Beam breakup simulation study for a high energy ERL

The maximum beam current that can be accelerated in an energy recovery linac (ERL) can be severely limited by the transverse multi-pass beam breakup instability (BBU), especially M. future EEL light sources with multi-GeV high energy beam energy and more than 100 mA average current. In this paper, the multi-pass BBU of such a high energy ERL is studied based on the simulation of a 3-GeV ERL light source that is proposed by KEK. This work is expected to provide a reference for future high energy ERL projects.