Benchmarking 2D against 3D FDTD codes in the assessment of reflectometry performance in fusion devices

Reflectometry is foreseen in the coming generation of tokamaks such as DTT, ITER and DEMO, creating a need to predict the behavior and capabilities of these new reflectometry systems through the used of synthetic diagnostics. The FDTD time-dependent codes use to implement synthetic diagnostics are computational demanding, the reason why 2 dimensional codes (as REFMUL or REFMULF) are used. REFMUL3, a newly developed performing parallel code gives access to 3D simulations, although at a much higher cost than the 2D ones. With this work we begin a benchmark effort to assess the main differences and compromises done when using 2D versus 3D.