Yang, YF (reprint author), CAS, Inst High Energy Phys, Beijing 100049, Peoples R China.
We numerically studied the microbunch instability driven by Coherent synchrotron radiation (CSR) in a magnet bunch compressor. High-frequency density perturbation may be significantly amplified when an electron beam passes through the Beijing XFEL Test Facility (BTF) magnet bunch compressor II. The dependence of CSR-driven microbunch instability on bunch twiss parameters is sensitive. Dangerous area of twiss parameters is outlined.