The effect of slippage on the saturated power in short pulse FEL SASE devices

The combined effect of slippage and energy spread in self-amplified-spontaneous-emission Free Electron Laser devices, operating in single spike regime, may impose limitations on the relevant performance. If the slippage is larger than the electron bunch length, the saturated power is significantly reduced. We provide a simple scaling formula capable of parameterizing the effect in terms of the device parameter and discuss possible mechanisms allowing the power output optimization. © 2018 Elsevier GmbH