Search

In this work we describe the concept of an electron maser based on the excitation of the single supermode formed by a fixed set of transverse eigenmodes is proposed. The high-Q supermode is proposed as an operating mode. This mode is formed inside a simple cavity by a set of its eigenmodes. The supermode is high-Q due to the Talbot effect, namely, periodic reproduction of the transverse structure of a multimode wave field in an oversized waveguide. Two mirrors at the input and output of the waveguide provide the mode localization inside the cavity.

There is a concept of the amplifier based on a principally non-linear effect of reflection of an electron bunch from the powerful wave pulse. This is effective mechanism of energy extraction by the wave from particles, when parameters of the electron bunch (initial energy spread, bunch length and emittance) haven’t significant influence on the efficiency of the electron-wave interaction. Two schemes of possible realization of this process (non-resonant and resonant electron-wave interaction) are described.

An important problem in realization of gyrotrons operating at high cyclotron harmonics is discrimination of parasitic oscillations exited at lower harmonics. In this work, we describe various schemes of gyrotron cavities with short irregularities providing an improved selectivity of the high-harmonic operation.

In this work, we propose a method of particle acceleration by the electromagnetic wave pulse propagating in the waveguide. The method is based on a “superposition” the electron cyclotron oscillations in the uniform longitudinal magnetic field and their bounce-oscillations in the periodical transverse magnetic field (undulator). Correspondingly, two mechanisms of the electron accelerations by the wave are provided simultaneously, namely, the well-known cyclotron acceleration and the undulator acceleration in the regime of the inversed free-electron laser. The multi-resonance character of this system leads to a chaotic behaviour of the electron motion in the field of the wave. In the process of this motion, electrons can get a very high energy (as compared to the case of the purely cyclotron acceleration by the same wave pulse.

In low-power gyrotrons with weak electron-wave interaction, there is a problem of determining the optimal length of the operating cavity, which is found as a result of a tradeoff between the enhancement of the electron efficiency and the increase in the Ohmic loss share with increasing cavity length. In fact, this is the problem of an optimal ratio between the diffraction and Ohmic Q-factors of the operating gyrotron mode, which determines the share of the radiated rf power lost in the cavity wall. In this paper, this problem is studied on the basis of a universal set of equations, which are appropriate for a wide class of electron oscillators with low efficiencies of the electron-wave interaction.