Modeling of Bouncing Electron Microbursts Induced by Ducted Chorus Waves

Short-lived (<1 s) but intense electron precipitation, known as "microbursts," may contribute significantly to electron losses in the outer radiation belt. Their origin has been suggested to correlate with resonant scattering by whistler-mode chorus waves, but existing models cannot fully explain the properties of microbursts, in particular, the bouncing electron packets in the form of a microburst that have been recently observed. A numerical model is presented that reproduces a series of electron bounce packets in response to individual chorus elements. Results indicate that the actual precipitation only occurs in the leading electron packet whereas subsequent packets form because of the following bounce motions of remaining fluxes. An analysis based on wave propagation and resonance condition yields an approximate time-energy regime of electron microbursts. Such a model is valuable for interpreting and modeling low Earth-orbiting satellite observations of electron flux variation in response to the interaction with magnetospheric chorus waves.