Thermal energy transport modeling of KSTAR ITB discharge and performance projection to heating and current drive upgrade*

The internal transport barrier formation is one of key KSTAR milestones but also expected to be the basis for future high performance operation. KSTAR has achieved internal transport barrier (ITB) formation with an early injection of the NBI power while maintaining a limited shape to avoid H-mode transition. In this study, kinetic profile of ITB plasma is reproduced by integrated modeling and performance projection with heating and current drive upgrade is presented. Thermal energy transport analyses of ITB shots have been conducted using the IPS-FASTRAN package with TGLF turbulent heat flux model and compared with neoclassical thermal transport, ExB shearing rate, and gradient scale length. The modeling results are quite consistent with the experimental data and predictive modeling according to the H & CD upgrade plan shows the prospect of achieving ITB with more peak kinetic profile and reduced turbulent transport.