Numerical Simulations of Dust Dynamics Around Small Asteroids

This paper presents a simulation study of the dynamics of dust grains around a small asteroid. Plasma-asteroid interactions and asteroid charging are obtained from fully kinetic particle-in-cell simulations. Dust transport simulation takes into account the electrostatic force, solar radiation pressure, and the gravitational force. Both the result derived from laboratory measurements of regolith surface charging and the single dust charging model are considered for dust charging. For the small asteroid considered in this paper, we find that dust transport is mostly determined by the competition between the electrostatic force and the solar pressure and dust distribution is sensitive to both dust charging and dust grain size. For dust grains in the tens of micrometer size range, the solar radiation pressure dominates dust transport at small dust charge-to-mass ratio, whereas the electrostatic force dictates dust transport at large dust charge-to-mass ratio.