摘要
提出了一种新型周期永磁(PPM)聚焦系统,其中,每半个周期的这种PPM聚焦系统由1件极靴和5块永磁体共同组成,第1、第3、第5块永磁体与第2、第4块永磁体的极化方向相反,且任何相距半个周期的2块永磁体均具有相反的极化方向。采用MTSS2018对这种新型PPM聚焦系统的磁场进行了计算,结果表明新型PPM聚焦系统的轴线上磁感应强度Bz具有显著的第3次和第5次空间谐波,在过0点后能够更快上升到峰值,整体构型十分接近具有理想矩形分布的PPM系统。采用MTSS2018对G波段分布作用速调管(EIK)所需的电子枪进行了模拟计算,并采用上面计算的Bz对该电子注进行聚焦,获得了电子注电压为22 kV,电子注电流为215 mA的电子注,电子注最大半径为0.08 mm,满足G波段EIK的应用要求。计算中的峰值磁感应强度仅为1.2√2BB,说明新型PPM聚焦系统与传统PPM聚焦系统相比,可以在较低的峰值磁感应强度的条件下实现电子注的有效聚焦。
This paper proposes a new-type periodical permanent magnet(PPM)focus system,each half period of which is composed of 1 magnetic pole and 5 permanent magnets,and the first,the third and the fifth magnets have reverse magnetization with the second and the fourth magnets.Besides,any two magnets spaced half period have inverse magnetization with each other.The new-type PPM focus system is modeled and calculated by MTSS2018,the results show that the axial component Bz of the magnetic induction intensity on the axis has conspicuous amplitude of the third and the fifth space harmonics,and Bz rises steeply after it reaches zero,so Bz has a profile very approximate to the periodical rectangular shape.An electron gun under the condition of the above calculated Bz is calculated by MTSS2018 too,a beam with 22 kV of voltage,215 mA current and 0.08 mm of maximum beam radius is obtained,which meets the demand of G band extended interaction klystron(EIK).In the calculations the peak value of Bz is only1.2√2 BB(subscript B is Brillouin magnetic field),it suggests that the new-type PPM focus system focuses the beam effectively even if it has a relatively lower peak value of Bz than the conventional PPM focus system does.
作者
王自成
王元坤
曲兆伟
Wang Zicheng;Wang Yuankun;Qu Zhaowei(Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 101400,China;Institute of Information Engineering,Chinese Academy of Sciences,Beijing 100093,China;School of Cyber Security,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《强激光与粒子束》
EI
CAS
CSCD
北大核心
2020年第6期47-52,共6页
High Power Laser and Particle Beams
基金
国家自然科学基金项目(61172016)
北京市自然科学基金重点项目(201511232037)。
关键词
分布作用速调管
电子注
电子注通道
周期永磁
周期永磁聚焦系统
extended interaction klystron
electron beam
tunnel of electron beam
periodical permanent magnet
PPM focus system
