Nuclear processes and nuclear decay modifications in plasmas

The advent of new high power lasers has opened a new field of investigations in nuclear physics dealing with the excitation or the de-excitation of nucleus in plasma. This can in particular find some applications in astrophysics in dynamic systems where the relative populations of the excited states cannot be assumed to be at thermodynamic equilibrium. In plasmas, the electronic environment in the immediate vicinity of the nucleus is modified, and thus, the plasma conditions influence key processes driving the lifetime of a nuclear level. A correct lifetime prediction requires every de-excitation process to be evaluated jointly with its corresponding excitation process. A complete description of the nuclear lifetime must also include some other nuclear levels through which indirect nuclear excitation or de-excitation may occur. This particular situation may provide a fast method to populate or depopulate nuclear isomers. Nuclear process in plasmas may occur through several different processes involving the coupling between the atom and the nucleus [1,2] as well as through direct interactions with other particles present in the plasma, such as electrons [3] and photons. In this conference, I intend to show the theoretical developments done by our group to take into account the influence of the plasma environment on the nuclear lifetime [4,5]. I will stress on the importance to get an accurate description of the statistical nature of the electronic spectrum. At last, I will present the various experimental attempts and future experiments done by our collaboration to observe nuclear excitation/deexcitation in plasma [6].