About the origin of peaks in the spectrum of inner belt electrons

A power spectral analysis of geomagnetic data between June and November 1982 from Vassouras, a low‐latitude observatory located in the South Atlantic Magnetic Anomaly (SAMA), is carried out in order to investigate the origin of multiple peaks commonly observed in the energetic electron spectra in the inner magnetosphere. Comparison with energetic electron observations made by the low‐altitude satellite S81‐1 during the same time interval [Datlowe et al., 1985] indicates that even if the peaks are due to a quasi‐resonance process as Cladis [1966] has suggested, whereby energetic electrons are accelerated and transported radially as a result of magnetic fluctuations with periods comparable to their azimuthal drift periods, the driver of such magnetic fluctuations is not the ionospheric current in the equatorial electrojet, modulated by electron precipitation in the SAMA region, such as Cladis [1966] proposed. We suggest that the source of drift‐resonant magnetic fluctuations, if they exist, must instead be sought in the solar wind. Otherwise, the drift‐resonant mechanism cannot be viable.