Simultaneous Observations of Localized and Global Drift Resonance

In this study, we present Van Allen Probe observations showing that seed (hundreds of keV) and core (greater than or similar to 1 MeV) electrons can resonate with ultra-low-frequency (ULF) wave modes with distinctivemvalues simultaneously. An unusual electron energy spectrogram with double-banded resonant structure was recorded by energetic particle, composition, and thermal plasma (ECT)-magnetic electron ion spectrometer (MagEIS) and, meanwhile, boomerang stripes in pitch angle spectrogram appeared at the lower energy band. A localized drift resonance withm = 10 wave component was responsible for the resonant band peaked at similar to 200 keV while a global drift resonance withm = 3 component gave rise to the upper band resonance peaked at similar to 1 MeV. Time-Of-Flight on boomerang stripes suggested that the localized drift resonance with similar to 200 keV electrons was confined within the plasmaspheric plume. Electron flux modulations were reproduced by numerical simulations in good consistency with the observations, supporting the scenario that localized and global drift resonance could coexist in the outer belt electron dynamics simultaneously.