The geometry of ICRF -induced wave-sol interaction: A multi-machine experimental review in view of ITER operation

Abstract : As part of ITPA-Integrated Operational Scenario (IOS) activities, this contribution reviews recent experimental characterization of Radio-Frequency (RF)-induced Scrape-Off Layer (SOL) modifications on various tokamaks worldwide and on the LArge Plasma Device (LAPD) at UCLA. The phenomenology, as observed using a large variety of measurement techniques, is consistent with the expectations from RF-sheath rectification. Emphasis is then put on the complex 3-Dimensional (3D) spatial patterns of RF-SOL interaction, in relation to the magnetic topology and the spatial distribution of RF currents over the metallic structures surrounding the RF wave-launchers. Dependence on the local plasma parameters in the antenna vicinity is also briefly addressed. The final part discusses implications for future devices.