左右旋双双绕螺旋线线极化摇摆器的磁场分布及束流传输

给出了双双绕螺旋线线极化Wiggler轴线上磁场的积分表达式,以此公式数字模拟此装置端口区的磁场分布,并进行了实验测定,结果表明,端口区磁场峰值突变和对称性均比圆极化好。另一方面,用洛仑兹运动方程,考虑了电子束空间电荷效应,证明此装置对电子束传输有自聚焦能力,给出了电子运动方程,电子束流与Wiggler峰值磁场的关系,数字模拟电子束运动轨迹也表明,此装置能自聚焦传输电子束,有希望应用于线极化自由电子激光实验中。

MAGNETIC FIELD PROFILE AND BEAM CURRENT TRANSPORTING OF LEFT-RIGHT ROTATION DOUBLE BELIX LINEAR WIGGLER

In free electron laser with a long, linear wiggler, the magnetic field at the entrance of wiggler and the external focusing required to deep the electron beam from dispersing can determine the character of the electron orbits and seriously influence the PEL gain. To obtain good results in PEL experiments, it is necessary to investigate the linearly polarized wiggler with good magnetic field at the entrance and self-focusing. In this paper, it is researched in details that the entrance magnetic field and self-focusing of the linearly polarized wiggler produced by doubje bifilar helix lines. (1 ) The integral formula of the magnetic field on Z axis of the wiggler is derived, the prediction by the formula is good with the experiment, the results show that the field symmetry is better than the bifilar helix wiggler's. (2 ) According to Lorentz equation, we have derived the electron trajactory equations with the stable motions, and the formula about the threshold transport e-beam current and the wiggler peak field, simulated the orbits of the electron at edge in the wiggler, those give us a result that the wiggler has a ability of self-focusing , and can be applied in the linearly polarized PEL experiment.