Radiation losses of charges and charged particle beams moving near inhomogeneties

Investigations have been made on the radiation of charges in proximity to two model nonuniformities (a thin metal tape and a hole in a shield of finite thickness). In the first problem the field source is a thin filament charo.ed at a constant linear density. The second structure is excited by a point charge moving along the axis of the hole. The hole radiation field is a single pulse whose maximum value exactly corresponds to the instants of the charge entry into and escape from the hole. Also present in this field, in addition to the single pulse, are almost harmonic oscillations the amplitude of which is two-three orders of magnitude less than the pulse amplitude