Predictive transport simulations of
real-time profile control in JET advanced
tokamak plasmas
T. Tala, L. Laborde, D. Mazon, D. Moreau, G. Corrigan,
F. Crisanti, X. Garbet, D. Heading, E. Joffrin, X. Litaudon,
V. Parail, A. Salmi and contributors to the EFDA-JET
workprogramme
Predictive, time-dependent transport simulations with a semi-empirical plasma model have been used in closedloop
simulations to control the q-profile and the strength and location of the internal transport barrier (ITB). Five
transport equations (Te, Ti, q, ne, v) are solved, and the power levels of lower hybrid current drive, NBI and ICRH are
calculated in a feedback loop determined by the feedback controller matrix. The real-time control (RTC) technique
and algorithms used in the transport simulations are identical to those implemented and used in JET experiments
(Laborde L. et al 2005 Plasma Phys. Control. Fusion 47 155 and Moreau D. et al 2003 Nucl. Fusion 43 870).
The closed-loop simulations with RTC demonstrate that varieties of q-profiles and pressure profiles in the ITB can
be achieved and controlled simultaneously. The simulations also showed that with the same RTC technique as used
in JET experiments, it is possible to sustain the q-profiles and pressure profiles close to their set-point profiles for
longer than the current diffusion time. In addition, the importance of being able to handle the multiple time scales
to control the location and strength of the ITB is pointed out. Several future improvements and perspectives of the
RTC scheme are presented.