Tracing X-ray-induced formation of warm dense gold with Boltzmann kinetic equations

0546984 - ÚFP 2022 RIV DE eng J - Journal Article
Ziaja, B. - Bekx, J.J. - Mašek, M. - Medvedev, Nikita - Piekarz, P. - Saxena, V. - Stránský, M. - Toleikis, S.
Tracing X-ray-induced formation of warm dense gold with Boltzmann kinetic equations.
European Physical Journal D. Roč. 75, č. 8 (2021), č. článku 224. ISSN 1434-6060. E-ISSN 1434-6079
R&D Projects: GA MŠMT LTT17015; GA MŠMT EF16_013/0001552; GA MŠMT(CZ) LM2015083
Grant - others:European Cooperation in Science and Technology(BE) CA17126
Program: COST
Institutional support: RVO:61389021
Keywords : X-ray * warm dense gold * Boltzmann kinetic equations
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 1.611, year: 2021
Method of publishing: Open access
https://link.springer.com/article/10.1140%2Fepjd%2Fs10053-021-00235-z

Abstract: In this paper, we report on the Boltzmann kinetic equation approach adapted for simulations of warm dense matter created by irradiation of bulk gold with intense ultrashort X-ray pulses. X-rays can excite inner-shell electrons, which triggers creation of deep-lying core holes. Their relaxation, especially in heavier elements such as gold (atomic number Z= 79) takes complicated pathways, involving collisional processes, and leading through a large number of active configurations. This number can be so high that solving a set of evolution equations for each configuration becomes computationally inefficient, and another modeling approach should be used instead. Here, we use the earlier introduced ’predominant excitation and relaxation path’ approach. It still uses true atomic configurations but limits their number by restricting material relaxation to a selected set of predominant pathways for material excitation and relaxation. With that, we obtain time-resolved predictions for excitation and relaxation in X-ray irradiated bulk of gold, including the respective change of gold optical properties. We compare the predictions with the available data from high-energy-density experiments. Their good agreement indicates ability of the Boltzmann kinetic equation approach to describe warm dense matter created from high-Z materials after their irradiation with X rays, which can be validated in future experiments. Graphic Abstract: [Figure not available: see fulltext.]
Permanent Link: http://hdl.handle.net/11104/0323354