First-principles simulations of electrostatic interactions between dust grains

TL;DR

This study uses first-principles N-body simulations to analyze electrostatic interactions between dust grains in plasma, finding repulsive forces and no evidence for the proposed attractive overlapping Debye sphere effect.

Contribution

The paper provides the first simulation-based evidence that electrostatic interactions between dust grains are repulsive, challenging previous claims of an attractive force due to overlapping Debye spheres.

Findings

Electrostatic interactions are repulsive and stronger than Yukawa potential.

Electric field measurements align with a corrected electrostatic potential model.

No evidence supports the attractive force due to overlapping Debye spheres.

Abstract

We investigated the electrostatic interaction between two identical dust grains of an infinite mass immersed in homogeneous plasma by employing first-principles N-body simulations combined with the Ewald method. We specifically tested the possibility of an attractive force due to overlapping Debye spheres (ODSs), as was suggested by Resendes et al. (1998). Our simulation results demonstrate that the electrostatic interaction is repulsive and even stronger than the standard Yukawa potential. We showed that the measured electric field acting on the grain is highly consistent with a model electrostatic potential around a single isolated grain that takes into account a correction due to the orbital motion limited theory. Our result is qualitatively consistent with the counterargument suggested by Markes and Williams (2000), indicating the absence of the ODS attractive force.