Review on interplanetary‐magnetosphere interactions

This review deals with the interplanetary‐magnetosphere coupling during intense geomagnetic activity, especially near solar maximum. For this purpose we use the plasma and magnetic field measurements obtained mainly by the ISEE‐3 satellite during the interval of time when it was at the L1 libration point of the sun‐earth system. During this interval 90% of the intense geomagnetic storms (Peak Dst<−100 nT) were preceded by the arrival of interplanetary fast forward shocks at 1 AU. For these events we show the interplanetary structures that are associated with the large‐amplitude and long‐duration negative Bz fields that were found in the sheath and/or driver gas regions of the shock and that are thought to be the main cause of the intense storms. On the other hand, during this same interval, ‘‘High‐Intensity, Long‐Duration, and Continuous Auroral Activity’’ events (HILDCAAs for short) were found to be caused by the southward magnetic fields of large‐amplitude interplanetary Alfven waves, presumably through...