Mapping for nonlinear electron interaction with whistler-mode waves

The resonant interaction of relativistic electrons and whistler-mode waves is an important mechanism of electron acceleration and scattering in the Earth radiation belts and other space plasma systems. For low amplitude waves, such an interaction is well described by the quasi-linear diffusion theory, whereas nonlinear resonant effects induced by high-amplitude waves are mostly investigated (analytically and numerically) using the test particle approach. In this paper, we develop a mapping technique for the description of this nonlinear resonant interaction. Using the Hamiltonian theory for resonant systems, we derive the main characteristics of electron transport in the phase space and combine these characteristics to construct the map. This map can be considered as a generalization of the classical Chirikov map for systems with nondiffusive particle transport and allows us to model the long-term evolution of the electron distribution function.