Analyzing mode stability to identify stable operating regions for the novel SMall Aspect Ratio Tokamak (SMART)*

The SMall Aspect Ratio Tokamak (SMART) is a novel spherical tokamak currently under construction at the University of Seville with the goal of identifying the effects of various plasma configurations on tokamak performance. Of particular interest are negative triangularity (NT) L-mode regimes that avoid edge-localized modes while potentially maintaining H-mode-like core confinement. Anticipated positive triangularity (PT) and NT equilibrium scenarios for SMART have been generated utilizing FIESTA for the magnetic equilibrium and TRANSP with turbulence models to evolve the plasma profiles. Using CHEASE, equilibrium parameters such as β_N were scanned, and DCON was used to determine the ideal magnetohydrodynamic (MHD) no-wall limit for n = 1 global modes. BALOO was also used to characterize the stability of infinite-n ballooning modes in these equilibria, comparing pedestal properties such as the pressure gradient to the calculated stability boundaries. These analyses provide indications of the stability qualities and stable operating regions for both PT and NT plasma designs in a compact spherical tokamak.