讨论了高平均功率自由电子激光太赫兹源波荡器的物理设计, 在确定了波荡器周期、周期数、峰值磁场强度范围和调制参数范围等总体参数后, 选用混合型Halbach结构为波荡器的基本结构, 永磁块长宽高为8 cm×1.3 cm×6 cm, 磁极长宽高为5 cm×0.6 cm×4.8 cm。波荡器工作在变间隙模式下, 间隙为1.81~3.05 cm时, 波荡器峰值磁场为0.529~0.184 T, 好场区为3.02~2.13 cm。同时, 考虑到波荡器磁场误差对自由电子激光的影响, 提出了波荡器各参数误差, 并对波荡器端部设计进行了重点讨论。

The physics design of the undulator in high average power free electronic laser terahertz source is discussed. Hybrid Halbach structure is selected, after the period length, period quantity and peak magnetic field strength, etc. are fixed. The dimension of permanent magnet block is 8 cm×1.3 cm×6 cm, and the dimension of pole is 5 cm×0.6 cm×4.8 cm. The gap of the undulator is variable. While the gap range is 1.81-3.05 cm, the range of peak magnetic field strength is 0.529-0.184 T, and the length of good field area is 3.02-2.13 cm. Meanwhile, as the error of undulator magnetic field has effect on free electronic laser, the tolerances of undulator parameters are brought in, and the end design of the undulator is discussed at last.