Multi-view areal-density maps of compressed shells in OMEGA direct-drive implosions extracted from MMI data*

In a series of implosion experiments performed at the OMEGA laser facility, spherical plastic shells doped with an embedded titanium tracer-layer and filled with deuterium gas were driven with high- and low-adiabat laser pulse shapes. The titanium emergent intensity distribution was recorded with a streaked spectrometer and three identical gated, multi-monochromatic x-ray imaging instruments (MMI) that observed the implosion along three quasi-orthogonal lines-of-sight. The data shows spectral signatures due to absorption K-shell line transitions in titanium L-shell ions that are backlit by the continuum radiation from the hot core. To interpret these observations, the MMI spectrally-resolved image data were processed to obtain narrow-band images and spatially-resolved spectra based on the titanium spectral features.\footnote{T. Nagayama, R.C. Mancini, R. Florido, \textit{et al}, J. App. Phys. \textbf{109}, 093303 (2011)} Areal-density maps were extracted using two independent methods based on narrow-band images and spatially-resolved spectra. The areal-density maps reveal the 3D structure and state of the compressed shell through the collapse of the implosion and the performance differences between high- and low-adiabat implosions.