ENERGY-TRANSFER BETWEEN THE IONOSPHERE AND MAGNETOSPHERE DURING THE JANUARY 1997 CME EVENT

This Letter shows that transient changes in convection and precipitati on patterns can significantly influence the electromagnetic energy tra nsfer between the magnetosphere and the ionosphere. At the times of th e transient events during the 10 January 1997 storm that was produced by a Coronal Mass Ejection (CME)-related magnetic cloud, the Sondrestr om incoherent scatter radar measured the local electrodynamic response of the high-latitude ionosphere. Important discrepancies between the net electrodynamic energy flux and the electromagnetic energy flux est imated for a stationary atmosphere suggest that the assumption of the ionosphere as a purely resistive load is often inadequate during these transient events as neutral winds cannot conform to the new orientati on of the electric field and thus impact the load/generator characteri stics of the ionosphere.