Collaborative Research: Fundamental Charging Processes of Dust in Complex Plasmas

合作研究：复杂等离子体中灰尘的基本充电过程

• 批准号: 1414523
• 负责人: Lorin Matthews
• 金额: $ 34.5万
• 依托单位: Baylor University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1414523&HistoricalAwards=false
• 关键词: Collaborative; Research; Fundamental; Charging; Processes

Complex plasmas, also known as dusty plasmas, consist of ions, electrons and charged dust, tiny solid particles much smaller than the width of a human hair. Dusty plasmas have long been of interest in the astrophysics community, due to the fact that dust and ionized gas are found in most space environments, including the clouds from which stars and planets form, comet tails, planetary rings, and noctilucent clouds in the earth's ionosphere. Dusty plasmas are also present on Earth in applied settings. They are formed in the chemically active gases used in industrial plasma processing devices to create computer chips, contaminating the end product and reducing overall yield. Dust contamination within fusion devices is also an issue, since dust produced through erosion of the containment walls raises both safety (operating instabilities) and health (long-term contamination) concerns. The formation of dust crystals, clusters and strings in laboratory plasmas has also proven to be a capable analog for atomic and molecular systems. Charging of dust grains is a unique and important aspect of dusty plasmas. Understanding the physics behind this charging and subsequent formation of dust structures immersed within plasma has proven to require nuanced details. The charge acquired by the dust grains is determined by the plasma environment, but the charged particles in turn influence this environment. Local variations in the charge, either over the surface of a single dust grain or the multiple dust grains comprising a larger structure, can affect both the grain's local dynamics and the evolution of the overall system. Many situations introduce asymmetries into this problem, making the charge difficult to describe analytically. Complicating factors include variations in space (due to geometry of the dust structure or of the plasma environment) as well as variations in time (due to the response of the plasma to the moving dust grains or stochastic charging processes). The dust charge is also extremely difficult to determine in experiments. Thus, the primary objective of this research is to determine how variations in charge in both time and space influence and respond to the dynamics and configuration of dust particles in plasma environments.In order to accomplish this goal, numerical modeling techniques will be combined with laboratory experiments to provide a proper understanding of the processes governing the system behavior. Numerical models will be used to model temporal and spatial charge variation over the dust structures, including stochastic effects to resolve the variations in time due to the discrete nature of the plasma particles. The charging will also be linked to numerical models of the plasma environment which define the response of the plasma to boundary conditions and the dust itself. Simultaneously, laboratory experiments will employ state-of-the-art techniques to control and confine the dust within dust clouds, strings, clusters, and aggregates in order to use them as in situ probes to measure the local plasma environment.

复杂的等离子体，也称为灰尘等离子体，由离子，电子和带电的灰尘组成，小固体颗粒比人头发的宽度小得多。由于在大多数太空环境中发现了灰尘和电离气体，包括在大多数太空环境中发现了灰尘的等离子体对天体物理学群落引起了人们的关注，其中包括恒星和行星形成的云，彗星尾巴，行星环和地球电离层中的夜光度。在应用设置中，地球上也存在尘土飞扬的等离子体。它们是在工业等离子体加工设备中使用的化学活性气体中形成的，以创建计算机芯片，污染最终产品并降低总产量。融合设备内的灰尘污染也是一个问题，因为通过侵蚀堵塞墙产生的尘埃引起了安全性（操作不稳定性）和健康（长期污染）的关注。实验室等离子体中尘埃晶体，簇和弦的形成也已被证明是原子和分子系统的能力类似物。 尘埃谷物的充电是尘土飞扬的独特而重要的方面。事实证明，了解浸入血浆中的灰尘结构的物理学和随后形成的粉尘结构需要细微的细节。灰尘晶粒获得的电荷取决于等离子体环境，但带电的颗粒反过来影响了这种环境。电荷的局部变化，无论是在单个灰尘晶粒的表面上还是包括较大结构的多个灰尘晶粒，都会影响晶粒的局部动力学和整体系统的演变。许多情况将不对称性引入此问题，从而使电荷难以分析描述。复杂因素包括空间的变化（由于灰尘结构或血浆环境的几何形状）以及时间的变化（由于等离子体对移动的粉尘粒或随机充电过程的响应）。在实验中，灰尘电荷也很难确定。因此，这项研究的主要目的是确定时间和空间的电荷变化如何影响，并响应等离子体环境中灰尘颗粒的动态和配置。为了实现这一目标，数值建模技术将与实验室实验相结合，以提供对系统行为的过程的正确理解。 数值模型将用于模拟灰尘结构上的时间和空间电荷变化，包括由于血浆颗粒的离散性质而导致时间变化的随机效应。 充电还将与等离子体环境的数值模型有关，该模型定义了血浆对边界条件和灰尘本身的响应。 同时，实验室实验将采用最新的技术来控制和局限尘埃云，字符串，簇和聚集体中的灰尘，以便将其用作原位探针来测量局部等离子体环境。