Nelissen K, Matulis A, Partoens B, Kong M, Peeters F M
Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium.
Phys Rev E Stat Nonlin Soft Matter Phys. 2006 Jan;73(1 Pt 2):016607. doi: 10.1103/PhysRevE.73.016607. Epub 2006 Jan 17.
The frequency spectrum of a system of classical charged particles interacting through a Coulomb repulsive potential and which are confined in a two-dimensional parabolic trap is studied. It is shown that, apart from the well-known center-of-mass and breathing modes, which are independent of the number of particles in the cluster, there are more "universal" modes whose frequencies depend only slightly on the number of particles. To understand these modes the spectrum of excitations as a function of the number of particles is compared with the spectrum obtained in the hydrodynamic approach. The modes are classified according to their averaged vorticity and it is shown that these "universal" modes have the smallest vorticity and follow the hydrodynamic behavior.
研究了通过库仑排斥势相互作用且被限制在二维抛物线陷阱中的经典带电粒子系统的频谱。结果表明，除了众所周知的质心模式和呼吸模式（它们与团簇中的粒子数无关）之外，还有更多“通用”模式，其频率仅略微依赖于粒子数。为了理解这些模式，将作为粒子数函数的激发频谱与流体动力学方法中获得的频谱进行了比较。根据它们的平均涡度对模式进行分类，结果表明这些“通用”模式具有最小的涡度并遵循流体动力学行为。
