Speaker
Description
Coupled-bunch instabilities will occur with long-range wakefields. And it's an effective way to adjust the chromaticity to suppress transverse coupled-bunch instabilities. In this study, transverse coupled-bunch instabilities with space charge are analysed and simulated using PyHEADTAIL. Results reveal that with strong space charge, there is one mode that depends solely on the longitudinal position (like 0 mode) in each l ≥ 1 intrabunch oscillation modes. When considering the chromaticity, the oscillating components cancel each other out if head-tail phase matches certain values of l, leaving a uniform dipole component which couples with impedance. In other words, the suppression of instabilities by chromaticity is weakened. Relevant experiments also yield similar results.