查看文章

Systematic experimental and modeling investigations on DIII-D show attractive transport properties of fully non-inductive high β p plasmas. Experiments on DIII-D show that the large-radius internal transport barrier (ITB), a key feature providing excellent confinement in the high β p regime, is maintained when the scenario is extended from q 95∼ 12 to 7 and from rapid to near-zero toroidal rotation. The robustness of confinement versus rotation was predicted by gyrofluid modeling showing dominant neoclassical ion energy transport even without the E× B shear effect. The physics mechanism of turbulence suppression, we found, is the Shafranov shift, which is essential and sets a β p threshold for large-radius ITB formation in the high β p scenario on DIII-D. This is confirmed by two different parameter-scan experiments, one for a β N scan and the other for a q 95 scan. They both give the same β p threshold at 1.9 in …