Vijay Sonnad

Theory and experiment for ultrahigh pressure shock Hugoniots

Abstract Several equation of state models for hot, dense matter are compared with experimental data for the shock Hugoniots of beryllium, aluminum, iron, copper, and molybdenum up to extreme pressures. The best models are in good agreement with experiment and with one another, suggesting that our understanding of dense, partially ionized matter is good.

A new detailed term accounting opacity code for mid-Z elements: TOPAZ

A new opacity code, TOPAZ, that explicitly includes the detailed configuration term structure for mid-Z elements is under development and preliminary results are presented. The main purpose is to extend the current capabilities of opacity codes such as OPAL, which are limited to elements of astrophysical interest, towards heavier elements. Results from the new code are compared to several past experiments.

Bayesian inference of inaccuracies in radiation transport physics from inertial confinement fusion experiments

First principles microphysics models are essential to the design and analysis of high energy density physics experiments. Using experimental data to investigate the underlying physics is also essential, particularly when simulations and experiments are not consistent with each other. This is a difficult task, due to the large number of physical models that play a role, and due to the complex (and as a result, noisy) nature of the experiments. This results in a large number of parameters that make any inference a daunting task; it is also very important to consistently treat both experimental and prior understanding of the problem. In this paper we present a Bayesian method that includes both these effects, and allows the inference of a set of modifiers which have been constructed to give information about microphysics models from experimental data. We pay particular attention to radiation transport models. The inference takes into account a large set of experimental parameters and an estimate of the prior knowledge through a modified

Development of a Bayesian method for the analysis of inertial confinement fusion experiments on the NIF

chi^{2}

A New Detailed Term Accounting Opacity Code: TOPAZ

function, which is minimised using an efficient genetic algorithm. Both factors play an essential role in our analysis. We find that although there is evidence of inaccuracies in off-line calculations of X ray drive intensity and Ge

Purgatorio- : a new implementation of the INFERNO algorithm

L

Partially resolved transition array model for atomic spectra

shell absorption, modifications to radiation transport are unable to reconcile differences between 1D HYDRA simulations and the experiment.

Frequency dependent electron collisional widths for opacity calculations

The complex nature of inertial confinement fusion (ICF) experiments results in a very large number of experimental parameters which, when combined with the myriad physical models that govern target evolution, make the reliable extraction of physics from experimental campaigns very difficult. We develop an inference method that allows all important experimental parameters, and previous knowledge, to be taken into account when investigating underlying microphysics models. The result is framed as a modified ?2 analysis which is easy to implement in existing analyses, and quite portable. We present a first application to a recent convergent ablator experiment performed at the National Ignition Facility (NIF), and investigate the effect of variations in all physical dimensions of the target (very difficult to do using other methods). We show that for well characterized targets in which dimensions vary at the 0.5% level there is little effect, but 3% variations change the results of inferences dramatically. Our Bayesian method allows particular inference results to be associated with prior errors in microphysics models; in our example, tuning the carbon opacity to match experimental data (i.e. ignoring prior knowledge) is equivalent to an assumed prior error of 400% in the tabop opacity tables. This large error is unreasonable, underlining the importance of including prior knowledge in the analysis of these experiments.

Robust algorithm for computing quasi-static stark broadening of spectral lines

A new opacity code, TOPAZ, which explicitly includes configuration term structure in the bound‐bound transitions is being developed. The goal is to extend the current capabilities of detailed term accounting opacity codes such as OPAL that are limited to lighter elements of astrophysical interest. At present, opacity calculations of heavier elements use statistical methods that rely on the presence of myriad spectral lines for accuracy. However, statistical approaches have been shown to be inadequate for astrophysical opacity calculations. An application of the TOPAZ code will be to study the limits of statistical methods. Comparisons of TOPAZ to other opacity codes as well as to experiments are presented.