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

Abstract

Broadband microwave reflectometry is a diagnostic technique that provides electron density profiles with both high temporal and spatial resolution. The information extracted is the distance to the cut-off layer where the waves are reflected. Here we analyze the spectral component due to distance as well as components associated with plasma turbulence that are usually filtered out for profile evaluation. The new analysis is applied to ASDEX Upgrade regimes, with improved core confinement and H-mode edge. It enables to detect the reduction of turbulence at the edge and core, following the formation of the edge and internal transport barriers, respectively, and also the increase of turbulence associated with edge localized modes. The potentialities and limitations of this analysis to study plasma turbulence are discussed.