Non-linear mode-mode coupling at a plasma-vacuum transition layer

An investigation is made of wave generation at combination frequencies for the oblique incidence of polarized electromagnetic waves on a semi-bounded plasma when the width of the plasma-vacuum transition layer is much less than the wavelength. The amplitudes of the waves radiated at combination frequencies are calculated. It is shown that the tangential electric field components of the waves at the combination frequencies are discontinuous at the plasma boundary. This explains the differences in our results from the corresponding results of earlier papers in which the tangential electric field components of higher harmonics at the plasma boundary were assumed to be continuous.