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Ann. Geophys., 26, 295-304, 2008
www.ann-geophys.net/26/295/2008/
© European Geosciences Union 2008
Wave and plasma measurements and GPS diagnostics of the main ionospheric trough as a hybrid method used for Space Weather purposes
H. Rothkaehl1, A. Krakowski2, I. Stanislawska1, J. Błęcki1, M. Parrot3, J.-J. Berthelier4, and J.-P. Lebreton5
1Space Research Centre PAS 00-716 Warsaw, Bartycka 18A, Poland
2University of Warmia and Mazury in Olsztyn, Poland
3LPCE/CNRS 3A, avenue de la Recherche Scientifique 45071 Orléans cedex 02, France
4CETP/ Observatoire de Saint-Maur 4, avenue de Neptune 94107 Saint-Maur-des-Fossés Cedex, France
5RSSD/ESTEC/ESA Postbus 2992200 AG Noordwijk, The Netherlands
Abstract. The region of the main ionospheric trough is a unique
region of the ionosphere, where different types of waves and instabilities
can be generated. This region of the ionosphere acts like a lens, focusing a
variety of indicators from the equator of plasmapause and local ionospheric
plasma. This paper reports the results of monitoring the mid-latitude trough
structure, dynamics and wave activity. For these purposes, the data gathered
by the currently-operating DEMETER satellite and past diagnostics located on
IK-19, Apex, and MAGION-3 spacecraft, as well as TEC measurements were used.
A global-time varying picture of the ionospheric trough was reconstructed
using the sequence of wave spectra registered and plasma measurements in the
top-side ionosphere. The authors present the wave activity from ULF
frequency band to the HF frequency detected inside the trough region and
discuss its properties during geomagnetic disturbances. It is thought that
broadband emissions are correlated with low frequency radiation, which is
excited by the wave-particle interaction in the equatorial plasmapause and
moves to the ionosphere along the geomagnetic field line. In the ionosphere,
the suprathermal electrons can interact with these electrostatic waves and
excite electron acoustic waves or HF longitudinal plasma waves.
Furthermore, the electron density trough can provide useful data on the
magnetosphere ionosphere dynamics and morphology and, in consequence, can be
used for Space Weather purposes.
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