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| Titel |
Inverse cascade in the structure of substorm aurora and non-linear dynamics of field-aligned current filaments |
| VerfasserIn |
B. V. Kozelov, I. V. Golovchanskaya, O. V. Mingalev |
| 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 ; 29, no. 8 ; Nr. 29, no. 8 (2011-08-09), S.1349-1354 |
| Datensatznummer |
250017069
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| Publikation (Nr.) |
 copernicus.org/angeo-29-1349-2011.pdf |
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| Zusammenfassung |
| We investigate time evolution of scaling index αA that characterizes
auroral luminosity fluctuations at the beginning of substorm expansion. With
the use of UVI images from the Polar satellite, it is shown that αA
typically varies from values less than unity to ~1.5, increasing with
breakup progress. Similar scaling features were previously reported for
fluctuations at smaller scales from all-sky TV observations. If this
signature is interpreted in terms of non-linear interactions between scales,
it means that the power of small-scale fluctuations is transferred with time
to larger scales, a kind of the inverse cascade. Scaling behavior in the
aurora during substorm activity is compared with that in the field-aligned
currents simulated numerically in the model of non-linear interactions of
Alfvénic coherent structures, according to the Chang et al. (2004) scenario.
This scenario also suggests an inverse cascade, manifesting in clustering of
small-scale field-aligned current filaments of the same polarity and
formation of "coarse-grained" structures of field-aligned currents. |
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