Operation of the NSTX Thomson scattering system

Abstract

The National Spherical Torus Experiment (NSTX) multipoint Thomson scattering system has been in operation for nearly two years and provides routine $T_e\mathrm{(R,t)}$ and $n_e\mathrm{(R,t)}$ measurements. The laser beams from two 30 Hz Nd:YAG lasers are imaged by a spherical mirror onto 36 fiber-optic bundles. In the present configuration, the output ends of 20 of these bundles are instrumented with filter polychromators and avalanche photodiode detectors. In this article, we discuss the laser implementation and the installed collection optics. We follow with examples of raw and analyzed data, and close with some comments about calibration.