ESTIMATING PLASMA TEMPERATURES FROM TRANSMISSION SPECTRA

Recent laser-produced plasma experiments have relied on spectroscopic comparisons with models to infer plasma temperatures. The models use an experimentally determined value for the matter density as input and treat the temperature as an adjustable parameter to obtain a best fit to the experimental absorption spectrum. However, uncertainties in the ionization balance theories lead to inferred temperatures that are model dependent. We report results of a new approach which combines high-quality atomic data with an ionization balance obtained from systematic expansions of the grand canonical ensemble. The latter avoids the ad hoc cutoffs required in free energy minimization schemes and includes Coulomb corrections usually neglected in other models. Comparisons to experimental spectra show excellent agreement.