Traveling wave gyrotron with double mode operations

Kinematics theory is formulated. The traveling wave gyrotron (TWG) at interaction with a previously rectilinear relativistic electron beam (REB) with connected E₁₁ and H₁₁ waves of a goffered waveguide has been investigated. It was shown that a TWG with thin REB has a mechanism which is independent from the initial electron input phase that allows prediction of the high efficiency of the device, which is nearing 100%. It is revealed that outlying electrons of a wide REB in a TWG have a combined Cherenkov-gyrotron type of interaction with waves E₁₁ and H₁₁, since the efficiency of a TWG with wide REB is much higher than in resonance gyrotrons.