Performance analysis and implementation details of the Energy Conserving Semi-Implicit Method code (ECsim)

TL;DR

This paper introduces ECsim, a fully electromagnetic, energy-conserving semi-implicit PIC code that is highly stable and parallelizable, enabling new plasma simulation capabilities previously unattainable with existing codes.

Contribution

The paper details the implementation of ECsim, a novel 3D PIC code that conserves energy, is unconditionally stable, and demonstrates superior performance over existing semi-implicit PIC codes.

Findings

ECsim is unconditionally stable and energy conserving.

ECsim effectively eliminates finite grid instability.

ECsim outperforms other semi-implicit PIC codes in stability and performance.

Abstract

We present in this work the implementation of the Energy Conserving Semi-Implicit Method in a parallel code called ECsim. This new code is a three-dimensional, fully electromagnetic particle in cell (PIC) code. It is written in C/C++ and uses MPI to allow massive parallelization. ECsim is unconditionally stable in time, eliminates the finite grid instability, has the same cycle scheme as the explicit code with a computational cost comparable to other semi-implicit PIC codes. All this features make it a very valuable tool to address situations which have not been possible to analyze until now with other PIC codes. In this work, we show the details of the algorithm implementation and we study its performance in different systems. ECsim is compared with another semi-implicit PIC code with different time and spectral resolution, showing its sability to address situations where other codes fail.