Observations of instabilities within hohlraum-like geometries.

Hohlraum targets present a complex geometry. There are discrepancies between simulated and experimentally measured x-ray temperatures [1] and various hohlraum designs have been used to try to isolate the sources of discrepancies. However some questions remain unresolved. Prior experiments [2-4] have also explored hohlraum-like targets using various laser facilities, but the measurements are often challenging to definitively characterize localized plasma dynamics due to diagnostic and target limitations.

A new platform has been developed on the Omega laser facility, using planar copper foils expanding into a helium gas to provide hohlraum-like conditions. We diagnose the plasma with proton radiography, optical probing and x-ray imaging. The data reveals significant instabilities forming within the expanding copper plasma as well as along the compressed gas layer. Simulations run using HYDRA [4], GORGON [5] and K2 [6] are compared to the results to determine the key physical processes that must be included in models to match observations. This presentation will discuss some of the preliminary data analysis and supporting simulations, highlighting the importance in understanding these dynamics for accurately modelling hohlraums.

[1] G. F. Swadling et al., PoP 32 (2025)

[2] C. K. Li et al., PRL 102 (2009)

[3] J. A. Pearcy et al., App. Opt. 63 (2024)

[4] M. M. Marinak et al., PoP 8 (2001)

[5] J. P. Chittenden et al., PPCF 46 (2004)

[6] M. Sherlock et al., PoP 24 (2017)