Soft X-ray Free-Electron Lasers Driven by Hybrid Laser- and Beam-Driven Plasma Wakefield Accelerators

In this work, we propose and systematically demonstrate, through numerical start-to-end simulations, a novel LPWFA (hybrid LWFA-PWFA) scheme for driving soft X-ray free-electron lasers (Soft-XFELs) with high-gain performance and sufficient robustness.

Non-ideal electron beams generated from the LWFA stage are directly employed to drive the PWFA stage. A self-optimizing mechanism operating within the PWFA blowout regime is revealed, which enables the generation of high-quality witness electron beams with a charge of 32.82 pC, and global and slice-averaged energy spreads as low as 0.42% and 0.15%, respectively. These high-quality electron beams in turn drive a soft X-ray FEL, producing pulses with an energy of 27.22 μJ and a peak power of approximately 5.69 GW at 10 nm.