Present Status of Integrated Performance Achieved in Tokamak Experiments and Critical Issues Towards DEMO Reactor

This paper reports the present status of the integrated performance achieved in tokamak experiments and critical issues towards DEMO reactor. The achieved integrated performance towards DEMO reactor is visualized using by introducing the radar-screen diagram with the normalized performance. The normalized plasma parameters foreseen in DEMO have been developed experimentally in world-wide, but the highly integrated performance and long sustainment have not yet been achieved. The main differences of physics requirements between ITER and DEMO provides the critical issues such as the capability for non-inductive current drive, power handling in edge and divertor, ELM mitigation and the controllability of self-organized system. Such critical issues towards DEMO should be addressed with attention to trade-off relationships.