NSTX Tangential Divertor Camera
Authors: A.L. Roquemore, Ted Biewer, D. Johnson, S.J. Zweben, Nobuhiro Nishino, and V.A. Soukhanovskii
Date of PPPL Report: July 2004
Presented at: the 15th Topical Conference on High-temperature Plasma Diagnostics, 19-22 April 2004, San Diego, CA; proceedings to be published in the Review of Scientific Instruments.
Strong magnetic field shear around the divertor x-point is numerically predicted to lead to strong spatial asymmetries in turbulence driven particle fluxes. To visualize the turbulence and associated impurity line emission near the lower x-point region, a new tangential observation port has been recently installed on NSTX. A reentrant sapphire window with a moveable in-vessel mirror images the divertor region from the center stack out to R∼ 80 cm and views the x-point for most plasma configurations. A coherent fiber optic bundle transmits the image through a remotely selected filter to a fast camera, for example a 40500 frames/sec Photron CCD camera. A gas puffer located in the lower inboard divertor will localize the turbulence in the region near the x-point. Edge fluid and turbulent codes UEDGE and BOUT will be used to interpret impurity and deuterium emission fluctuation measurements in the divertor.