Benchmark of Lower Hybrid coupling codes (Brambilla, GRILL3D-U, TOPLHA) with the FTU conventional grill experimental data

The present work compares and experimentally validates the results coming out from the following three Lower Hybrid (LH) coupling codes: Brambilla code (M. Brambilla), GRILL3D‐U (Mikhail Irzak, A. F. Ioffe Physico‐Technical Institute, Russia) and TOPLHA (Politecnico di Torino, Italy). The conventional grill antenna, operating in FTU in different scenarios, is used as benchmark.The validation with experimental data is carried out with respect to the average reflection coefficients at the input of a row of the grill, considering two different phasings between adjacent waveguides: −90 ° and −75 °. A comparison between calculated power spectra is also presented.Good agreement can be observed for all the simulated plasma profiles and waveguide phasings between experimental data and codes, in particular for the most recent numerical tools, namely GRILL3D‐U and TOPLHA.