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On the origin of lower- and upper-frequency cutoffs on wedge-like spectrograms observed by DEMETER in the midlatitude ionosphere
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SYSNO ASEP 0343319 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title On the origin of lower- and upper-frequency cutoffs on wedge-like spectrograms observed by DEMETER in the midlatitude ionosphere Author(s) Shklyar, D. R. (RU)
Parrot, M. (FR)
Chum, Jaroslav (UFA-U) RID, ORCID
Santolík, Ondřej (UFA-U) RID, ORCID
Titova, E. E. (RU)Source Title Journal of Geophysical Research - ISSN 0148-0227
Roč. 115, - (2010), A05203/1-A05203/12Number of pages 12 s. Language eng - English Country US - United States Keywords DEMETER ; midlatitude ionosphere ; spectrograms Subject RIV BL - Plasma and Gas Discharge Physics R&D Projects ME09107 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) GA205/09/1253 GA ČR - Czech Science Foundation (CSF) CEZ AV0Z30420517 - UFA-U, BC-A (2005-2011) UT WOS 000277480900002 DOI 10.1029/2009JA014672 Annotation We report observations of unusual lower and upper cutoff frequencies on VLF spectrograms recorded by the DEMETER satellite orbiting at 700 km. The upper cutoff frequencies vary approximately in proportion to L-3. The lower cutoff frequencies in the spectrograms are almost constant. Between these cutoffs, which form a wedge, intense whistlers are observed, whereas only 0+ whistlers, and probably, ducted whistlers are present outside the cutoffs. We explain the observed spectrograms on the basis of the features of whistler-mode wave propagation in the inner magnetosphere. The upper cutoff frequency is determined by the limiting trajectories that confine the waves of a given frequency propagating obliquely from a source located in the opposite hemisphere. The lower frequency cutoff is determined by the LHR maximum, since quasiresonant waves with lower frequencies originating in the opposite hemisphere do not reach the satellite due to the LHR reflection above it. Workplace Institute of Atmospheric Physics Contact Kateřina Adamovičová, adamovicova@ufa.cas.cz, Tel.: 272 016 012 ; Kateřina Potužníková, kaca@ufa.cas.cz, Tel.: 272 016 019 Year of Publishing 2011
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