Control of the Current Profile Evolution During the Ramp-Up Phase at DIII-D

Y. Ou, E. Schuster, J. Ferron, T.C. Luce, M.L. Walker, D.A. Humphreys, T.A. Casper, W.H. Meyer

Division of Plasma Physics (DPP) Annual Meeting of the American Physical Society (APS)

Dallas, Texas, November 17-21, 2008

Abstract

Setting up a suitable current profile has been demon- strated to be a key condition for advanced scenarios with improved confinement and possible steady-state operation. Experiments at DIII-D focus on creating the desired q profile during the plasma current ramp-up and early flattop phases with the aim of maintaining this profile during the subsequent phases of the discharge. Active feedback control of the q profile evolution at DIII-D has already been demonstrated [1], and an open-loop control scheme has been proposed [2] based on a simplified control-oriented dynamic model [3]. The use of Corsica for both control testing and design is reported, and results of open-loop current profile control experiments are presented.

[1] J.R. Ferron, et al., Nucl. Fusion 46 (2006) L13.
[2] Y. Ou, et al., Proc. Am. Control Conf., New York (2007).
[3] Y. Ou, et al., Fusion Eng. & Design 82 (2007) 1153.