Stochastic Analysis Of The Process Of Multicarrier Multipactor

In this dissertation, assisted by Random walk theory and the nonstationary multipactor theory for long-term multicarrier signals, approach with active elements, research on active metamaterials with strong microwave responses of nonlinearity and gyroelectricity were conducted.Multipactor effect is a high power radio-frequency (RF) breakdown occurring in vacuum or near vacuum microwave systems. In the multipactor discharge, electrons impact against the device surfaces while accelerated by the electromagnetic fields. Secondary electrons are released after each impact, due to secondary electron emission, developing an exponential charge growth which ultimately produces an electron discharge. Its effects range from signal degradation to the complete destruction of the component. Hence, the design of multipactor-free components is essential for the microwave industry, especially for RF space systems and particle accelerators.Recently, a new mechanism of secondary electron multipaction, termed "long-term" multicarrier multipactor, was found in wideband high-power systems used in vacuum environments. Due to the long-term accumulation of secondary electrons between consecutive periods of the multicarrier signal, the long-term multicarrier multipactor has relatively low discharge threshold and is difficult to predict, thus causes potential reliability problems in in space and accelerator applications. In this paper, we propose a stochastic approach for the analytical analysis of the multicarrier multipactor discharge occurring in inhomogeneous electric fields. By introducing the random walk and Levy walk theory, the probabilistic model of the lateral diffusion of secondary electrons in the process of a multipactor discharge is derived. Based on the derived probability density, pure theoretical calculation of the accumulation of secondary electrons of a multicarrier multipactor in a rectangular waveguide supporting TE10mode is given. The theoretical results comply well with the results achieved by the time-consuming particle simulation, while costs one-order less computational time.The presented probability density of the lateral diffusion of secondary electrons can be used in a wide range of applications in the areas of high-power electronics and electromagnetism.