High-Fidelity RF Gun Simulations with the Parallel 3D Finite Element Particle-In-Cell Code Pic3P

SLAC’s Advanced Computations Department (ACD) has developed the first parallel Finite Element 3D Particle‐In‐Cell (PIC) code, Pic3P, for simulations of RF guns and other spacecharge dominated beam‐cavity interactions. Pic3P solves the complete set of Maxwell‐Lorentz equations and thus includes space charge, retardation and wakefield effects from first principles. Pic3P uses higher‐order Finite Element methods on unstructured conformal meshes. A novel scheme for causal adaptive refinement and dynamic load balancing enable unprecedented simulation accuracy, aiding the design and operation of the next generation of accelerator facilities. Application to the Linac Coherent Light Source (LCLS) RF gun is presented.