Investigation of the diffusion of impurity atoms in plasmas by laser fluorescence

A pulse of aluminum atoms was injected into hydrogen gas and plasma by focusing a TEA CO2-laser beam onto a solid target. The propagation along the axis of the target was investigated by measuring the local atomic densities using dye laser excited fluorescence. A diffusion model allowed the derivation of diffusion coefficients as well as of the rate coefficient for ionization of the Al atoms from the observations.