Ahmad Naghidokht - School of physics, Damghan University, Damghan, Semnan, Iran
Mahmood Ghoranneviss - Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran

One of the essential requirements for tokamak operation, and then energy extraction from nuclear fusionreactor, is plasma motion control to avoid any contact of the hot plasma with the wall during the burn phase.For the plasma horizontal position feedback control in IR-T۱ tokamak, a linear model is considered. Also,the system of vertical field (VF) coil and of the disturbances are modeled. For this purpose, the controlvariable is specified as the vertical field coil voltage. Here, the overall system of IR-T۱ tokamak includesVF coil, vacuum vessel, and plasma itself. For control, the PID and LQG control designs are proposed.Bode diagrams of these controllers satisfy the stability of the model, especially for the LQG design. In thispaper, a ۰.۲ drop in (􀀁􀀂 + 􀀄􀀅/۲) is considered as the disturbance. To study this disturbance effect on controlsystem design, magnetic probes are used to determine the disturbed plasma horizontal displacement in IRT۱tokamak. Analysis of feedback response of horizontal plasma displacement by the PID and LQGcontrollers showed that the designed LQG controller satisfies the control requirement and horizontalposition recovery time, rigidly, guaranteeing a well-damped closed-loop behavior, for this tokamak. Furtherinvestigations, simulations, and experiments must be carried out for finding and validating the bestcontroller.

IR-T۱ Tokamak, Perturbation Effect, Plasma Horizontal Position, PID and LQG Controllers