JT-60U advanced tokamak research towards JT-60SA

Ide, Shunsuke; JT-60 Team

Development of high normalized beta () and high bootstrap current fraction () advanced tokamak (AT) plasma has been pursued in JT-60U. In the AT development, increasing the key parameters and extending the sustaining duration are both important. In recent JT-60U experiments, 4.2 and 100% have been achieved in short time scale (energy confinement time) and sustainment of =2.3 for 23 s and =70% for 8 s in long time scale (several to several tens of current diffusion time) have been demonstrated. These achievements have been supported and stimulated progress in understanding of physics issue: effect of plasma rotation on resistive wall mode, energy confinement, effect of localized current drive on neo-classical tearing mode, off-axis current drive by NBI and so forth. Based on the physics understanding, integrated active control has been developed. These results will contribute establishing physics operation in JT-60SA. In this presentation, recent progress in AT development in JT-60U will be discussed with emphasis on their impact for JT-60SA.