Accurately and Efficiently Studying the RF Structures Using a Conformal Finite-Difference Time-Domain Particle-in-Cell Method

This work introduces a conformal finite difference time domain (CFDTD) particle-in-cell (PIC) method to accurately and efficiently study electromagnetic or radio frequency (RF) structures and their interactions with charged particles. For illustration, the dispersion relation of an A6 relativistic magnetron has been determined and a preliminary hot test including electrons has been done. The accuracy of the CFDTD method is measured by comparing with calculations based on the finite element method. The results show that an accuracy of 99.4% can be achieved by using only 10,000 mesh points with the Dey-Mittra algorithm as implemented in the CFDTD method. By comparison, a mesh number of 250,000 is needed to preserve 99% accuracy using a staircased FDTD method. This suggests one can more efficiently and accurately study the hot tests of microwave tubes or the interactions of charged particles and RF structures using the CFDTD PIC method than a conventional FDTD one.