Energy-Preserving Coupling of Explicit Particle-In-Cell with Monte Carlo Collisions

TL;DR

This paper reviews the explicit PIC-MCC algorithm, identifies the cause of anomalous numerical heating when coupling the methods, and proposes a coupling approach that preserves energy and avoids heating.

Contribution

It introduces a novel coupling technique for PIC and MCC that maintains energy conservation and prevents numerical heating in simulations.

Findings

Identifies the source of anomalous numerical heating in PIC-MCC coupling.

Provides a coupling method that preserves energy conservation.

Demonstrates the effectiveness of the method in avoiding numerical heating.

Abstract

The Particle-In-Cell (PIC) and Monte Carlo Collisions (MCC) methods are workhorses of many numerical simulations of physical systems. Recently, it was pointed out that, while the two methods can be exactly - or nearly - energy-conserving independently, combining the two is leading to anomalous numerical heating. This paper reviews the standard explicit PIC-MCC algorithm, elucidates the origins of the anomalous numerical heating and explains how to couple the two methods such that the anomalous numerical heating is avoided.