Simulations of the TJNAF FEL with a Tapered Undulator and Experimental Results of Laser Damage

The modern maritime battlefield is dominated by the new generation of sea-skimming, high-speed, stealthy and highly agile anti-ship missiles. Anti- ship cruise missile technology continues to evolve, overcoming the performance of the existing ship self-defense weapon systems. The Free Electron Laser (FEL) could be the ultimate speed-of-light, hard-kill weapon system, offering unique features such as tunability, high power, pinpoint accuracy and infinite magazine. Multimode computer simulations were used to explore the operation of the Thomas Jefferson National Acceleration Facility (TJNAF) FEL with untapered and positively tapered undulator. The final steady-state power, the steady-state gain and the electron energy spread as a function of desynchronism were determined for both 34.5 Mev and 47.5 Mev electron beam energies. This thesis also includes an experimental study of damage induced to Polyimide Fiberglass and F2 Epoxy samples, by the TJNAF FEL. Irradiations of the samples were conducted changing various parameters such as the wavelength, average power, pulse repetition frequency, cross wind and spot size in order to explore the damage mechanism. At this stage of evolution, TJNAF FEL is capable of 500W output average power, and in order to achieve the required intensity of 10 kW/ cm2 the beam was focused to a small radius. Scaling guidelines were developed in order to predict the damage caused by a high power laser over a large area.Naval Postgraduate School Monterey CA is the author of 'Simulations of the TJNAF FEL with a Tapered Undulator and Experimental Results of Laser Damage', published 2000 under ISBN 9781423532385 and ISBN 1423532384.