2002 Volume 78 Issue 9 Pages 949-967
With the main aim of providing physics basis for ITER and the steady-state tokamak reactor, JT-60U has been optimizing the operational concepts and extending discharge regimes toward the sustainment of high integrated performance. In the two advanced operation regimes, the reversed magnetic shear (RS) and the weak magnetic shear (high-βp) ELMy H modes characterized by both internal (ITB) and edge (ETB) transport barriers, JT-60U has clarified responses of the transport barrier structure to magnetic shear, heating power, momentum, density, etc. Based on these observations, possible parameter linkages and feedback loops in the core and pedestal regimes have been proposed. With the optimization of profile and shape control, both confinement and high β stability have been enhanced and favorable integrated performance has been achieved. Such operational regimes have been extended to the reactor-relevant regime.