Resistive Wall Instability in the NLC Main Damping Rings

Wolski, Andrzej

Lawrence Berkeley National Laboratory

关键词: Feedback;    43 Particle Accelerators;    Simulation;    Damping;    Impedance;   

DOI  :  10.2172/889311
RP-ID  :  LBNL--59526
RP-ID  :  DE-AC02-05CH11231
RP-ID  :  889311

美国|英语

来源: UNT Digital Library

【 摘 要 】

We study transverse coupled-bunch instabilities driven by the resistive-wall impedance in the NLC Main Damping Rings. We compare the growth rates of the different modes predicted by a simple theory using a simplified lattice model with the results of a detailed simulation that includes variation of the beta functions and the actual fill structure of the machine. We find that the results of the analytical calculations are in reasonable agreement with the simulations. We include a simple model of a bunch-by-bunch feedback system in the simulation to show that the instabilities can be damped by a feedback system having parameters that are realistic, and possibly conservative. The noise level on the feedback system pick-up must be low, to avoid driving random bunch-to-bunch jitter above the specified limit of 10 percent of the vertical beam size.