Fluctuations spectra in TORE SUPRA from scattering experiment

In order to measure the density fluctuations in the Tore Supra tokamak, a collective scattering CO2 laser experiment has been installed. Taking into account the pitch angle variation of the magnetic field lines in the tokamak and the perpendicularity of the fluctuation wave vectors to these field lines, some spatial resolution is obtained along the observed vertical chord. By rotating the observation wave vector ks, imposed by the geometry of the apparatus, in a horizontal plane around the measurement chord, it is possible to detect the turbulence coming mostly from the region where ks is locally aligned with k. Thus an observation zone (the top, the center or the bottom of the plasma) can be selected along the vertical chord. (author) 4 refs., 4 figs