Tens to Hundreds of keV Electron Precipitation Driven by Kinetic Alfvén Waves During an Electron Injection

Electron injections are critical processes associated with magnetospheric substorms, which deposit significant electron energy into the ionosphere. Although wave scattering of <10 keV electrons during has been well studied, link between magnetotail and energetic (≥100 keV) precipitation remains elusive. Using conjugate observations Loss Fields Investigation (ELFIN) Magnetospheric Multiscale (MMS) missions, we present evidence tens to hundreds ionosphere potentially driven by kinetic Alfvén waves (KAWs) magnetic field gradients. Test particle simulations adapted show that dipolarization-front gradients ∇B drifts allow Doppler-shifted Landau resonances injected KAWs, producing spatial across front results in pitch-angle decreases subsequent precipitation. such KAW-driven can account for ELFIN below ∼300 keV.