Energy spread minimization in a beam-driven plasma wakefield accelerator
Next-generation plasma-based accelerators can push electron bunches to gigaelectronvolt energies within centimetre distances1,2. The plasma, excited by a driver pulse, generates large electric fields that can efficiently accelerate a trailing witness bunch3–5, enabling the realization of laboratory-scale applications ranging from high-energy colliders6 to ultrabright light sources7. So far, several experiments have demonstrated large accelerations8–10 but the resulting beam quality, particularly the energy spread, is still far from state-of-the-art conventional accelerators.