Fusion Science and Technology / Volume 59 / Number 3 / April 2011 / Pages 427-439
Lecture / Fourth ITER International Summer School (IISS2010)
Controlling the plasma in ITER to achieve its primary mission goals requires a complex and sophisticated plasma control system (PCS) that will be based initially on those of existing tokamaks, with some significant differences. An overview of the physical phenomena on which the ITER PCS will be based is presented with particular emphasis on magnetohydrodynamic (MHD) instabilities. The ITER PCS is logically structured into five parts that work closely together: (a) wall conditioning and tritium removal; (b) plasma axisymmetric magnetic control, including plasma initiation, inductive plasma current, position, and shape control; (c) plasma kinetic control, including fueling, power and particle flux to the first wall and divertor, noninductive plasma current, plasma pressure, and fusion burn control; (d) nonaxisymmetric control, which includes sawteeth, neoclassical tearing modes, edge localized modes, error fields and resistive wall modes, and Alfven eigenmodes; and (e) event handling, including changing the control algorithm or scenario when a plant system fault or a plasma-related event occurs that could affect plasma operation, which includes disruption mitigation. At high plasma performance, the control of MHD instabilities will become particularly important in ITER to maintain the fusion burn and to avoid potential damage to the first wall.