Beam breakup simulation study for high energy ERL
  The maximum beam current can be accelerated in an Energy Recovery Linac (ERL) can be severely limited by the transverse multi-pass beam breakup instability (BBU), especially in future ERL 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 on a 3-GeV ERL light source proposed by KEK. It is expected to provide a reference to the future high energy ERL projects by this work. 
Si Chen, Miho Shimada, Norio Nakamura, Senlin Huang, Kexin Liu, Jia-er   Chen
physics.acc-ph