Edge plasma turbulence analysis by collective light scattering in the Tore Supra tokamak

Collective light scattering measurement is a powerful tool for investigating fluctuations and their relation with anomalous transport since it allows a direct, discriminating analysis of the turbulent scales. This high scale resolution has a counterpart in a poor spatial resolution, but some localization can be recovered allowing us to discriminate edge from core turbulence behavior and to determine turbulence profiles. More information about localization can be obtained using temporal dynamics of the scattered signal when the fluctuation velocity in the poloidal plane is sheared. Making use of the consequently separated Doppler shifts, different technics are used to extract localized information from frequency spectra and from the signal phase derivative. Capabilities of the diagnostic are illustrated by recent results obtained on Tore Supra in different regimes.