Studies of ICRF Discharge Conditioning (ICRF‐DC) on ASDEX Upgrade, JET and TEXTOR

The present paper reviews the recent results achieved in the ICRF‐DC experiments performed in helium/hydrogen mixtures in the non‐circular tokamaks ASDEX Upgrade and JET and first tests of the ICRF discharges in helium/oxygen mixtures in the circular tokamak TEXTOR. Special emphasis was given to study the physics of ICRF discharges. A new recipe for safe and reliable RF plasma production [〈ne〉∼(3–5)×1017 m−3, Te∼(3–5) eV] with improved antenna coupling efficiency (by 1.5–3 times) and improved radial/poloidal homogeneity was proposed and successfully tested: coupling the RF power in the FW‐IBW mode conversion scenario in plasmas with two ion species. The first results on ICRF wall conditioning in helium/hydrogen and in helium/oxygen mixtures are analyzed.