A visible spectral survey from the Alcator C-Mod tokamak

A visible spectral survey (3675-6744 angstrom) from the Alcator C-Mod tokamak has been performed using a high-resolution visible spectrometer constructed at the Lawrence Livermore National Laboratory. The Alcator C-Mod deuterium plasma is shown to have visible emission from numerous atomic species and low charge state ions including, D I, B II-III, B V, C II-III, N II-III, O II-IV, F II-III, Ne I, Na X, Al II-III, Si I-II, Cl II-III, Ar I-III, Ar X, Ti I and III, Fe I-III, Cu I, and III, Mo I, and W I. Nearly all of the emission is thought to come from the cooler edge of the plasma including the scrape-off layer, outside of the last closed magnetic flux surface. However, there is at least one example, included here, where intrinsic visible emission persists deeper into the plasma.