Simultaneous observations of plasmaspheric and ionospheric variations during magnetic storms in 2011: First result from Chinese Meridian Project

Abstract

The plasma transport between the plasmasphere and ionosphere during magnetic storms is a long-standing problem and is still not fully understood. Simultaneous observations of the plasmasphere and ionosphere are vital to understand the coupling between the two regions. In this study, using the measurements from the newly developed Chinese ground-based space weather monitoring network (Meridian Project), we investigate the plasmaspheric density at L ≃ 2 inferred from ground magnetometers and the ionospheric electron density inferred by digital ionosondes and GPS signals during magnetic storms in 2011. Five moderate magnetic storms with minimum Dst index between -47 and -103 nT during this period have been investigated. The observations show that the plasmaspheric density drops significantly by more than half of the prestorm value. The ionospheric F2 layer electron density NmF2 and the total electron content (TEC) show ∼20-50% decreases, and the NmF2 and TEC reductions take place before the plasmaspheric density reaches its minimum. These findings suggest that the plasmaspheric depletion is very likely due to the reduced plasma supply from the ionosphere for the five moderate magnetic storms in 2011. Therefore, the plasmasphere dynamics seems to be controlled by the ionosphere during magnetic storms. © 2012. American Geophysical Union. All Rights Reserved.