Magnetic control of plasma current, position, and shape in Tokamaks: a survey or modeling and control approaches

Plasma current, position and shape control systems and modeling approaches were reviewed. The literature was divided into three categories, namely plasma radial position and current control, vertical stabilization of elongated plasmas, and plasma shape control. The plasma current and radial position control problem can be easily solved using a filament plasma model - the Shafarov lumped parameter equation and two separate PID controllers. At most, a MIMO controller can be used if decoupling is desired. Stabilization of the plasma vertical motion requires new control strategies in which the control algorithm is changed on the basis of an estimate of the measurement accuracy. For controlling the shape during the plasma formation and start-up phase, controllers based on magnetic flux control are useful when control requirements are not stringent.