Plasma Diagnostics at ITER (Keynote Speech)

M. Walsh (ITER Organization, France)

In southern France, 7 partners comprising of 35 nations are collaborating to build the world's largest tokamak. This is a magnetic fusion device called ITER that has been designed to prove the commercial feasibility of fusion. This device will carry up to 15MA of plasma current and produce about 500MW of power, 400MW approximately in high energy neutrons. The typical temperatures of the electrons inside this device are in the region of a few hundred million Kelvin. This project is now well advanced in its construction. This includes the buildings, the major components and the independent systems. Amongst these are the diagnostic systems. These diagnostics will be installed on the ITER machine to provide the measurements necessary to control, evaluate and optimize plasma performance in ITER and to further the understanding of plasma physics. These include amongst others, measurements of the plasma shape, temperature, density, impurity concentration, and particle and energy confinement times. The system will comprise about 45 individual measuring systems drawn from the full range of modern plasma diagnostic techniques, including magnetics, lasers, X-rays, neutron cameras, impurity monitors, particle spectrometers, radiation bolometers, pressure and gas analysis, and optical fibres. These devices will have to be made to work in the new and challenging environment inside the and outside the vacuum vessel. These systems will have to cope with a range of phenomena that extend the current knowledge in the Fusion field. The levels of neutral particle flux, neutron flux and neutron fluence will be respectively about 5, 10 and 10,000 times higher than the harshest experienced in today's machines. The pulse length of the fusion reaction—or the amount of time the reaction is sustained—will be about 100 times longer. Several teams across the world have been working on the diagnostics and the engineering developments, and currently the diagnostic systems are in various stages of development from thise that are manufactured to some that are still in early design. This talk will give an overview of the status of ITER and the diagnostic systems.