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An Experimental Protocol for Femtosecond NIR/UV - XUV Pump-Probe Experiments with Free-Electron Lasers
Published on: October 23, 2018
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Relaxation pathways in x-ray free-electron-laser heated iron
L Ansia1, P Velarde2, M Fajardo3
1Universidad Politécnica de Madrid, Universidade de Lisboa, GoLP/Instituto de Plasmas e Fusão Nuclear, 1049-001 Lisboa, Portugal Instituto de Fusión Nuclear, José Gutiérrez Abascal 2, 28006 Madrid, Spain.
Physical Review. E
|September 16, 2025
Summary
Nonthermal photoionized plasmas require accurate atomic models. This study shows M-shell ionization in iron is key for understanding electron relaxation, offering a new way to refine atomic cross-section calculations.
Area of Science:
- Plasma Physics
- Atomic Physics
- Astrophysical Plasmas
Background:
- Nonthermal photoionized plasmas are crucial in laboratory astrophysics and require self-consistent atomic and electron distribution models.
- Understanding atomic processes under intense X-ray irradiation is essential for accurate plasma simulations.
Purpose of the Study:
- To investigate the impact of inelastic thermalization on iron under intense X-ray irradiation.
- To analyze the role of M-shell ionization in the relaxation of nonthermal electrons.
- To assess the potential of M-shell satellite intensities for refining collisional cross-section calculations.
Main Methods:
- Utilizing the BigBarT atomic model for self-consistent electron continuum evolution, including degeneracy effects.
- Focusing on collisional M-shell ionization as the primary electron relaxation mechanism.
- Analyzing M-shell satellite intensities as indicators of nonthermal ionization.
Main Results:
- Collisional M-shell ionization is identified as the dominant relaxation process for nonthermal electrons in iron plasmas.
- M-shell satellite intensities demonstrate sensitivity to nonthermal ionization effects.
- The study highlights a potential method for refining difficult-to-compute collisional cross sections.
Conclusions:
- Nonthermal ionization significantly influences M-shell satellite intensities in iron plasmas.
- M-shell satellite spectroscopy offers a viable approach to improve the accuracy of atomic collisional cross sections.
- Accurate atomic data is critical for modeling laboratory nonthermal photoionized plasmas.
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