ENERGY LOCALIZATION IN NONLINEAR LATTICES

We discuss the process by which energy, initially evenly distributed i n a nonlinear lattice, can localize itself into large amplitude excita tions. We show that the standard modulational instability mechanism, w hich can initiate the process by the formation of small amplitude brea thers, is completed efficiently, in the presence of discreteness, by e nergy exchange mechanisms between the nonlinear excitations which favo r systematically the growth of the larger excitations. The process is, however, self-regulated because the large amplitude excitations are f inally trapped by the Peierls-Nabarro potential.