Progress towards steady-state operation and real time control of internal transport barriers in JET

In JET advanced tokamak research mainly focuses on plasmas with internal transport barriers (ITBs), generated by modifications of the current profile. The formerly developed optimised shear regime with low magnetic shear in the plasma center has been extended to deeply reversed magnetic shear configurations. High fusion performance with wide ITBs has been obtained transiently in deeply reversed magnetic shear configuration: HIPB98(y,2)∼1.9, βN=2.4 at Ip=2.5MA. At somewhat reduced performance electron and ion ITBs have been sustained in full current drive operation with 1MA of bootstrap current: HIPB98(y,2)∼1, βN=1.7 at Ip=2.0MA. The ITBs have been maintained up to 11s. This duration, much larger than the energy confinement time (37 times larger), is already approaching a current resistive time. New real-time measurements and feedback control algorithms have been developed and implemented in JET for successfully controlling the ITB dynamics and the current density profile in the highly non-inductive regime. (author)