高功率微波介质窗表面电子倍增二维粒子模拟

基于第一性原理的粒子模拟方法,对高功率微波器件中介质窗表面电子实际形成和发展的变化情况进行了研究。使用VORPAL粒子模拟软件,建立一个简单的TEM波垂直入射介质窗表面的二维模型,采用Vaughan二次电子发射模型,利用蒙特卡罗碰撞方法处理电子与背景气体之间的弹性碰撞、激发碰撞和电离碰撞,获得了介质窗表面电子倍增的图像。模拟结果表明,介质窗表面电子数量在一定的时间内达到饱和状态,其振荡频率是入射射频电场频率的两倍。改变初始发射种子电子的数量、入射射频电场的幅值以及背景气体的压强等关键性参数,可得到不同条件下介质窗表面电子数量的变化规律。

Two dimensional particle-in-cell simulation of electron multipactor on high power microwave dielectric window surface

Based on the particle-in-cell (PIC) simulation method of the first principle, this paper studies the situation about formation and development of the electron process on the dielectric window surface in high power microwave (HPM) devices. We establish a simple two-dimensional model that the TEM wave irradiates the dielectric window surface vertically with the PIC simulation software VORPAL, employ the Vaughans secondary electron emission model, utilize Monte Carlo collision model to deal with the elastic collision, the excitation collision and the ionization collision between electron and background gas, and acquire the electron multipactor images on the dielectric window surface. The simulation results show that the electron number on the dielectric window surface reaches saturation in a period of time and its oscillation frequency is twice as much as that of the incident electric field. Changing the initial emissive number of the seed electrons, the amplitude of the incident electric field and the pressure of the background gas, we can obtain the variation of the electron number on the dielectric window surface in different conditions.