Simulation of beam behavior caused by odd harmonics of beam loading in J-PARC RCS

Yamamoto, Masanobu   ; Nomura, Masahiro  ; Shimada, Taihei ; Tamura, Fumihiko   ; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Toda, Makoto*; Yoshii, Masahito*

The J-PARC RCS accelerates 2 bunches at the harmonic number 2. The major Fourier component of the beam current is even harmonics. However, the odd harmonics grow under some conditions even though they are very small amplitude at the beginning. Particle tracking simulation suggests that the displacement and the deformation of the bunch are caused by the odd harmonics, it is synchronized with the potential distortion, and it results in the beam instability. We describe the particle tracking simulation results for the odd harmonic beam loading effect in the RCS.