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| Titel |
Modeling stretched solitary waves along magnetic field lines |
| VerfasserIn |
L. Muschietti, I. Roth, C. W. Carlson, M. Berthomier |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 9, no. 2 ; Nr. 9, no. 2, S.101-109 |
| Datensatznummer |
250006691
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| Publikation (Nr.) |
 copernicus.org/npg-9-101-2002.pdf |
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| Zusammenfassung |
| A model is presented
for a new type of fast solitary waves which is observed in downward
current regions of the auroral zone. The three-dimensional, coherent
structures are electrostatic, have a positive potential, and move along
the magnetic field lines with speeds on the order of the electron drift.
Their parallel potential profile is flattened and cannot fit to the
Gaussian shape used in previous work. We develop a detailed BGK model
which includes a flattened potential and an assumed cylindrical symmetry
around a centric magnetic field line. The model envisions concentric
shells of trapped electrons slowly drifting azimuthally while bouncing
back and forth in the parallel direction. The electron dynamics is
analysed in terms of three basic motions that occur on different time
scales characterized by the cyclotron frequency We
, the bounce frequency wb , and the
azimuthal drift frequency wg. The
ordering We >> wb
>> wg is required.
Self-consistent distribution functions are calculated in terms of
approximate constants of motion. Constraints on the parameters
characterizing the amplitude and shape of the stretched solitary wave are
discussed. |
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