110 GHz微波输出窗内表面次级电子倍增特性的电磁粒子模拟  

Electromagnetic particle simulation of secondary electron multipactor characteristics in inner surface of 110 GHz microwave output window

作　　者：舒盼盼 赵朋程[2] 王瑞[3] Shu Pan-Pan;Zhao Peng-Cheng;Wang Rui(School of Science,Xi’an University of Technology,Xi’an 710054,China;School of Physics,Xidian University,Xi’an 710071,China;National Key Laboratory of Science and Technology on Space Microwave,Xi’an Institute of Space Radio Technology,Xi’an 710100,China)

机构地区：[1]西安理工大学理学院,西安710054 [2]西安电子科技大学物理学院,西安710071 [3]西安空间无线电技术研究所空间微波技术重点实验室,西安710100

出　　处：《物理学报》2023年第9期259-269,共11页Acta Physica Sinica

基　　金：2021-JCJQ-LB-006重点实验室基金(批准号:6142411132116);陕西省自然科学基础研究计划(批准号:2023-JC-YB-512,2023-JCYB-042);中央高校基本科研业务费专项资金(批准号:ZYTS23075);中国博士后科学基金(批准号:2019M653545)资助的课题。

摘　　要：在输出窗内表面上,次级电子倍增是限制高功率微波功率容量的主要因素之一,因而开展相关研究具有重要的意义.在微波频率为110 GHz下,本文通过一维空间分布和三维速度分布的电磁粒子模型对次级电子倍增过程及其引起的损失功率进行了数值模拟.重点研究了介质表面处的微波电场和介质材料种类对损失功率的影响.模拟结果表明,在次级电子倍增达到稳态之后,尽管电子数密度高于临界的截止数密度,但是微波电场没有发生明显的改变.这是因为在很高的静电场下,电子主要聚集在介质表面附近若干微米的区域,远小于相应的趋肤深度.倍增稳态时的电子数密度随着微波电场升高而增加,然而损失功率与表面处的微波功率之比增加得较为缓慢.在倍增达到稳态之后,由于蓝宝石表面附近的电子数密度最高,石英晶体表面附近的次之,熔融石英表面附近的数密度最低,所以相应的损失功率依次减小.为验证模型的准确性,将倍增阈值的模拟值与实验数据进行了对比,并讨论了两者之间的差异.The secondary electron multipactor on the inner surface of the output window is one of the main factors limiting the power capacity of high power microwave.Therefore,it is of great significance to carry out relevant research.In this work,the process of secondary electron multipactor and the resulting loss of power are numerically simulated by using the electromagnetic particle model with one-dimensional spatial distribution and three-dimensional velocity distribution at the microwave frequency of 110 GHz.The influences of microwave electric field at the surface and dielectric material type on the power loss are studied.The simulation results show that the electron number density is higher than the critical cut-off number density after the secondary electron multipactor has reached the steady state,but the microwave electric field does not show obvious change.This is because the electrons in a very high electrostatic field are mainly concentrated in the domain of several micrometers near the dielectric surface,which is far less than the corresponding skin depth.The electron number density in the multipactor steady state increases with the microwave electric field increasing,but the ratio of the power loss to the microwave power at the surface increases slowly.After the multipactor reaches the steady state,the number density of electrons near the sapphire surface is the highest,followed by the number density near the crystal quartz surface,and the number density near the fused quartz surface is the lowest,so the corresponding power loss decreases successively.In order to verify the accuracy of the model,the simulated value of the multipactor threshold is compared with the experimental data,and the difference between them is discussed.

关 键 词：高功率微波 次级电子倍增 电磁粒子模型 

分 类 号：O572.322[理学—粒子物理与原子核物理] O441.4[理学—物理]