MODULATIONAL INSTABILITY OF SURFACE PLASMA-WAVES IN THE 2ND-HARMONIC RESONANCE REGION

The propagation of nonlinear surface waves in a semibounded cold elect ron plasma is studied with allowance for nonlinearities related to the motion of both space and surface charges, as well as for the plasma r esonance at the second harmonic of the fundamental frequency of a surf ace wave. Equations for the slowly varying amplitudes of oscillations at the first and second harmonics of the fundamental frequency of a su rface wave are derived. With allowance for these factors, the regions are determined in which the envelope solitons can propagate and the mo dulational instability can occur.