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- A.Y. Molodojentsev, E. Forest, S. Machida
KEK, Ibaraki
- H. Hotchi, F. Noda, M.J. Shirakata, Y. Shobuda, H. Suzuki, K. Yamamoto
JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- Y. Ishi
Mitsubishi Electric Corp, Energy & Public Infrastructure Systems Center, Kobe
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Main intrinsic field nonlinearities, which are common for synchrotrons with large aperture, are the nonlinear field of the bending magnets, the fringing field of the magnets and the sextupole field nonlinearity, used for the chromaticity correction. The particle motion in the ring bending magnets has been analyzed by two methods: (1) by direct integration of the particle motion equations in the 3D magnetic field (Tosca output), based on the 4th order Runge-Kutta integrator and (2) by determination the transfer 8th order map of the bending magnet by using the Gaussian wavelet in the 3D space. The second technique allows us to use powerful tools such as the normal form analysis, to define the resonance driving terms, which can be used for the resonance correction. As the result of this study it was shown that the main limitation of the RCS dynamic aperture can be caused by the structure normal sextupole-order resonance and the normal octupole-order resonance. Other high-order resonances have smaller effects on the particles motion than the resonances mentioned above. The correction scheme to improve the dynamic aperture near the normal sextupole-order resonance has been analyzed.
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