Control of Plasma Instabilities and Transport

本研究是等离子体不稳定性的控制和不稳定性驱动的异常输运的研究。具体来说，利用“正模态”的新概念，将研究等离子体不稳定性的多模反馈稳定化。结合状态重构器或卡尔曼滤波器设计一种状态反馈方案。还将研制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异常扩散进行实验研究，包括不稳定参数与异常扩散的关系。实验工作将利用重新设计的哥伦比亚直线机。本文的研究方向是等离子体不稳定性的反馈控制及其引起的等离子体异常输运。不稳定性影响着所有的等离子体，不管它们是设备的一部分，也不管它们的预期用途是什么。这些包括基本的实验装置，用于中性、电子和离子束的等离子体源，用于固态制造和聚变机器的等离子体蚀刻装置。这种不稳定性会导致等离子体的不均匀性，增加输运，如果强度足够大，还会导致宏观上的分裂。消除这些不稳定性有时是必要的，但为了获得更好的性能，对它们的抑制总是可取的。由于重新设计越来越好的平衡往往不能完全消除这些不稳定性，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.