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| Titel |
Comprehensive survey of Pc4 and Pc5 band spectral content in Cluster magnetic field data |
| VerfasserIn |
L. B. N. Clausen, T. K. Yeoman |
| 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 ; 27, no. 8 ; Nr. 27, no. 8 (2009-08-19), S.3237-3248 |
| Datensatznummer |
250016628
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| Publikation (Nr.) |
 copernicus.org/angeo-27-3237-2009.pdf |
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| Zusammenfassung |
| In the first part of this study we present two case studies of pulsations
that, with the help of ground-based data, are identified as field line
resonances (FLRs). These pulsations occurred at frequencies which belong to a
set of frequencies that has been suggested to be preferred in the terrestrial
magnetosphere (CMS frequencies). We go on to show that for both events there
is a significant signature at the same frequency in the time series of the
compressional magnetic field observed by the conjugate Cluster satellites. We
interpret these as signatures of the compressional mode driving the FLRs. In
the second part we present a statistical study including one year's worth of
Cluster magnetic field data. For each orbit between May 2004 and June 2005 we
identified a three hour interval during which the satellites were located on
closed magnetic field lines. We identified peaks in the spectrum between 1.0
and 15.0 mHz of the compressional, poloidal and toroidal components of
the magnetic field. We use this database of spectral peaks observed on closed
magnetic field lines to investigate whether peaks occur at a preferred set of
frequencies which would be indicative for the Earth's magnetosphere behaving
like a cavity/waveguide. We find no consistent preference for all CMS
frequencies in our dataset, however we do find a preference for certain
higher frequencies suggesting that higher harmonics of the cavity/waveguide
are a persistent feature of the inner magnetosphere, and are detected by the
Cluster spacecraft. This result could be explained by the polar orbit of the
Cluster satellites. |
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