Visible spectroscopy on RF heated discharges in the Princeton large Torus tokamak

The lineshape and intensity of the H alpha line are used in calculations of the radial dependences of the neutral particle densities, H alpha emissivity, and electron production rate which are then related to particle confinement in the discharge. Stark shift of Balmer series lines is proposed for detecting rectified RF fields near ICRH antennas, provided the electron temperature varies little as the RF power is raised. The intensity ratio of Cr I lines at a Bernstein wave antenna was found to vary by less than 30% as the power was raised to 100 kW.