Enhanced energy confinement and performance in a low-recycling tokamak

Extensive lithium wall coatings and liquid lithium plasma-limiting surfaces reduce recycling, with dramatic improvements in Ohmic plasma discharges in the Current Drive Experiment-Upgrade. Global energy confinement times increase by up to 6 times. These results exceed confinement scalings such as $\mathrm{ITER}98\mathrm{P}(y,1)$ by $2--3$ times, and represent the largest increase in energy confinement ever observed for an Ohmic tokamak plasma. Measurements of ${D}_{\ensuremath{\alpha}}$ emission indicate that global recycling coefficients decrease to approximately 0.3, the lowest documented for a magnetically confined hydrogen plasma.