Synthetic conventional reflectometry probing of edge and scrape-off layer plasma turbulence

Microwave reflectometry techniques have been successfully applied to measure electron density fluctuations in magnetic confined fusion devices with good spatial and time resolutions. However, quantitative interpretation of turbulence measurements has driven continuous development of both analytical theory and sophisticated numerical codes in support of reflectometry. Comparisons between experimental and synthetic reflectometry have been performed previously while only recently realistic gyro-fluid simulations have been employed together with a full-wave code to simulate measured turbulence properties with reflectometry. In this work, we report on recent efforts to employ the two-dimensional full-wave code REFMUL to implement a synthetic reflectometry diagnostic to model plasma turbulence measurements on the edge and scrape-off layer (SOL) peripheral regions of fusion devices. Numerical descriptions of microscopic turbulence were obtained from both an analytical model (following a Kolgomorov-like wavenumber spectrum) and from the GEMR turbulence code based on gyro-fluid theory. Simulations of fixed frequency conventional reflectometry with ordinary mode (O-mode) wave propagation were carried out for both turbulence cases separately. Preliminary comparisons between synthetic measurements, numerical plasma characteristics, and experimental data from ASDEX Upgrade tokamak are made. As previously described in literature, regimes of linear and non-linear response occurring at low and high turbulence levels, respectively, are observed and characterized. Synthetic spectra across moderate to high turbulence levels display qualitatively good agreement with experimental data across the edge region.