Novel data processing tools to localize turbulence and MHD activity from broadband reflectometry on ASDEX upgrade

Broadband microwave reflectometry is a diagnostic technique that provides e lectron density profiles with both high temporal and spatial resolution. Th e information extracted is the distance to the cut-off layer where the wave s are reflected. Here we analyze the spectral component due to distance as well as components associated with plasma turbulence that are usually filte red out for profile evaluation. The new analysis is applied to ASDEX Upgrad e regimes, with improved core confinement and H-mode edge. It enables to de tect the reduction of turbulence at the edge and core, following the format ion of the edge and internal transport barriers, respectively, and also the increase of turbulence associated with edge localized modes. The potential ities and limitations of this analysis to study plasma turbulence are discu ssed. (C) 2000 Elsevier Science S.A. All rights reserved.