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论文类型：期刊论文

发表时间：2005-04-01

发表刊物：Physics of Plasmas

收录刊物：EI

卷号：12

期号：4

页面范围：1-9

ISSN号：1070664X

摘要：The formation and rotation of two-dimensional (2D) dust Coulomb crystals with finite number of particles are simulated in a self-consistent manner, based on a dynamical model for radio-frequency sheath over a concave electrode with an axial magnetic field. The dust particles are initially placed at random positions inside the sheath, and then their motions are tracked by a molecular-dynamics method until stable, ordered 2D structures are formed, which rotate in a plane perpendicular to the magnetic field, driven by the azimuthal ion flow due to the E×B effect. The rotation patterns are found to depend, in a complex way, on the particle number, the crystal structure, and the discharge parameters, such as the discharge pressure and the magnetic field. In particular, a rigid rotation is typically observed for those clusters with high symmetry structures, for example, the cluster 19 (1,6,12), with the rotation angular frequency of the order of 10-2 Hz, which is proportional to the magnetic field magnitude, but decreases with the increasing discharge pressures. However, the intershell rotations are also observed for those structures of the dust crystals with less symmetry, e.g., 20 (1,7,12), especially for strong magnetic fields. © 2005 American Institute of Physics.