Components for the cold-testing of a co-harmonic gyrotron

A key design process in the construction of a waveguide component is the cold-test stage, involving measuring the response of the component to radiation, propagating with a specific electromagnetic mode and a certain frequency, or range of frequencies. However, for components that require high order modes, such as resonant cavities used in high-power¹, or high-harmonic gyrotrons, it can be challenging to generate the necessary mode. A scheme for co-harmonic generation of radiation through the cyclotron resonance maser instability has been proposed^2,3, involving the generation of two harmonics of the cyclotron frequency, with the electromagnetic modes stimulated being the TE_2,2 and TE_4,3.