Measurements of temperature and density in magnetic confinement fusion devices

Abstract

Controlled thermonuclear fusion can fulfil the demand of mankind to have an inexhaustible source of energy that does not cause any serious environmental pollution. The aim of fusion research is to build a continuously operating reactor in which the energy released by the fusion reactions is sufficiently high to keep the plasma hot and to produce more fusion reactions. The knowledge of the plasma temperature and density, together with the energy confinement time, is therefore very important for the effective control of the self-sustained fusion reactor. Various methods and diagnostics for measurements of the plasma temperature and density in present experimental fusion devices, as well as requirements for the future fusion reactors, will be discussed. A special attention will be given to the temperature and density diagnostics in ITER tokamak, which is presently under construction by several international partners at Cadarache in France. Development of these diagnostics is a major challenge because of severe environment, strict engineering requirements, safety issues and the need for high reliability in the measurements.