Application of the Transition Model of Edge Pedestal Properties in j _ϕ -α Space to a KSTAR-like Tokamak

We calculated the transition of edge pedestal properties in j _ϕ -α space for a KSTAR-like plasma and compared the results with those from the analytical transition model. The transition is from a critical equilibrium that is marginally stable to the peeling or the ballooning mode to another critical equilibrium when plasma parameters such as triangularity, elongation, and β _p change. The transition should not be confused with the L-H transition. We have divided the transition into two. The first transition is when plasma parameters change for fixed pedestal width while the second transition is when the pedestal width changes for fixed plasma parameters. The direction of the first transition when triangularity or elongation increases is as such that j _ϕ decreases and α increases. The direction of the first transition with varying β _p depends on the choice of how the temperature or the current density is modified. The direction of the second transition is determined from the stability condition of the new equilibrium after the first transition.