CHARGE-EXCHANGE NEUTRAL PARTICLE DIAGNOSTICS FOR THE MEV ENERGY-RANGEIN MODERN LARGE TOKAMAKS

In modern large tokamaks, the density of fast ions, which are produced as a result of auxiliary plasma heating or thermonuclear reactions, a ttains considerable values, and these ions can affect the confinement and transport of plasma particles and energy Therefore, the developmen t of diagnostic methods for studying the behavior of fast ions in plas ma is of considerable importance for controlled nuclear fusion. In thi s paper, we discuss new methods for studying MeV energy particles emit ted from plasma and the implementation of these methods in large tokam aks. A review is presented of experiments in which charge-exchange neu tral particle diagnostics are used for studying the distribution funct ion of fast ions (various isotopes of hydrogen and helium); these expe riments were carried out in the JET, TFTR, and JT-60U tokamaks during the last five years. With the help of an analysis of the experimental results, the possibility of using these methods for plasma diagnostics in the next-generation tokamaks is estimated. The basic physical prob lems that need to be solved in order to develop these diagnostics and use them for studying the fast-ion component in the tokamak-reactor pl asma are formulated.