Conformal FDTD modeling of 3-D wake fields

The use of the conformal finite-difference time-domain (CFDTD) method used to model the wake fields generated by a rigid beam traveling through various accelerating structures is discussed. The non-cylindrical symmetry of some of the problems considered requires the use of a three-dimensional code. In traditional FDTD codes, curved surfaces are approximated by rectangular steps. The errors introduced in wake field calculations by such an approximation can be reduced by increasing the mesh size, therefore increasing the cost of computing. Another approach, validated in this work, deforms Ampere and Faraday contours near a media interface so as to conform to the interface.<>