Collaborative Research: Understanding of Presheaths and Sheaths in Plasmas

合作研究：了解等离子体中的预鞘和鞘

• 批准号: 0903832
• 负责人: Greg Severn
• 金额: $ 17.5万
• 依托单位: University of San Diego
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0903832&HistoricalAwards=false
• 关键词: Collaborative; Research; Understanding; Presheaths; Sheaths

AWARD Public Abstract Proposal Title: Collaborative Research: Understanding Sheaths and Pre-Sheaths in PlasmasPrincipal Investigator: Hershkowitz, Noah / Severn, Greg Institution: University of Wisconsin-Madison / University of San DiegoProposal No: CBET- 0903783 / CBET- 0903832 This research addresses basic science questions concerning the sheath-presheath physics in multispecies plasmas that are central to many fields of plasma science and technology, including plasma thrusters, plasma processing, divertors of fusion devices, Langmuir probes, and RF plasmas. After more than 80 years, many important questions associated with sheaths will be addressed for the first time.Proposed experiments are aimed at establishing the basic properties of sheaths and associated presheaths for a variety of situations for which theoretical predictions and assumptions have not yet been verified. Coordinated studies will be carried out at the University of Wisconsin and San Diego University to determine the presheath and sheath plasma potential profiles and the resulting ion velocity distribution functions associated with ion acceleration. Most of the experiments are to be carried out in the laboratory of Prof. Hershkowitz. However, LIF diagnostic development is being carried out on both campuses and is led by Prof. Severn. Plasma parameters will be determined with two or more techniques; e.g., combinations of emissive probes, Ar and Xe metastable ion LIF, Langmuir probes, the phase velocities of ion acoustic waves, pseudo-wave velocities and optical emission spectroscopy. Agreement of several diagnostics is needed because of the invasive or incomplete nature of the diagnostics due to (e.g.) particle depletion by probes and LIF measurements of metastable rather than ground state ions. Experiments will employ hot-filament multi-dipole, capacitive, inductive, and helicon sources currently in operation in our laboratory. Negative ions will be produced by adding O2, SF6, or Cl2 into Ar and Xe plasmas. As noted above, many plasma-based technologies would benefit. The results of the proposed research will be disseminated broadly in the scientific community and industry through publications and conference presentations. The panel considered it likely that the results will be used in plasma physics textbooks and will be widely referenced for years to come. Graduate and undergraduate students will participate in the research, and the experiments used in these investigations will be used in student laboratory courses. The relatively inexpensive tabletop experiments used in these investigations are suited to student laboratory courses, permitting students to perform state-of-the-art experiments.

公共摘要提案标题：合作研究：了解等离子体中的鞘管和预鞘管主要研究者：Hershkowitz，Noah /塞文，Greg 机构：威斯康星大学麦迪逊分校/圣地亚哥大学提案号：CBET- 0903783 / CBET- 0903832这项研究解决了关于鞘层预鞘物理学的基础科学问题，在多物种等离子体中，这些等离子体是等离子体科学和技术的许多领域的核心，包括等离子体推进器，等离子体处理，聚变装置的偏滤器，朗缪尔探针和RF等离子体。80多年过去了，许多与鞘层相关的重要问题将首次得到解决。拟议的实验旨在为各种理论预测和假设尚未得到验证的情况建立鞘层和相关预鞘层的基本性质。将在威斯康星州大学和圣地亚哥大学进行协调研究，以确定鞘前和鞘层等离子体电位分布以及由此产生的与离子加速有关的离子速度分布函数。大部分实验将在Hershkowitz教授的实验室进行。然而，LIF诊断开发正在两个校区进行，并由塞文教授领导。等离子体参数将用两种或更多种技术来确定;例如，发射探针的组合、Ar和Ar亚稳离子LIF、朗缪尔探针、离子声波的相速度、伪波速度和光学发射光谱。由于诊断的侵入性或不完整性，需要对几种诊断达成一致（例如）粒子耗尽探针和LIF测量的亚稳态，而不是基态离子。实验将采用热灯丝多偶极子，电容，电感，和螺旋源目前在我们的实验室工作。在Ar和Ar等离子体中加入O2、SF6或Cl 2可产生负离子。如上所述，许多基于等离子体的技术将受益。 拟议研究的结果将通过出版物和会议介绍在科学界和工业界广泛传播。该小组认为，这些结果可能会被用于等离子体物理教科书，并在未来几年内被广泛引用。 研究生和本科生将参与研究，这些调查中使用的实验将用于学生实验室课程。 在这些调查中使用的相对便宜的桌面实验适合学生的实验室课程，让学生进行国家的最先进的实验。