The thesis is devoted on the study of emissivity and opacity in inertial confinement fusion plasmas (ICF), and on atomic processes in magnetic fusion plasmas (MCF).In ICF, we have studied the emissivity of the hohlraum and the opacity of ablator’s dopants in the indirect drive scheme. The knowledge of these quantities allows the improvement of the target compression and, as a consequence, the fusion reactions. We have characterized the bound-bound spectrum of gold, carbon and germanium with detailed line calculation (PPP code). Such calculations are time consuming and thus restricted to small numbers of levels/ions. To optimize the time calculation without lack of precision, a hybrid approach statistical/detailed (SCO-RCG code) was compared with the PPP code for test cases. Then the hybrid approach was applied to total opacity calculations (bound-bound, bound-free and free-free transitions) for each ionization state of germanium and silicon. The spectra are compared in a large temperature range in order to optimize the target compression.In MCF, from experiences carried out on Tore Supra (CEA Cadarache) and ASDEX Upgrade (Max Planck Institut, Garching) tokomak, we have provided new atomic data (cross sections, rates of processes) with the HULLAC code in order to analyze the transport coefficients. The aim of this study is the sensitivity of atomic data on the reconstruction of transport coefficients by the ITC code. For the argon case, the cross sections of some processes are presented and the rate coefficients are compared to those of ADAS consortium.
