Characterization of Supersonic Jet and Shock Wave with High-Resolution Quantitative Schlieren Imaging

This paper presents an enhanced optical configuration for a single-pass quantitative Schlieren imaging system that achieves an optical resolution of approximately 4.6 micrometers. The modified setup decouples sensitivity from resolution, enabling independent optimization of these critical parameters. Using this high-resolution system, we conduct quantitative analyses of supersonic jets emitted from sub-millimeter nozzles into the atmosphere and investigate shock waves induced by knife blades interacting with these jets in a vacuum environment. The fine resolution allows for detailed visualization of shock wave structures and accurate measurement of density gradients. We demonstrate the system's effectiveness by examining the density gradient profile along the shock diamonds and mapping density profiles across shock waves. These density profiles are analyzed for their relevance in laser-plasma applications, including laser wakefield acceleration and the Analog Black Hole Evaporation via Laser (AnaBHEL) experiment. Our findings indicate that this system can help determine key parameters such as peak density, plateau length, and shock wave thickness-essential for optimizing electron acceleration and achieving specific plasma density profiles. This high-resolution quantitative Schlieren imaging technique thus serves as a valuable tool for exploring complex fluid dynamics and supporting advancements in laser-plasma physics research.