Collective effects for long bunches in dual harmonic RF systems
Collective effects for long bunches in dual harmonic RF systems
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DOI：
10.1088/1674-1137/32/2/013
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发表时间：
2008-02
影响因子：
3.6
通讯作者：
An Shizhong;K. Bongardt;R. Maier;Tang Jing-yu;Zhang Tian-jue
中科院分区：
文献类型：
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作者：
An Shizhong;K. Bongardt;R. Maier;Tang Jing-yu;Zhang Tian-jue
长束的长时间间隔存储需要具有大铲斗高度的扁平固定铲斗。集体效应的空间电荷和电阻阻抗的研究，通过在非相干粒子运动的匹配和失配束。随着粒子数量增加RF振幅提供了适度强度的r.m.s明智匹配。大振幅粒子的非相干运动依赖于射频系统的细节。由此产生的散束过程是太小的全RF接受度与失配的组合，由集体效应增强。不规则的单粒子运动与相干偶极不稳定性无关。对于Hofmann-Pedersen方法的固定相空间分布和双谐波RF系统，给出了稳定性限制，如果使用实际输入分布，则稳定性限制过低。对于d=0.31的单和双谐波RF系统，示出了强度的跟踪结果，其系数高于阈值3。小的电阻性阻抗导致平衡相位值周围的相干振荡，因为电阻性阻抗的能量损失由RF系统的能量增益补偿。
The storage of,long bunches for large time intervals needs flattened stationary buckets with a large bucket height. Collective effects from the space charge and resistive impedance are studied by looking at the incoherent particle motion for the matched and mismatched bunches. Increasing the RF amplitude with particle number provides r.m.s wise matching for modest intensities. The incoherent motion of large amplitude particles depends on the details of the RF system. The resulting debunching process is a combination of the too small full RF acceptance together with the mismatch, enhanced by the collective effects. Irregular single particle motion is not associated with the coherent dipole instability. For the stationary phase space distribution of the Hofmann-Pedersen approach and for the dual harmonic RF system, stability limits are presented, which are too low if using realistic input distributions. For single and dual harmonic RF system with d=0.31, the tracking results are shown for intensities, by a factor of 3 above the threshold values. Small resistive impedances lead to coherent oscillations around the equilibrium phase value, as energy loss by resistive impedance is compensated by the energy gain of the RF system.