四注行波管周期永磁聚焦系统的优化设计

根据电子注参数、布里渊磁场公式及周期聚焦系统轴向磁通密度峰值经验公式，计算出永磁聚焦系统轴向峰值磁通密度，利用Ansoft Maxwell 3D软件建立了四注行波管周期永磁聚焦系统仿真模型，对模型结构尺寸进行了参数化分析，研究了周期永磁聚焦系统结构尺寸对聚焦系统通道内磁通密度的影响，确定了磁聚焦系统结构最佳尺寸配合，优化设计出了四注行波管周期永磁聚焦系统。其电子注通道中心轴线上轴向磁通密度峰值B_z=309 mT，横向磁通密度B_t=2.86 mT，B_t/B_z=0.92%。

Optimal design of periodic permanent magnetic focusing system for four-beam traveling wave tubes

According to the electron beam parameters and Brillouin magnetic field formula and the axial magnetic flux density peak empirical formula of the periodic focusing system, the axial peak magnetic flux density of the permanent magnet focusing system is calculated. The simulation model of the permanent magnet focusing system of the four-beam travelling wave tube is established by Ansoft Maxwell 3D software. The structural dimensions of the model are parametrically analyzed, the influence of the structural dimension of the periodic permanent magnet focusing system on the magnetic field in the tunnel is studied, the optimal size matching of the magnetic focusing system is determined, and the periodic permanent magnet focusing system of the four-beam traveling wave tube is optimally designed. The axial magnetic flux density peak B_z=309 mT, the transverse magnetic flux density B_t=2.86 mT, B_t/B_z=0.92% on the central axis of the electron beam tunnel.