ELECTRODYNAMICS AS A PROBLEM OF EIGENVALUES .3. MAXWELL OPERATOR AND PERTURBATION-THEORY

This part of the work deals with perturbation theory. The standard tec hnique permits us to solve problems of volume disturbances in free spa ce, waveguides, and cavities, of disturbances of boundary conditions c aused by finite conductivity of walls, and of disturbances of the boun dary shape. Expressions for frequency and wave number shifts caused by the perturbation are obtained by the unified method. Several examples are presented: wave amplification in the waveguide filled with a reso nant medium like an electron beam in a longitudinal magnetic field, th e frequency shift (and increment/decrement) of a cavity loaded by an e lectron beam, and the field disturbance in the waveguide caused by fin ite conductivity of the walls. (C) 1996 American Institute of Physics.