Speaker
Description
Accurate modeling of inner magnetospheric dynamics requires quantifying the cross-scale coupling processes that control electron transport, acceleration, and loss. Recent results indicate that ring current models tend to overestimate electron fluxes in the 10–50 keV energy range during geomagnetic storms, suggesting that an important loss mechanism is missing in the pre-midnight sector. Previous studies have shown that electrostatic electron cyclotron harmonic (ECH) waves and time domain structures (TDS) can efficiently scatter electrons from hundreds of eV to several keV, depending on wave intensity, and may therefore contribute to this unresolved loss process. These processes couple plasma sheet injections and wave generation to the evolution of electron populations in the inner magnetosphere.
In this study, we analyze the efficiency of ECH wave scattering during a geomagnetic storm on 17 March 2013 by computing quasi-linear bounce-averaged diffusion rates, and we further estimate pitch-angle diffusion coefficients due to TDS. The resulting lifetimes are incorporated into simulations with the 4D Versatile Electron Radiation Belt (VERB-4D) code. Our results show that while ECH waves scatter electrons across a wide energy range, the associated lifetimes are too long to substantially modify pitch angle distributions. Including TDS scattering leads to a reduction of the overestimated electron flux, but the effect is too small to fully explain the missing loss process in the inner magnetosphere. These results suggest that additional mechanisms, possibly including ECH wave and TDS scattering at larger radial distances (L > 6), need to be considered to capture the full extent of storm-time electron losses.
