Fel Oscillators with Tapered Undulators: Inclusion of Harmonic Generation and Pulse Propagation

TL;DR

This paper reviews FEL oscillators with tapered undulators, analyzing how tapering influences gain, saturation, pulse propagation, harmonic generation, and pulse shaping, providing insights into controlling FEL output characteristics.

Contribution

It introduces a parameter to quantify tapering effects and analyzes pulse propagation and harmonic control in tapered FEL oscillators.

Findings

Tapering affects gain and saturation intensity significantly.

Tapering can be used to control higher harmonic intensities.

Pulse propagation effects are crucial in tapered FEL dynamics.

Abstract

We review the theory of FEL oscillators operating with tapered undulators. We consider the case of a uniform tapering and introduce a parameter which characterizes the effect of the tapering on the gain and on the saturation intensity. We analyze the effect of the tapering on the FEL dynamics by including the pulse propagation effects too. We analyze the importance of tapering as a tool to model the optical pulse shapes and to control the higher harmonic intensities.