Control of Plasma Instabilities and Transport

这项研究是在等离子体不稳定性的控制和不稳定性驱动的反常输运研究方面进行的。具体地说，我们将研究利用“正常模态”这一新概念实现等离子体不稳定性的多模反馈镇定。将设计一种与状态重建器或卡尔曼滤波相结合的状态反馈方案。还将开发一种适用于高温等离子体的远程抑制器。此外，还将对不稳定驱动的反常扩散进行实验研究，包括它与不稳定参数的关系。实验工作将利用重新设计的哥伦比亚线性机器。本文致力于等离子体不稳定性的反馈控制及其引起的反常等离子体输运。不稳定性困扰着所有的等离子体，无论它们是哪种设备的一部分，以及它们的预期应用。这些设备包括基本实验设备、用于中性、电子束和离子束的等离子体源、用于固态制造和聚变机的等离子体刻蚀设备。这些不稳定性导致了等离子体中的不均匀，增加了传输，如果足够猛烈，可能会导致宏观分裂。消除这些不稳定性有时是必要的，但为了获得更好的性能，抑制它们总是可取的。由于重新设计越来越好的均衡往往不能完全消除这些不稳定，反馈控制似乎是一个非常有吸引力但被忽视的研究领域。

This research is in the control of plasma instabilities and the study of instability driven anomalous transport. Specifically, the multimode feedback stabilization of plasma instabilities utilizing a new concept of 'normal mode states' will be studied. A state feedback scheme in conjunction with either a state reconstructor or a Kalman filter will be devised. A remote suppressor appropriate for high temperature plasma will also be developed. Furthermore, instability driven anomalous diffusion will be experimentally studied including its relationship with instability parameters. The experimental work will utilize the redesigned Columbia Linear Machine. This research effort is in the feedback control of plasma instabilities and on the anomalous plasma transport induced by them. Instabilities afflict all plasmas irrespective of the type of devices they are part of and their intended applications. These include basic experimental devices, plasma sources for neutral, electron and ion beams, plasma etching devices for solid state fabrication and fusion machines. The instabilities cause non-uniformities in plasma, increased transport and, if violent enough, can cause macroscopic break up. The elimination of these instabilities is sometimes necessary, but their suppression is always desirable for better performance. As redesigning increasingly better equilibria has often failed to eliminate these instabilities completely, feedback control appears to be a very attractive but neglected area of researach.