Transformation of radiation by appearance of a cylindrical plasma inclusion in a waveguide

The excitation of electromagnetic field by a line emitter in microcavity with time-varying plasma is considered. The microcavity is made up in a planar dielectric waveguide by a circular cylinder of the plasma. The cylinder is perpendicular to perfectly conducting plates of waveguide boundaries that simulates semiconductor layers of very high conductivity. It is assumed that until zero moment of time the waveguide was filled with some homogeneous dielectric medium. At zero moment of time, homogeneous time-varying plasma is created by an extrinsic source inside a cylinder of some finite radius. A vertical driving line current that is co-axial to the cylinder and has an arbitrary temporal dependence excites the electromagnetic field in the whole system. This current is considered as a sort of light emitter model and can be turned on at arbitrary moment, either before or after plasma appearance.