Simulations of powerful microwave oscillators with oversized electrodynamics systems

Nowadays, various types of numerical codes are effective tools for analysis and optimization of electron microwave devices. Special codes are widely used to simulate the microwave components, the electron-optical system, and nonlinear dynamics. Nevertheless, up to now most of the simulations related to electron optics and electron-wave interaction were restricted by exploiting 2D self-consistent numerical models. At the same time, the state-of-the-art high-performance computational clusters combined with modern commercial codes look sufficient for 3D physical modeling of vacuum electronic devices with strongly oversized interaction space. The paper is devoted to review of recent results of the CST STUDIO SUITE particle-in-cell (PIC) simulations of broad class of relativistic and sub relativistic microwave oscillators and amplifiers. In this report we consider terahertz-band gyrotrons with conventional cylindrical and planar configurations of the interaction space [1–3]. Here we discuss generators operating at the fundamental harmonic, as well as at the second and third harmonics. For improvement of stability of high cyclotron harmonic operation regime, multiple-beam schemes of gyrotrons are investigated [2]. Studies of relativistic surface wave Cherenkov oscillators with 1D and 2D periodical slow-wave structures were investigated [4, 5]. For all models comparison with experimental data and results of theoretical consideration based on simplified averaged equations are carried out. This analysis demonstrates that at present stage 3D PIC simulations can be considered as an effective tool for design and development of new schemes of powerful microwave generators and amplifiers. In addition, with the use of modern graphics processing units, it is possible to optimize parameters of electron devices for improvement characteristics within a reasonable calculation time.