Assessing Surface Roughness Effect in Gyrotrons With the Gradient Conductivity Model

To accurately characterize the effect of the cavity surface roughness on the ohmic loss in gyrotron oscillators, this article proposes a method by using the gradient conductivity (GC) assessment model, in which a derived effective conductivity parameter is used to characterize the surface roughness. The results show that it has higher accuracy than the conventional methods such as the H-B formula, especially in the terahertz frequency band. This model also provides a reasonable explanation for the low-efficiency problem in terahertz gyrotrons, and it is beneficial to promote the design and analysis of gyrotrons.