Abstract
The applied method of slowly varying amplitudes gives us the
possibility to reduce the nonlinear vector integrodifferential
wave equation of the electrical and magnetic vector fields to the
amplitude vector nonlinear differential equations. Using this
approximation, different orders of dispersion of the linear and
nonlinear susceptibility can be estimated. Critical values of
parameters to observe different linear and nonlinear effects are
determined. The obtained amplitude equations are a vector version
of