Predictive integrated modelling of plasmas and their operation scenarios towards exploitation of JT-60SA experiment

Plasmas and their operation scenarios have been predicted by using integrated modelling codes towards the exploitation of JT-60SA experiment. Through the close collaboration between Japan and EU including the model validation and verification using JT-60U and JET experimental data, the following key results were obtained in various modelling activities. Integrated rotation and pedestal modelling for inductive scenarios revealed that the rotation with the neoclassical toroidal viscosity (NTV) due to the toroidal magnetic field ripple degrades the pedestal height, but it is high enough to achieve target parameters, and error field correction coils in JT-60SA can control the rotation by enhancing NTV. The neoclassical tearing mode (NTM) modelling with the mode frequency for inductive scenarios clarified the feasibility of electron cyclotron current drive to stabilize fully NTM or reduce the island width without mode locking. Nonlinear MHD simulations starting from a time slice of integrated simulation of current ramp up showed that an off-axis negative-ion-based neutral beam induces fast-ion-driven and reconnecting instabilities through making transiently the off-axis pressure peak and non-monotonic safety factor profile, resulting in flattening of plasma profiles. Improved modelling predicted a steady-state high-beta (βN ≳ 4) plasma with an internal transport barrier (ITB), its controllability to sustain the ITB location and target performance, its controllability to reduce the divertor heat load below 10 MW/m2 by impurity seeding, and its tolerance to the core accumulation of seeded impurity. The obtained predictions clarified the JT-60SA capability to explore the plasma scenarios indispensable to ITER and DEMO