The physics and technology basis of ITER and its mission on the path to demo

The paper will give a very brief introduction to magnetic fusion and the presently available facilities (physics and technology) which were and are essential to develop the physics and technology basis for ITER. In the next section ITER's mission as well as the mission of planned satellite facilities will be briefly described. The core of the paper will then concentrate on the physics and technology basis of ITER and demonstrate on a few examples the very significant developments which had to be successfully performed in physics and technology to make the construction of ITER viable and feasible. These include in the area of Physics: ▪ the improved understanding of energy and particle confinement in a tokamakwhich permitted the design of a machine with limited performance margin( costeffective) ▪ Realization of the impact of magnetic ripple on confinement and its mitigation by ferromagnetic inserts ▪ An emerging understanding of instabilities and of conceptual ways of stabilizing them (e.g. ELMs, RWM, etc) ▪ The development of radiative divertorregimes which are essential for operating a reactor class tokamak