1. Measurements of ionization states in warm dense aluminum with betatron radiation.
- Author
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Mo, M. Z., Chen, Z., Fourmaux, S., Saraf, A., Kerr, S., Otani, K., Masoud, R., Kieffer, J.-C., Tsui, Y., Ng, A., and Fedosejevs, R.
- Subjects
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BETATRONS , *IONIZATION (Atomic physics) , *ALUMINUM - Abstract
Time-resolved measurements of the ionization states of warm dense aluminum via K-shell absorption spectroscopy are demonstrated using betatron radiation generated from laser wakefield acceleration as a probe. The warm dense aluminum is generated by irradiating a free-standing nanofoil with a femtosecond optical laser pulse and was heated to an electron temperature of ~20-25 eV at a close-to-solid mass density. Absorption dips in the transmitted x-ray spectrum due to the Al4+ and Al5+ ions are clearly seen during the experiments. The measured absorption spectra are compared to simulations with various ionization potential depression models, including the commonly used Stewart-Pyatt model and an alternative modified Ecker-Kröll model. The observed absorption spectra are in approximate agreement with these models, though indicating a slightly higher state of ionization and closer agreement for simulations with the modified Ecker-Kröll model. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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