Mitigation of beam instability due to space charge effects at 3 GeV RCS in J-PARC

Shobuda, Yoshihiro   ; Tamura, Fumihiko   ; Yamamoto, Masanobu   ; Chin, Y. H.*

In order to accomplish high intensity proton beams, it is important to identify impedance sources in accelerators. At 3 GeV rapid cycling synchrotron (RCS) in Japan Proton Research Complex (J-PARC), the kicker impedance is the most dominant among such impedance sources. Beam instability can be observed by correcting chromaticity during the acceleration. Growth rate of the beam instability can be reduced by increasing peak current (reducing bunching factor). In other words, it is experimentally found that space charge effects mitigate the beam instability.