The high poloidal beta path towards steady state tokamak fusion.

Results from coordinated research on DIII-D and EAST are illustrating the promise of high poloidal-beta ($\beta_{\mathrm{P}})$ tokamaks for attractive fusion power reactors. By optimizing at low plasma current and high plasma pressure, high-$\beta_{\mathrm{P}}$ operation drastically reduces the disruptivity and potential disruption damage, the requirements on external current drive, the ELM size and ELM control challenge, and the difficulty of divertor detachment, while a high energy confinement time (despite the low plasma current) is achieved through Shafranov shift suppression of turbulence enhanced by core density gradients. Fully noninductive operation with a tungsten divertor has been demonstrated on EAST with normalized performance projected to achieve steady state operation with 500 MW of fusion power production in CFETR (Q$=$5). In DIII-D experiments, high confinement, internal transport barrier operation that projects nearly to Q$=$10 in ITER at 9 MA has been demonstrated with a fully detached divertor. A synergy between the H-mode pedestal and ITB is found that maintains high global performance as the edge conditions are modified for divertor detachment and heat flux control. Self-consistent simulations predict that, using day-one heating and current drive capabilities, the high-$\beta_{\mathrm{P}}$ scenario in ITER could achieve either mission goals: inductive Q$=$10 performance or steady-state Q$=$5 performance.