COALESCENCE OF ELECTROMAGNETIC TRAVELING WAVES IN A SATURATED FERRITE

We investigate how dissipation and nonlinearity affect an electromagne tic perturbation propagating into a saturated ferromagnet in the prese nce of an external magnetic field. We study the problem in (1+1) and ( 2+1) dimensions. It is found that at lowest order of the perturbation theory, the Burgers' equation in (1+1) dimensions governs such dynamic s. In (2+1) dimensions we show that the phenomena obeys a nonlinear ev olution equation (non-integrable) of Burgers type. We give exact solut ions which describe in (1+1) dimensions the propagation of a travellin g electromagnetic wave and the coalescence of N travelling fronts and in (2+1) dimensions the propagation of a nearly one-dimensional travel ling front. We establish, in terms of the physical parameters of the s ystem, whether breaking or diffusion of the initial perturbation domin ates.