Density and H-alpha diagnostics and results for the sustained spheromak physics experiment

A newly installed density diagnostic using CO2 laser interferometry and an H-alpha diagnostic using interference filters and photomultiplier tubes for the recently constructed sustained spheromak physics experiment (SSPX) are described. First diagnostic results of the H-alpha diagnostic were useful to understand the breakdown physics in the new SSPX experiments. Low-noise density data validates techniques to reduce vibration and electronic pickup . The data-processing electronics of the new interferometer can yield unamb iguous density data that is equivalent to 16 fringe shifts. Density data is also critical to understand the particle source, and the J/n(e) parameter for SSPX. (C) 2001 American Institute of Physics.