Nonlinear energy transmission in the gap

Numerical simulations of the scattering of a linear plane wave incoming ont o a nonlinear medium (sine-Gordon) reveals that: (i) nonlinearity allows en ergy transmission in the forbidden band, (ii) this nonlinear transmission o ccurs beyond an energy threshold of the incoming wave, (iii) the process be gins (at the threshold) with large amplitude breathers, and then energy is generically transmitted both by kink-antikink pairs and breathers. (C) 2001 Elsevier Science B.V. All rights reserved.