Control of Plasma Instabilities

所有的等离子体都有各种各样的不稳定性，而不管产生等离子体的设备类型和它们的预期应用。这些包括用于中性、电子和离子束的等离子体源、任何类型的电弧放电、用于固态加工的等离子体蚀刻装置、基础实验装置、地球物理和天体物理等离子体和聚变机。这种不稳定性的有害后果有很多：等离子体的不均匀性、输运的增加，以及——如果足够剧烈的话——宏观上的分裂。这些可能会导致设备或系统性能的最低限度的下降，有时甚至会导致其崩溃。因此，消除这些不稳定因素总是可取的，有时是必要的。该项目继续研究等离子体不稳定性的主动反馈控制。具体来说，将使用一种使用小离子束的新型远程抑制器，这将对系统产生最小的扰动。鲁棒控制器也将被研究。将探讨这些控制器在工业等离子体器件中的应用。两名教员和一名研究生将使用哥伦比亚大学等离子体研究实验室的设备进行拟议的研究。实验工作将利用重新设计的哥伦比亚直线机。

All plasmas are subject to a variety of instabilities, irrespective of the type of devices in which these are produced and their intended applications. These include plasma sources for neutral, electron and ion beams, any type of arc discharge, plasma etching devices for solid state processing, basic experimental devices, geophysical and astrophysical plasma and fusion machines. The deleterious consequences of the instabilities are many: non-uniformities in plasma, increased transport and, if violent enough, a macroscopic break up. These can lead minimally to degradation of the performance of the device or system and sometimes to its break down. Therefore the elimination of these instabilities is always desirable and sometimes imperative. This project continues research into active feedback control of plasma instabilities. Specifically, a new remote suppressor using a small ion beam will be used, which will have minimal perturbation to the system. Robust controllers will also be studied. Applications of these controllers to industrial plasma devices will be explored. Two faculty members and one graduate student will carry out the proposed research using the facilities of the Columbia University Plasma Research Laboratory. The experimental work will utilize the redesigned Columbia Linear Machine.