Temperature in subsonic and supersonic radiation fronts measured at OMEGA

Propagation of heat fronts relevant to astrophysical plasmas is challenging in the supersonic regime. Plasma T$_{\mathrm{e}}$ changes affect opacity and equation of state without hydrodynamic change. In the subsonic phase density perturbations form at material interfaces as the plasma responds to radiation pressure of the front. Recent experiments at OMEGA studied this transition in aerogel foams driven by a hohlraum. In COAX, two orthogonal backlighters drive x-ray radiography and K-shell absorption spectroscopy to diagnose the subsonic shape of the front and supersonic T$_{\mathrm{e\thinspace }}$profiles. Past experiments used absorption spectroscopy in chlorinated foams to measure the heat front$^{\mathrm{1}}$; however, Cl dopant is not suitable for higher material temperatures at NIF. COAX has developed use of Sc and Ti dopants to diagnose T$_{\mathrm{e\thinspace }}$between 60-100eV and 100-180eV. Analysis with PrismSPECT using OPLIB$^{\mathrm{3}}$ tabular opacity data$^{\mathrm{4}}$ will evaluate the platform's ability to advance radiation transport in this regime. 1. D. Hoarty \textit{et al} PRL \textbf{82}, 3070, 1999 2. J. Hager, \textit{et al}, submitted to RSI 3. J. Colgan, \textit{et al}, Astrophys. J. \textbf{817}, 116, (2016) 4. H. Johns, \textit{et al}, RSI \textbf{87} 11E337 (2016)