Emittance Evolution in a Single Stage Plasma Wake FieldAccelerator with Plasma Ramps

Emittance growth of the accelerated beam can be controlled when the beam is matched inside wake of a drive beam in the plasma wake field accelerator (PWFA). When there is a plasma density up ramp at the entrance and a plasma density down ramp at the exit, the initial matching condition for the accelerated beam can be calculated for a given plasma density profile. However, the real beam parameters at the entrance of the plasma may differ from the ideal matched condition. We use QuickPIC simulations to study the initial beam parameters’ influence on the beam emittance growth by changing the initial focal positon, the initial value of the beta star, the initial energy and the initial energy spread of the trailing beam. In the end, we give the comparison between the theoretical analysis
and the simulation results.