Hailu, Girma2018-06-262023-11-092018-06-262023-11-091992-06http://10.90.10.223:4000/handle/123456789/3636A collisional radiative model is applied to study the ionization, recombination, and energy loss rates of an optically thin hydrogen plasma in a Tokamak thermonuclear fusion reactor. The effective ionization and recombination coefficients are found to be increasing functions of electron density, the increase being bigger when the temprature is low. The rate of radiative energy loss is significant only in low density plasmas; and the estimate that has been used by most plasma modelers is pretty big that it cannot be applied for dense plasmas. Edge plasma cooling due to the interaction of recycling neutral particles near diverter targets with the scrape off layer is an important effect to reduce the heat load on Tokamak vessel components. The relevant atomic data for hydrogenic atoms are well established, whereas the data base for molecules is less complete. Collisional radiative processes are considered to study the effects of hydrogen molecules in the edge plasma boundary. Effective dissociation and dissociative ionization rate coefficients are calculated. Rate coefficients for the production of neutral atoms from hydrogen molecules are also evaluated. Finally the rate of electron energy loss per dissociation of molecules into atoms and/or ions is calculated. The rate of this energy loss is significant and the dissociation of the molecules may account for the missing heating power in the divertor regionenCollisional Radiative ModelsThesis