Active dipole clusters: From helical motion to fission

Andreas Kaiser, Katarina Popowa, and Hartmut Löwen
Phys. Rev. E 92, 012301 – Published 2 July 2015
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Abstract

The structure of a finite particle cluster is typically determined by total energy minimization. Here we consider the case where a cluster of soft-sphere dipoles becomes active, i.e., when the individual particles exhibit an additional self-propulsion along their dipole moments. We numerically solve the overdamped equations of motion for soft-sphere dipoles in a solvent. Starting from an initial metastable dipolar cluster, the self-propulsion generates a complex cluster dynamics. The final cluster state has in general a structure widely different to the initial one, the details depend on the model parameters and on the protocol of how the self-propulsion is turned on. The center of mass of the cluster moves on a helical path, the details of which are governed by the initial cluster magnetization. An instantaneous switch to a high self-propulsion leads to fission of the cluster. However, fission does not occur if the self-propulsion is increased slowly to high strengths. Our predictions can be verified through experiments with self-phoretic colloidal Janus particles and for macroscopic self-propelled dipoles in a highly viscous solvent.

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  • Received 11 March 2015

DOI:https://doi.org/10.1103/PhysRevE.92.012301

©2015 American Physical Society

Authors & Affiliations

Andreas Kaiser*, Katarina Popowa, and Hartmut Löwen

  • Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany

  • *kaiser@thphy.uni-duesseldorf.de

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Issue

Vol. 92, Iss. 1 — July 2015

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