Energy Phase Correlation and Pulse Dynamics in Short Bunch High Gain FELs

摘要

We analyze the dynamics of Free Electron Laser (FEL) devices, operating witha bunched beam exhibiting a longitudinal phase space correlation. We show thatthe presence of an energy-position correlation term is responsible for veryinteresting effects like an enhancement of the peak output power, a shorteningof the laser pulses and an increase of the non linearly generated harmonicintensities. We conjecture that the mechanism is due to a kind of energytapering effect associated with the correlation. We discuss the difference ofthe dynamics with respect to an ordinary undulator tapering and the relativeadvantages.