Observations of Anisotropic Ion Temperature in the NSTX Edge during RF Heating
Authors: T.M. Biewer, R.E. Bell, P.M. Ryan, and J.R. Wilson
Date of PPPL Report: June 2004
To be presented: at the Thirty-First EPS Conference on Plasma Physics, 28 June - 2 July 2004, London, United Kingdom.
A new spectroscopic diagnostic with both toroidal and poloidal views has been implemented in the edge of the National Spherical Torus Experiment (NSTX). This edge rotation diagnostic (ERD) was designed to measure the velocity and temperature of ions. The intersection of the diagnostic sightlines with the intrinsic emission shell provides the localization of the measurement. There are 7 toroidally directed views and 6 poloidally directed views of the outboard plasma edge. The poloidal view is ∼20 cm (toroidally) from the RF antenna, and the toroidal view is ∼2 m away. The sightlines are nearly tangent to the flux surfaces. The C2+ triplet near 4651 Å and the He+ line at 4685 Å are measured. In the results presented here, helium is the bulk, "working" ion of the discharge.