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 - CONF AU - Karpov, I. ED - Cai, Yunhai ED - Nagaitsev, Sergei ED - Kim, Dong Eon ED - Marx, Michaela ED - Schaa, Volker R. W. TI - New Understanding of Longitudinal Beam Instabilities and Comparison with Measurements J2 - Proc. of HB2023, Geneva, Switzerland, 09-13 October 2023 CY - Geneva, Switzerland T2 - ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams T3 - 68 LA - english AB - Beam instabilities driven by broad- and narrowband impedance sources have been treated separately so far. In this contribution, we present the generalised beam stability analysis based on the concept of van Kampen modes. In the presence of broadband impedance, the loss of Landau damping (LLD) in the longitudinal plane can occur above a certain single-bunch intensity. For significantly higher intensities, the broad-band impedance can drive violent radial or azimuthal mode-coupling instabilities. We have shown that the synchrotron frequency spread due to RF field non-linearity, counter-intuitively, reduces the single-bunch instability threshold. We have also demonstrated that a multi-bunch instability driven by a narrow-band impedance source can be significantly affected by LLD when adding broad-band impedance. These findings are supported by macroparticle simulations and beam observations in the Super Proton Synchrotron and the Large Hadron Collider at CERN. PB - JACoW Publishing CP - Geneva, Switzerland SP - 45 EP - 52 KW - impedance KW - synchrotron KW - coupling KW - damping KW - proton DA - 2024/04 PY - 2024 SN - 2673-5571 SN - 978-3-95450-253-0 DO - doi:10.18429/JACoW-HB2023-TUA1I2 UR - https://jacow.org/hb2023/papers/tua1i2.pdf ER -