Pt. Springer et al., SPECTROSCOPIC MEASUREMENTS OF ROSSELAND MEAN OPACITY, Journal of quantitative spectroscopy & radiative transfer, 51(1-2), 1994, pp. 371-377
The first quantitative measurement of photoabsorption in the region de
termining Rosseland and Planck mean opacity, is obtained for an x-ray
heated iron plasma, using novel techniques and instrumentation. The pl
asma density of 0.0113 +/- 0.0013 g/cm3 and temperature of 59 +/- 3 eV
are accurately constrained experimentally by imaging plasma expansion
and observing and modeling absorption in sodium dopant ions. The meas
ured iron absorption spectrum is compared with several newly developed
opacity models. The data constrains Rosseland and Planck group means
with of order 15% precision. This is the first quantitative experiment
al certification of opacity models germane to radiative transfer in LT
E plasmas.