Multi‐pass whistler gain in a magnetospheric cavity due to induced nonlinear scattering

Multi‐pass gain in whistler energy is possible in the radiation belts if the wave amplitude is sufficiently large. Large amplitude magnetospherically reflected whistlers can induce nonlinear scattering and form a magnetospheric cavity filled with nearly isotropic spectrum of wave vectors perpendicular to the magnetic field with low obliqueness. This increases the wave‐particle resonance time and maintains a large pitch angle scattering rate. Enhanced pitch angle scattering and precipitation of trapped electrons into the radiation belt loss cone provides a proportionate gain in the whistler energy.