Extremum seeking without external dithering and its application to plasma RF heating on FTU

We propose a new global extremum seeking algorithm to optimize the coupling between the emitting Lower Hybrid (LH) antennas and the plasma scrape off layer in the radiofrequency (RF) heating system of tokamak plasmas. The new algorithm, where the disturbances affecting the system are used as probing signals, requires less stringent properties than the previous algorithms, and is more robust. Simulation results are presented illustrating the effectiveness of the algorithm on the Lower Hybrid RF heating system of the Frascati Tokamak Upgrade (FTU).