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| Titel |
E-region mid-latitude decametre irregularities observed at four radar frequencies. Experiment and first results |
| VerfasserIn |
G. C. Hussey, J. Delloue, C. Haldoupis, A. Bourdillon |
| 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 ; 15, no. 7 ; Nr. 15, no. 7, S.918-924 |
| Datensatznummer |
250012876
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| Publikation (Nr.) |
 copernicus.org/angeo-15-918-1997.pdf |
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| Zusammenfassung |
| In this paper an experiment designed for
multifrequency azimuthal Doppler-spectrum investigations of decametre-scale
plasma irregularities in the mid-latitude E region is introduced and some
preliminary results are presented. The observations were made with the
high-frequency Valensole radar in the south of France. The radar operated in a
multifrequency mode that allowed simultaneous measurements of Doppler spectra at
the four frequencies of 9.23, 11.03, 12.71 and 16.09 MHz, which correspond to
scatter from field-aligned irregularities with wavelengths of 16.2, 13.6, 11.8
and 9.3 m, respectively. In addition, a digital ionosonde was operating beneath
a small part of the radar viewing region. The data show that lower-frequency
echoes are stronger, more frequent and more spatially extended than
higher-frequency ones, in general agreement with theory and rocket measurements.
On the other hand, the preliminary analysis shows no pronounced differences of
the Doppler spectrum with radar frequency. Some trends in the spectral moments
do exist, however, which can be understood as the result of temporal and/or
spatial mixing of backscatter from directly generated (primary) plasma waves by
the gradient drift instability and secondary low-velocity waves. Finally, a
close relation of mid-latitude coherent backscatter with patchy sporadic E-layers
is present in the data, but the details of this relation remain unresolved. |
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