Active dipole clusters: From helical motion to fission
Active dipole clusters: From helical motion to fission
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DOI：
10.1103/physreve.92.012301
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发表时间：
2015-07-02
影响因子：
2.4
通讯作者：
Loewen, Hartmut
中科院分区：
文献类型：
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作者：
Kaiser, Andreas;Popowa, Katarina;Loewen, Hartmut
有限粒子团簇的结构通常由总能量最小化决定。这里我们考虑一簇软球偶极子变得活跃的情况，即当单个粒子沿着其偶极矩表现出额外的自推力时。我们数值求解了软球偶极子在溶剂中的过阻尼运动方程。从最初的亚稳偶极星系团开始，自推进产生复杂的星系团动力学。最终的星系团状态通常具有与初始状态完全不同的结构，细节取决于模型参数和如何开启自推进的协议。星团的质心沿螺旋路径移动，其细节由初始的团簇磁化强度决定。瞬间切换到高自推力会导致星系团的裂变。然而，如果自我推进缓慢增加到高强度，就不会发生裂变。我们的预测可以通过使用自发光胶体Janus粒子和在高粘性溶剂中宏观自推进偶极子的实验来验证。
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.