No abstract

This paper investigates the microwave breakdown threshold in a circular waveguide excited in the lowest order (TE11) mode, where the electric field strength depends on both the radius and the azimuthal angle. This analysis complements and extends previous investigations of breakdown in cylindrical waveguides and resonators that have been restricted to circularly symmetric waveguide modes so far. A simple analytical approximation of the breakdown threshold of the TE11 mode is found, using a direct variational approach. The predictions are compared with the results of numerical calculations and the agreement is found to be very good.

In the present work, the microwave breakdown threshold in a gas-filled spherical resonator, is determined for the case when the cavity is excited in its lowest order mode, which implies that the microwave field strength depends on both radius and azimuthal angle. A semi-analytical approximation of the breakdown threshold is found using a direct variational approach. The variational predictions are compared with the results of full numerical calculations and demonstrate very good agreement