This project aims to develop high current, low impurity, electroninjectors, based upon emission from a plasma, which arewell-suited for plasma control in large fusion devices. A rangeof innovative plasma control techniques have been introducedwhich are based on electrostatic injection of current intoplasmas, e.g., current drive, current profile control, andparticle and impurity control. In Phase I, a novel, inexpensive,working prototype injector will form the basis for extension tothese applications. Non-fusion applications could also benefitfrom this compact source which produces high quality,mostly-ionized plasma streams as well as high current electron(and ion) beams. Several advantages can be realized throughcurrent emission from plasma sources rather than material sourceslike thermionic emitters. In particular, preparing sources ofabout 1 kA current and about 1 kA/cm2 current density with smallimpurity content is routine. Emission from a plasma allows thesource to be enclosed in low Z refractory materials suitable forimmersion in hot, dense plasmas.Anticipated Results/Potential Commercial Applications as described by the awardee: A plasma-based current source withlarge current density and low impurity content could be used forplasma control in large fusion plasmas. The high current, lowimpurity, and compactness of the source should make itwell-suited for non-fusion applications requiring a high qualityplasma or beam source.
