Status of far infrared tangential interferometry/polarimetry (FIReTIP) on NSTX

Abstract

The Influence of paramagnetism and diamagnetism will significantly alter the vacuum toroidal magnetic field in spherical torus. Therefore, plasma parameters dependent upon B T such as the q-profile and local b value needs an independent measurement of B T (r,t). The multi-chord Tangential Far Infrared Interferometer/ Polarimeter (FIReTIP) system [1] currently under development for National Spherical Torus Experiment (NSTX) will provide temporally and radially resolved toroidal field profile [B T (r,t)] and 2-D electron density profile [n e (r,t)] data. Two channel interferometer will be operational this year and full system will be ready by 2002.