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| Titel |
Solar wind reconstruction from magnetosheath data using an adjoint approach |
| VerfasserIn |
C. Nabert, C. Othmer, K.-H. Glassmeier |
| 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 ; 33, no. 12 ; Nr. 33, no. 12 (2015-12-21), S.1513-1524 |
| Datensatznummer |
250121279
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| Publikation (Nr.) |
 copernicus.org/angeo-33-1513-2015.pdf |
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| Zusammenfassung |
| We present a new method to reconstruct solar wind conditions from spacecraft
data taken during magnetosheath passages, which can be used to support, e.g.,
magnetospheric models. The unknown parameters of the solar wind are used as
boundary conditions of an MHD (magnetohydrodynamics) magnetosheath model. The boundary conditions
are varied until the spacecraft data matches the model predictions. The
matching process is performed using a gradient-based minimization of the
misfit between data and model. To achieve this time-consuming procedure, we
introduce the adjoint of the magnetosheath model, which allows efficient
calculation of the gradients. An automatic differentiation tool is used to
generate the adjoint source code of the model. The reconstruction method is
applied to THEMIS (Time History of Events and Macroscale Interactions
during Substorms) data to calculate the solar wind conditions during
spacecraft magnetosheath transitions. The results are compared to actual
solar wind data. This allows validation of our reconstruction method and
indicates the limitations of the MHD magnetosheath model used. |
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