UC San Diego

Accurately predicting temperature and density profiles in the near-edge region—roughly the outer 10% of closed flux surfaces—is critical for modeling tokamak performance because fusion power scales with the square of pedestal-top pressure. Building upon an existing framework for accelerated core transport solutions, this dissertation presents a workflow for self-consistently solving transport-limited pedestals using 1D, steady-state flux matching. Inverse scale lengths are represented using an asymmetric hyperbolic tangent parameterization, anchored at the separatrix. Modular near-edge physics including neutral and impurity penetration are added to account for their effects on source terms in the flux matching solution. Diamagnetic and neoclassical terms in the rotation profile are self-consistently updated, while the toroidal velocity is held constant at this stage. Neoclassical and turbulent transport models developed for core plasmas were chosen to determine their range of validity. Five discharges spanning L-mode, H-mode at contrasting collisionalities, negative triangularity, and I-mode are used to test the workflow. Only the NT result falls within the desired sub-10% error in pedestal-top pressure for reactor predictions, while the remaining cases miss the experimental pedestal-top pressure by 17–84%. That error is attributed to three factors: uncertainties in the separatrix boundary conditions, degeneracy between solver objective and pedestal values, and transport model limitations most severe in the region that most strongly determines pedestal shape. Together, these errors do not exclude flux matching as a solution to the transport-limited pedestal prediction problem, but do suggest limitations of the approach, particularly until an accurate near-edge turbulence model can be made tractable within an iterative framework. This work is thus a step toward a unified, self-consistent treatment of core-edge coupling suitable for integrated tokamak modeling.