Nonlinear resonances of electrons with quasi-periodical whistler mode emissions

Abstract:

Resonant electron scattering by whistler-mode chorus waves is one of the main drivers of the electron precipitation into the Earth’s atmosphere. Electron scattering by whistler waves modulated by ultra-low-frequency (ULF) waves can lead to variations in the electron precipitation. In this presentation we consider two-pronged impact of the ULF waves on the resonant interaction of electrons with whistlers. First, ULF waves modulate the whistler waves; and second, ULF waves directly affect electron distribution functions. We implement THEMIS observations of ULF waves and modulated whistler waves to perform numerical simulations of electron dynamics. We show how the quasi-linear and nonlinear regimes of electron scattering by whistlers interchange within one ULF period and how this interplay of the two regimes affect the electron scattering (precipitation) rates.