Introductory paper 1. The role of atomic and molecular processes in fusion research

This paper considers the relevance of atomic and molecular processes to researh into controlled nuclear fusion and in particular their effects upon the magnetically confined plasma in Tokamak experiments and conceptual Tokamak reactors. The relative significance of collective phenomena and of single particle collisions to both plasma heating and loss processes are discussed and the pertinent principles of plasma refuelling and plasma diagnostics are outlined. The methods by which atomic and molecular data are applied to these problems, the contributing effects of surface interactions and the consequent implications upon the acccuracy and the type of data needed are described in a qualitative manner. Whilst particular atomic and molecular processes are not discussed in detail, sufficient information is given of the physical environments of Tokamak devices for significant processe to be self-evident.