H-mode plasmas at very low aspect ratio on the Pegasus Toroidal Experiment

H-mode is obtained at A ∼ 1.2 in the Pegasus Toroidal Experiment via Ohmic heating, high-field-side fueling, and low edge recycling in both limited and diverted magnetic topologies. These H-mode plasmas show the formation of edge current and pressure pedestals and a doubling of the energy confinement time to H 98 y , 2 ∼ 1 . The L–H power threshold P LH increases with density, and there is no P LH minimum observed in the attainable density space. The power threshold is equivalent in limited and diverted plasmas, consistent with the FM 3 model. However, the measured P LH is ∼ 15 × higher than that predicted by conventional International Tokamak Physics Activity (ITPA) scalings, and P LH / P ITPA 08 increases as A → 1 . Small ELMs are present at low input power