Passive plasma lens experiments at FACET-II

The beam-driven, passive plasma lens can provide axisymmetric focusing with strengths orders of magnitude greater than conventional quadrupole magnets, while remaining ultra-compact. These characteristics make it attractive for beam matching into a plasma wakefield accelerator and for controlling beam divergence downstream of plasma stages. Optimal performance can be achieved in the underdense regime, resulting in a linear focusing force and emittance preservation of the focused beam. We report progress on experimental results from SLAC’s FACET-II facility, where we utilized a fs Ti:Sapphire laser pulse to ionize hydrogen gas from a supersonic gas jet to focus several hundred pCs of charge of a 10 GeV electron beam.