EZ: An efficient, charge conserving current deposition algorithm for electromagnetic particle-in-cell simulations

We present EZ, a novel current deposition algorithm for particle-in-cell (PIC) simulations. EZ calculates the current density on the electromagnetic grid due to macro-particle motion within a time step by solving the continuity equation of electrodynamics. Being a charge conserving hybridization of Esirkepov's method and ZigZag, we refer to it as EZ as shorthand for Esirkepov meets ZigZag. Simulations of a warm, relativistic plasma with PIConGPU show that EZ achieves the same level of charge conservation as the commonly used method by Esirkepov, yet reaches higher performance for macro-particle assignment-functions up to third-order. In addition to a detailed description of the functioning of EZ, reasons for the expected and observed performance increase are given, and guidelines for its implementation aiming at highest performance on GPUs are provided.& COPY; 2023 Elsevier B.V. All rights reserved.

Automated summary

We propose a novel current deposition algorithm called EZ for particle-in-cell (PIC) simulations. EZ solves the continuity equation of electrodynamics to calculate the current density on the electromagnetic grid due to macro-particle motion within a time step. It combines Esirkepov's method and ZigZag to achieve charge conservation and higher performance for higher-order macro-particle assignment-functions, as demonstrated in simulations of a warm, relativistic plasma with PIConGPU.