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| Titel |
Azimuthal expansion of high-latitude auroral arcs |
| VerfasserIn |
V. V. Safargaleev, A. E. Kozlovsky, S. V. Osipenko, V. R. Tagirov |
| 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 ; 21, no. 8 ; Nr. 21, no. 8, S.1793-1805 |
| Datensatznummer |
250014678
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| Publikation (Nr.) |
 copernicus.org/angeo-21-1793-2003.pdf |
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| Zusammenfassung |
We used the TV auroral
observations in Barentsburg (78.05° N 14.12° E) in Spitsbergen archipelago,
together with the data of the CUTLASS HF radars and the POLAR satellite images
to study azimuthal (in the east-west direction) expansion of the high-latitude
auroral arcs. It is shown that the east or west edge of the arc moved in the
same direction as the convection flow, westward in the pre-midnight sector and
eastward in the post-midnight sector. The velocity of arc expansion was of the
order of 2.5 km/s, which is 2–3 times larger than the convection velocity
measured in the arc vicinity and 2–3 times smaller than the velocity of the
bright patches propagating along the arc. The arc expanded from the active
auroras seen from the POLAR satellite around midnight as a region of enhanced
luminosity, which might be the auroral bulge or WTS. The pole- or equatorward
drift of the arcs occurred at the velocity of the order of 100 m/s that was
close to the convection velocity in the same direction. These experimental
results can be well explained in terms of the interchange (or flute)
instability.
Key words. Ionosphere (plasma
convection) – Magnetospheric physics (auroral phenomena; magnetospheric
configuration and dynamics) |
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