High performance reversed shear plasmas with a large radius transport barrier in JT-60U

摘要

The operation of reversed shear plasma in JT-60U has been extended to the low-q, high-I_p region keeping a large radius transport barrier, and a high fusion performance has been achieved. Record values of deuterium-tritium(DT)-equivalent power gain in JT-60U have been obtained: Q~eq_DT = 1.05,τ_E = 0.97 s, n_D(0)=4.9×10~19 m~-3 and T_i(0)=16.5 keV. A large improve- ment in confinement resulted from the formation of an internal transport barrier(ITB)with a large radius, which was characterized by steep gradients in electron density, electron temperature and ion temperature just inside the position of q_min.