Axisymmetric approximation of the KSTAR passive plates for vertical stabilization*

As the KSTAR structure includes non-axisymmetric stabilizing passive plates, the correct axisymmetric approximation of the plates is essential to accurately model vertical stabilization in KSTAR. Here, we perform a comparison of various axisymmetric passive plate approximations in order to determine which conforms best to KSTAR empirical data. The modeling is implemented using General Atomics Tokamak System toolbox (TokSys) environment in Matlab/Simulink.Comparisons of measured vertical displacement events (VDE) growth rates with those calculated from linear "with-plasma" tokamak modelling for a variety of candidate axisymmetric passive plate models will be presented in order to determine the most accurate option. Uncertainties in growth rate measurement from empirical data and uncertainties in plasma parameter estimation for the calculation of growth rates will be described.