• Magnetosphere: Whistlers

In this paper, the so-called triggered emissions of whistlers are considered. The effects of a nonlinear interaction between a whistler wave and the particles resonating with it are considered in some detail. The interaction gives rise to two closely related effects, namely a change in the amplification or absorption by the plasma, and a phase-bunching of the resonant and near-resonant particles, thus giving rise to a current. The current due to the phase-bunched particles has roughly the same structure (frequency and wave number) as the wave causing it, and will therefore give rise to emission of a new whistler wave, acting like an antenna. The possibility of having a self-sustained process of phase-bunching and emission is investigated. The structure of a region where this process can take place is proposed, and the corresponding conditions that must be met are stated.