Towards estimation of the effects of misalignment of electron beam injected into a high power gyrotron with depressed collector

The simulation of gyrotron operation starts with the assumption that the axis of the hollow electron beam is perfectly aligned with the axis of the tube into which it is injected. In practice there is likely to be some degree of misalignment between the two. It is desirable to estimate the effects on the operation of the tube vis-a-vis the degree of misalignment. In a tube with depressed collectors, the effects on collector efficiency and on the heat dissipation density profile are of particular interest. When the two axes do not coincide, ideally speaking the simulation of the electron beam trajectories would need a 3D code. However, for small deviations from perfect alignment, it is possible to get an initial estimation of the effects by using an approximation. Results from such an approximation are the subject of this paper.