漂移管中相对论电子束引导的匹配条件

本文介绍了对连续型相对论电子束的两种引导及箍缩方法:磁场引导和离子通道的静电引导。在线性引导力的假定下,求得了单磁场引导、单静电引导以及同时使用磁场和电场的混合引导的这三种情况下的匹配条件的解析结果。解析公式表明。在混合引导情况下,为了使电子束匹配,当电子束的中和因子线性增加时,相应的引导磁场不是线性地减小。而是抛物线形地减小。本文还使用了模拟束片内电子横向运动的LGERKB编码,通过对N_0个束内电子的模拟计算,求得了电子束包络。电子束的均方根发射度、典型电子轨道、失配和匹配情况下的束内电子相空间分布(相图)及其演变过程等大量资料。线性模拟结果与解析分析结果完全一致。

THE MATCHING CONDITIONS FOR GUIDED RELATIVISTIC ELECTRON BEAMS IN A DRIFT TUBE

Two guiding methods of continuous relativistic electron beams are presented. They are the axial magnetic guiding and radial electrostatic guiding. In the assumption of the linear force, the analytic formulations of matched beams are obtained for three guiding technologies: the magnetic guiding. electrostatic guiding and mixed guiding of the two technologies. The results indicate that solenoid strength over the mixed guiding region is reduced not linearly but parabolically. when the neutralization fraction is increased linearly to create a constant guiding strength channel over the entire length of the region. Using LGERKB code to simulate transverse motion of V electrons in abeam slice, we have obtained lots of information including envelope and its evolution, r. m. s. emittance. electron trajectories, and phase space distribution of the N , electrons-phase space diagram, etc. In the case of linear force. the simulated and analytic results are in agreement with each other. The envelope osillation is found in transport computation of the unmatched beam. Its wave number is about twice as large as the betatron number of the corresponding matched beam. It must be noticed that the length of mixed guiding region Lm should be as long as possible to keep the axial motion of the beam umattec-ted affecting. Gaussian Unit is used.