No abstract

A klystron-like gyro-amplifier based on the excitation of a wave propagating across a spatially developed (in the transverse direction) electron beam is described within the simplest 2-D model. Such a configuration is attractive as a way of implementation of a short-wavelength source with a relatively high level of output power and with the possibility of quasicontinuous frequency tuning. We study the peculiarities of the 2-D process (developing in both the axial and transverse directions) of electron bunching and “free” wave emission from the electron beam in the open drift space, as well as the excitation of the output cavity used to provide formation of a compact and powerful output wave signal. The main problem of this 2-D process is that different fractions of the electron beam (located at different points of its cross-section) move in different wave fields. In addition, excitation of the parasitic wave propagating in the opposite direction relative to the operating wave is possible. However, we show that it is possible to organize effective electron–wave energy exchange for almost all fractions of the electron beam.

In low-power short-wavelength gyrotrons with weak intensity of the electron–wave interaction, determining of the optimal parameters of the system is a result of a trade-off between the enhancement of the electron efficiency and the increase in the Ohmic loss share with an increasing cavity length. In this paper, we investigate the question of whether it is more advantageous to use operating regimes with a higher current at a fixed electron beam power, or whether it is better to increase the accelerating voltage. The answer to the question is determined strictly by the number of the operating cyclotron harmonic of the gyrotron.