Nonlinear propagation of electromagnetic ion-cyclotron waves in an electron-ion plasma in the presence of ion temperature gradient drift

Nonlinear coupling between the electromagnetic ion cyclotron waves and the background ion-temperature gradient drift modes is investigated in an electron-ion plasma. This interaction is governed by a system of two coupled equations consisting of a nonlinear Schroedinger equation for the electromagnetic wave envelopes and a dynamical equation, derived from the Braginskii's fluid model, for the drift fluctuations. A general dispersion relation for the nonlinear electromagnetic waves is derived, and modulational (with two branches) and filamentational instabilities are shown to exist. The nonlinear electromagnetic wave envelopes are also found to have a stationary localized structure. The importance of our investigation is discussed. (orig.)