Kinetic Equilibrium Reconstruction of KSTAR and the Impact on Stability Analysis of High Performance Plasmas

High fidelity equilibrium reconstructions are an essential analysis for the accurate determination of physics-based models of plasma operational limits (e.g. density limits, power balance, stability) for disruption event characterization and forecasting analysis (DECAF). The safety factor is a key plasma profile used to optimize the confinement and determine the stability of a tokamak plasma. Kinetic equilibrium reconstructions include constraints from Thomson scattering and ion temperature from charge exchange spectroscopy diagnostics, as well as magnetic field pitch angle profile constraints diagnosed by motional Stark effect (MSE) to produce a reliable computation of the safety factor, q, profile. Low q shear near the pedestal and slightly negative shear in the plasma core are found by both polynomial and spline basis function models applied to represent the toroidal plasma current profile for high non-inductive plasmas in KSTAR. MHD stability analyses using the DCON and resistive DCON codes utilize these kinetic equilibrium reconstructions to compare to the experimental plasma stability. The stability analyses using kinetic equilibria from various models show sensitivity to the local q low shear, q_min, and pressure pedestal profile