IPAC'24 - 15th International Particle Accelerator Conference

Measures to mitigate the coherent beam-beam instability at CEPC

WECD2

22 May 2024, 15:20

20m

Davidson Ballroom (Music City Center)

Contributed Oral Presentation MC1.A02 Lepton Circular Colliders WECD: Colliders and other Particle and Nuclear Physics Acclerators (Contributed)

Speaker

Yuan Zhang (Institute of High Energy Physics)

Description

Both horizontal and vertical coherent beam-beam instability are important issues at CEPC. The horizontal instability (X-Z instability) could be induced by beam-beam itself. The main method to suppress the X-Z instability is the optimization of machine parameters. In this paper we try to study the effect of chromaticity, local vacuum impedance and resistive feedback by analysis and simulation. The vertical instability may be induced due to the combined effect of beam-beam interaction and vacuum impedance. Finite chromaticity and asymmetrical tunes have been proposed to suppress the vertical instability. Due to the further increase of impedance budget, we need to find more measures to mitigate the instability. The effect of resistive feedback and hourglass effect are evaluated by analysis and/or simulation.