Absorption of electromagnetic radiation in a plasma with density jump

The possibility of significant absorption of the s-polarized component of radiation on a density jump in a plasma is shown in an analysis of the nonlinear stage of saturation of surface noise related to the mechanism of secondary parametric excitation by growing oscillations of surface waves. The analysis concerns a plasma with nonhomogeneous particle density profile varying smoothly everywhere except in a neighborhood of a critical point where the frequency of a normally incident electromagnetic wave equals the electron Langmuir frequency. Nonpotential surface oscillations are parametrically excited, and the level of turbulence of these oscillations is calculated along with the pump field dissipation rate.