Maximizing plasma confinement via shape optimization*

Tokamak reactors are susceptible to turbulent losses, which are deleterious to particle and energy confinement and subsequently limit achievable fusion performance. Plasma shaping, in addition to impacting magnetohydrodynamic stability, also plays a considerable role in enhancing or weakening turbulent modes.  Using select DIII-D discharges considered for operation in future fusion reactors as reference scenarios, a workflow is developed to determine the plasma shaping parameters that minimize turbulent losses. The python-based workflow will leverage extensively validated fluid turbulence codes, with the goal of automatic convergence on the optimal plasma geometry. The effect of shaping parameters such as aspect ratio, elongation, triangularity, and squareness are investigated, identifying operating regimes of interest for future studies and informing scenario design for fusion reactors.