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Titel |
Excitation of Alfvén impulse by the anomalous resistance onset on the auroral field lines |
VerfasserIn |
V. Pilipenko, N. Mazur, E. Fedorov, T. Uozumi, K. Yumoto |
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 ; 23, no. 4 ; Nr. 23, no. 4 (2005-06-03), S.1455-1465 |
Datensatznummer |
250015235
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Publikation (Nr.) |
copernicus.org/angeo-23-1455-2005.pdf |
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Zusammenfassung |
The onset of anomalous resistance in a layer on auroral
field lines is shown to be accompanied by the excitation of an Alfvénic impulse
(AI).
The generated AI marks the transition of the global
magnetosphere-ionosphere instability
into an explosive phase with positive feedback.
The spatial structure of this impulse both in space and on the
ground has been described analytically and numerically under the thin
layer approximation.
The field-aligned currents transported by the Alfvénic impulse are concentrated
near the edges of the layer with anomalous resistivity, whereas the reverse
currents are spread throughout the layer.
For some parameters of the layer the ionospheric attenuation of even
small-scale structures is not dramatically large, so the magnetic response to
the generated AI may be observed on the ground.
The considered event on 3 January 1997 with magnetic-auroral intensification observed by
ground magnetometers and Polar UV imager agrees with the model proposed. |
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