We use the Solar, Anomalous, and Magnetospheric Particle Explorer to explore the relationship between microbursts and global flux decay of electrons from the outer Van Allen belt during the recovery phase of geomagnetic storms. We investigate the correlation between microbursts and global electron loss in each of the quasi‐trapped (drift loss cone), stably trapped, and untrapped electron (bounce loss cone) populations. For the quasi‐trapped electrons, we separately classify the storms as driven by coronal mass ejections or corotating interaction regions and explore their connection to microburst loss. We find that the decay lifetime of electron fluxes, that is, e‐folding times of macroscopic fluxes in the recovery phase is correlated with strong microburst activity. That is, when the microburst activity is high, global flux decay times are short, and vice versa, suggesting a cross‐scale coupling between microloss and macroloss phenomena. Furthermore, we find that the microburst to global loss coupling is predominant in the quasi‐trapped population of radiation belt electrons while having negligible influence on the untrapped and stably trapped populations. We find that microburst activity during storms driven by coronal mass ejections is coupled more strongly with global flux decay as compared with corotating interaction regions. In addition, we find that distance from the plasmapause is likely a better indicator of microburst location than L‐shell, with most microbursts occurring ~0.5–2.0 L from the model plasmapause location.

Solar wind structures act as critical drivers of magnetospheric dynamics, resulting in wave generation, magnetospheric reconfigurations, and geomagnetic storms. Magnetospheric responses, including particles and waves, to large-scale structures such as interplanetary (IP) shocks, interplanetary coronal mass ejections (ICMEs), and co-rotating interaction regions (CIRs) have been studied for decades. In particular, IP shocks have been shown to produce magnetosonic pulses that can propagate through the magnetosphere and resonate with MeV electrons, leading to particle acceleration and distinct drift echo signatures (e.g.,

We present an analysis of the relativistic electron precipitation (REP) event measured by the CALorimetric Electron Telescope (CALET) experiment on board the International Space Station during a relatively weak geomagnetic storm on 31 December 2016. CALET observations were compared with the measurements of the Van Allen Probes in the near‐equatorial plane to investigate the global radiation belt dynamics and the REP drivers. The magnetically conjugate observations from these two missions demonstrate that the significant MeV precipitation directly detected by CALET in low‐Earth orbit during a period of radiation belt depletion following the passage of a high‐speed stream, was associated with dusk‐side electromagnetic ion cyclotron (EMIC) waves. In addition, the combined wave, REP and trapped electron data suggest that the reported radiation belt depletion can be likely ascribed to the concomitant loss effects of EMIC wave scattering driving the atmospheric precipitation, as well as outward radial diffusion associated with magnetopause shadowing.