U.S. Particle Accelerator School

The Physics of Free Electron Lasers course

Sponsoring University:

Vanderbilt University


The Physics of Free Electron Lasers


James B. Murphy, Brookhaven National Lab and Juhao Wu, SLAC

Purpose and Audience
The purpose of this course is to introduce the students to the physics of Free Electron Lasers and Synchrotron Radiation. This course is suitable for graduate students who want to learn more about Free Electron Lasers and Synchrotron Radiation physics.

Graduate courses in Classical Mechanics and Classical Electrodynamics.

This graduate course will focus on the physics of Free Electron Lasers with a general introduction to Synchrotron Radiation. The fundamental physics will be explored with up to date analytical and numerical skills elaborated. With the LINAC Coherent Light Source (LCLS) [the world’s first x-ray Self-Amplified Spontaneous Emission (SASE) FEL] and Source Development Lab (SDL) [the only functioning high-gain single-pass seeded FEL] as example facilities, the students will be exposed to the most advanced technology as well. On completion of this course, the students are expected to understand the physics of FELs and the key accelerator components to drive a FEL. Furthermore, the students are expected to be able to design a simple high-gain FEL from first principles.

Instructional Method
This course will offer a series of lectures during the morning sessions and afternoon sessions on Monday and Tuesday. The afternoon of Wednesday and Thursday will be laboratory sessions, where the students will be introduced to computer simulations. The computer simulation will be compared to real experimental data. Homework problems will be assigned each day and instructors will be available to help answer questions about the homework and lectures during the evening exercise sessions. There will be a final exam on the last day of the class.

Course Content
Synchrotron Radiation and Undulator Radiation will be introduced first as spontaneous radiation sources. Stimulated emission and Free Electron Lasers (FELs) are then introduced with comparison to spontaneous radiation sources. FEL oscillators and amplifiers are explored as various operational modes. The small gain limit and the high-gain regime are explored. The FEL spatial and temporal coherence is emphasized with further study of the effect of electron beam and undulator quality on the FEL performance. SASE FELs and seeded FELs are compared with respect to their coherence properties. The High-Gain Harmonic Generation (HGHG) scheme will be detailed as an example of a seeded FEL. High-order Harmonic Generation (HHG) in a gas will be introduced specifically as the coherent seed for a seeded x-ray FEL. Three-Dimensional effects are studied with the Vlasov-Maxwell coupled equations and with numerical simulation. LCLS and SDL will be used throughout as examples of all the effects.

Reading Requirements
(to be provided by the USPAS) “The Physics of Free Electron Lasers”, Springer-Verlag (1999) by E.L. Saldin, E.A. Schneidmiller, and M.V. Yurkov. Suggested reference that will not be provided to students: “Introduction to the physics of the free electron laser” by J.B. Murphy and C. Pellegrini, in “LASER HANDBOOK”, VOLUME 6, Elsevier Science & Technology (1990) by W.B. Colson, C. Pellegrini, and A. Renieri.

Credit Requirements
Students will be evaluated based on their performance: final exam (40 % of final grade), homework assignments (40 % of final grade), and computer sessions (20 % of final grade).