Computational Studies on the Suppression of Parasitic Oscillations in Gyrotron Beam Tunnels

Parasitic oscillations frequently appear in several modern gyrotron beam tunnels. In this paper, the CST Studio Suite is used to study the performance of dielectric-loaded beam tunnel designs in attenuating the spurious modes. Two common designs are considered and the effect of the ceramic material's dielectric constant on the beam tunnel's performance is studied. For this purpose, the ohmic quality factor Q
_ohm
and the normalized shunt impedance R/Q are calculated to measure this performance. These studies focus on the backward propagating axisymmetric parasitic modes.