Recent Results on Turbulence and MHD Activity Achieved by Reflectometry

Over the last years, help by the development of new methods and technical progresses, reflectometry diagnostics brought news results on transport, turbulence and MHD. Combining density profile and fluctuation measurement, it was shown on Tore-Supra that the particle pinch inside the q=1 surface is close to neo-classical value in ohmic plasma, while the observed small diffusion is in agreement with a very low level of density fluctuations inside the q=1 surface. In b scaling experiment, not change in the fluctuations levels was found, in agreement with the very weak confinement degradation with increasing b. Zonal flows have been detected by Doppler in Asdex-Upgrade and with correlation reflectometry in T-10. On Tore-Supra, a fast decrease of density fluctuation level at high poloidal wave number was measured with Doppler reflectometry, suggesting a minor role of Electron Temperature Gradient driven modes (ETG). Various forms of Alfvén eigen modes (TAEs, Alfvén Cascades, possibly BAEs) have been detected with reflectometry in JET and Tore-Supra, they present an anti ballooning profile.
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