Single-Shot Imaging of Plasma Jet Dynamics and Laser Shockwave Propagation in Low-Density Voids*

The recent record-breaking 5.2 MJ yield in Inertial Fusion Energy (IFE) at the National ignition Facility (NIF) highlights nuclear fusion's potential as a sustainable, limitless energy source. However, voids and other defects in the IFE capsule ablator material induce hydrodynamic instabilities, leading to plasma jetting and lower compression, limiting fusion yield. Therefore, maximizing energy yield and generating sufficient energy for practical power plant implementation requires dynamic, high-resolution characterization of ablator materials during laser shock compression. To address these challenges, our team has implemented x-ray phase contrast imaging (XPCI) of plasma jets and phase transformations at the Linac Coherent Light Source (LCLS) Matter in Extreme Conditions (MEC) instrument. Here, we use a sample of SU-8 embedded with an SiO2 glass shell to imitate an IFE ablator and void. By comparing experimental images with xRAGE hydrodynamic code simulations, we tune parameters to match experimental shock physics, providing insights to mitigate or leverage voids for maximum yield. For quantitative analysis, we apply phase retrieval techniques to extract phase from complex, dynamic images, potentially revolutionizing compression approaches and enhancing computational models of void collapse.