T-method Time-domain Analysis of Eddy Currents on Bellows Duct of Booster Synchrotron in Synchrotron Radiation Facility

This paper presents 3D eddy current analysis using current vector potential method (T-method) for bellows beam duct of booster synchrotron at the UVSOR synchrotron radiation facility. To achieve immediate acceleration of an electron bunch, rapidly increased and strong dipole magnetic field is imposed at curved section of beam duct of booster synchrotron (Fig.1). Accordingly high intensity eddy currents are induced at the curved section and it is necessary to consider to suppress influences of the eddy currents for electron beam dynamics. For this purpose, beam duct of the booster synchrotron at the UVSOR has bellows structure for longitudinal direction of electron motion (see Fig.1). On the other hand, effects of such the bellows structure for suppression of eddy currents were not evaluated quantitatively yet.