TY  - CONF
AU  - Oeftiger, Adrian
AU  - Boine-Frankenheim, Oliver
AU  - Hofmann, Ingo
A3  - Gianfelice, Eliana
A3  - Nagaitsev, Sergei
A3  - Kim, Dong Eon
A3  - Marx, Michaela
A3  - Schaa, Volker R. W.
TI  - Self-Consistent Long-Term Dynamics of Space Charge Driven Resonances in 2D and 3D
CY  - Geneva, Switzerland
PB  - JACoW Publishing
M1  - GSI-2025-00448
SP  - 160-169 p.
PY  - 2021
N1  - Published by JACoW Publishing under the terms of the Creative Commons Attribution 3.0 International license.
AB  - 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.
T2  - 64th ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams
CY  - 4 Oct 2021 - 8 Oct 2021, Batavia, IL (USA)
Y2  - 4 Oct 2021 - 8 Oct 2021
M2  - Batavia, IL, USA
KW  - Accelerator Physics (Other)
KW  - Beam Dynamics in Rings (Other)
LB  - PUB:(DE-HGF)8
DO  - DOI:10.18429/JACOW-HB2021-TUAC1
UR  - https://repository.gsi.de/record/357767
ER  -