An Experimentally Validated Magnetic Force Model for Discrete Element Modeling of Paramagnetic Granular Media

Magnetic interactions between metallic granular particles can lead to magnetic cohesion, influencing the flow characteristics of granular media. This magnetic cohesion has been studied in the context of Magneto-Rheological Fluids (MRF) for their unique flow properties and use in multiple industries. In Planetary Science, magnetic cohesion can influence the behavior of regolith on metallic asteroids with remnant magnetic fields. The upcoming NASA Psyche mission will study the metallic asteroid 16 Psyche, which is expected to have a surface magnetic field. Modeling and simulating the effect of magnetic cohesion on granular media is crucial for accurately simulating the behavior of magnetic granular materials in both terrestrial and planetary applications. We introduce an improved magnetic force model in LIGGGHTS, an open-source discrete element modeling software, to calculate magnetic forces between paramagnetic grains. The model is based on the Mutual Dipole Method and the Inclusion Model, extensions of the Fixed Dipole Method. We validate the model using 1-D unit tests and compare the results from avalanche simulations of paramagnetic regolith with experiments. This work contributes to understanding the role of magnetic cohesion in small body surface processes and provides a tool for future studies of magnetic granular materials in DEM.