Abstract: Energetic electron precipitation (EEP) into Earth’s upper atmosphere is a key mechanism regulating the dynamics of the outer radiation belt. By scattering electrons into the atmospheric loss cone, precipitation both depletes the radiation belt population and couples magnetospheric processes to the upper atmosphere. Plasma waves play a central role in this process. In particular, whistler-mode chorus waves and lightning-generated whistlers drive pitch-angle scattering that produces short-lived but intense bursts of precipitation, as well as more continuous fluxes. Recent observations from CubeSats (ELFIN), balloon campaigns (BARREL), and LEO satellites (SAMPEX) provide detailed measurements of such precipitation. Simulations of events observed by these spacecrafts reveal multiple linear and quasi-linear processes that together drive precipitation, which will be discussed in this presentation.
Beyond these linear and quasi-linear processes, nonlinear wave–particle interactions are increasingly recognized as critical. For intense chorus waves, anomalous nonlinear interactions—recently revisited after being overlooked for decades—can inhibit precipitation by trapping electrons outside the loss cone. This challenges long-standing theoretical assumptions and modifies estimates of radiation belt loss rates. Recent studies on the role of nonlinear interactions in precipitation will also be presented.

Hosted by Professor Robyn Millan

Join Zoom meeting

https://dartmouth.zoom.us/s/99960465228

Email Rowan.m.kowalsky@dartmouth.edu for passcode