SPECTROSCOPIC DIAGNOSTICS OF EDGE PLASMAS IN TOKAMAKS

Particle fluxes into the plasma and their velocity distributions are d erived from the intensities and profiles of hydrogen and intrinsic imp urity lines. In order to obtain local electron densities and temperatu res, He- or Li-atom beams are injected, the line intensities of which yield the desired data. If excitation rates by plasma electrons are to o low, more specialized diagnostics are used: e.g. the measurement of highly stripped ion densities and velocity distributions can be perfor med with the aid of charge exchange excitation by fast atom beams or t he measurement of neutral atom densities and their velocity distributi ons near the wall by laser-induced fluorescence. principles and typica l results are discussed with special emphasis on the atomic data requi red, these being mainly excitation and ionization rate coefficients as well as transition probabilities of the light elements.