Unstructured-grid and conservative electromagnetic particle-in-cell: Application to micromachined slow-wave structures

摘要

We present an accurate and efficient electromagnetic particle-in-cell (EMPIC) algorithm on unstructured grids for the analysis and design of axisymmetric slow-wave structures. The use of unstructured grids allows for more fidelity in the modeling of micromachined geometries. The use of a reduced-dimensionality algorithm decreases the computational costs significantly and enables its integration as a forward engine into a design loop. Special gather and scatter steps are employed to yield exact charge conservation on unstructured grids. We provide numerical examples involving travelling-wave tube amplifiers designed to harness bunching effects arisen from Cherenkov radiation.