Role of radial electric field and plasma rotation in the time evolution of internal transport barrier in JT-60U

The effects of radial electric field and plasma rotation on the characteristics of internal transport barriers (ITBs) and core confinement properties are studied in JT-60U reversed shear plasmas. The combination of on-axis and off-axis tangential NBI in the co- and counter-directions allows various profiles of the toroidal rotation. With the same core absorbed power, the case of a small momentum source at the ITB layer is more favourable for sustainment of the ITB layer and the retention of the core energy confinement than the cases of the excess co- or counter-momentum source. (author)