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) that are strongly influenced by the current density profile. A previously developed optimized shear regime with low magnetic shear in the plasma centre has been extended to deeply negative magnetic shear configurations. High fusion performance with wide ITBs has been obtained transiently with negative central magnetic shear configuration: (H(IPB98(y,2)) approximately 1.9, Beta(N) = 2.4 at I(p) = 2.5 MA. At somewhat reduced performance, electron and ion ITBs have been sustained in full current drive operation with 1 MA of bootstrap current: H(IPB98(y,2)) ~ 1, Beta(N) = 1.7 at I(p) = 2.0 MA. The ITBs were maintained for up to 11 s for the latter case. 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 current regime.
Bibliographic Reference: An article published in: Nuclear Fusion 43 (July 2003) 565-572
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://stacks.iop.org/0029-5515/43/565
Record Number: 200317054 / Last updated on: 2003-10-29
Original language: en
Available languages: en