Investigating the Role of Magnetic Cohesion in Avalanching on 16-Psyche: A Discrete Element Modeling Approach

We investigate the role of magnetic cohesion in avalanching on the metallic asteroid 16-Psyche using discrete element method (DEM) simulations. A dynamo or the solar nebula could have magnetized Psyche, creating global dipole moments of up to 2 × 10 14 –2 × 10 17 A m 2 . For sufficiently small particles, magnetic forces can dominate over gravity in such fields. We simulate avalanches of regolith particles (10 mm diameter) under scaled magnetic field strengths (0–1000 μ T) for different material compositions: nonsusceptible, low-susceptible, and high-susceptible in various mixtures. We employ a recently validated magnetic force model based on the inclusion theory and analyze the results using angle-of-repose and surface-roughness metrics. Our results show that magnetic cohesion does not significantly affect avalanche dynamics at field strengths below 500 μ T for 10 mm particles. However, at 1000 μ T, we observe a transition from granular flow to a plastic regime for high-susceptible materials, accompanied by increased surface roughness. To extrapolate these findings, we propose a predictive bulk magnetic Bond number ( B mag, bulk ) that incorporates multibody field amplification ( S ) and mineralogical dilution ( P ). Applying this formulation to Psyche’s microgravity ( g ≈ 0.13 m s −2 ), ambient fields of 30 μ T can cohesively bind grains up to radius a ≈ 0.31 mm, creating steeper angles of repose and irregular surface morphologies than expected from purely gravitational considerations. The density, magnetic susceptibility, and particle size of Psyche’s regolith all play critical roles in determining whether magnetic cohesion substantially influences mass-wasting processes, with important implications for surface morphology and data analysis for the Psyche mission.