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| Titel |
A numerical method to compute Euler potentials for non dipolar magnetic fields |
| VerfasserIn |
C. Peymirat, D. Fontaine |
| 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 ; 17, no. 3 ; Nr. 17, no. 3, S.328-337 |
| Datensatznummer |
250013689
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| Publikation (Nr.) |
 copernicus.org/angeo-17-328-1999.pdf |
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| Zusammenfassung |
The magnetospheric magnetic field may be
conveniently described by two scalar functions (α, β),
known as the Euler potentials. They are not uniquely defined, and they may be
difficult to derive for configuration more complex than a simple dipole. We
propose here a simple numerical method to compute one possible pair
(α, β). In magnetospheric regions of closed field lines,
α can be chosen as a function of the tube volume of unit magnetic
flux. The method can be applied to a wide class of magnetic fields which
describe the magnetospheric domain of closed field lines and the conjugated
ionosphere. Here, it is used with the T87 Tsyganenko model. The results coincide
with the dipolar potentials at close distances from the Earth. At larger
distances, they display an increasing distortion with the radial distance (or
the invariant latitude in the ionosphere) and the magnetic activity. In the
magnetosphere, the contours of α and β are stretched
towards the nightside. In the ionosphere, they also extend towards the nightside
and present major distortions in a narrow ring at the polar cap boundary, which
maps distant boundary layers in the magnetosphere.
Key words. Ionosphere (ionosphere-magnetosphere
interactions; modeling and forecasting). Magnetospheric physics (plasma
convection). |
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