Dust as probes: Determining confinement and interaction forces
Dust as probes: Determining confinement and interaction forces
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DOI：
10.1103/physreve.102.043210
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发表时间：
2020-10-16
影响因子：
2.4
通讯作者：
Hyde, Truell W.
中科院分区：
文献类型：
--
作者：
Ashrafi, Khandaker Sharmin;Yousefi, Razieh;Hyde, Truell W.
复杂的等离子体是有趣的系统，因为带电的尘埃可以自组装成不同类型的有序结构。为了理解从一种结构到另一种结构的转变机制，有必要知道环境中的尘埃电荷和限制电场，这些参数很难独立测量。由于灰尘通常被限制在等离子体鞘中，在该鞘中，离子从主体等离子体流到负下电极，因此离子尾流场使问题进一步复杂化，该离子尾流场在流动等离子体中的灰尘颗粒的下游发展。尾流场引起的局域离子密度的差异改变了尘埃粒子的平衡电荷和屏蔽距离，从而影响了粒子间的相互作用。在这里，我们使用一个分子动力学模拟的离子流通过尘埃颗粒来研究尘埃粒子和离子之间的相互作用。我们考虑一个长的垂直链的颗粒被限制在一个玻璃盒放置在较低的电极上的气体电子会议射频参考电池。我们应用该模型迭代自洽地确定灰尘的电荷，电场，离子密度沿着的长度的链以及离子流的速度。模拟结果表明，离子流在盒内的速度为亚音速。
Complex plasmas are interesting systems as the charged dust can self-assemble into different types of ordered structures. To understand the mechanisms which govern the transitions from one type of structure to another, it is necessary to know both the dust charge and the confining electric fields within the environment, parameters which are difficult to measure independently. As dust is usually confined in a plasma sheath where the ions stream from the bulk plasma to the negative lower electrode, the problem is further complicated by the ion wake field, which develops downstream of the dust grains in a flowing plasma. The differences in local ion density caused by the wake field change the equilibrium dust charge and shielding distance of the dust grains, and thus affect the interaction between grains. Here we use a molecular dynamics simulation of ion flow past dust grains to investigate the interaction between the dust particles and ions. We consider a long vertical chain of particles confined within a glass box placed on the lower electrode of a Gaseous Electronics Conference rf reference cell. We apply the model iteratively to self-consistently determine the dust charge, electric field, and ion density along the length of the chain as well as the ion flow speed. Simulation results indicate that the ion flow speed within the box is subsonic.