Dynamic Aperture and Resonance Correction for JPARC-RCS

The rapid cycling synchrotron (RCS) of the J-PARC project should provide the beam power of 1 MW at the final stage. One of the main issues for high-power proton machine is strict limitation of uncontrolled beam losses. The space-charge detuning effect of the high-intensity low-energy proton beam can lead to crossing different resonance lines and perturb the particle motion significantly, reducing the dynamic aperture of the machine. Main intrinsic field nonlinearities, which are common for this kind of synchrotrons, are the nonlinear field of the bending magnets, the fringing field of the magnets and the sextupole field nonlinearity, used for the chromaticity correction. To model the particle motion in the RCS bending magnets, the 3D (Tosca) field map has been taken into account. We discuss the nonlinear single particle dynamics for the RCS focusing structure, limitation of the machine dynamic aperture and the resonance correction technique.