Nonlinear Surface Waves in a Strongly Inhomogeneous Plasma

Abstract

A nonlinear Schrodinger equation which governs the slow modulation of high-frequency surface waves is derived. This evolution equation is obtained from a nonlinear dispersion relation, derived for a weakly nonlinear semi-infinite cold plasma, where effects of the finite transition layer are taken into account. The fact that the surface wave frequency coincides with the local plasma frequency somewhere inside the transition layer results in a strongly peaked electric field and a significant modification of previously derived dispersion relations assuming a sharp boundary. The consequences of the weakly nonlinear assumptions are discussed.