Plasma vertical position control with internal coils in CFETR

Plasma vertical displacement events (VDEs) are critically important in tokamak operation and design due to their direct influence on plasma performance and device safety. For the China Fusion Engineering Test Reactor (CFETR) -China's next-generation tokamak currently in its conceptual design phase - particular emphasis must therefore be placed on developing reliable VDE control strategies. The Tokamak Simulation Code (TSC) and TokSys have been widely applied in VDE studies on multiple tokamaks worldwide, including DIII-D, EAST, JT-60U, and ITER. A key parameter for characterizing vertical instability is the plasma vertical growth rate. In this work, free-drift plasma evolution was simulated using TSC, and the vertical growth rate was extracted by fitting the plasma vertical position trajectory - a result consistent with predictions from TokSys. Furthermore, active feedback control of VDEs in CFETR has been implemented in TSC for three representative internal control (IC) coil configurations: mounted on the inner vacuum vessel wall, on the outer wall of the blanket, and on the inner wall of the blanket. The corresponding IC coil current control waveforms obtained from TSC have also been benchmarked against TokSys simulations.