Magnetic impulse events at the nightside auroral latitudes and associated phenomena

Abstract The connection between auroral activation and magnetic impulse events, (MIE) on the nightside is the issue of this study. MIE can be seen during the growth phase and onset of a substorm in association with field-aligned currents (FACs) connecting the auroral ionosphere and plasma sheet. We suggest that the intensity of the FAC studied with magnetometers, pulsation magnetometers, riometer and optical data can be regarded as a key parameter for characteristic of the magnitude of energy released during each activation. The threshold value of the FAC density contributing to a substorm intensification is estimated in the present study.