Chaotic electric motion driven by whistler waves in the magnetosphere

In the magnetosphere, energetic charged particles are trapped by Earth's magnetic field. When a large amplitude whistler wave is present, the particles' trajectories become perturbed from uniform bouncing motion. Particularly when the wave frequency approaches a sub-harmonic of the cyclotron frequency. The nonlinear interaction due to the spatial dependence of the fields leads to chaos in the particle trajectories. This can lead to scattering into the loss cone, and offers a possible explanation to the observed electron precipitation into the polar regions