RUI: Studies of Particle Transport in a Non-Neutral Plasma Trap

RUI：非中性等离子体陷阱中粒子输运的研究

• 批准号: 1003952
• 负责人: Dennis Eggleston
• 金额: $ 1.5万
• 依托单位: Occidental College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1003952&HistoricalAwards=false
• 关键词: RUI; Studies; Particle; Transport; Non

This award is made in response to a proposal submitted to and reviewed under the NSF/DOE Partnership in Basic Plasma Science and Engineering joint solicitation NSF 09-596. The award provides funds to support undergraduate participation in the overall research effort, which is being funded separately by the DOE under contract to Occidental College (Grant DE-FG02-06ER54882). This project studies electron transport in a cylindrical non-neutral plasma trap due to the presence of applied asymmetric electric fields. Previous work on this project found some superficial agreement with theory, but also identified significant areas of disagreement. The work of this grant will focus on testing a new model for the transport based on previous experimental and simulation results. In this model, the transport is dominated by low velocity, axially trapped particles that are scattered through a chaotic, collisionless process. To test this model, experiments will be performed to measure and manipulate the trapped particles. To further refine the model, transport at the low asymmetry frequencies will be studied where the experiments diverge most dramatically from resonant particle theory. Finally, this work will be supported with a simple particle simulation which will be extended to focus on previously observed chaotic dynamics. The experimental work is performed in a specially designed trap in order to avoid previously encountered complications and to test transport theory under simple conditions. The spectrum of the field asymmetry is simplified by using up to forty wall sectors to create it. The electron density is reduced by a factor of 100 to reduce non-essential complications due to collective effects, while a biased wire running along the axis of the trap produces a radial electric field which maintains the azimuthal drift normally present in higher density plasmas. Electron position and density are determined by dumping the electrons from the trap onto a phosphor-coated screen and analyzing the resultant image. Experimental transport fluxes are then calculated from the time evolution of these images and compared to theoretical models. There are several broader impacts of the activities. Occidental College is a national leader in the area of undergraduate research participation and has been recognized for its integration of research and education. As in previous years, undergraduate students will be involved as participants and co-workers in this research, and these students will present the results of their research at local and regional meetings. Because Occidental is one of the most diverse of national liberal arts colleges, students from underrepresented groups are likely to be members of the research groups. Dissemination of results will be broadened beyond the usual publication venues and papers given at the annual APS/DPP meeting by participation in the multidisciplinary Workshop on Non-Neutral Plasmas (held every two to three years) and by developing a web site. Finally, there are also scientific broader impacts to this research. This project advances understanding of plasmas by testing a fundamental theory of plasma transport and will benefit any application that requires the containment and manipulation of non-neutral plasmas. An understanding of the complex issues involved in neo-classical transport is also of value in conventional (neutral) confinement devices. The NSF support of undergraduate participation adds a broader educational impact through the early-year training of students by introducing them to scientific research as a possible career path.

该奖项是为了响应提交给NSF/DOE基础等离子体科学与工程合作伙伴关系NSF 09-596的提案。该奖项提供资金，以支持本科生参与整体研究工作，这是由能源部根据合同单独资助西方学院（授予DE-FG 02 - 06 ER 54882）。本计画研究非对称电场作用下，电子在圆柱形非中性电浆阱中的输运。这个项目的先前工作发现了一些与理论表面上的一致，但也确定了重大的分歧领域。这笔赠款的工作将集中在测试一个新的模型的基础上以前的实验和模拟结果的运输。在该模型中，输运由低速、轴向捕获的粒子主导，这些粒子通过混沌、无碰撞的过程散射。为了测试这个模型，将进行实验来测量和操纵被捕获的粒子。为了进一步完善模型，将研究低不对称频率下的传输，其中实验与共振粒子理论的差异最大。最后，这项工作将支持一个简单的粒子模拟，将扩展到以前观察到的混沌动力学的重点。实验工作是在一个专门设计的陷阱，以避免以前遇到的并发症，并在简单的条件下测试运输理论。场不对称性的频谱被简化，通过使用多达40个壁扇区来创建它。电子密度被降低了100倍，以减少由于集体效应而引起的不必要的复杂性，而沿阱的轴沿着运行的偏置线产生径向电场，该径向电场保持通常存在于较高密度等离子体中的方位角漂移。电子的位置和密度是通过将电子从陷阱倾倒到涂有磷光体的屏幕上并分析所得图像来确定的。实验传输通量，然后从这些图像的时间演变计算和理论模型相比。这些活动有几个更广泛的影响。西方学院在本科生参与研究领域处于全国领先地位，并因其研究与教育的融合而受到认可。与往年一样，本科生将作为参与者和合作者参与这项研究，这些学生将在当地和区域会议上展示他们的研究成果。由于西方是最多样化的国家文科院校之一，来自代表性不足的群体的学生很可能是研究小组的成员。通过参加非中性等离子体多学科讲习班（每两至三年举行一次）和建立一个网站，将扩大成果的传播范围，使之超出通常的出版场所和在APS/DPP年度会议上发表的论文。最后，这项研究也有更广泛的科学影响。该项目通过测试等离子体传输的基本理论来推进对等离子体的理解，并将有利于任何需要遏制和操纵非中性等离子体的应用。理解新古典输运中涉及的复杂问题在传统（中性）约束装置中也是有价值的。NSF对本科生参与的支持通过向学生介绍科学研究作为可能的职业道路，通过对学生的早期培训增加了更广泛的教育影响。