(Cont.) 3) Two-dimensional emissivity profiles of visible continuum (420-430nm) have been measured and found to be an order of magnitude too large when compared to expected levels from electron-ion bremsstrahlung and radiative recombination. Several atomic and molecular processes have been considered to explain the enhanced continuum. However, none of the considered processes could explain the continuum level without particle densities inconsistent with current modeling efforts. The visible imaging system was also used in identifying the causes of impurity injections during discharges, in identifying the failure of invessel components, and as a monitor of vessel and plasma conditions. Both the physics results and the operational benefits of the visible imaging system show that the system is a valuable quantitative and qualitative diagnostic.

A multi-channel diagnostic for measuring low amplitude, long wavelength (k{sub {perpendicular}[rho]i}