The microinjection is a phenomenon observed by spacecraft in the magnetosphere, exhibiting a repetitive dispersive electron signature similar to classical substorm-associated injections. Early studies attribute the formation mechanism to the electron source. For example, Sarafopoulos (2002, GRL) postulated the existence of a sharp and meandering injection boundary near the geosynchronous orbit and this boundary could supply energetic electrons, causing pulsating injections into the earthward region. In a recent study using MMS data, Luo et al. (2022, GRL) suggested that the drift resonance between electrons and ULF toroidal waves may serve as a potential driving mechanism. Building on the drift resonance theory, they provide an explanation for the phase differences observed in the flux during microinjection events. In this study, we utilize an analytical model for ULF Toroidal mode waves to replicate the observed magnetic and electric fields. Subsequently, using the reproduced field model and a test particle simulation method, we investigate the dynamics of electrons during the microinjection event. The simulated electron flux exhibits characteristics similar to the observations, suggesting the validity of the drift resonance theory in explaining microinjection phenomena.

Microinjection,Wave-particle interaction,ULF Toroidal mode