Micropulsations in the electric field near the plasmapause, observed by Isee 1

The results of a survey of occurrence of micropulsations near and inside the plasmapause, made on the basis of 1 year of data from the double probe electric field instrument on Isee 1, are presented. It is reported that the observed pulsations are classified as Pc 3 and P 2, and that one single Pc 1 event is observed. It is found that Pc 3 events are common during the local day, with a maximum percentage of occurrence as high as 72 in the morning hours. Attention is given to Pi 2 events showing that they are concentrated on the local nightside. Finally, it is noted that pulsations in the Pc 1 range appear on only one inbound pass, which makes the Pc 1 a rare phenomenon at low and moderate latitudes in the plasmasphere.