Calculations of X-ray yields in annular argon gas puff experiments

Summary form only given. We have compared the measured yield and timing of x-ray pulses in Double Eagle 2D radiation-MM calculations performed using MACH2. For the twin shell masses involved, the plasma was treated as optically thin to the K-shell radiation and two collisional radiative (CR) models were used to assess their ability to predict output. We found that calculations of both timing and yield of radiation above 1 keV gave reasonably accurate agreement with measurements if (1) the spatial resolution of the plasma during the peak compression and radiation output pulse was adequate and (2) the magnetic field gradients near the plasma-vacuum interface during implosion were sufficiently accurate. For an Eulerian code such as MACH2, such calculations, while possible, are not always straightforward to carry out. Practical values of the pseudovacuum resistivity in the absence of special treatment, may lead to compressed plasma densities that are too low and temperatures that are too high, resulting in radiative yield predictions that fall below measured values. We discuss differences in the spectra calculated using the two CR models and compare them with experimental data.