BEAM EMISSION-SPECTROSCOPY DIAGNOSTIC FOR THE STUDY OF TURBULENCE IN PHAEDRUS-T TOKAMAK PLASMAS

A flexible beam emission spectroscopy diagnostic system is being installed on the Phaedrus-T tokamak. It consists of a low-power diagnostic neutral beam (H0 or He0) coupled with visible and vacuum UV collection optics to study low-amplitude, high-frequency fluctuations in local plasma density in ohmically and rf-heated plasmas. Neutral beam geometry and optical sightlines are chosen to optimize localization and radial resolution (<1 cm) over the whole plasma region. The ability to inject either a H or He neutral beam and observe in both the vacuum UV and the visible spectral ranges allows a wide choice of atomic transitions (e.g., Hα, L α, He singlet or triplet lines, etc.) to be compared and optimized for a given experimental condition.