Suppression of Beam-Ion Instability in Electron Rings with Multi-Bunch Train Beam Fillings
Suppression of Beam-Ion Instability in Electron Rings with Multi-Bunch Train Beam Fillings
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DOI：
10.1103/physrevstab.14.084401
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发表时间：
2011-08
影响因子：
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通讯作者：
L. Wang;Yunhai Cai;T. Raubenheimer;H. Fukuma
中科院分区：
文献类型：
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作者：
L. Wang;Yunhai Cai;T. Raubenheimer;H. Fukuma
在未来的光源和电子阻尼环中，由于高束流和皮度计水平的超小发射度，离子引起的束流不稳定可能会很严重。一种简单而有效的缓解不稳定性的方法是多束团列束填充模式，它可以显著降低束流附近的离子密度，从而将不稳定性增长率降低高达两个数量级。这种抑制对低发射度的高强度光束更为有效。为了验证本文所用模型的有效性，对俘获离子的分布和场进行了基准测试。对离子云尾迹场和束流-离子不稳定性进行了解析和数值研究。我们推导出了多束流填充模式下离子云的积聚和不稳定增长率的简单公式。用ILC阻尼环、SuperKEKB和SPEAR3中的离子不稳定性与我们的分析进行了比较。本文的分析结果与仿真结果吻合较好。
The ion-caused beam instability in the future light sources and electron damping rings can be serious due to the high beam current and ultra-small emittance of picometer level. One simple and effective mitigation of the instability is a multi-bunch train beam filling pattern which can significantly reduce the ion density near the beam, and therefore reduce the instability growth rate up to two orders of magnitude. The suppression is more effective for high intensity beams with low emittance. The distribution and the field of trapped ions are benchmarked to validate the model used in the paper. The wake field of ion-cloud and the beam-ion instability is investigated both analytically and numerically. We derived a simple formula for the build-up of ion-cloud and instability growth rate with the multi-bunch-train filling pattern. The ion instabilities in ILC damping ring, SuperKEKB and SPEAR3 are used to compare with our analyses. The analyses in this paper agree well with simulations.