| Summary: | This thesis describes an unaveraged 3D mathematical model and parallel code of the free electron laser. It is unique in that it is a 3D model which does not perform limiting assumptions performed by commonly used FEL codes. ) This allows it to model the FEL with a higher resolution, and to model effects which other codes cannot. The code is written in Fortran 90. The enhanced frequency range results in an increased memory and process uptake, and so the code is written for use on parallel processors using the MPI standard. The problems associated with finding an efficient method of parallelization of the FEL system are described and solutions are considered. The enhanced frequency range also results in a model of diffraction in the transverse dimensions which is frequency dependant, which becomes problematic at low frequencies. To solve this, a low frequency cut-off is defined, and the frequencies below the cut-off are filtered out during the simulations. Several simulations are presented to test the code against previously published results with the enhanced frequency range in ID; Then 3D simulations are pre- sented showing the amplification arising from effects which cannot be predicted in more commonly used codes. Finally, a new effect is reported involving the evolution of short chirped electron bunches in an undulator.
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