Radiation from a charged particle travelling parallel to a rough surface has
been considered. Spectral-angular intensity is calculated in the weak
scattering regime. It is shown that the main contribution to the radiation
intensity is determined by the multiple scattering of polaritons induced by a
charge on the surface. Multiple scattering effects lead to strong frequency
dependence of radiation intensity. Possible applications in beam and surface
diagnostics are discussed.Comment: submitted to Europhys.Let
