波荡器磁场误差对其自发辐射的影响模拟研究

波荡器由多个单磁块组成，磁块不可避免的剩磁离散性和尺寸离散性是引起波荡器磁场误差的根本原因。波荡器磁场误差将影响波荡器自发辐射谱的质量。本文给出一种新的单磁块磁场、波荡器磁场及自发辐射的模拟方法，从单磁块磁场模拟人手，使用正态分布随机数发生器产生多组不同剩磁或者不同尺寸的单磁块，再由这种方式产生的单磁块组成波荡器，然后计算自发辐射，从而研究波荡器磁场误差对自发辐射的影响。

Simulation study of influence of undulator magnetic field error on spontaneous emission

An undulator consists of many magnets. The unavoidable remanence divergence and dimension divergence of these magnets cause the undulator magnetic field error, including the peak magnetic field error, phase error, etc, which will affect the quality of the spontaneous emission spectrum. This paper presents the simulation method of permanent magnet magnetic field, undulator magnetic field and spontaneous emission. The normal school random numbers generator is applied to produce groups of magnets of different remanences or different sizes. Each group of the magnets can constitute the undulator. Then the spontaneous emission is calculated. And accordingly we can make a study of the influence of undulator magnetic field errors on spontaneous emission. Finally, the correlations between intensities of spontaneous emission and various magnetic filed errors are illustrated, including RMS magnetic remanence error, RMS magnetic width error, RMS phase error and RMS field error.