ITER Similarity Current Ramp-Down Experiments at JET
Developing safe, non-disruptive plasma termination scenarios is essential for the preparation of ITER operation. The ITER Poloidal Field (PF) system, internal Vertical Stability (VS) coils and Central Solenoid (CS) will have to provide plasma position control (slow and fast) and respond to plasma disturbances within a range of plasma internal inductance (li). In addition, the central solenoid will have to provide adequate magnetic flux for the entire discharge; however, little or no transformer flux may be available for the plasma ramp-down. JET has investigated the ITER rampdown in both ohmic and in H-mode, and methods for controlling li staying within the limits of the PF system as well as avoiding any resistive flux consumption. These discharges have been modelled using JETTO and fully predictive simulations with the standard JETTO Bohm/gyro-Bohm transport model.