Study on the relationship between the Earth's plasmapause and geomagnetic activity

Based on the plasmaspheric images observed by IMAGE EUV imager, the plasmapause locations on the magnetic equatorial plane are reconstructed with the Minimum L Algorithm. 3579 plasmaspheric images are selected from 2000 to 2002 and a plasmapause location database is compiled containing 48899 plasmapause locations in 1 h MLT intervals. This database is used to statistically study the relationships between the plasmapause locations and the geomagnetic activities. It is found that the plasmapause shapes are highly dependent on the geomagnetic activities, and the plasmapause locations are negatively correlated with K-p, Dst and AE with their variation tendencies all significantly changing with MLT. It is also found that the effects of the substorm activity on the plasmapause locations are different under different geomagnetic conditions with the effects being larger for quiet periods compared with disturbed periods. The results in this paper will provide an important basis for future construction of a plasmapause model and understanding the dynamic structure of the plasmapause.