Recent results and future plan on JT-60U

Recently, JT-60U has intensively addressed enhancement and long sustainment of steady state performance in the use of negative-ion based neutral beam injection (N-NBI) and electron cyclotron (EC) wave injection. The N-NBI increased the current drive efficiency up to 1.55/spl times/10/sup 19/ A/m/sup 2//W at 360 keV and enhanced the fusion triple product up to n/sub i/(0)/spl tau//sub E/T/sub l/(0)/spl sim/3.0/spl times/10/sup 20/ keV sm/sup -3/ during, a full current drive condition. Increasing the plasma triangularity extended the duration of a plasma with /spl beta//sub N//spl sim/2.7 up to /spl sim/60 /spl tau//sub E/. The EC heating in combination with lower hybrid wave injection produced a very high electron temperature of /spl sim/26 keV for a reversed shear plasma. For reversed shear plasmas, the formation and sustainment of a central current hole was also discovered. High-field-side pellet injection extended the confinement up to H/sub 89p//spl sim/2 at n/n/sub G//spl sim/0.7. For the modification of JT-60, a fully superconducting tokamak, JT-60SC, is planned to further economical and environmental attractiveness in a tokamak DEMO reactor. The mission of JT-60SC is to realize high performance steady state operation and demonstrate the plasma applicability of low activation material for a plasma of break-even class relevant to the reactor plasma. Physics issues, design and machine description for JT-60SC with I/sub p/=4 MA, B/sub t/=3.8 T and R/sub p/=2.8 in are outlined.