Some Characteristics of Irregular Micropulsations Pi2 at High Latitude Stations

Abstract

Pi2 micropulsations were studied for the period July 12 to August 16, 1968, from four observatories at different latitudes in Canada. Maximum occurrence was near midnight with a preference for 5–6 h UT at all longitudes studied. The relationship of Pi2 occurrence to magnetic bays and to Kp is examined. The correlation of Pi amplitudes and periods with Kp and other parameters reveals a different pattern for lower latitude stations (Ottawa and Meanook) compared with Baker Lake (73.9 °N). These results are interpreted as evidence for two different types of Pi in the different latitude regions, the lower latitude Pi being associated with hydromagnetic waves on the plasmapause. In studies of simultaneous Pi events at the four stations, the maximum amplitude occurred most frequently at Meanook. Polarization of such events was found to be different at different stations and so previously reported patterns of Pi polarization could not be confirmed.