Statistical evaluation of radiative power losses from thermal plasmas due to spectral lines

By combining the technique of statistical spectroscopy with a probabilistic theory of radiative transport the authors develop a new method for evaluating the radiative power emitted from a thermal plasma by spectra lines. The method involves three steps: (1) calculation of the ionisation equilibrium for the specified plasma composition, (2) statistical estimation of the number of spectral lines as a function of both wavenumber and line strength, and (3) summation over the radiative power losses in these lines, using escape factors to account for self-absorption. The method does not require an extensive body of line-strength data; it suffices to know only the approximate distribution of energy levels in the ionic stages of interest. The method is illustrated by applications to plasmas of argon and iron vapour.