Magnetospheric resonance, auroral structure and multipoint measurements

Multipoint ''satellite'' diagnostics from a magnetically incompressible, two-fluid simulation model for resonant, dispersive Alfven waves standing on auroral field lines suggest a causal link between shear Alfven resonances, usually identified on the basis of ground-based and equatorial magnetospheric signatures, and some of the large-amplitude, kilometer-scale electric fields, typically measured by polar-orbiting satellites in the lower magnetosphere. It is also shown that one documented DE 1 electric field event exhibits the waveform, impedance, and phase signatures of a dispersive field line resonance. (C) 1997 COSPAR. Published by Elsevier Science Ltd.