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Ann. Geophys., 16, 1117-1136, 1998
www.ann-geophys.net/16/1117/1998/
© European Geosciences Union 1998
Preliminary results from the MEMO multicomponent measurements of waves on-board INTERBALL 2
F. Lefeuvre1, M. Parrot1, J. L. Rauch1, B. Poirier1, A. Masson1, and M. Mogilevsky2
1CNRS/LPCE 45071 Orléans cedex 02, France
2IKI, Russian Academy of Sciences, 117081, Moscow, Russia
Abstract. The MEMO (MEsure Multicomposante des Ondes)
experiment is a part of the INTERBALL 2 wave consortium. It is connected to a
total of six electric and nine magnetic independent sensors. It provides
waveforms associated with the measurement of two to five components in three
frequency bands: ELF (5–1000 Hz), VLF (1–20 kHz), LF (20–250 kHz). Preliminary
analyses of low and high resolution data are presented. The emphasis is put on
the estimation of the propagation characteristics of the observed waves.VLF hiss
emissions are shown to be mainly whistler mode emissions, but other modes are
present. An accurate estimation of the local plasma frequency is proposed when
the low L = 0 cutoff frequency is identified. AKR emissions observed just
above source regions are studied. R-X and L-O modes are found: the first at the
lowest frequencies and the second at the highest. Both propagate with wave
normal directions weakly oblique or quasi-parallel to the Earth's magnetic field
direction. Propagation characteristics are also determined for a (non-drifting)
fine structure of AKR. There is no fundamental difference with structurless
events. Nightside and dayside bursts of ELF electromagnetic emissions are
presented. It is not clear whether the two emissions belong to the "lion
roar" emissions or not.
Key words. Magnetospheric physics (auroral phenomena;
plasma waves and instabilities; instruments and techniques)
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