Benchmark for two-dimensional large scale coherent structures in partially magnetized ExB plasmas -- Community collaboration & lessons learned

TL;DR

This paper presents a collaborative benchmarking effort of 17 simulation codes modeling large-scale coherent structures in partially magnetized ExB plasmas, highlighting agreement in key plasma properties and lessons learned for future code verification.

Contribution

It provides the first large-scale community benchmark for ExB plasma simulations, demonstrating code agreement and sharing insights on best practices and challenges.

Findings

Excellent agreement on spoke rotation frequency

Consistent plasma density, potential, and temperature profiles

Lessons learned for future benchmarking campaigns

Abstract

Low-temperature plasmas are essential to both fundamental scientific research and critical industrial applications. As in many areas of science, numerical simulations have become a vital tool for uncovering new physical phenomena and guiding technological development. Code benchmarking remains crucial for verifying implementations and evaluating performance. This work continues the Landmark benchmark initiative, a series specifically designed to support the verification of low-temperature plasma codes. In this study, seventeen simulation codes from a collaborative community of nineteen international institutions modeled a partially magnetized ExB Penning discharge. The emergence of large scale coherent structures, or rotating plasma spokes, endows this configuration with an enormous range of time scales, making it particularly challenging to simulate. The codes showed excellent agreement on the rotation frequency of the spoke as well as key plasma properties, including time-averaged ion density, plasma potential, and electron temperature profiles. Achieving this level of agreement came with challenges, and we share lessons learned on how to conduct future benchmarking campaigns. Comparing code implementations, computational hardware, and simulation runtimes also revealed interesting trends, which are summarized with the aim of guiding future plasma simulation software development.