Collaborative Research: Understanding of Presheaths and Sheaths in Plasmas

获奖公共摘要提案标题：合作研究：了解等离子体中的鞘和预鞘主要研究员：赫什科维茨，诺亚/塞文，格雷格研究所：威斯康星大学麦迪逊分校/圣迭戈大学提案编号：cBet-0903783/cBet-0903832这项研究解决了与多物种等离子体中的鞘-预鞘物理有关的基础科学问题，这些物理问题是许多等离子体科学与技术领域的核心，包括等离子体推进器、等离子体处理、聚变设备的偏转器、朗缪尔探测器和射频等离子体。80多年后，许多与鞘相关的重要问题将首次被解决。拟议的实验旨在建立各种情况下鞘及其相关预护层的基本性质，这些情况下的理论预测和假设尚未得到验证。威斯康星大学和圣地亚哥大学将进行协调研究，以确定鞘前和鞘等离子体的电势分布以及与离子加速有关的离子速度分布函数。大多数实验将在赫什科维茨教授的实验室进行。然而，LIF诊断开发正在两个校区进行，并由Severn教授领导。等离子体参数将通过两种或两种以上技术来确定；例如，发射探头、Ar和Xe亚稳态离子激光诱导荧光、朗缪尔探头、离子声波相速度、伪波速度和光学发射光谱的组合。由于(例如)诊断的侵入性或不完全性质，需要几个诊断的一致性。亚稳离子而不是基态离子的探针和激光诱导荧光测量的粒子耗竭。实验将使用我们实验室目前运行的热丝多极子、电容源、感应源和螺旋源。在Ar和Xe等离子体中加入O2、SF6或Cl2将产生负离子。如上所述，许多基于等离子的技术将受益。拟议研究的结果将通过出版物和会议发言在科学界和工业界广泛传播。该小组认为，这一结果很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参考。研究生和本科生将参与这项研究，这些调查中使用的实验将用于学生的实验室课程。这些调查中使用的相对便宜的桌面实验适合学生实验室课程，允许学生进行最先进的实验。

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.