A model for the saturation of a storage ring free electron laser

The dynamical properties of a storage ring free electron laser oscillator are reproduced using a model combining three different saturation mechanisms: laser induced energy spread of the e-beam, associated bunch lengthening and longitudinal synchronism between laser and electron pulses. The stationary output power is shown to be always linked to the power emitted via synchrotron radiation in one machine turn by the circulating e-beam.