This thesis focuses on ULF (Ultra-low-frequency) waves' interaction with
plasmasphere particles and ring current ions in the inner magnetosphere.
It first reports and reveals mutual effect between ULF waves and
plasmasphere using Van Allen Probes data. The differences and
similarities of different ring current ions interacting with ULF waves
are extensively explored using Cluster data, which provides a potential
explanation for O+-dominated ring current during the magnetic
storms. Furthermore, this thesis finds a method to study the phase
relationship between ULF waves and drift-bounce resonant particles, and
proposes that the phase relationship can be used to diagnose the
parallel structure of standing wave electric field and energy transfer
directions between waves and particles. The findings in this thesis can
significantly promote our understanding of ULF waves' role in the
dynamics of inner magnetosphere.