JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
TY - UNPB AU - Tian, S.K. AU - Du, C.C. AU - Wang, J.Q. AU - Wang, N. AU - Xu, H.S. ED - Schaa, Volker RW ED - Huang, Wenhui ED - Yan, Xueqing ED - Tang, Chuanxiang ED - Li, Lu TI - Studies of Ion Effects in the Heps Storage Ring J2 - presented at SAP2023, Xichang, China, 10-12 July 2023 CY - Xichang, China T2 - Symposium on Accelerator Physics T3 - 14 LA - english AB - In the fourth generation synchrotron radiation light source, the accelerator design aims to deliver low-emittance electron beams¿to maximize the brightness of the photon beams. This brings new challenges to maintain low emittance with potential collective instabilities. One particular source of concern is the ion-driven instability, which can be induced by ionization of the residual gas by the circulating electron beam. The ion effects in the HEPS storage ring are estimated by both analytical formula and macro-particle simulations. More detailed simulations considering actual filling patterns and vacuum conditions are performed. The results indicate that at the design beam current, the ions will be over-focused due to the very high beam densities, and the beam will not be perturbed by the ions. This is somewhat different from widely accepted understanding that the coupled motion between the beam and the ions is inversely proportional to the beam size and is typically proportional to the average beam current and residual gas pressure. In this paper the results of the instability amplitude and beam emittance growth, the variation process of trapped ion density is presented. ER -