EXPERIMENTAL INVESTIGATION OF NON-LTE POPULATION REDISTRIBUTION IN RADIATIVELY PUMPED PLASMAS

Experiments are described in which simultaneous absorption and fluores cence spectra of K-shell transitions were observed from a well charact erized x-ray driven aluminium plasma. Fluorescence was caused by photo pumping with the M-band x-rays from a high-Z laser produced plasma. Pu mp and drive spectra, ionization and density histories and fluorescenc e spectra were all carefully measured. Fluorescence was observed also from transitions which were not directly photopumped. This is attribut ed to collisional-radiative redistribution in ions with a Is vacancy. The fluorescent intensity suggests a redistribution rate much faster t han the total rate at which the Is vacancy is filled, contrary to expe ctations based on simple estimates of the rates.