CONCERNING POSSIBLE EFFECTS OF IONOSPHERIC CONDUCTIVITY UPON THE OCCURRENCE PATTERNS OF IMPULSIVE EVENTS IN HIGH-LATITUDE GROUND MAGNETOGRAMS

Previous studies have interpreted the occurrence patterns of impulsive events in the high-latitude dayside ionosphere in terms of transient processes occurring near the dayside magnetopause. In particular, the fact that most impulsive ground magnetometer events occur prior to loc al noon has been interpreted as evidence for a dawn/dusk asymmetry in transient processes at the magnetopause. In this paper, we seek to rai se the awareness of the community that the high-latitude distribution of the Hall conductivity also influences the signatures observed by gr ound magnetometers. In particular, we will show that impulsive event o ccurrence patterns bear a striking resemblance to reported statistical patterns for the Hall conductivity. We suggest that this similarity b e taken into account when interpreting occurrence patterns for impulsi ve ground events.