Predictive transport simulations of real-time profile control in JET advanced tokamak plasmas
Predictive, time-dependent transport simulations with a semi-empirical plasma model have been used in closed loop simulations to control the q-profile and the strength and location of the internal transport barrier (ITB). Five transport equations (T(e), T(i), q, n(e), 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 Morean D. et al 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.
Bibliographic Reference: An article published in: Nuclear Fusion 45 (2005) 1�12
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: stacks.iop.org/NF/45
Record Number: 200518286 / Last updated on: 2005-07-26
Original language: en
Available languages: en