Relativistic Electron Precipitation Driven by Nonlinear Resonance With Whistler‐Mode Waves

Electron losses from the outer radiation belt are typically attributed to resonant electron scattering by whistler-mode waves. Although quasi-linear diffusive regime of such is well understood, observed waves often quite intense and in nonlinear wave-particle interaction. Such interactions still being actively studied due their potential for driving fast precipitation. However, direct observations resonance with distributions scarce. Here, we present evidence high-resolution energy pitch angle spectra acquired at low-altitudes dual Losses Fields INvestgation (ELFIN) CubeSats combined conjugate measurements equatorial plasma parameters, wave properties, Time History Events Macroscale Interactions during Substorms Magnetospheric MultiScale missions. ELFIN has obtained numerous conjunction events exhibiting whistler driven precipitation; this study, two which epitomize signatures scattering. A test particle simulation prescribed equator employed directly compare modeled precipitation observations. We show that precipitating match expectations within observational uncertainties amplitude reasonable assumptions power distribution along magnetic field line. These results indicate importance effects when describing patterns energetic electrons open possibility remotely investigating properties using just spectra.