Sustainment of high confinement in JT-60U reversed shear plasmas

摘要

Expeimental results towards long sustainment of JT-60U reversed shear (RS) plasmas, where high confinement is achieved owing to strong internal transport barriers, are reported. In a high current plasma with an L model edge, a deuterium-tritium-equivalent fusion power gain Q~eq_DT =0.5 was sustained for 0.8 s (≈the energy confinement time) by precise adjustment of the plasma bet using feedback control of stored energy. In a high triangularity plasma with an ELMy H mode edge, a high bootstrap current fraction (≈80/100) was obtained in a high q regime (q95≈9), which led to the full non-inductive current drive condition.