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| Titel |
Hydromagnetic spectroscopy of the magnetosphere with Pc3 geomagnetic pulsations along the 210° meridian |
| VerfasserIn |
V. Pilipenko, K. Yumoto, E. Fedorov, N. Yagova |
| 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 ; 17, no. 1 ; Nr. 17, no. 1, S.53-65 |
| Datensatznummer |
250013644
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| Publikation (Nr.) |
 copernicus.org/angeo-17-53-1999.pdf |
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| Zusammenfassung |
Analysis of Pc3 observational data along the
210° magnetic meridian showed a complicated frequency-latitude structure at
middle latitudes. The observed period-latitude distributions vary between events
with a "noisy source": the D component has a colored-noise spectrum,
while the spectrum of H component exhibits regular peaks that vary with
latitude, and events with a "band-limited source": the spectral power
density of the D component is enhanced at certain frequencies throughout
the network. For most ULF events a local gap of the H component amplitude
has been exhibited at both conjugate stations at L ~ 2.1. A
quantitative interpretation has been given assuming that band-limited MHD
emission from an extra-magnetospheric source is distorted by local field line
resonances. Resonant frequencies had been singled out with the use of the
asymmetry between spectra of H and D components. Additionally, a
local resonant frequency at L ~ 1.6 was determined by the
quasi-gradient method using the data from nearly conjugate stations. The
experimentally determined local resonance frequencies agree satisfactorily with
those obtained from a numerical model of the Alfven resonator with the
equatorial plasma density taken by extrapolation of Carpenter-Anderson model. We
demonstrate how simple methods of hydromagnetic spectroscopy enable us to
monitor simultaneously both the magnitude of the IMF and the magnetospheric
plasma density from ULF data.
Key words. Magnetospheric physics
(Magnetosphere-ionosphere interactions; MHD waves and instabilities;
plasmasphere) |
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