ACCURACY OF EIGENVALUE OBTAINED WITH HYBRID ELEMENTS ON AXISYMMETRICAL DOMAINS

Eigenvalues of dipole modes in a cylindrical cavity and a spherical ca vity were calculated with hybrid triangular elements assuming the sin m theta and cos m theta dependencies of the field, and compared with t heir analytical values. The elements are a combination of linear edge elements for r- and z-components and quadratic nodal elements for the azimuthal one. Because two out of eight degrees of freedom in the line ar edge element are internal, they are often omitted. The 14-parameter elements showed a quadratic convergence on mesh refinement, while the 12-parameter ones showed the linear rate like constant edge elements.