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Titel |
Ducted whistler-mode signals received at two widely spaced locations |
VerfasserIn |
M. A. Clilverd, N. R. Thomson, A. J. Smith |
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 ; 14, no. 6 ; Nr. 14, no. 6, S.619-627 |
Datensatznummer |
250012321
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Publikation (Nr.) |
copernicus.org/angeo-14-619-1996.pdf |
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Zusammenfassung |
Whistler-mode signals from a single VLF
transmitter that have propagated in the same duct, have been observed
simultaneously at Faraday, Antarctica (65°S, 64°W) and Dunedin, New Zealand
(46°S, 171°E). The signals received have group-delay times that differ in the
order of 10 ms, which can be explained by the differences in southern-hemisphere
sub-ionospheric propagation time from duct exit region to receiver for the two
sites. This difference has been used to determine the location of the duct exit
region, with confirmation provided by arrival-bearing information from both
sites. The whistler-mode signals typically occur one or two days after
geomagnetic activity, with Kp\geq5. The sub-ionospheric-propagation
model, LWPC, is used to estimate the whistler-mode power radiated from the duct
exit region. These results are then combined with estimated loss values for
ionospheric and ducted transmission to investigate the role of wave-particle
amplification or absorption. On at least half of the events studied,
plasmaspheric amplification of the signals appears to be needed to explain the
observed whistler-mode signal strengths. |
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