Saurova T. O-type microwave amplifiers with excitation of electron bunches by an electromagnetic wave field

The thesis is dedicated to modeling of physical processes and development of new ways of high-performance amplification in non-relativistic auto-phase O-type microwave devices, amplification modes optimization that can improve weight and size, and performance characteristics of the devices. The mathematical nonlinear model of the auto-phase multi-ray TWT, and TWT with azimuthally asymmetric wave (self-phasing traveling-wave tube) at the increased focusing magnetic field at which the cyclotron frequency is greater than twice the angular frequency signal were developed. Analytical nonlinear models enable: with the use of Lyapunov theory to determine stability conditions for the trapped wave bunches of electrons corresponding to the slow and relatively rapid parameter changes of the electrodynamic system, with the space-charge field; to optimize the conversion of the electron bunches energy to the energy of electromagnetic wave in auto-phase mode with increasing of longitudinal gain coefficient of a device and maintaining high values of electron efficiency. For test modifications of the auto-phase TWT the analytical expressions for the optimal laws of profiling of the increased focusing magnetic field and the phase velocity of the wave were found. The implementation of the optimal laws in the device design will lead to decrease of the length of the electrodynamic system by 1.3 - 2 times, and, as a result, to decrease of the device size and weight. On the base of the proposed analytical models, the techniques for simplified calculation of the self-phasing traveling-wave tube basic characteristics are developed thereby reducing the time of the devices conceptual design.