Pál Gergo, Kun Ferenc, Varga Imre, Sohler Dóra, Sun Gang
Department of Theoretical Physics, University of Debrecen, Debrecen, Hungary.
Phys Rev E Stat Nonlin Soft Matter Phys. 2011 Jun;83(6 Pt 1):061504. doi: 10.1103/PhysRevE.83.061504. Epub 2011 Jun 16.
We present a detailed experimental study of the aggregation of particles of permanent magnetic moment in an external magnetic field. The experiments are performed with millimeter-sized particles floating on the surface of water. Due to the large size of the particles, thermal noise does not have any relevance in the system; the particles undergo deterministic motion. Experiments are carried out varying the concentration which also controls the relative importance of the dipole-external field and the dipole-dipole interactions. We determined the exponents characterizing the aggregation process and found that the attraction driven aggregation of dipolar particles obeys the Vicsek-Family dynamic scaling. The exponents are found to have a concentration dependence which can be attributed to the change of mobility of clusters and their interaction at higher concentrations.
我们展示了在外部磁场中具有永久磁矩的粒子聚集的详细实验研究。实验是用漂浮在水面上的毫米大小的粒子进行的。由于粒子尺寸较大，热噪声在该系统中无关紧要；粒子经历确定性运动。通过改变浓度进行实验，浓度也控制着偶极 - 外场和偶极 - 偶极相互作用的相对重要性。我们确定了表征聚集过程的指数，发现偶极粒子的吸引驱动聚集遵循维克塞克家族动态标度。发现这些指数具有浓度依赖性，这可归因于团簇迁移率的变化及其在较高浓度下的相互作用。
