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Abstract: A real-time profile control system based on PCI-bus modules has been installed in the existing plasma control system (PCS) to control high performance plasmas. In profile control, pre-programmed profile reference data, which are two-dimensional, must be manipulated as the other mono-dimensional pre-programmed reference data such as plasma current in the discharge parameter set-up and in the post-discharge data archiving process, to re-use of the existing man–machine communication tools. An preprogram algorithm number was introduced to allow the change not only of control gains but also of control algorithm during a discharge, providing flexibility and extensibility to cope with future requirements coming from control studies that are now in progress. This system has been successfully applied to safety factor profile control by lower hybrid radio frequency heating system. [Copyright &y& Elsevier]

Abstract: CCS (Cauchy Condition Surface) method is a numerical approach to reproduce plasma shape, which has good precision in conventional tokamaks. In order to apply it in plasma shape reproduction of ST (Spherical Tokamak), the calculation precision of the CCS method in a spherical tokamak CPD (Compact PWI experimental Device) (B t =0.25T, R =0.3m, a =0.2m) has been analyzed. The precision was confirmed also in ST and decided to be applied to a spherical tokamak QUEST (B t =0.25T, R =0.68m, a =0.40m).. In present stage from the magnetic measurement, it is known that the eddy current effect is large in QUEST experiment, and there are no special magnetic measurements for eddy current now, so some proper model should be selected to evaluate the eddy current effect. The eddy current density by not only CS (Center Solenoid) coil but also plasma current is calculated using EDDYCAL (JAEA). The eddy current magnitudes are taken as unknown variables and solved together with plasma shape reconstruction in ohmic discharge and ECCD (Electron Cyclotron Current Drive) discharge. [Copyright &y& Elsevier]