Pre- and Post-Midnight Equatorial Plasma Bubbles

The development of equatorial plasma bubbles was considered in the latitude-altitude and local time dynamics. The obtained pattern was used to study the particular features of the pre- and post-midnight equatorial plasma bubbles. For this purpose, a detailed comparative analysis of the histograms of latitudinal and local-time variations in the occurrence probability of bubbles at altitudes was carried out. Data from the AE-E (~350–475 km), ROCSAT-1 (~600 km) and ISS-b (~972–1220 km) satellites which different orbital altitudes were included. Observations were carried out during the years of the increasing and maximum solar activity. It was found that the probability of occurrence of the equatorial plasma bubbles in the equatorial and low-latitude regions at the altitudes of ~350–1200 km is maximum before the midnight. On the other hand, the maximum occurrence probability of bubbles in the mid-latitude region at the altitudes of ~600–1200 km was recorded after midnight. It was concluded that the dominance of post-midnight equatorial plasma bubbles in the mid-latitude region is associated with the dynamics of their rise and increase in geometric size.