Modifications to the edge radial electric field by angular momentum injection in JT-60U and their implication for pedestal transport

The first detailed measurements of ion-impurity dynamics for NBI-heated ELMy H-modes at the edge of the JT-60U tokamak are reported. We investigated the ability of external momentum/power input to modify and control the radial electric field, E-r, and pedestal structures. The relationship between E-r and pedestal structures of ion-impurity density, n(i), and temperature, T-i, during the ELMing H-mode phase for various momentum input directions (i.e. co-, balanced-and counter-NBI) and input powers from perpendicular NBI are compared with the ELM-free phase. The observed trend is that the edge E-r-well width increases in the co-NBI discharge, while the E-r value at the base of the E-r-well becomes more negative in the counter-NBI discharge. The scale length for both ni and Ti in the pedestal is similar to 2 cm and eta(i) = L-ni/L-Ti values are similar to 1 for both ELM-free and ELMing phases with different magnitudes of E-r (and/or E-r shear). Characteristics of the turbulent density fluctuation, in addition to a uniform toroidal MHD oscillation (i.e. n = 0), during both ELM-free and ELMing phases are also reported.