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| Titel |
Standing Alfvén waves with m ≫ 1 in an axisymmetric magnetosphere excited by a stochastic source |
| VerfasserIn |
A. S. Leonovich, V. A. Mazur |
| 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 ; 16, no. 8 ; Nr. 16, no. 8, S.900-913 |
| Datensatznummer |
250013387
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| Publikation (Nr.) |
 copernicus.org/angeo-16-900-1998.pdf |
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| Zusammenfassung |
In the framework of an axisymmetric
magnetospheric model, we have constructed a theory for broad-band standing
Alfvén waves with large azimuthal wave number m » 1 excited by a
stochastic source. External currents in the ionosphere are taken as the
oscillation source. The source with statistical properties of "white
noise" is considered at length. It is shown that such a source drives
oscillations which also have the "white noise" properties. The
spectrum of such oscillations for each harmonic of standing Alfvén waves has
two maxima: near the poloidal and toroidal eigenfrequencies of the magnetic
shell of the observation. In the case of a small attenuation in the ionosphere
the maximum near the toroidal frequency is dominated, and the oscillations are
nearly toroidally polarized. With a large attenuation, a maximum is dominant
near the poloidal frequency, and the oscillations are nearly poloidally
polarized.<
Key words. Ionosphere-magnetosphere interaction · Wave
propagation · Magnetospheric physics · MHD waves and instabilities |
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