Method to decrease ohmic losses in cavities of low-power terahertz gyrotrons

In sub-THz and THz gyrotrons with oversized cavities, there is the problem of implementation of stable single-mode generation in modes, operating at high cyclotron harmonics. It is shown that a high fraction of ohmic losses in sub-THz and THz gyrotrons affects not only the efficiency and output power, but also affects the stability of the operating regime. A cooling the gyrotron cavity to cryogenic (nitrogen) temperatures as one of the promising methods for reducing ohmic losses in terahertz gyrotrons is considered.