X-ray radiography of microjetting from grooved surfaces in tin sample subjected to laser driven shock

When a triangular shock wave reflects from the free surface of a solid sample, microjetting may emit from the grooved surface, leading to high velocity approximately micrometer-size fragments. Microjetting is an important issue for material dynamic response under shock loading in both fundamental science and practical applications. In this paper, the dynamic process of microjetting is investigated in the laser-driven shock loading conditions, the experiments were performed at the ShenguangII-U (SGII-U) laser facility. Microjetting from the triangular grooves in the free surface of a tin sample is diagnosed with x-ray radiography, where the 40-200 keV high energy x-ray is created with the picosecond laser beam focused on a Au mu-wire target. The density distribution along the microjetting and cumulated mass can be inferred from the images radiographied by such ultrashot high energy x-ray. The density distribution shows two representative regions including the head region of microjetting with low density and high speed, and the root region with high density and low speed. The microjets from three continuous parallel grooves with 60 degrees angle are significantly different from that of 120 degrees angle, the effect of the groove angle was verified by numerical simulation and experimental results.