Melzer André, Schella André, Mulsow Matthias
Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Jan;89(1):013109. doi: 10.1103/PhysRevE.89.013109. Epub 2014 Jan 30.
The dynamic properties of finite three-dimensional dust clusters in a dusty plasma under the influence of an ion focus are studied by normal modes. The mode analysis has been extended to account for the ion focus using the point-charge model for the horizontal interaction of the dust particles. From that, an analytical model for a few-particle system is derived accounting for three distinct dynamical regimes at different focus strengths, namely, absolutely unstable and fully stable configurations as well as an unstable oscillatory regime. The techniques of normal mode analysis (NMA) and instantaneous normal modes (INM) extended by the ion focus have been applied to dust systems in the experiment and compared to the model. From this, the ion focus strength has been derived. The specific sensitivity of NMA and INM allows one to identify equilibrium configurations in this nonequilibrium environment for these finite clusters.
通过简正模式研究了尘埃等离子体中有限三维尘埃团簇在离子聚焦影响下的动力学特性。利用尘埃粒子水平相互作用的点电荷模型，将模式分析扩展到考虑离子聚焦的情况。由此，推导了一个多粒子系统的解析模型，该模型考虑了不同聚焦强度下的三种不同动力学状态，即绝对不稳定和完全稳定构型以及不稳定振荡状态。由离子聚焦扩展的简正模式分析（NMA）和瞬时简正模式（INM）技术已应用于实验中的尘埃系统，并与模型进行了比较。据此，得出了离子聚焦强度。NMA和INM的特定灵敏度使人们能够在这种非平衡环境中识别这些有限团簇的平衡构型。
