采用圆极化变参数摇摆器能延缓自由电子激光器件进入饱和,提高束波互作用效率。通过计算电子运动的柯尔莫哥洛夫熵来研究变参数摇摆器自由电子运动的稳定性。研究结果表明:摇摆器无论采用正坡度还是负坡度,平衡态电子的柯尔莫哥洛夫熵值均小于零,稳定性均比无坡度时好,但电子的运动轨迹趋于发散;当有激光场存在时,正坡度破坏电子运动的稳定性,负坡度改善电子运动的稳定性。其结果为电子运动稳定性的进一步研究提供参考。

The circular polarization variable parameter wiggler is used for postponement of saturation of free-electron laser, and enhancing the efficiency of the beam-wave interaction. The stability of electron motion in a free-electron laser with variable parameter wiggler is studied by means of the Kolmogorov entropy(K-entropy). The study results indicate that the values of K-entropy of the equilibrium electron are less than zero for the positive taper and the negative taper are used in the wiggler, their stabilities are better than that of the un-tapered. However, the trajectory of the electron motion ends to divergence in the tapered wiggler. The positive taper will weaken stability of electron motion when there is the laser field, but the negative taper will improve stability of electron motion. The results can provide references for studying further stability of electron motion.