUMICS-4 by combining high and low IMF magnitudes with high and
low Mach number values by means of varying IMF By and Bz and solar wind
plasma flow speed. The duration of every simulation run was 5 hours containing a
stepwise changing plasma flow speed every one hour from 350 km/s to 750 km/s in
100 km/s steps. The magnitude of the IMF magnitude remained constant in every
simulation run, however five different values (3.5 nT, 7 nT, 10 nT, 20 nT, 30 nT)
were used thus making it a total of five simulation runs.
This study contributes to explaining processes leading to the CPCP non-linear
response to the solar wind electric field Y component and, most importantly, in
which part of the system the nonlinearity arises. |
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