Influence of two-electron processes on properties of NLTE plasmas

The influence of autoionization and dielectronic recombination processes on non-local thermodynamic equilibrium (NLTE) plasmas is studied using the SC AALP and RTFM models. First, the average ionization of a steady-state NLTE gold plasma predicted by these two approaches is compared to experimental d ata deduced from Thomson scattering measurements. It is shown that results obtained with the RADIOM concept used in RTFM, which does not take into acc ount the autoionization and dielectronic recombination processes, differ no tably from the SCAALP model prediction when it does not contain these two-e lectron processes (TEP). Secondly, it is shown that the TEP must be include d to obtain agreement for the peak position and the width of the charge-sta te distribution with experiments. Finally, TEP effects on the integrated em issivity above the K- and L-thresholds of copper and titanium plasmas have been studied with SCAALP. (C) 2001 Elsevier Science Ltd. All rights reserve d.