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| Titel |
Irregular structures observed below 71 km in the night-time polar D-region |
| VerfasserIn |
E. V. Thrane, T. A. Blix, K. R. Svenes |
| 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 ; 18, no. 2 ; Nr. 18, no. 2, S.215-222 |
| Datensatznummer |
250013910
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| Publikation (Nr.) |
 copernicus.org/angeo-18-215-2000.pdf |
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| Zusammenfassung |
| A new rocket range, SvalRak, was opened in
November 1997 at Ny-Ålesund (79°N) in the Svalbard archipelago. The first
instrumented rocket was launched on 20 November, 1997, at 1730 UT during
geomagnetically quiet conditions. The payload was instrumented to measure plasma
parameters in the mesosphere and lower thermosphere, but the payload only
reached an altitude of 71 km. This resulted in a very flat trajectory through
the lower D-region. The positive ion concentrations were larger than expected,
and some unexpected plasma irregularities were observed below 71 km. The
irregularities were typically 100 m in spatial extent, with plasma densities a
factor of two to five above the ambient background. In the dark polar night the
plasma below 71 km must consist mainly of positive and negative ions and the
only conceivable ionising radiation is a flux of energetic particles.
Furthermore only relativistic electrons have the large energies and the small
gyro radii required in order to explain the observed spatial structure. The
source of these electrons is uncertain.
Key words: Ionosphere (ionospheric irregularities;
ionization mechanisms) - Magnetospheric physics (polar cap phenomena) |
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