ULF waves in the low-latitude boundary layer and their relationship to magnetospheric pulsations - A multisatellite observation

Combined data from five spacecraft have been analyzed to understand the structure of the low-latitude boundary layer (LLBL), the ULF waves in the LLBL, and the relation of the LLBL waves to magnetic pulsations in the magnetosphere. Both the intensity and the pitch angle distribution of the particles clearly show the presence of the LLBL for the time interval studied. The average magnetic field is rotated slightly at or near the LLBL/magnetosphere interface, which is consistent with a field-aligned current sheet with region 1 flow direction. For ULF waves, a 5-10 min compressional perturbation is present both in the LLBL and the magnetosphere. In the boundary layer, large-amplitude transverse oscillations are present. Magnetic Pc 4-5 pulsations are present in the magnetosphere with azimuthal perturbations and position-dependent frequency.