Achieving a breakthrough in Inertial Confinement Fusion (ICF) is dependent upon the homogeneous compression of a fuel capsule to form a central hot spot, crucial for reaching the necessary conditions of high temperature, pressure, and density needed for ignition. However, micro-voids within the fuel layer can disrupt this uniformity, leading to hydrodynamic instabilities such as Rayleigh-Taylor and Richtmyer-Meshkov, which diminishes the energy yield. In the interest of mitigating instabilities caused by micro-voids which lead to energy yield degradation, we conducted multiple experimental campaigns at the Matter in Extreme Conditions (MEC) instrument at the Linac Coherent Light Source (LCLS). We utilized an x-ray free electron laser (XFEL) to generate dynamic x-ray phase contrast images capturing void-shock interactions in both direct and holographic regimes. Striving for conditions that parallel those in ICF, we subjected these void-bearing samples to a high-intensity, long-pulse laser shockwave, to replicate the shock compression environment of ICF. Integrating an Ultrafast X-ray Imager (UXI), we observed and quantified the impact of voids during dynamic compression, allowing us to capture multiple frames of a single sample with high temporal precision (2-3ns between frames) and high spatial resolution. We conducted a qualitative comparison of the collapse structure with xRAGE simulations to gain insights into how defects affect ablator materials at the sub-um and sub-ns scale. By implementing a flat-field correction scheme through image alignment, we applied phase retrieval techniques to extract phase and consequently areal density information. Acquiring areal density information is vital, providing insights into the challenges of achieving sustainable fusion energy reactions in current ICF experiments, has the potential to fundamentally transform experimental compression strategies, and can significantly refine the computational models used in ICF research.
2025-04-09 09:00:00
