Experimental Measurements of the Lower Hybrid Electric Field and Induced Neutral Flow in Tore Supra by Optical Emission Spectroscopy

Recently, the RF electric field vector (\textbf{E}$_{\mathrm{\mathbf{LH}}})$ in front of a lower hybrid (LH) launcher, operating at 3.7 GHz, at the low field side of the Tore Supra tokamak was determined by spectroscopic analysis of passive D$_{\mathrm{\beta }}$ spectral emission from the near-antenna plasma. The \textbf{E}$_{\mathrm{\mathbf{LH}}}$ was determined by globally minimizing the $\chi $ associated with the experimental and theoretical spectral line profile. The theoretical profile is calculated from a non-perturbative solution to the Schr\"{o}dinger equation, which includes the magnetic and dynamic electric field vectors. The magnitude, the direction, and the scaling with LH power of the measured \textbf{E}$_{\mathrm{\mathbf{LH}}}$ were fairly consistent with those calculated from a full-wave LH model. In addition to \textbf{E}$_{\mathrm{\mathbf{LH}}}$ the inboard and an outboard neutral flow was determined from the Doppler shifts associated with the D$_{\mathrm{\alpha }}$ and D$_{\mathrm{\beta }}$ spectral profiles. It was found that excitation of the LH wave induced both an inboard and outboard co-current neutral flow, which is linearly dependent on injected power; preliminary results indicate ICRH decreases the LH wave-induced co-current neutral flow. Neutral flow velocities are consistent with measurements of ion flow velocities obtained by charge exchange recombination spectroscopy.