The Phase Jump Method for Efficiency Enhancement in Free-Electron Lasers

by Mr Alan Mak (Lund University)

Wednesday 15 Feb 2017, 15:00 → 17:00 Europe/Stockholm

Ångström (10234)

In this seminar, I shall discuss my ongoing theoretical work on the phase jump method for free-electron lasers. The method utilizes phase shifters, which are compact chicanes installed in the drift sections between undulator segments. The purpose is to sustain the radiation power growth beyond the initial saturation point, thus enhancing the efficiency of the free-electron laser. The seminar presents a steady-state model of the phase jump method. The model elucidates the energy extraction process in the longitudinal phase space. The main ingredient is the microbunch deceleration cycle, which enables the microbunched electron beam to decelerate and radiate coherently. While the ponderomotive bucket is stationary, energy can be extracted from electrons outside the bucket. The seminar concludes with a comparison of the phase jump method to undulator tapering, another common method for enhancing the efficiency of a free-electron laser.

Slides Alan_Mak_seminar_20170215.pdf