A CASE-STUDY OF TRANSIENT EVENT MOTION IN THE MAGNETOSPHERE AND IN THE IONOSPHERE

We present a case study of the magnetospheric and ionospheric response to a series of repetitive (7-8 min) solar wind dynamic pressure and i nterplanetary magnetic field (IMF) strength variations generated at th e bow shock. During a period of duskward and antisunward IMF orientati on, the magnetospheric and ionospheric observations indicate transient events moving dawnward and duskward away from a point of origin at or after local noon. In contrast, during a subsequent period of dawnward and antisunward IMF orientation, the observations indicate events mov ing duskward away from a point of origin at or prior to 0900 LT. We co nsider explanations in terms of pressure pulse driven riplets on the m agnetopause or directly driven bursts of antiparallel merging.