Studies of ion beam instabilities for low energy RHIC operations with electron cooling

Electron cooling has the potential to compensate the emittance growth of the circulating ion beam due to intrabeam scattering at low energy. A test of electron cooling for RHIC low energy operations has been planned at IP2. It is useful to investigate beam stability at the design stage to set limits on various beam parameters and avoid 'overcooling' of the ion beam. Furthermore, in the presence of electron cooling, the coherent interaction between the electron beam and ion beam could also play a role in the beam stability. In this work, we first present simulation results of ion beam instability in the absence of coherent electron-ion interactions. Then, we apply the hydrodynamics model to obtain the one pass change of ions' location and momentum due to the dipole mode coherent electron-ion interaction. Finally, we include this one pass map into the simulation code, TRANFT, to study the effects of this coherent electron-ion interaction for RHIC Low Energy electron Cooling (LEeC).