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

利用NSF以前的支持，设计和构造了一种新的高性能环形陷阱，用于非中性等离子体(即带有单一符号带电粒子的等离子体)。在过去的一年里，实验的建造已经完成，在环面的一部分进行的早期实验产生了几乎稳定的等离子体条件(几次二次限制时间)。目前的奖项允许P.I.和他的本科生更详细地探索长寿命环状非中性等离子体的物理。在这个实验中，环形磁场的非均匀特性被预测为最终将限制在十秒量级的次数。将进行实验，以确定这一尚未验证的理论所预测的损失机制。还将进行其他实验，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，本奖项将资助开发必要的仪器和技术，以从环状部分的实验过渡(和诊断)到整个环状的禁闭。将非中性等离子体隔离很长时间以便观察和操纵它们的实验，为近距离测试等离子体和中性流体理论提供了极好的“风洞”；有助于完善我们对自然形成的流体系统和等离子体以及在社会上应用的实验室等离子体的基本理解。非中性等离子体可以在具有简单几何结构的陷阱(即圆柱体)中重复产生并被限制很长时间。然而，在本装置的建造完成之前，在更复杂的磁场布置(如环面)中捕获非中性等离子体的尝试已经导致了非常短的捕获时间(约为100微秒)。没有其他现有的实验能够回答基本的问题，如稳定平衡态的标准，对等离子体动力学的环状效应，以及对此类系统的限制。该奖项资助的活动将为本科生提供研究经验(以及科学著述和演讲机会)，激励他们中的一些人从事物理学研究生工作。该设备还将被用来招收有前途的高中生参加劳伦斯大学的物理项目，并将校园和当地社区暴露在等离子体物理学科中。

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.