Regime of very high confinement in the boronized DIII-D tokamak

Following boronization, tokamak discharges in DIII-D have been obtained with confinement times up to a factor of 3.5 above the ITER89-P L-mode scaling and 1.8 times greater than the DIII-D/JET H-mode scaling relation. Very high confinement phases are characterized by relatively high central density with nₑ(0){}1×{}10²⁰ m^-3, and central ion temperatures up to 13.6 keV at moderate plasma currents (1.6 MA) and heating powers (12.5--15.3 MW). These discharges exhibit a low fraction of radiated power, P{≤}25%, Zeff(0) close to unity, and lower impurity influxes than comparable DIII-D discharges before boronization.