Ponderomotive force effects on slow-wave coupling

Localized plasma density depressions are observed to form near a multi-ring slow-wave structure when the value of the nonlinearity parameter, s = ω2/sub p/eVertical BarE/sub z/Vertical Bar2/8πω2nkappaT, is of order unity. Consequent changes in the wave propagation and coupling efficiency are reported. For large enough values of s, the coupling efficiency may be reduced by 50% from the linear value