Study of Beam Coupling Impedance and Beam Collective Effect in High Energy Photon Source

In the storage ring of high energy photon source (HEPS), due to the small vacuum chamber and high bunch intensity, the total beam coupling impedance remarkably increases and the beam collective effect becomes the key limit of the machine performance. In this paper, the element-by-element model of beam coupling impedance for HEPS storage ring was carried out based on analytical theory and numerical simulation program, and a systematic estimation on the possible beam collective effect was carried out. A reasonable impedance model was established. The instability threshold and the growth time were given, and the effective suppression method for the key instability was presented.