Progress in the theoretical description and the experimental characterization of tungsten transport in tokamaks

Recent theoretical results on the properties of turbulent transport of heavy impurities are briefly reviewed. The results of new experiments on ASDEX Upgrade are reported which investigate the impact of central wave heating on the avoidance of W accumulation in H- mode plasmas with dominant neutral beam injection heating. Experiments show that ion cyclotron and electron cyclotron heating have similar effects on theWbehavior when similar power density profiles are produced with the two wave heating systems. The theory-based modelling of these experimental results allows the identification of important ingredients which govern the W transport in the central region in the presence of RF heating, but also reveals some limitations for fully quantitative predictions, also connected with the neglected impact of (1,1) MHD activity.