Optimal Shaping of the Safety Factor Profile in the EAST Tokamak
Z. Wang, H. Wang, E. Schuster, Z. Luo, Y. Huang, Q. Yuan, B. Xiao, D. Humphreys
Proceedings of the 2021 IEEE Conference on Control Technology and Applications (CCTA)
San Diego, California, USA, August 8-11, 2021
Abstract
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Tokamaks, which are one of the most promising approaches to energy
generation from nuclear fusion, are toroidal devices confining a very
hot ionized gas, i.e. plasma, where the nuclear reactions take place.
Studies have shown that the shape of the safety-factor profile, which
is related to the helical pitch of the magnetic fields used for plasma
confinement, is a key factor towards achieving advanced operating
conditions characterized by improved confinement, magnetohydrodynamic
stability, and possible steady-state operation. In this work, a
first-principles-driven, control-oriented model of the safety-factor
profile evolution has been used to design linear-quadratic-integral
(LQI) controllers for q-profile shaping in combination, in some cases,
with plasma-energy regulation. Results based on nonlinear simulations
are presented together with some initial experimental results from the
EAST tokamak. A general framework for real-time control of both magnetic
and kinetic plasma profiles and scalars has been implemented in the EAST
Plasma Control System (PCS), enabling in this way the experimental
testing of the proposed controllers. These experiments are among the
first experiments on safety-factor profile control ever conducted on
the EAST tokamak