Dynamic space charge structures in high fluence laser ablation plumes

The formation and dynamics of the space charge structures have been studied by means of multiple Langmuir probes in a laser ablation plume produced by high fluence ns laser ablation of a copper target. Based on the analysis of the temporal evolution and angular distribution of ionic densities, a schematic view of space charge structure dynamics is proposed. The observation of periodic oscillations in the MHz range suggests the presence of a self-organization process.