¹Andrei Yakovlev, ¹Dmitriy Beloborodov
Icarus (in Press) Link to Article [DOI: 10.1016/j.icarus.2026.117363]
¹St. Petersburg State University, 28, Universitetskaya prospekt, St. Petersburg, 198504, Russia

Copyright Elsevier

We investigate the dynamics of levitation and horizontal transport of lunar regolith particles in the vicinity of the terminator, taking into account the radiation pressure of solar irradiation. In contrast to earlier simplified models, the radiation pressure efficiency factor Q_pr(R) is calculated based on Mie theory using experimental data for the complex refractive index of vitreous silicate that is characteristic of lunar soil. We consider a two-dimensional model of particle motion in the near-surface photoelectron sheath that incorporates electrostatic, gravitational and radiation forces. Within this framework, the dependence of the minimum levitation angle θ_min(R) on particle radius is analyzed, and numerical calculations of the maximum horizontal transport distance L_max(R) during sunrise and sunset periods are performed. Our results show that incorporating the real optical properties of particles leads to quantitative changes in the dependence of L_max(R) compared to earlier estimates. At sunset, the transport maximum is attained for particle radii of approximately 0.075 μm, whereas at sunrise a non-monotonic dependence L_max(R) appears, along with significantly larger transport distances for small particles. Our findings show that the realistic optical properties of particles have a significant impact on the spatial scales over which lunar regolith is redistributed horizontally.