RUI: Equilibrium, Stability, Dynamics, and Transport Physics for Electron Plasma in a Toroidal Magnetic Field

先前的NSF支持被用于设计和构建一种新的高性能环形阱，用于非中性等离子体（即具有单个带电粒子符号的等离子体）。 在过去的一年中，实验的建设已经完成，在环的一部分进行的早期实验产生了接近稳态的等离子体条件（几秒的约束时间）。 目前的裁决允许P.I.和他的本科生们更详细地探索长寿命环形非中性等离子体的物理学。 在这个实验中的环形磁场的非均匀性的字符被预测到最终限制的时间在十秒的顺序。 将进行实验，以确定这一尚未经过检验的理论所预测的损失机制。 将进行更多的实验，以确定弯曲和不均匀的环形磁场对在非中性等离子体中传播的振荡（即波）的自然模式的影响。 此外，本奖项将资助必要的仪器和技术的发展，从（和诊断）实验的一部分环过渡到限制在整个环。 实验中，非中性等离子体被隔离了很长一段时间，使他们可以观察和操纵提供了良好的“风洞”等离子体和中性流体理论的密切测试;帮助完善我们的基本理解自然发生的流体系统和等离子体和实验室等离子体，发现在社会中的应用。 非中性等离子体可以重复产生，并在具有简单几何形状（即圆柱体）的陷阱中被限制很长时间。 然而，直到本装置的构造完成，在更复杂的磁场布置（例如圆环）中捕获非中性等离子体的尝试导致非常短的捕获时间（100微秒量级）。 没有其他现有的实验准备回答基本问题的标准，稳定的平衡状态，等离子体动力学的环形效应，以及限制这种系统。该奖项资助的活动将为本科生提供研究经验（以及科学作者和演讲机会），激励他们中的一些人从事物理学研究生工作。 该设备还将用于招募有前途的高中生参加劳伦斯大学的物理课程，并使校园和当地社区接触等离子体物理学。

Prior NSF support was used to design and construct a new high performance toroidal trap for non-neutral plasmas (i.e. plasmas with a single sign of charged particle). In the past year, construction of the experiment was completed and early experiments conducted in a portion of the torus produced nearly steady state plasma conditions (several second confinement times). The present award permits the P.I. and his undergraduate students to explore the physics of long-lived toroidal non-neutral plasmas in much greater detail. The non-uniform character of the toroidal magnetic field in this experiment is predicted to ultimately limit the confinement to times on the order of ten seconds. Experiments will be conducted to identify the loss mechanism predicted by this as yet untested theory. Additional experiments will be conducted to identify the effect of the curved and non-uniform toroidal magnetic field on the natural modes of oscillation (i.e. waves) that propagate in non-neutral plasmas. In addition, the present award will fund development of instruments and techniques necessary to transition from (and diagnose) experiments in a portion of the torus, to confinement in the full torus. Experiments in which non-neutral plasmas are isolated for long times so that they can be observed and manipulated provide excellent "wind tunnels" for close testing of plasma and neutral fluid theories; helping refine our fundamental understanding of naturally occurring fluid systems and plasmas and of laboratory plasmas that find application in society. Non-neutral plasmas can be generated reproducibly and confined for very long times in traps with a simple geometry (i.e. a cylinder). However, until construction of the present device was completed, attempts to trap non-neutral plasmas in more complicated magnetic field arrangements (such as a torus) have resulted in very short trapping times (of order 100 microseconds). No other existing experiment is poised answer fundamental questions about the criteria for stable equilibrium states, the toroidal effects on plasma dynamics, and the limitations on confinement for such systems. The activity funded under this award will provide research experiences (as well as scientific authorship and presentation opportunities) for undergraduate students, inspiring some of them to pursue graduate work in physics. The apparatus will also be used to recruit promising high school students to the Lawrence University physics program and expose the campus and local communities to the subject of plasma physics.