1. Analytical Force Model
Derived an empirical inter-particle force model for paramagnetic grains subjected to uniform external magnetic fields, resolving dipole-dipole interactions and orientation-dependent cohesion.
Geophysical Context & Motivation
Granular Mechanics on M-Type Asteroids
Asteroid (16) Psyche is the largest M-type (metallic) asteroid in our solar system, targeted by NASA's Psyche mission. Unlike silicate asteroids like Bennu or Ryugu, M-type bodies contain high concentrations of metal and paramagnetic iron-nickel grains.
In low-gravity environments, inter-particle cohesive forces govern surface morphology, crater degradation, and mass-wasting events. When an intrinsic or remnant magnetic field is present, paramagnetic inter-particle forces introduce directional cohesion that alters avalanche slope angles and granular fluidity.
This dissertation research developed the mathematical formulation, experimental validation, and open-source simulation tools required to model magnetic cohesion in space science.
Project Snapshot
- Institution: University of Maryland, College Park
- Advisor: Prof. Christine Hartzell
- Degree: PhD Dissertation (Aerospace Engineering, 2026)
- Software Framework: LIGGGHTS Open-Source DEM (C++)
- Primary Target: Asteroid (16) Psyche & M-type Regolith
- Keywords: Paramagnetic Cohesion, Avalanching, Mass Wasting, DEM, LIGGGHTS
Key Research Contributions
Methodology & Key Findings
2. Open-Source Code Release
Developed and published LIGGGHTS-Public-Mag v1.0.0 on GitHub — the first open-source DEM code enabling magnetic cohesion integration for planetary scientists.
3. Numerical Time-Step Rules
Formulated explicit mathematical criteria for integration time-step bounds to ensure numerical stability under steep magnetic force gradients in high-particle DEM runs.
4. Avalanche Angle Mapping
Conducted multi-scenario avalanching simulations to map surface morphology conditions on metallic asteroid 16-Psyche under remnant magnetic fields.
5. Bulk Magnetic Bond Number Scaling
Proposed a bulk magnetic bond number (Bmag, bulk) framework defining flow regime transitions: cohesion onset at Bmag, bulk ≈ 5, correlated avalanching at Bmag, bulk ≳ 14, and plastic flow at Bmag, bulk ≳ 25.
6. Regolith Cohesion Thresholds
Accounting for multi-body field amplification (S ≈ 49.14) and Psyche's microgravity (g ≈ 0.13 m s-2), ambient remanent fields of 30 µT cohesively bind metallic grains up to a ≈ 0.31 mm, whereas weak 0.3 µT fields govern nanoscale regolith dynamics (a ≈ 31 nm).
Associated Scholarship
Peer-Reviewed Publications
Accepted (2026)
Investigating the Role of Magnetic Cohesion in Avalanching on 16-Psyche: A Discrete Element Modeling Approach
Sikka, A. & Hartzell, C. M. · Accepted to The Planetary Science Journal (PSJ).
Published (2026)
An Experimentally Validated Magnetic Force Model for Discrete Element Modeling of Paramagnetic Granular Media
Sikka, A. & Hartzell, C. · Granular Matter, Vol. 28, No. 3, pp. 53.
DOI: 10.1007/s10035-026-01643-x ↗
Published (2023)
Development of an Empirical Model of the Force between Paramagnetic Particles in Uniform Magnetic Field on M-type Asteroids
Sikka, A., DesJardin, I., Leps, T., & Hartzell, C. · The Planetary Science Journal, Vol. 4, No. 7, pp. 129.
DOI: 10.3847/PSJ/ace323 ↗Open-Source Repository & Citation
The custom LIGGGHTS C++ source code, force fix modules, and sample simulation scripts are publicly available on GitHub under an open-source license.
git clone https://github.com/AstroAnmol/LIGGGHTS-Public-Mag.git
cd LIGGGHTS-Public-Mag/src
make auto
Visit GitHub v1.0.0 Release ↗
cd LIGGGHTS-Public-Mag/src
make auto