Electromagnetic fluctuations in the vicinity of the magnetopause
Résumé
A detailed analysis of electromagnetic fluctuations recorded during several magnetopause and boundary layer crossings by the ESA GEOS-2 geostationary spacecraft is presented. A high level of electromagnetic fluctuations in the ULF (0 - 10 Hz) range is observed for each such crossing. The obtained frequency spectra are shown to fit with a power law f exp -alpha. The distribution of these alpha indexes is found to be narrow, with a peak value of about 2.5 which does not depend on the direction with respect to the magnetic field. Data suggest that the magnetopause boundary layer is the source of these intense fluctuations.
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