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Titel |
Simultaneous conjugate ground-satellite ULF pulsation measurements at the middle latitudes |
VerfasserIn |
K. Prikner |
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. 6 ; Nr. 15, no. 6, S.645-655 |
Datensatznummer |
250012824
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Publikation (Nr.) |
copernicus.org/angeo-15-645-1997.pdf |
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Zusammenfassung |
The spectra of three series of simultaneous
ground (Budkov Observatory) and satellite (Freja) ULF measurements have been
processed. The following features were studied in the FFT spectra, power-spectra
and cross-spectra of the six-minute samples, recorded during quasi-conjugate
approaches of Freja to the local Budkov magnetic field line: (a) the Doppler
frequency shift (about 1mHz and less) in the predominant and some particular
spectral components on Freja; (b) the amplitude relations between the ground and
satellite (ratios 0.3 to 0.8); (c) phase shifts between particular signal
components on the spacecraft above the ionosphere (in the azimuthal y-direction
on Freja) and on the ground (in the meridional x-direction at Budkov)
have been estimated (phase lags on the ground ≤ 0.9rad) and (d) also dynamical
characteristics of the fundamental wave modes in the (x,y)-plane,
perpendicular to the magnetic field line, have been estimated for the
predominant spectral components, considering standing oscillation along the
field line. Azimuthal wave numbers were about 2.0, propagating northwest at
~400km/s. |
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