Collaborative Research: Fundamental Charging Processes of Dust in Complex Plasmas

复杂等离子体，也被称为尘埃等离子体，由离子、电子和带电尘埃组成，这些尘埃是比人类头发丝的宽度小得多的微小固体颗粒。尘埃等离子体长期以来一直是天体物理学界的兴趣所在，因为尘埃和电离气体存在于大多数太空环境中，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日冕云。尘埃等离子体也存在于地球上的应用环境中。它们是在工业等离子体处理设备中使用的化学活性气体中形成的，用于制造计算机芯片，污染最终产品并降低总产量。聚变装置内的粉尘污染也是一个问题，因为通过侵蚀安全壳壁产生的粉尘引起了安全（操作不稳定性）和健康（长期污染）方面的关切。实验室等离子体中尘埃晶体、团簇和弦的形成也被证明是原子和分子系统的一个有能力的模拟。 尘埃粒子的带电是尘埃等离子体的一个独特而重要的方面。事实证明，要理解这种充电背后的物理原理以及随后浸入等离子体中的尘埃结构的形成，需要细致入微的细节。尘埃颗粒所获得的电荷由等离子体环境决定，但带电粒子反过来影响这种环境。电荷的局部变化，无论是在一个单一的尘埃颗粒或多个尘埃颗粒的表面组成一个更大的结构，可以影响颗粒的局部动力学和整个系统的演变。许多情况下引入不对称到这个问题中，使得电荷难以分析地描述。复杂的因素包括空间的变化（由于尘埃结构或等离子体环境的几何形状）以及时间的变化（由于等离子体对移动的尘埃颗粒或随机充电过程的响应）。粉尘的电荷在实验中也极难确定。因此，本研究的主要目标是确定如何在时间和空间的变化的电荷的影响和响应的动力学和尘埃粒子在等离子体环境中的配置。为了实现这一目标，数值模拟技术将结合实验室实验，以提供一个正确的理解的过程中，管理系统的行为。 数值模型将用于模拟尘埃结构的时间和空间电荷变化，包括随机效应，以解决由于等离子体粒子的离散性质而引起的时间变化。 充电还将与等离子体环境的数值模型相联系，这些模型定义了等离子体对边界条件和尘埃本身的响应。 与此同时，实验室实验将采用最先进的技术来控制和限制尘埃云，字符串，集群和聚合物内的尘埃，以便使用它们作为原位探针来测量当地的等离子体环境。

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.