Clustering of Magnetic Swimmers in a Poiseuille Flow

TL;DR

This paper studies how magnetic swimmers in a flow form clusters due to magnetic interactions and external fields, combining analytical and simulation methods to explain experimental clustering phenomena.

Contribution

It introduces a combined analytical and simulation approach to understand magnetic swimmer clustering in flow, highlighting the role of magnetic dipole interactions and external fields.

Findings

Magnetic dipole interactions promote clustering of swimmers.

External magnetic fields influence the formation and stability of clusters.

Theoretical results explain recent experimental observations of clustering instability.

Abstract

We investigate the collective behavior of magnetic swimmers, which are suspended in a Poiseuille flow and placed under an external magnetic field, using analytical techniques and Brownian dynamics simulations. We find that the interplay between intrinsic activity, external alignment, and magnetic dipole-dipole interactions leads to longitudinal structure formation. Our work sheds light on a recent experimental observation of a clustering instability in this system.