The free-electron laser (FEL) is a device for converting kinetic energy in a relativistic electron beam directly into laser light. A classical theory of the FEL is discussed. This theory uses the Boltzmann distribution to describe the electrons and Maxwell equation to describe the evolution of the laser field. The harmonic expansion of the Boltzmann equation leads to a set of "quasi-Bloch" equations describing the electron distribution. The behavior of the momentum distribution is discussed theoretically in the small-signal regime of the FEL. The distribution function changes in nontrivial ways. The electron distribution does not only experience a recoil, but is also subject to spread through the amplification process. The recoil plays a relatively minor role compared to the spread. This behavior of the electron distribution may play an important role in the efficiency of the FEL. Free-electron lasers, except for those using helical wigglers, are predicted in most cases to generate higher harmonics, of the fundamental optical frequency, in the forward direction. The basic equations describing this process are derived by using the multiple-scaling perturbation theory, which leads to the slowly-varying Maxwell and Boltzmann equations. Harmonic generation in the FEL offers a possible means to extend the wavelength range of the device towards high frequency. Numerical calculations are shown for CW operation using a linearly polarized wiggler. Higher harmonic emission becomes enhanced as the magnetic field is increased and as the energy spread in the electron beam is reduced. Coherent pulse propagation in the picosecond pulse regime of the FEL is treated. Coherent transient effects such as laser lethargy are discussed. The effect of laser lethargy is seen to play an important role in the pulsed FEL, as it does in conventional swept-gain amplifiers based on an atomic medium. Numerical calculations of the harmonics in the pulsed FEL are presented. The optical pulses show a ringing behavior which is sensitive to the reflectivity of the cavity mirrors and to the electron current.

by Ip Tak-wa. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1989. / Bibliography: leaves 62-64.

by Chan, Siu Cheung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1989. / Bibliography: leaves 65.

Thesis (M.S. in Physics)--Naval Postgraduate School, December 2002. / Thesis advisor(s): William B. Colson, Robert L. Armstead. Includes bibliographical references (p. 97-99). Also available online.

by Wong Tong Pak. / Bibliography: leaves 188-189 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1986

by Cheung Chin Tao. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1989. / Bibliography: leaf [67].

Thesis (M.S. in Applied Physics)--Naval Postgraduate School, December 2003. / Thesis advisor(s): William B. Coulson, Robert L. Armstead. Includes bibliographical references (p. 71-72). Also available online.

Thesis (M.S. in Physics)--Naval Postgraduate School, December 2002. / Thesis advisor(s): William B. Colson, Robert L. Armstead. Includes bibliographical references (p. 79-80). Also available online.

Approved for public release; distribution is unlimited / Theory and simulations of the railgun and free electron laser are presented, as well as a suggestion for extending the railgun lifecycle. The theory, design, and analysis of an electromagnetic railgun using a numerical model are discussed. The effects of varying electrical pulse formations, rail materials and geometries are explored. The application of a metallurgical process to mitigate hypervelocity gouging in railgun rails is proposed. This concept, to delay the onset velocity of gouging by laser-peening rails surfaces, may significantly increase the velocity at which projectiles acceptably traverse the barrel and extend the useful life of rails. If successful, this process would apply to any pair of materials in sliding contact at high relative velocity, including rocket sled tracks and light gas guns barrels. The status of proof-of-concept tests at LLNL, UC Davis, and UT is covered. FEL simulations investigating the effect that electron beam focal point variations have on the optical mode within the undulator are presented. / Lieutenant, United States Navy

The Free Electron Laser (FEL) can provide the naval surface combatant with a directed energy weapon that can be used against a large target set. Due to space constraints in a shipboard installation, an exploration is conducted to show the feasibility of short Rayleigh length FELs using a FEL simulation. Low atmosphere engagements are discussed through the modeling of a turbulence module for laser propagation in cruise missile defense applications. In particular, this thesis explores the difficulties in engaging a short/medium range theater ballistic missile (TBM) in the terminal phase as an engagement scenario in support of littoral operations using HELCoMES, developed by SAIC, as an engagement analysis tool. A concept of operations (CONOPS) for the use of a FEL as an area TBM defensive weapon is explored, using a unitary, high explosive warhead model and extrapolations to other TBM warhead types.