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.
