Improvements to the Modeling of the Opacity-on-NIF hohlraum for Anchor 2*

The Opacity-on-NIF experiments have begun taking data for LTE opacity measurements of iron at conditions referred to as Anchor 2: 180 eV and 3´10²² cm^-3 [1]. Iron opacities are important for understanding the structure of the sun, yet there is an ongoing disagreement between opacity theory and data that makes corroboration highly important. We use Lasnex calculations to predict hohlraum temperature and to aid in understanding spectrometer background. The modeled hohlraum temperature comes from both the conversion of laser power to X-ray radiation and the coupling of radiation within the complex features of the Apollo hohlraum [2]. These processes are dependent on LTE tables of opacity and EOS and on inline calculations of non-LTE opacity. By using variations of these tables, we will show that the Apollo hohlraum geometry leads to separate LTE and non-LTE regions. We will also show results from recent updates to the non-LTE opacity model, and a comparison of calculated temperature to measurement.

[1] J. E. Bailey, et al., Nature 517, 56 (2015).

[2] E. S. Dodd, et al., Phys. Plasmas 25, 063301 (2018).