Eigenvalues and Ohmic Losses in Coaxial Gyrotron Cavity

The authors present the mathematical analysis for the calculation of the dispersion relation, the field distributions, and the ohmic losses for TEm,pmodes in an infinite coaxial waveguide with a longitudinally corrugated insert. The method employed is based on an appropriate eigenfunction expansion, and its main advantage is the very fast convergence with a few spatial harmonics. The analysis is properly extended to include tapered cavities with varying, in respect to the z-coordinate, outer and/or inner radius. Numerical results are presented for several tapered cavity geometries and compared with already published methods