A new method for measuring divertor configuration parameters (plasma position, location of separatrix surface, βp + ℓi/2) for feedback control in JT-60 is presented. By using the MHD equilibrium database, it is possible to derive statistical relations expressed by simple functions between these parameters and the measured values of quantities such as poloidal magnetic fields, plasma current and external coil currents. These functions can be used as the measurement formulas of these parameters. In JT-60, the second order polynomial functions of these magnetically measured values, which are obtained as the measurement formulas, are sufficiently accurate to be applicable to feedback control.
Real-time calculation of plasma parameters for feedback control in JET