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| Titel |
Trans-sonic cusped shaped, periodic waves and solitary waves of the electrostatic ion-cyclotron type |
| VerfasserIn |
J. F. McKenzie, T. B. Doyle |
| 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. 4 ; Nr. 11, no. 4 (2004-09-24), S.421-425 |
| Datensatznummer |
250009322
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| Publikation (Nr.) |
 copernicus.org/npg-11-421-2004.pdf |
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| Zusammenfassung |
| By adopting an essentially fluid dynamic viewpoint we derive the
wave structure equation for stationary, fully nonlinear,
electrostatic, ion-cyclotron waves. The existence of two
fundamental constants of the motion, namely, conservation of
momentum flux parallel to the ambient magnetic field, and energy
flux parallel to the direction of wave propagation, enables the wave
structure equation to be reduced to a first order differential
equation, which has solutions that are physically transparent. The
analysis shows that sufficiently oblique waves, propagating at
sub-ion acoustic speeds, form soliton pulse-like solutions whose
amplitudes are greatest for perpendicular propagation. Waves that
propagate supersonically have periodic cnoidal waveforms, which are
asymmetric about the compressive and rarefactive phases of the wave.
It is also shown that there exist critical driver fields for which
the end point of the compressive phase goes sonic (in the wave
frame), with the consequence that the wave form develops a cusp. It
is possible that this trans-sonic, choked flow feature provides a
mechanism for the "spiky" waveforms observed in auroral electric
field measurements. |
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