Modeling of Ionization and Recombination Processes in Plasma with Arbitrary Non-Maxwellian Electron Distribution
In astronomical environments, the high-temperature emission of plasma mainly depends on ion charge states, requiring accurate analysis of the ionization and recombination processes. For various phenomena involving energetic particles, non-Maxwellian distributions of electrons exhibiting high-energy...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/ade2cf |
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| author | Chengcai Shen Xiaocan Li Yuan-Kuen Ko John C. Raymond Fan Guo Vanessa Polito Viviane Pierrard |
| author_facet | Chengcai Shen Xiaocan Li Yuan-Kuen Ko John C. Raymond Fan Guo Vanessa Polito Viviane Pierrard |
| author_sort | Chengcai Shen |
| collection | DOAJ |
| description | In astronomical environments, the high-temperature emission of plasma mainly depends on ion charge states, requiring accurate analysis of the ionization and recombination processes. For various phenomena involving energetic particles, non-Maxwellian distributions of electrons exhibiting high-energy tails can significantly enhance the ionization process. Therefore, accurately computing ionization and recombination rates with non-Maxwellian electron distributions is essential for emission diagnostic analysis. In this work, we report two methods for fitting various non-Maxwellian distributions by using the Maxwellian decomposition strategy. For standard κ -distributions, the calculated ionization and recombination rate coefficients show comparable accuracy to other public packages. Additionally, our methods support arbitrary electron distributions and can be easily extended to updated atomic databases. We apply the above methods to two specific non-Maxwellian distribution scenarios: (i) accelerated electron distributions due to magnetic reconnection revealed in a combined MHD–particle simulation; and (ii) the high-energy truncated κ -distribution predicted by the exospheric model of the solar wind. During the electron acceleration process, we show that the ionization rates of high-temperature iron ions increase significantly compared to their initial Maxwellian distribution, while the recombination rates may decrease due to the electron distribution changes in low-energy ranges. This can potentially lead to an overestimation of the plasma temperature when analyzing the Fe emission lines under the Maxwellian distribution assumption. For the truncated κ -distribution in the solar wind, our results show that the ionization rates are lower than those for the standard κ -distribution, while the recombination rates remain similar. This leads to an overestimation of the plasma temperature when assuming a κ -distribution. |
| format | Article |
| id | doaj-art-4e8b944b76784b56bf8dac768d27d5d5 |
| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-4e8b944b76784b56bf8dac768d27d5d52025-08-20T03:13:35ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01988215110.3847/1538-4357/ade2cfModeling of Ionization and Recombination Processes in Plasma with Arbitrary Non-Maxwellian Electron DistributionChengcai Shen0https://orcid.org/0000-0002-9258-4490Xiaocan Li1https://orcid.org/0000-0001-5278-8029Yuan-Kuen Ko2https://orcid.org/0000-0002-8747-4772John C. Raymond3https://orcid.org/0000-0002-7868-1622Fan Guo4https://orcid.org/0000-0003-4315-3755Vanessa Polito5https://orcid.org/0000-0002-4980-7126Viviane Pierrard6https://orcid.org/0000-0001-5014-7682Center for Astrophysics |Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; chengcaishen@cfa.harvard.eduDartmouth College , Hanover, NH 03750, USASpace Science Division, Naval Research Laboratory , Washington, DC 20375, USACenter for Astrophysics |Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; chengcaishen@cfa.harvard.eduLos Alamos National Laboratory , Los Alamos, NM 87545, USALockheed Martin Solar and Astrophysics Laboratory , Palo Alto, CA 94306, USA; Department of Physics, Oregon State University , 301 Weniger Hall, Corvallis, OR 97331, USARoyal Belgian Institute for Space Aeronomy (BIRA-IASB) , Space Physics, Solar Terrestrial Center of Excellence (STCE), Brussels B-1180, Belgium; Earth and Life Institute—Climate Sciences (ELI-C), Université Catholique de Louvain , Louvain-la-Neuve B-1348, BelgiumIn astronomical environments, the high-temperature emission of plasma mainly depends on ion charge states, requiring accurate analysis of the ionization and recombination processes. For various phenomena involving energetic particles, non-Maxwellian distributions of electrons exhibiting high-energy tails can significantly enhance the ionization process. Therefore, accurately computing ionization and recombination rates with non-Maxwellian electron distributions is essential for emission diagnostic analysis. In this work, we report two methods for fitting various non-Maxwellian distributions by using the Maxwellian decomposition strategy. For standard κ -distributions, the calculated ionization and recombination rate coefficients show comparable accuracy to other public packages. Additionally, our methods support arbitrary electron distributions and can be easily extended to updated atomic databases. We apply the above methods to two specific non-Maxwellian distribution scenarios: (i) accelerated electron distributions due to magnetic reconnection revealed in a combined MHD–particle simulation; and (ii) the high-energy truncated κ -distribution predicted by the exospheric model of the solar wind. During the electron acceleration process, we show that the ionization rates of high-temperature iron ions increase significantly compared to their initial Maxwellian distribution, while the recombination rates may decrease due to the electron distribution changes in low-energy ranges. This can potentially lead to an overestimation of the plasma temperature when analyzing the Fe emission lines under the Maxwellian distribution assumption. For the truncated κ -distribution in the solar wind, our results show that the ionization rates are lower than those for the standard κ -distribution, while the recombination rates remain similar. This leads to an overestimation of the plasma temperature when assuming a κ -distribution.https://doi.org/10.3847/1538-4357/ade2cfAstronomical simulationsIonizationRecombinationNon-thermal radiation sourcesSolar magnetic reconnectionSolar wind |
| spellingShingle | Chengcai Shen Xiaocan Li Yuan-Kuen Ko John C. Raymond Fan Guo Vanessa Polito Viviane Pierrard Modeling of Ionization and Recombination Processes in Plasma with Arbitrary Non-Maxwellian Electron Distribution The Astrophysical Journal Astronomical simulations Ionization Recombination Non-thermal radiation sources Solar magnetic reconnection Solar wind |
| title | Modeling of Ionization and Recombination Processes in Plasma with Arbitrary Non-Maxwellian Electron Distribution |
| title_full | Modeling of Ionization and Recombination Processes in Plasma with Arbitrary Non-Maxwellian Electron Distribution |
| title_fullStr | Modeling of Ionization and Recombination Processes in Plasma with Arbitrary Non-Maxwellian Electron Distribution |
| title_full_unstemmed | Modeling of Ionization and Recombination Processes in Plasma with Arbitrary Non-Maxwellian Electron Distribution |
| title_short | Modeling of Ionization and Recombination Processes in Plasma with Arbitrary Non-Maxwellian Electron Distribution |
| title_sort | modeling of ionization and recombination processes in plasma with arbitrary non maxwellian electron distribution |
| topic | Astronomical simulations Ionization Recombination Non-thermal radiation sources Solar magnetic reconnection Solar wind |
| url | https://doi.org/10.3847/1538-4357/ade2cf |
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