Ducted Chorus Waves Cause Sub?Relativistic and Relativistic Electron Microbursts

During magnetospheric storms, radiation belt electrons are produced and then removed by collisions with the lower atmosphere on varying timescales. An efficient loss process is microbursts, strong, transient precipitation of over a wide energy range, from tens keV to sub-relativistic relativistic energies (100s above). However, detailed generation mechanism especially energies, remains unknown. Here, we show that these energetic electron microbursts may be caused ducted whistler-mode lower-band chorus waves. Using observations equatorial waves nearby low-altitude as well data-driven simulations, demonstrate observed result resonant interaction rather than nonducted ones. Revealing physical behind advances our understanding dynamics its impact space weather.