Asymmetric Distribution of Plasma Blobs During High Solar Activity in the Low- to Middle-Latitude Ionosphere

Using the data from the first satellite of the Republic of China (ROCSAT-1) obtained during high-solar-activity periods (2000–2003), the distributions of plasma density enhancement (plasma blobs) with local time, season and longitude were investigated. Some new features of plasma blobs can be concluded: (a) The distribution of plasma blobs shows remarkable seasonal and interhemispheric asymmetries, with the higher occurrence in June solstice months and in the winter hemisphere. (b) The occurrence of plasma blobs displays longitude dependence, more in the −180~−90°E, −60~0°E and 90~180°E longitude regions. (c) The seasonal and interhemispheric asymmetries of plasma blobs also depend on the longitude. Meridional wind plays an important role in the formation and evolution of low-latitude plasma blobs. Inclination and declination may control the longitudinal distribution of plasma blobs.