Nonlinear absorption of a localized electron cyclotron wave

A theoretical model for nonlinear electron interaction with an electron cyclotron wave pulse is developed. The analysis is performed within the relativistic Hamiltonian formalism. In adiabatic conditions, the main features of the nonlinear interaction process in momentum space are pointed out, and an expression for the absorbed power density is determined. The results obtained are shown to be in good agreement with those given by numerical simulation codes.