Parameters of the Luminous Region Surrounding Deuterium Pellets in the Princeton Large Torus Tokamak

The luminous region of the plasma cloud surrounding deuterium pellets injected into a tokamak is studied spectroscopically. At the time of peak luminosity the electron density is 2.4×${10}^{17}$ ${\mathrm{cm}}^{-3\mathrm{}}$ to within 30% and the temperature is at most 2.0 eV. The intensity ratio of the Balmer-alpha and -beta light from the pellets, the total number of emitted photons, and the apparent size of the radiating region are consistent with local thermodynamic equilibrium at this temperature and density.