Robustness of a plasma acceleration based free electron laser

Abstract

Laser plasma accelerators (LPA) can sustain GeV/m accelerating fields offering outstanding new possibilities for compact applications. The LPA beam brightness can now be comparable to radio-frequency accelerators' (RFA), thanks essentially to the beams short duration (<3 fs) and low emittance (as small as 0.1 micron). Still, the mrad level divergence and few percent level energy spread, remain limiting parameters in the cases of demanding applications such as free electron lasers (FELs). Several concepts of transfer line were proposed to mitigate those intrinsic properties targeting undulator radiation applications. We study here the robustness of the chromatic matching strategy for FEL amplification at 200 nm in a dedicated transport line, and analyze its sensitivity to several parameters. We consider not only the possible LPA source jitters, but also various realistic defaults of the equipment such as magnetic elements misalignments or focussing strength errors, imperfect undulator fields, etc.