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| Titel |
A new method for solving the MHD equations in the magnetosheath |
| VerfasserIn |
C. Nabert, K.-H. Glassmeier, F. Plaschke |
| 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 (2013-03-05), S.419-437 |
| Datensatznummer |
250019003
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| Publikation (Nr.) |
 copernicus.org/angeo-31-419-2013.pdf |
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| Zusammenfassung |
| We present a new analytical method to derive steady-state magnetohydrodynamic (MHD) solutions of
the magnetosheath in different levels of approximation. With this method, we
calculate the magnetosheath's density, velocity, and magnetic field
distribution as well as its geometry. Thereby, the solution depends on the
geomagnetic dipole moment and solar wind conditions only. To simplify the
representation, we restrict our model to northward IMF with the solar wind
flow along the stagnation streamline. The sheath's geometry, with its
boundaries, bow shock and magnetopause, is determined self-consistently. Our
model is stationary and time relaxation has not to be considered as in global
MHD simulations. Our method uses series expansion to transfer the MHD
equations into a new set of ordinary differential equations. The number of
equations is related to the level of approximation considered including
different physical processes. These equations can be solved numerically;
however, an analytical approach for the lowest-order approximation is also
presented. This yields explicit expressions, not only for the flow and field
variations but also for the magnetosheath thickness, depending on the solar
wind parameters. Results are compared to THEMIS data and offer a detailed
explanation of, e.g., the pile-up process and the corresponding plasma
depletion layer, the bow shock and magnetopause geometry, the magnetosheath
thickness, and the flow deceleration. |
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