Modifications introduced in the nonlinear whistler-electron interaction by parallel electric fields

Large scale magnetospheric parallel electric fields expected to occur beyond the plasmapause modify the nonlinear behaviour of the cyclotron resonance between electrons and coherent whistler mode waves. Enhancement of the effects originated in the interaction requires waves of varying frequency which might be generated in natural emissions, or artificially injected into the magnetosphere. Adopting a static electric field model based on a differential pitch-angle anisotropy in the geomagnetic mirror the evolution of the resonant particles and the adequate ground transmitter frequency format is contrasted with the corresponding results for the zero electric field case. The outcome, obtained for a field line with L = 6.2, demonstrates the strong influence of the parallel electric field on the nonlinear cyclotron resonance. (author)