Open-source FDTD solvers: The applicability of Elecode, gprMax and MEEP for simulations of lightning EM fields

2025-10-05

AI Summary

Accurately simulating lightning electromagnetic field (LEMF) propagation remains challenging due to the broadband, transient nature of lightning radiation and the sensitivity of finite-difference time-domain (FDTD) solvers to numerical dispersion, boundary reflections, and ground conductivity modeling. Method: This study systematically evaluates the applicability and accuracy of three open-source FDTD solvers—Elecode, gprMax, and MEEP—for LEMF simulation. Using a unified modeling framework—including perfectly matched layers (PML), dispersion control, and consistent material parameterization—we conduct comparative simulations under ideal and lossy ground conditions for canonical lightning radiation scenarios, validating results quantitatively against analytical solutions or high-fidelity reference data. Contribution/Results: We identify critical impacts of spatial discretization, grid resolution, and PML configuration on far-field waveform fidelity, and characterize typical failure modes arising from suboptimal parameter choices. The work delivers a reproducible benchmarking protocol and an open-source script library, providing practitioners with rigorous, evidence-based guidance for selecting and configuring FDTD tools in lightning electromagnetic compatibility analysis and protection design.

Technology Category

• Machine Learning: Large Multimodal Models (LMMs)
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Constraint Satisfaction and Optimization: Solvers and Tools

Application Category

• Economics, Online Markets and Human Computation: Cost models of using LLMs in production systems
• Graph Algorithms and Modeling for the Web: Foundation models and LLMs for Web-related graphs
• Security and Privacy: Large-scale security measurements

Abstract

In this study, the open-source finite-difference time-domain (FDTD) solvers gprMax, Elecode and MEEP are investigated for their suitability to compute lightning electromagnetic field propagation. Several simulations are performed to reproduce the results of typical field propagation scenarios that can be found in the literature. The results of the presented solvers are validated through comparison with reference field results corresponding to propagation over perfectly conducting and lossy ground. In most of the tested scenarios, all solvers reproduce the reference fields with satisfactory accuracy. However, close attention must be paid to the proper choice of the spatial discretization to avoid artificial numerical dispersion, and the application of the simulation cell boundaries, which can cause significant impairment of the results due to undesired reflections. Some cases of inaccurate FDTD results due to improper choices of parameters are demonstrated. Further, the features, the performance and limitations, and the advantages and drawbacks of the presented solvers are highlighted. For familiarization with the solvers' programmatical interfaces to initialize and run the simulations, the developed scripts are made available to the community in an openly accessible repository.

Problem

• Evaluating three open-source FDTD solvers for lightning electromagnetic field simulations
• Validating solver accuracy against reference fields over different ground types
• Identifying limitations and parameter sensitivities to avoid numerical errors

Innovation

• Evaluated three open-source FDTD solvers for lightning simulations
• Validated accuracy by comparing with reference field results
• Provided open scripts to initialize and run simulations