3D full-wave simulations of reflectometry

The characterization of fluctuation amplitudes, spatial correlation lengths, and wave vectors through measurement of the correlation properties of reflected microwave diagnostic signals depends on a quantitaive knowledge of propagation in toroidal, magnetized plasma. The disparity between the radiation wavelength (mm) and the plasma size makes full wave computations challenging. We extend a two dimensional model [1] which computes propagation in a poloidal plane to include toroidal variation. The model reduces the computational burden compared to that of solving the full-wave equation everywhere-but retains both diffraction and refraction-by merging a description appropriate to the under dense plasma (paraxial) with the required full-wave description near the reflection layer. Initial results for ITER-like profiles demonstrate the utility of the tool as an aid in specifying antenna positioning and setting sensitivity requirements.