Carbon ionization from a quantum average-atom model up to gigabar pressures
Gérald Faussurier1, Christophe Blancard1, Mandy Bethkenhagen2
1CEA, DAM, DIF, F-91297 Arpajon, France and Université Paris-Saclay, CEA, LMCE, F-91680 Bruyères-le-Châtel, France.
Physical Review. E
|September 16, 2021
Summary
This study calculates carbon ionization under extreme pressures using an average-atom model, finding good agreement with simulations for pressure but noting discrepancies in ionization calculations.
Area of Science:
- Plasma physics
- Computational physics
- Materials science under extreme conditions
Background:
- Understanding carbon ionization is crucial for modeling dense plasmas found in astrophysical objects and inertial confinement fusion.
- Accurate calculation of pressure and ionization states is essential for predicting material properties under extreme conditions.
Purpose of the Study:
- To calculate carbon ionization and pressure at megabar and gigabar pressures using a nonrelativistic average-atom model.
- To compare the results with quantum molecular dynamic simulations and the PURGATORIO code.
- To investigate the accuracy of the average-atom model in predicting these properties.
Main Methods:
- Utilized a nonrelativistic average-atom model.
- Calculated pressure via the stress-tensor method.
- Incorporated electronic electrical conductivity using the Kubo-Greenwood approach.
- Performed comparisons with quantum molecular dynamic simulations.
Main Results:
- Achieved good agreement for pressure between the average-atom model and quantum molecular dynamic simulations at gigabar pressures.
- Observed a discrepancy in average ionization, consistent with previous findings using the PURGATORIO code.
- Demonstrated excellent agreement for average ionization when compared directly with the PURGATORIO code.
Conclusions:
- The nonrelativistic average-atom model provides a reliable method for calculating pressure in dense carbon plasmas.
- Further investigation is needed to resolve discrepancies in average ionization calculations between different simulation methods.
- The study highlights the importance of cross-validation between theoretical models and simulation codes for accurate plasma property prediction.
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