Neoclassical and Turbulent Transport of W in Toroidally Rotating JET Plasmas
The physical understanding of the transport of heavy impurities, like W, is important for the achievement of practical fusion energy. Among the plasma parameters which affect impurity transport, rotation has only recently received the deserved consideration. In addition to the off-diagonal contribution related to the presence of a radial gradient of the toroidal rotation (usually dubbed roto­diffusion), even in moderately rotating plasmas, centrifugal effects of heavy impurities become non-negligible. Plasmas obtained in the hybrid scenario in JET with the ITER-like wall (JETILW) can be used to study these effects on W, since the deuterium toroidal rotation reaches central thermal Mach numbers around 0.4 (Mach of W up to 3.8). At the same time, this study allows us to explore the transport mechanisms which are responsible for the central W accumulation which is often observed in this type of discharges.