Laboratory Astrophysics

Laboratory Astrophysics

Our group is engaged in different imaging tools for electron density retrieval in the X-ray regime at poly- as well as monochromatic sources. We are looking for potential applications of X-ray phase-contrast and dark-field imaging on plasma physics especially with regard to the field of laboratory astrophysics (see e.g. testing of shock waves in the laboratory, Figure 1). In collaboration with plasma physics groups the developed imaging tools can be tested at real and simulated plasmas. We aim at the observation and the analysis of dynamic processes of laser-shocked plasmas.

Figure 1: Computer simulations of the turbulent structure of the magnetic field in counter streaming shock waves (Credit: Frederico Fiuza/SLAC National Accelerator Laboratory)

Recently, we investigated the propagation of homogenisaion in foams of very low density. The process was detectable only by the X-ray dark-field image which lead to a measurable signal caused by the microstructure of the foam (Figure 2). The homogenisation disturbs this structure which leads to a measurable decrease in the dark-field signal.

Figure 2: Low-density foam shown in (a) transmission, (b) differential phase-contrast, and (c) dark-field image. The dark spot in the transmission image is a sapphire bead. The foam half sphere itself is visible in the dark-field (From Ref. L. Wegert et al., Demonstrating grating-based phase-contrast imaging of laser-driven shock waves, 2024, Matter Radiat. Extremes, Vol. 9, No. 4. DOI: 10.1063/5.0200440; used under Creative Commons CC-BY 4.0 license).

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