A case study of the day-to-day occurrence of plasma irregularities in low-latitude ionosphere from multi-satellite observations

Abstract. Day-to-day variability of the occurrence of plasma irregularities in low-latitude ionosphere is still an open issue. In this study, we report the occurrence of post-sunset plasma bubbles and blobs detected by the First satellite of the Republic of China (ROCSAT-1) in the same longitude sector (170° E) on two successive days, under geomagnetically quiet and disturbed conditions, respectively. Multi-Low Earth orbit (LEO) missions, like the Defense Meteorological Satellite Program (DMSP) F13 and F15, the Gravity Recovery and Climate Experiment (GRACE) and the Challenging Mini-satellite Payload (CHAMP) satellites are used to study the preferable conditions for the occurrence of plasma bubbles and blobs. The observations from the CHAMP and GRACE show that the Equatorial Ionization Anomaly (EIA) was enhanced significantly before the occurrence of plasma irregularities on both two successive days. We suggest that the enhancement of post-sunset eastward electric field is the most important factor for the day-to-day development of the plasma irregularity in equatorial and low-latitude ionosphere. In addition, the meridional neutral wind plays an important role in the occurrence of low-latitude plasma blobs.