横磁模下介质表面二次电子倍增的抑制  

Suppression of secondary electron multipactor on dielectric surface in TM mode

作　　者：李爽[1,2] 常超[1,3] 王建国[1,2] 刘彦升[1] 朱梦[1] 郭乐田 谢佳玲[1] 

机构地区：[1]西北核技术研究所高功率微波重点实验室,西安710024 [2]西安交通大学电子与信息工程学院,西安710049 [3]西安交通大学电子物理与器件教育部重点实验室,西安710049

出　　处：《物理学报》2015年第13期380-387,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:1110518;61231003)资助的课题~~

摘　　要：在介质加载加速器结构(DLA)内,提出采用刻槽结构结合外加磁场的方法用于在电磁场横磁(TM)模式下抑制介质表面的电子倍增.通过理论分析和数值模拟,比较了刻槽结构和纵向磁场对斜面上电子碰撞能量和渡越时间的影响,得到了在介质表面同时存在法向RF电场及切向RF电场时,采用刻槽结构并施加一定的纵向磁场强度,可有效抑制二次电子倍增的发展,提高介质面的击穿阈值.To suppress the secondary electron multipactor on dielectric surfaces of a dielectric load accelerator under an electromagnetic field in TM mode, the method of adopting both groove structure and external axial magnetic field is introduced. As the electric field distribution of the TM mode is composed of both normal and tangential components, it is different from that under the condition of dielectric window in HPM. Thus, theoretical analysis and numerical simulation are employed to study the movement of electrons under different conditions： such as dielectric surface shapes, electric field strength, and magnetic field strength etc. Based on the particle-in-cell （PIC） simulation, the collision energy and transmit-duration of secondary electrons in different groove structures and axial magnetic fields are compared with one another. Results show that the magnetic field is useful for suppressing the development of secondary electron on dielectric surface, while it is not very e？cient under high electric field strength. The method of introducing groove structure and certain axial magnetic field on dielectric surface at the same time is capable of affecting the movement of electrons in electric field of different strength. So it is great helpful in improving the ability of multipactor suppression, which is significant for improving the threshold of breakdown on dielectric surface and the power of cavity. However, a too high or too low magnetic field is not very useful for the suppression of multipactor. Furthermore, employing only one of the two parts of the method is also less effective in suppressing the multipactor.

关 键 词：介质加载加速器 横磁模 二次电子倍增 击穿 

分 类 号：O485[理学—固体物理]