变参数自由电子激光放大器的设计方法  

THE DESIGN METHOD OF TAPERED -WIGGLER FREE ELECTRON LASER AMPLIFIER

作　　者：田世洪[1] 董志伟[1] 杨震华[1] 

机构地区：[1]北京应用物理与计算数学研究所

出　　处：《强激光与粒子束》1990年第4期467-473,共7页High Power Laser and Particle Beams

摘　　要：据自由电子激光原理,利用变参数摇摆器设计可以大幅度提高自由电子激光放大器的效率,在分析文献中所提出的“单电子共振”和“磁场指数下降法”基础上,提出了变参数摇摆器的“多电子自洽设计和最佳选择”的设计方法。经数值计算证明,所提出的方法明显优于其它方法。It is well known that the efficiency of constant-variable wiggler free electron laser amplifier is only several percent of the incident power. In order to obtain high efficiency of laser output, the wiggler must be tapered. As we know, under the longitudinal periodic force, the electrons trapped in ponderomotive potential become 'bunched' and form 'electron ensemble'. When the output power of laser gets saturated, the average energy of the trapped electron ensemble reaches the minimum, (relative to the resonant energy). After that , the energy of electron ensemble rises, meanwhile the power of laser goes down. The trapped electron ensemble makes synchrotron motion in the ponderomotive potential. The main design idea of tapered wiggler is to keep the ensemble in the energy -lose state as long as possible by adjusting the resonant energy when the average energy of the ensemble reaches its minimum. In this paper, we have analysed the design methods of tapered wiggler with the previously proposed, 'single particle resonance' and 'exponential decreasing method of magnetic field', and then propose a new design method of 'consistent design with multi -electrons and optimal selection' . The 3 -D simulation results show that our method is much better than the others.

关 键 词：自由电子 激光 放大器 摇摆器 

分 类 号：TN722.32[电子电信—电路与系统]