TY - CONF AU - Lin, C.T. AU - Ohmi, K. AU - Zhang, Y. ED - Schaa, Volker RW ED - Huang, Wenhui ED - Yan, Xueqing ED - Tang, Chuanxiang ED - Li, Lu TI - Beam-Beam Interaction with Longitudinal Impedance and Its Application in TMCI Study J2 - Proc. of SAP2023, Xichang, China, 10-12 July 2023 CY - Xichang, China T2 - Symposium on Accelerator Physics T3 - 14 LA - english AB - Simulations have showed a novel coherent head-tail instability induced by beam-beam interaction with a large Piwinski angle. The localized cross-wake force has been introduced to explain the instability. The longitudinal impedance would cause coherent and incoherent synchrotron tune shift and distort the particle¿s trajectories in longitudinal phase space. Further beam-beam simulation revealed that the longitudinal impedance has strong impacts on the beam stability, squeezing the horizontal stable tune area seriously. The instability has become an important issue during the designs of CEPC and FCC-ee. In this paper, we develop a transverse mode coupling analysis method that could be used to study beam-beam instability with and without longitudinal impedance. This method can also be applied in synchrotron light sources to study transverse mode coupling instability (TMCI) with longitudinal impedance and harmonic cavity. Some preliminary results at Shenzhen Innovation Light Source (SILF) are also shown. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1 EP - 3 KW - impedance KW - coupling KW - synchrotron KW - simulation KW - electron DA - 2024/11 PY - 2024 SN - 978-3-95450-265-3 DO - doi:10.18429/JACoW-SAP2023-MOCXA02 UR - https://jacow.org/sap2023/papers/mocxa02.pdf ER - TY - CONF AU - Xu, J.Y. AU - Lin, C.T. AU - Wang, N. AU - Xu, H.S. AU - Zhang, Y. ED - Schaa, Volker RW ED - Huang, Wenhui ED - Yan, Xueqing ED - Tang, Chuanxiang ED - Li, Lu TI - Development of a Vlasov Solver for Arbitrary Sub-optimal Lengthening Conditions in Double-RF System J2 - Proc. of SAP2023, Xichang, China, 10-12 July 2023 CY - Xichang, China T2 - Symposium on Accelerator Physics T3 - 14 LA - english AB - Solving Vlasov equation is a classic method for analyzing collective beam instabilities. Considering longitudinal impedance and the nonlinear longitudinal potential well, we developed a new Vlasov solver which can be used to study the transverse mode-coupling instability under the arbitrary sub-optimal lengthening and the optimal lengthening conditions in a double-RF system. Several different techniques to deal with the radial direction of longitudinal phase space have been tested. Numerical discretization method is selected in this paper. The development of the solver is presented in details here. Benchmarks and crosscheck of the solver have been made and presented as well. PB - JACoW Publishing CP - Geneva, Switzerland SP - 34 EP - 36 KW - synchrotron KW - coupling KW - impedance KW - betatron KW - cavity DA - 2024/11 PY - 2024 SN - 978-3-95450-265-3 DO - doi:10.18429/JACoW-SAP2023-MOPB014 UR - https://jacow.org/sap2023/papers/mopb014.pdf ER - TY - CONF AU - Liu, W.B. AU - Dai, Y.X. AU - Duan, Z. AU - Geng, H. AU - Li, Z.H. AU - Lu, X.H. AU - Su, M.Y. AU - Xin, T. AU - Zhang, Y. AU - Zhao, Y.L. ED - Schaa, Volker RW ED - Huang, Wenhui ED - Yan, Xueqing ED - Tang, Chuanxiang ED - Li, Lu TI - Development Status of Beam Dynamics Software APES for CEPC J2 - Proc. of SAP2023, Xichang, China, 10-12 July 2023 CY - Xichang, China T2 - Symposium on Accelerator Physics T3 - 14 LA - english AB - The physical design and research work of China Electron Positron Collider (CEPC) is an unprecedented challenge in the field of international accelerator collider. In the simulation research, many physical phenomena must be considered, including large Piwinski angle, crab waist colliding, strong nonlinear effect, energy sawtooth, beam-beam, etc. To address this challenge, a software project APES is proposed in 2021. And this project received support from the IHEP innovative fund in 2022. The progress and future plans of APES project will be introduced in the poster. PB - JACoW Publishing CP - Geneva, Switzerland SP - 49 EP - 54 KW - collider KW - alignment KW - positron KW - lattice KW - software DA - 2024/11 PY - 2024 SN - 978-3-95450-265-3 DO - doi:10.18429/JACoW-SAP2023-MOPB019 UR - https://jacow.org/sap2023/papers/mopb019.pdf ER - TY - CONF AU - Yue, S. AU - Li, J.T. AU - Tian, S.K. AU - Wang, N. ED - Schaa, Volker RW ED - Huang, Wenhui ED - Yan, Xueqing ED - Tang, Chuanxiang ED - Li, Lu TI - Investigation on the Trapped Modes of CPMU at HEPS J2 - Proc. of SAP2023, Xichang, China, 10-12 July 2023 CY - Xichang, China T2 - Symposium on Accelerator Physics T3 - 14 LA - english AB - The Cryogenic Permanent Magnet Undulator (CPMU) is a crucial component in synchrotron radiation sources. Due to the small magnet gap of CPMU, the interaction between the beam and its surroundings is strong, which can result in a significant contribution to coupling impedance. In this work, the influence of CPMU on coupling impedance was investigated using wakefield and eigenmode solvers. The results indicated that some of the transverse impedance resonances in CPMU were much stronger than the impedance threshold determined by synchrotron radiation damping, which could cause vertical beam instability. To address this issue, different types of damping materials were investigated through simulations to suppress the resonances. PB - JACoW Publishing CP - Geneva, Switzerland SP - 62 EP - 65 KW - damping KW - impedance KW - synchrotron KW - simulation KW - wakefield DA - 2024/11 PY - 2024 SN - 978-3-95450-265-3 DO - doi:10.18429/JACoW-SAP2023-MOPB028 UR - https://jacow.org/sap2023/papers/mopb028.pdf ER - TY - CONF AU - Wang, B. AU - Shi, H.Y. AU - Yu, C.H. ED - Schaa, Volker RW ED - Huang, Wenhui ED - Yan, Xueqing ED - Tang, Chuanxiang ED - Li, Lu TI - Recent Progress of the Beam Background Experiment in the BEPCII J2 - Proc. of SAP2023, Xichang, China, 10-12 July 2023 CY - Xichang, China T2 - Symposium on Accelerator Physics T3 - 14 LA - english AB - The Beijing Electron Positron Collider II will upgrade to extend the beam energy and the luminosity by increasing the beam current and slightly compressing the beam size, where the beam energy will be extended from 2.3 GeV to 2.8 GeV and the peak luminosity will be up to 1.1×10³³\rmcm⁻²\rms⁻¹ at the optimizing beam energy of 2.35 GeV. The BEPCII upgrade is expected to result in challenging levels of beam related background in the interaction region. An precise simulating and mitigating beam background is necessary to protect the BESIII detector and increase the beam current and peak luminosity. The beam related background at BEPCII is mainly from the Touschek effect and the beam gas effect, this paper presents the recent progress of the beam background simulation and experiment. PB - JACoW Publishing CP - Geneva, Switzerland SP - 155 EP - 157 KW - background KW - experiment KW - electron KW - simulation KW - positron DA - 2024/11 PY - 2024 SN - 978-3-95450-265-3 DO - doi:10.18429/JACoW-SAP2023-TUPB035 UR - https://jacow.org/sap2023/papers/tupb035.pdf ER -