About theory of hybride TWTO and an amplifire with a complex permittivity

The purpose of this work is to construct a nonlinear theory of a hybrid between travelling wave tube (TWT) and an amplifier with a complex permittivity. Methods. The following model is considered: an ion-compensated one-dimensional electron beam penetrates the input travelling wave tube section, then flies into a medium with a complex permittivity, and then enters the output travelling wave tube section. A linear theory of this hybrid is constructed, and its results are compared with the results of the well-known linear theory of travelling wave tube. A nonlinear theory of this hybrid was constructed by a modified wave method, and the results were compared with the nonlinear travelling wave tube theory obtained by the classical Ovcharov–Solntsev’s wave method. In addition, to test the limits of applicability of the obtained results, a stationary nonlinear theory of the hybrid was constructed, obtained using the large particle method. The results of this theory were also compared with the stationary nonlinear travelling wave tube theory constructed using the large particle method. Results and conclusion. Based on the results of the developed theories, it is shown that, under certain parameters, the linear theory and nonlinear theories (both by the modified Ovcharov–Solntsev’s wave method and by the large particle method) make it possible to obtain comparable results both in the case of a classical travelling wave tube and for the hybrid under study. It is shown that under certain parameters, due to the resistive instability, the bunching of electrons can be noticeably improved and, as a result, the gain of the hybrid can exceed the gain in a classical travelling wave tube with the same parameters and the same total length of the device in the linear mode of operation. In the nonlinear mode of operation, the specified hybrid, with optimal environmental parameters, can have significantly higher values of output power and efficiency than travelling wave tube with the same value of the space charge parameter and the Pierce parameter.