A Case Study for Imperfect Magnetosphere-Ionosphere Coupling by STARE-TRIAD Joint Observations

A case from STARE-TRIAD simultaneous observations is used to investigate the Magnetosphere-Ionosphere imperfect coupling. The latitudinal profiles of the STARE observed E-fields, the TRIADmeasured field-aligned currents and the deduced heigh-tintegrated Pederson conductivities near the Harang discontinuity are found to be in good agreement with the theoritical model of Kan and Lee. The observations support the prediction that the U-shape electric equipotential contours at the discontinuity is accompanied by a S-shape contour equatorward, which is associated with a second enhancement of height integrated Pederson conductivity and a valley in the latitudinal profiles of the ionospheric E-fields. Other samples from the STARE observations show that the results here have some universal significance.