Parallelization of an implicit algorithm for multi-dimensional particle-in-cell simulations

TL;DR

This paper describes the parallelization of an implicit 2D3V particle-in-cell code using MPI, achieving significant speedups and enabling future extensions to include atomic physics and three-dimensional simulations.

Contribution

The paper introduces an MPI-based parallelization of an existing implicit PIC code, optimizing performance and setting the stage for advanced physics modeling and 3D simulations.

Findings

Significant speedup in particle-dominated regime

Parallelization achieves 75-80% of maximum theoretical speedup in field-dominated regime

Code optimization through overlapping computations and communications

Abstract

The implicit 2D3V particle-in-cell (PIC) code developed to study the interaction of ultrashort pulse lasers with matter [G. M. Petrov and J. Davis, Computer Phys. Comm. 179, 868 (2008); Phys. Plasmas 18, 073102 (2011)] has been parallelized using MPI (Message Passing Interface). Details on the algorithm implementation are given with emphasis on code optimization by overlapping computations with communications. Performance evaluation has been made on a small Linux cluster with 32 processors for two typical regimes of PIC operation: "particle dominated", for which the bulk of the computation time is spent on pushing particles, and "field dominated", for which computing the fields is prevalent. We found that the MPI implementation of the code offers a significant numerical speedup. In the "particle dominated" regime it is close to the maximum theoretical one, while in the other regime it is about 75-80 % of the maximum speed-up. The code parallelization will allow future implementation of atomic physics and extension to three dimensions.