Dynamics of Strongly Coupled Complex Plasma Systems with Directed Ion Flow

具有定向离子流的强耦合复杂等离子体系统的动力学

基本信息

批准号：
1707215
负责人：
Lorin Matthews
金额：
$ 23万
依托单位：
Baylor University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2020-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1707215&HistoricalAwards=false
关键词：
Dynamics Strongly Coupled Complex Plasma

项目摘要

This research project will investigate wakes, a phenomenon widely encountered in nature and spanning a range of length scales. Wakes are observed in the bow shock of a neutron star speeding through interstellar gas, in cloud patterns as air flows past ocean islands, and behind rocks in flowing streams. Cyclists take advantage of the wake created by their teammates, riding close behind each other to conserve energy. This research investigates the wakes formed by positively charged ions flowing past negatively charged dust particles in a complex plasma. The micron-sized dust particles in a complex (dusty) plasma have the ability to self-organize into a wide variety of structures. Much like drafting cyclists, dust particles trapped in the flowing plasma tend to line up downstream of each other. The energy savings due to dust alignment in the wakefield has an effect on the dynamics and the stability of dust structures. Complex plasmas are an excellent system for studying dynamic effects such as structure formation, as they allow direct observation at easily accessible space and time scales. An investigation of the modes of oscillation and structural transitions in a complex plasma can also provide insight into the dynamics of other finite systems which cannot be easily imaged.Many dusty plasma experiments utilize dust grains suspended in the sheath formed between the plasma and a bounding surface. The electric fields present in the sheath accelerate the plasma ions towards the bounding surface, leading to an ion wake downstream of the grains. The primary objective of this research is to investigate the effect of the plasma wakefield interaction on the self-organization, dynamics, and phase transitions in self-assembled dust structures within a complex plasma environment. This research merges computational and experimental techniques. A dynamic computational simulation is needed, as forces, charges, and wakes all change with particle location and the proximity of other particles. Numerical models will provide self-consistent calculations of dynamics, charging and anisotropic screening of dust particles in an ion flow. Charging and wakefield formation will be linked to the plasma environment, defining the response of the plasma to boundary conditions. At the same time, experimental techniques are needed that can produce specific particle structures in a controlled manner. Laboratory experiments will employ state-of-the-art techniques designed to control and confine the dust within dust clouds, strings, clusters, and crystals with defined characteristics. Experimentally, dust particles will also be used as in situ probes to measure the local plasma environment providing data for use in the numerical models.

该研究项目将研究尾流，这是一种在自然界中广泛存在的现象，涵盖了一系列长度尺度。在中子星快速穿过星际气体的弓形激波中、在空气流过海洋岛屿时的云图案中以及在流动的溪流中的岩石后面观察到尾流。骑自行车的人利用队友产生的尾流，紧跟在后面骑行以节省体力。这项研究研究了带正电的离子流过复杂等离子体中带负电的尘埃颗粒时形成的尾流。复杂（尘埃）等离子体中的微米级尘埃颗粒能够自组织成多种结构。就像牵引骑自行车的人一样，流动的等离子体中捕获的灰尘颗粒往往会在彼此的下游排列。由于尾流场中的灰尘排列而节省的能量对灰尘结构的动力学和稳定性有影响。复杂等离子体是研究结构形成等动态效应的优秀系统，因为它们允许在易于访问的空间和时间尺度上进行直接观察。对复杂等离子体中振荡模式和结构转变的研究还可以深入了解其他不易成像的有限系统的动力学。许多尘埃等离子体实验利用悬浮在等离子体和边界表面之间形成的鞘中的尘埃颗粒。鞘层中存在的电场将等离子体离子加速到边界表面，从而导致颗粒下游的离子尾迹。本研究的主要目的是研究等离子体尾场相互作用对复杂等离子体环境中自组装尘埃结构的自组织、动力学和相变的影响。这项研究融合了计算和实验技术。需要动态计算模拟，因为力、电荷和尾流都会随着粒子位置和其他粒子的接近程度而变化。数值模型将提供离子流中灰尘颗粒的动力学、充电和各向异性筛选的自洽计算。充电和尾场形成将与等离子体环境相关联，定义等离子体对边界条件的响应。同时，需要能够以受控方式产生特定颗粒结构的实验技术。实验室实验将采用最先进的技术，旨在控制和限制具有明确特征的尘埃云、尘埃线、尘埃簇和晶体中的尘埃。在实验上，尘埃颗粒也将用作原位探针来测量局部等离子体环境，提供用于数值模型的数据。