An exact particle splitting algorithm for PIC codes

TL;DR

This paper introduces a novel exact particle splitting algorithm for PIC codes using AMR grids, which preserves particle properties precisely and reduces numerical noise compared to traditional approximate methods.

Contribution

The paper presents a new exact splitting algorithm for macro-particles in PIC codes that leverages AMR grid properties and B-spline functions, applicable for any refinement factor and spline order.

Findings

Exact splitting preserves particle properties precisely.

The method reduces numerical noise compared to approximate splitting.

Applicable for any integer refinement factor and B-spline order.

Abstract

Splitting and merging are long standing issues in PIC codes. I propose a novel algorithm devoted to exact splitting for Particle-In-Cell (PIC) codes relying on Adaptive Mesh Refinement (AMR) grids. AMR grids have - by definition - a constant refinement factor between levels, this strong property combined with B-spline shape functions makes possible exact splitting of macro-particles in space. The proposed exact splitting method is applicable for any integer refinement factor and B-spline shape functions of arbitrary order. Besides, this exact algorithm removes by construction the usual numerical noise increase resulting from approximate particle splitting strategies.