Multi-GeV cascaded laser wakefield acceleration in a hybrid capillary discharge waveguide

Based on a 6 cm-long two-segment hybrid capillary discharge waveguide, a multi-GeV electronbeam with energy up to 3.2 GeV and 9.7% rms energy spread was achieved in a cascaded laserwakefield acceleration scheme, powered by an on-target 210 TW laser pulse. The electron beamwas trapped in the first segment via ionization-induced injection, and then seeded into the secondsegment for further acceleration. The long-distance stable guiding of the laser pulse andsuppression of the dark current inside the second-segment capillary played an important role inthe generation of high-energy electron beams, as demonstrated by quasi-three-dimensionalparticle-in-cell simulations.