Perturbative formulation for nonlinear chromaticity of circular accelerators.
The nonlinear chromaticity plays an important part in the dynamics of a particle at far off-momentum in a strong focusing circular accelerator. We derived the exact perturbative formula of the nonlinear dispersion function of a ring accelerator and gave explicit expressions of higher-order terms. Using the perturbative formula for the dispersion function, we derived the higher-order expressions for the nonlinear chromaticity up to the third order. We numerically estimated the nonlinear chromaticity of the SPring-8 storage ring, and it showed fairly good agreement with the measurement.
SPring-8, Mikazuki, Sayo-gun, Hyogo 679-5198, Japan. takao@spring8.or.jp
Masaru
M
Takao
Hitoshi
H
Tanaka
Kouichi
K
Soutome
Jun
J
Schimizu