Parameters analysis of nonlinear saturation power in a FEL amplifier

Influences of parameters on the nonlinear power are simulated by using a Hamiltonian model. Results show that the saturation power is mainly determined by the mismatched parameter, and optimum of the mismatched parameter increases the saturation power and shortens the saturation-interaction length. Also, higher beam current leads to a higher saturation power and shorter saturation-interaction length.