涡流效应是较快重复频率加速器必须考虑的问题。涡流效应引入的六极、四极、二极分量, 以及发热效应都会对环的参数如色品、工作点、共振、能量漂移等产生影响。通过计算引入不同效应的强度, 模拟了各种效应对环参数的影响, 并针对不同升能曲线和升能频率引入涡流效应的计算和比较, 得出了在目前考虑的频率范围内, 对主环影响较大的效应为六极场, 其它效应的影响需要较大的重复频率。并以此为依据选择了最终的工作曲线为半正弦, 上升时间为0.7 s。

Eddy currect effects should be considered in a accelerator with magnets ramping with a large repetition frequency. Field components like dipolar, quadrupolar and sextupolar ones and heating effects induced by eddy current effects will affect the chromaticities, tunes, resonance, etc. The field components and their effects on beam parameters in the ring are evaluated for difference ramping curves and ramping frequencies. The most important effect is found to be from sextupolar component in the frequency range of proton therapy, and other components will play more important roles when the repetition frequency increases. Accordingly, the ramping curve for operation is selected as a sinusoidal curve with ramping time of 0.7 s.