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https://doi.org/10.18429/JACoW-HB2021-TUAC1
Title Self-Consistent Long-Term Dynamics of Space Charge Driven Resonances in 2D and 3D
Authors
  • A. Oeftiger, I. Hofmann
    GSI, Darmstadt, Germany
  • O. Boine-Frankenheim
    TEMF, TU Darmstadt, Darmstadt, Germany
Abstract Understanding the 3D collective long-term response of beams exposed to resonances is of theoretical interest and essential for advancing high intensity synchrotrons. This study of a hitherto unexplored beam dynamical regime is based on 2D and 3D self-consistent particle-in-cell simulations and on careful analysis using tune spectra and phase space. It shows that in Gaussian-like beams Landau damping suppresses all coherent parametric resonances, which are of higher than second order (the "envelope instability"). Our 3D results are obtained in an exemplary stopband, which includes the second order coherent parametric resonance and a fourth order structural resonance. They show that slow synchrotron oscillation plays a significant role. Moreover, for the early time evolution of emittance growth the interplay of incoherent and coherent resonance response matters, and differentiation between halo and different core regions is essential. In the long-term behavior we identify a progressive, self-consistent drift of particles toward and across the resonance, which results in effective compression of the initial tune spectrum. However, no visible imprint of the coherent features is left over, which only control the picture during the first one or two synchrotron periods. An intensity limit criterion and an asymptotic formula for long-term rms emittance growth are suggested. Comparison with the commonly used non-self-consistent "frozen space charge" model shows that in 3D this approximation yields a fast and useful orientation, but it is a conservative estimate of the tolerable intensity.
Footnotes & References HB’21 talk on "Effect of Space Charge on Bunch Stability and Space Charge Compensation Schemes" based on this APS PR-AB published contribution.
Paper download TUAC1.PDF [1.321 MB / 10 pages]
Slides download TUAC1_TALK.PDF [2.836 MB]
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Conference HB2021
Series ICFA ABDW on High-Intensity and High-Brightness Hadron Beams (64th)
Location Batavia, IL, USA
Date 04-08 October 2021
Publisher JACoW Publishing, Geneva, Switzerland
Editorial Board Eliana Gianfelice (FNAL, Batavia, IL, USA); Sergei Nagaitsev (FNAL, Batavia, IL, USA); Dong Eon Kim (PAL, Pohang, South Korea); Michaela Marx (DESY, Hamburg, Germany); Volker R. W. Schaa (GSI, Darmstadt, Germany)
Online ISBN 978-3-95450-225-7
Online ISSN 2673-5571
Received 11 October 2021
Revised 04 November 2021
Accepted 05 November 2021
Issue Date 23 November 2021
DOI doi:10.18429/JACoW-HB2021-TUAC1
Pages 160-169
Copyright
Creative Commons CC logoPublished by JACoW Publishing under the terms of the Creative Commons Attribution 3.0 International license. Any further distribution of this work must maintain attribution to the author(s), the published article's title, publisher, and DOI.