Understanding how geomagnetic fields change in response to solar activities,  how energetic charged particles transport within the magnetosphere-ionosphere system, and how the ionosphere varies are among the most important research topics of the solar wind-magnetosphere-ionosphere coupling area. Knowing these physical processes and interactions therein can crucially promote the space weather forecasting capability. 

Methods：MHD models, spacecraft measurements 

The Earth inner magnetosphere (within 3-7 Earth Radii around the Earth) is composed of different populations with various energies, including cold plasmasphere, warm ring current, and energetic radiation belts. These populations overlop in space and interact closely with each other, leading to highly dynamic environment that may pose threats on orbiting spacecraft. It is therefore important to understand the dynamics of these inner magnetosphere populations and their coupling with plasma waves as well as with other regions (e.g., ionosphere and magnetotail). 

Methods：kinetic model, spacecraft measurements ,test-particle tracing technique