Electrostatic and Electromagnetic Particle-in-Cell Solvers for Electron Beam Device Simulations

This article presents an open source implementation of an axisymmetric solver capable of analyzing a vacuum electron device called a multicavity klystron, which consists of three cavities. Additionally, we describe results of three types of simulations with sufficient details that allow re-creation of these results. Important assumptions and parameters are presented for a particular klystron cavity and compared with the literature as well as similar results obtained using another software package. We also describe the problem of nonzero divergence due to an electron beam source, which we solved using a known procedure called divergence cleaning. The first part of the article focuses on an analysis of the first two cavities using a 2-D axisymmetric code. As the third cavity in the klystron cannot be simulated using an axisymmetric code without introducing additional assumptions, we perform an analysis of this cavity using a newly developed 3-D Julia code.