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| Titel |
Anomalous width variation of rarefactive ion acoustic solitary waves in the context of auroral plasmas |
| VerfasserIn |
S. S. Ghosh, G. S. Lakhina |
| 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 ; 11, no. 2 ; Nr. 11, no. 2 (2004-04-14), S.219-228 |
| Datensatznummer |
250009134
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| Publikation (Nr.) |
 copernicus.org/npg-11-219-2004.pdf |
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| Zusammenfassung |
| The presence of dynamic, large amplitude solitary waves in the
auroral regions of space is well known. Since their velocities
are of the order of the ion acoustic speed, they may well be
considered as being generated from the nonlinear evolution of ion
acoustic waves. However, they do not show the expected
width-amplitude correlation for K-dV solitons. Recent POLAR
observations have actually revealed that the low altitude
rarefactive ion acoustic solitary waves are associated with an
increase in the width with increasing amplitude. This indicates
that a weakly nonlinear theory is not appropriate to describe the
solitary structures in the auroral regions. In the present work,
a fully nonlinear analysis based on Sagdeev pseudopotential
technique has been adopted for both parallel and oblique
propagation of rarefactive solitary waves in a two electron
temperature multi-ion plasma. The large amplitude solutions have
consistently shown an increase in the width with increasing
amplitude. The width-amplitude variation profile of obliquely
propagating rarefactive solitary waves in a magnetized plasma
have been compared with the recent POLAR observations. The
width-amplitude variation pattern is found to fit well with the
analytical results. It indicates that a fully nonlinear theory of
ion acoustic solitary waves may well explain the observed
anomalous width variations of large amplitude structures in the
auroral region. |
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