Locally conformal three-dimensional FDTD mesh generator with application to modeling a novel linear accelerator

The finite-difference time-domain (FDTD) method is subject to significant errors due to the staircasing of surfaces that are not precisely aligned with major grid planes. A new, locally conformal method D-FDTD has shown substantial gains in the accuracy of modeling arbitrary surfaces in the FDTD grid. It requires only modest stability conditions and may be implemented with little modification to existing FDTD solvers. It is shown in this thesis to reduce the required FDTD grid resolution by up to 4:1 in each Cartesian direction in 3-D relative to conventional staircased FDTD models when simulating complex curved PEC structures.; In this dissertation, the formulation and validation of a CAD-based mesh generator for D-FDTD for arbitrary 3-D PEC scatterers and resonators is presented, and the numerical modeling of a standing-wave linear accelerator is evaluated. Modifications to the design of the proposed twisted, circular accelerator are created using Pro Engineer™ and imported into the 3-D CAD-based mesh generator. The mesh generator enables rapid processing of the geometry for use in the D-FDTD solver, and permits a design study to be performed for the linear accelerator.; The primary goal of this research is to demonstrate the improved accuracy of the conformal D-FDTD method and to demonstrate the advantages of this technique. Conformal electromagnetic solvers using the finite element method are shown to have an order of magnitude greater memory requirement and a substantially greater solution time with comparable accuracy as compared with the conformal time-domain D-FDTD method.