Zhang Yu, Wang Xiaogang, Liu Jinyuan
State Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Dalian 116024, China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Jul;78(1 Pt 2):016405. doi: 10.1103/PhysRevE.78.016405. Epub 2008 Jul 25.
Formation of a cylindrical dust void in dust plasma crystals is simulated using the molecular dynamics method in a three-dimensional fluid sheath model with axisymmetry. The dust trajectories are integrated under a self-consistent field composed of the interactions with the electrostatic sheath field, gravity, drags, wakes, and nonlinear screened Coulomb forces. The simulation successfully explains how a uniform dust cloud transforms into a dust void as the dust particles grow to a sufficient size [D. Samsonov, Phys. Rev. E 59, 1047 (1999)] or the power supply and/or gas pressure increases to certain levels [R. P. Dahiya, Phys. Rev. Lett. 89, 125001 (2002)]. It is found that instead of the ion drag or thermophoretic force effect, the formation of the dust void in the axisymmetric three-dimensional sheath is due to a gentle potential bump in the central region of the electrode caused by the cylindrical geometry.
在具有轴对称性的三维流体鞘层模型中，采用分子动力学方法模拟了尘埃等离子体晶体中圆柱形尘埃空洞的形成。尘埃轨迹在一个自洽场中进行积分，该自洽场由与静电鞘层场、重力、阻力、尾流以及非线性屏蔽库仑力的相互作用组成。该模拟成功解释了随着尘埃颗粒生长到足够大的尺寸[D. 萨姆索诺夫，《物理评论E》59，1047（1999）]或电源和/或气压增加到一定水平[R. P. 达希亚，《物理评论快报》89，125001（2002）]时，均匀尘埃云如何转变为尘埃空洞。研究发现，在轴对称三维鞘层中尘埃空洞的形成并非由于离子阻力或热泳力效应，而是由于圆柱形几何形状在电极中心区域引起的一个平缓的势垒。
