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| Titel |
Combined optical, EISCAT and magnetic observations of the omega bands/Ps6 pulsations and an auroral torch in the late morning hours: a case study |
| VerfasserIn |
V. Safargaleev, T. Sergienko, H. Nilsson, A. Kozlovsky, S. Massetti, S. Osipenko, A. Kotikov |
| 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. 5 ; Nr. 23, no. 5 (2005-07-28), S.1821-1838 |
| Datensatznummer |
250015269
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| Publikation (Nr.) |
 copernicus.org/angeo-23-1821-2005.pdf |
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| Zusammenfassung |
| We present here the results of multi-instrument observations of auroral
torch and Ps6 magnetic pulsations, which are assumed to be the magnetic
signature of the spatially periodic optical auroras known as omega bands.
Data from TV and ASC cameras in Barentsburg and Ny Ålesund, EISCAT
radars in Longyearbyen and Tromsø, as well as IMAGE network were used in
this study. The auroral phenomenon which was considered differed from that
previously discussed, as it occurred both in an unusual place (high
latitudes) and at an unusual time (late morning hours). We show that this
might occur due to specific conditions in the interplanetary medium, causing
the appropriate deformation of the magnetosphere. In such a case, the IMF
turned out to be an additional factor in driving the regime of Ps6/omega
bands, namely, only by acting together could a substorm onset in the night
sector and Bz variations result in their generation. Since the presumable
source of Ps6/omega bands does not co-locate with convection reversal
boundaries, we suggest the interpretation of the phenomena in the frame of
the interchange instability instead of the Kelvin-Helmholtz instability
that is widely discussed in the literature in connection with omega auroras. Some
numerical characteristics of the auroral torch were obtained. We also
emphasize to the dark hole in the background luminosity and the short-lived
azimuthally-restricted auroral arc, since their appearance could initiate the
auroral torch development.
Keywords. Magnetospheric physics (Auroral phenomena;
Plasma convection; Solar wind-magnetosphere interaction) |
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