Nonlinear effects produced by continuous electromagnetic waves propagating in weakly dissipative plasmas

A general perturbation method, founded on the multiple-space-scales technique, is applied to the kinetic analysis of the nonlinear effects generated by continuous transverse electromagnetic waves of finite amplitude propagating in warm and partially ionized plasmas. The collisional and weakly collisional cases are successively studied for a typical ordering of the significant parameters. In each case, it is first shown that the zero-order electron distribution function is determined by a set of two coupled equations and that it becomes inhomogeneous and generally non-Maxwellian under the effect of the collisional heating due to the wave absorption in the medium. The electron distribution function and the electric field inside the plasma are then completely determined up to second order in terms of the zero-order quantities by exact formulas which allow discussion of the influence of the microscopic interaction law on the nonlinear behavior of the medium. Some other applications of this method are outlined, particularly for the case of amplitude-modulated electric fields.