Speaker
Description
Plasma accelerators can accelerate electron bunches in fields exceeding 1 GV/m, making them a promising technology to greatly reduce the footprint of future linear colliders. In this scheme, a dense electron bunch drives a charge density wave in the plasma. The strong fields of this ‘wakefield’ are used to accelerate a trailing bunch. Fundamental research on this scheme is performed at the FLASHForward experiment at DESY using FEL-quality bunches from the FLASH linac. This talk will summarise recent results from FLASHForward to help provide an overview of the current status of plasma accelerator research. The experimental results shown here will cover three broad topics: beam-quality preservation, energy efficient acceleration and repetition rate limits. These will include the preservation of per-mille energy spread during acceleration by 45 MeV in GV/m fields with > 40% instantaneous energy transfer efficiency, followed by preservation of the normalised emittance of the trailing bunch with > 20% instantaneous energy-transfer efficiency. Progress towards larger energy gains and higher overall efficiency will be shown, which has been aided by the use of Bayesian optimisation techniques. Finally, results will be presented on the ultimate repetition rate of plasma accelerators, which can be limited by the motion of plasma ions as the wakefield decays.
