Dipole-Dipole Interactions of Charged Magnetic Grains

TL;DR

This paper investigates how electrostatic and magnetic dipole-dipole interactions influence the coagulation, orientation, and structure of charged and magnetic dust aggregates, with implications for planetesimal formation and material processing.

Contribution

It introduces a numerical model to compare coagulation behaviors of charged, magnetic, and uncharged dust grains, highlighting the role of dipole interactions in aggregate formation.

Findings

Dipole-dipole interactions influence aggregate orientation.

Magnetic and charge properties affect aggregate structure.

Grain composition impacts fractal dimension of dust populations.

Abstract

The interaction between dust grains is an important process in fields as diverse as planetesimal formation or the plasma processing of silicon wafers into computer chips. This interaction depends in large part on the material properties of the grains, for example whether the grains are conducting, non-conducting, ferrous or non-ferrous. This work considers the effects that electrostatic and magnetic forces, alone or in combination, can have on the coagulation of dust in various environments. A numerical model is used to simulate the coagulation of charged, charged-magnetic and magnetic dust aggregates formed from ferrous material and the results are compared to each other as well as to those from uncharged, non-magnetic material. The interactions between extended dust aggregates are also examined, specifically looking at how the arrangement of charge over the aggregate surface or the inclusion of magnetic material produces dipole-dipole interactions. It will be shown that these dipole-dipole interactions can affect the orientation and structural formation of aggregates as they collide and stick. Analysis of the resulting dust populations will also demonstrate the impact that grain composition and/or charge can have on the structure of the aggregate as characterized by the resulting fractal dimension.