Plasma rotation research for advanced tokamak plasma control in JT-60U

Kamada, Yutaka; JT-60 Team

JT-60U has promoted an integrated research project focusing on "rotation" utilizing co/counter (ctr)/perpendicular NBs, ferritic insert for reducing toroidal field ripple, innovative momentum transport analyses. Critical rotation for resistive wall mode stability was estimated to be 0.3% of Alfvn velocity. Type I and Grassy ELM frequencies increased and W/W decreased with ctr-rotation. Pedestal height and gradient increased with co-rotation and H-mode confinement is better for co-rotation due mainly to pedestal improvement. Ferritic insert indicated that ripple loss of fast ions enhances edge ctr-rotation. Momentum diffusivity () and convection velocity (V) have been separately evaluated using perturbative technique. The value of decreased with increasing plasma current, increased with heating power. The value of was similar to the value of (). The absolute value of V increased with increasing over a wide range in radii. Pressure gradient caused the local value of ctr-directed intrinsic rotation. ITB strength can be controlled by momentum input and high bootstrap reversed shear plasmas successfully sustained by controlling momentum input.