Multifluid Simulations of Upper-chromospheric Magnetic Reconnection with Helium–Hydrogen Mixture
Our understanding of magnetic reconnection (MR) under chromospheric conditions remains limited. Recent observations have demonstrated the important role of ion–neutral interactions in the dynamics of the chromosphere. Furthermore, the comparison between the spectral profiles and synthetic observatio...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acbfb1 |
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| author | Q. M. Wargnier J. Martínez-Sykora V. H. Hansteen B. De Pontieu |
| author_facet | Q. M. Wargnier J. Martínez-Sykora V. H. Hansteen B. De Pontieu |
| author_sort | Q. M. Wargnier |
| collection | DOAJ |
| description | Our understanding of magnetic reconnection (MR) under chromospheric conditions remains limited. Recent observations have demonstrated the important role of ion–neutral interactions in the dynamics of the chromosphere. Furthermore, the comparison between the spectral profiles and synthetic observations of reconnection events suggests that current MHD approaches appear to be inconsistent with observations. First, collisions and multithermal aspects of the plasma play a role in these regions. Second, hydrogen and helium ionization effects are relevant to the energy balance of the chromosphere. This work investigates the multifluid multispecies (MFMS) effects on MR in conditions representative of the upper chromosphere using the multifluid Ebysus code. We compare an MFMS approach based on a helium–hydrogen mixture with a two-fluid MHD model based on hydrogen only. The simulations of MR are performed in a Lundquist number regime high enough to develop plasmoids and instabilities. We study the evolution of the MR and compare the two approaches including the structure of the current sheet and plasmoids, the decoupling of the particles, the evolution of the heating mechanisms, and the composition. The presence of helium species leads to more efficient heating mechanisms than the two-fluid case. This scenario, which is out of reach of the two-fluid or single-fluid models, can reach transition region temperatures starting from upper-chromospheric thermodynamic conditions, representative of a quiet Sun scenario. The different dynamics between helium and hydrogen species could lead to chemical fractionation and, under certain conditions, enrichment of helium in the strongest outflows. This could be of significance for recent observations of helium enrichment in the solar wind in switchbacks and coronal mass ejections. |
| first_indexed | 2024-03-12T03:17:05Z |
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| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:17:05Z |
| publishDate | 2023-01-01 |
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| series | The Astrophysical Journal |
| spelling | doaj.art-848e70d25ab044b4adbe6fa2271449e82023-09-03T14:08:23ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01946211510.3847/1538-4357/acbfb1Multifluid Simulations of Upper-chromospheric Magnetic Reconnection with Helium–Hydrogen MixtureQ. M. Wargnier0J. Martínez-Sykora1https://orcid.org/0000-0002-0333-5717V. H. Hansteen2https://orcid.org/0000-0003-0975-6659B. De Pontieu3https://orcid.org/0000-0002-8370-952XLockheed Martin Solar & Astrophysics Laboratory , 3251 Hanover St, Palo Alto, CA 94304, USA; Bay Area Environmental Research Institute , NASA Research Park, Moffett Field, CA 94035, USALockheed Martin Solar & Astrophysics Laboratory , 3251 Hanover St, Palo Alto, CA 94304, USA; Bay Area Environmental Research Institute , NASA Research Park, Moffett Field, CA 94035, USA; Rosseland Centre for Solar Physics, University of Oslo , P.O. Box 1029 Blindern, NO-0315 Oslo, Norway; Institute of Theoretical Astrophysics, University of Oslo , P.O. Box 1029 Blindern, NO-0315 Oslo, NorwayLockheed Martin Solar & Astrophysics Laboratory , 3251 Hanover St, Palo Alto, CA 94304, USA; Bay Area Environmental Research Institute , NASA Research Park, Moffett Field, CA 94035, USA; Rosseland Centre for Solar Physics, University of Oslo , P.O. Box 1029 Blindern, NO-0315 Oslo, Norway; Institute of Theoretical Astrophysics, University of Oslo , P.O. Box 1029 Blindern, NO-0315 Oslo, NorwayLockheed Martin Solar & Astrophysics Laboratory , 3251 Hanover St, Palo Alto, CA 94304, USA; Rosseland Centre for Solar Physics, University of Oslo , P.O. Box 1029 Blindern, NO-0315 Oslo, Norway; Institute of Theoretical Astrophysics, University of Oslo , P.O. Box 1029 Blindern, NO-0315 Oslo, NorwayOur understanding of magnetic reconnection (MR) under chromospheric conditions remains limited. Recent observations have demonstrated the important role of ion–neutral interactions in the dynamics of the chromosphere. Furthermore, the comparison between the spectral profiles and synthetic observations of reconnection events suggests that current MHD approaches appear to be inconsistent with observations. First, collisions and multithermal aspects of the plasma play a role in these regions. Second, hydrogen and helium ionization effects are relevant to the energy balance of the chromosphere. This work investigates the multifluid multispecies (MFMS) effects on MR in conditions representative of the upper chromosphere using the multifluid Ebysus code. We compare an MFMS approach based on a helium–hydrogen mixture with a two-fluid MHD model based on hydrogen only. The simulations of MR are performed in a Lundquist number regime high enough to develop plasmoids and instabilities. We study the evolution of the MR and compare the two approaches including the structure of the current sheet and plasmoids, the decoupling of the particles, the evolution of the heating mechanisms, and the composition. The presence of helium species leads to more efficient heating mechanisms than the two-fluid case. This scenario, which is out of reach of the two-fluid or single-fluid models, can reach transition region temperatures starting from upper-chromospheric thermodynamic conditions, representative of a quiet Sun scenario. The different dynamics between helium and hydrogen species could lead to chemical fractionation and, under certain conditions, enrichment of helium in the strongest outflows. This could be of significance for recent observations of helium enrichment in the solar wind in switchbacks and coronal mass ejections.https://doi.org/10.3847/1538-4357/acbfb1Solar chromosphereSolar magnetic reconnection |
| spellingShingle | Q. M. Wargnier J. Martínez-Sykora V. H. Hansteen B. De Pontieu Multifluid Simulations of Upper-chromospheric Magnetic Reconnection with Helium–Hydrogen Mixture The Astrophysical Journal Solar chromosphere Solar magnetic reconnection |
| title | Multifluid Simulations of Upper-chromospheric Magnetic Reconnection with Helium–Hydrogen Mixture |
| title_full | Multifluid Simulations of Upper-chromospheric Magnetic Reconnection with Helium–Hydrogen Mixture |
| title_fullStr | Multifluid Simulations of Upper-chromospheric Magnetic Reconnection with Helium–Hydrogen Mixture |
| title_full_unstemmed | Multifluid Simulations of Upper-chromospheric Magnetic Reconnection with Helium–Hydrogen Mixture |
| title_short | Multifluid Simulations of Upper-chromospheric Magnetic Reconnection with Helium–Hydrogen Mixture |
| title_sort | multifluid simulations of upper chromospheric magnetic reconnection with helium hydrogen mixture |
| topic | Solar chromosphere Solar magnetic reconnection |
| url | https://doi.org/10.3847/1538-4357/acbfb1 |
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