On applicability of absorbing rectilinear electron beams in high-frequency gyrotrons operating at cyclotron harmonics

This paper presents the studies of electron–wave interaction in a high-frequency harmonic gyrotron with an additional absorbing rectilinear electron beam. The expression for the starting current of the gyrotron in the presence of an absorbing beam is obtained within the model of a fixed axial field structure. We investigate the effectiveness of mode selection by absorbing beam in gyrotrons with different resonator lengths to wavelength ratios on the basis of simple theory, as well as the results of numerical simulation within a self-consistent model.