Development of a multi-keV shadowgraphy of indirectly driven plasmas using sub-TW laser pulses

Abstract

Bright x-ray sources play a key role in high-energy density physics experiments. Such sources, when acting as backlighting sources, may shed more light on the dynamics of various high-energy time depended processes. This work describes a shadowgraphy experiment of a dynamic shock-wave propagating inside a silica foam using a Ti foil as a backlighter source, that supports the theoretical simulations. This was carried out using a relatively low (38 J) laser beam for backlighting, providing a 50 µm spot size, a 94 ps pulse duration, and 0.01-0.05 conversion efficiency from laser energy to 4.7 keV x-ray photons. The lateral resolution values of a Ti foil and a narrow Ti wire were measured to be 50 µm and 12 µm, accordingly. The shock front was observed about 200 µm from initial reference point, with a good agreement to theory. Its detection throughout an opaque halfraum was possible using dedicated viewing slits. This work describes the preliminary experiments of the backlighting implementation for future experiments.