Dynamic self-assembly and patterns in electrostatically driven granular media

TL;DR

This paper demonstrates how metallic microparticles in a liquid under strong electric fields self-assemble into various static and dynamic patterns, driven by electrohydrodynamic flows and charge interactions.

Contribution

It introduces new phases of self-assembled structures in electrostatically driven granular media and explains their formation mechanisms.

Findings

Formation of honeycombs and Wigner crystals

Observation of toroidal vortices and pulsating rings

Structures explained by charged granular gas and electrohydrodynamics

Abstract

We show that granular media consisting of metallic microparticles immersed in a poorly conducting liquid in strong DC electric field self-assemble a rich variety of novel phases. These phases include static precipitate: honeycombs and Wigner crystals; and novel dynamic condensate: toroidal vortices and pulsating rings. The observed structures are explained by the interplay between charged granular gas and electrohydrodynamic convective flows in the liquid.