Continuum Enhancement and Line Asymmetries of Solar Flares in Different Heating Models: Alfvén Waves, Nonthermal Electron Beams, and Their Joint Effect
How the plasma in the atmosphere is heated during a solar flare remains inconclusive. Nonthermal electron beams are usually considered as an essential heating source, yet Alfvén waves have also been proposed as a promising heating mechanism. Based on radiative hydrodynamic simulations, we explored t...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/addd0e |
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| author | Jun Tian Ying Li Jie Hong M. D. Ding |
| author_facet | Jun Tian Ying Li Jie Hong M. D. Ding |
| author_sort | Jun Tian |
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| description | How the plasma in the atmosphere is heated during a solar flare remains inconclusive. Nonthermal electron beams are usually considered as an essential heating source, yet Alfvén waves have also been proposed as a promising heating mechanism. Based on radiative hydrodynamic simulations, we explored the performance of different heating mechanisms, including nonthermal electron beams, Alfvén waves, and their joint effects. We studied the parameter space of Alfvén waves, focusing on the heating depth and the continuum emissions at 3600 and 6170 Å. We compared the atmospheric structures, continuum enhancements, and line profiles of hydrogen Ly α and H α in beam-heated, wave-heated, and jointly heated flare models. We find that the heating location of waves is strongly dependent on the wavenumber and frequency. The Alfvén wave can penetrate into the lower chromosphere and even the photosphere, causing a prominent continuum emission. There are different atmospheric responses in the Alfvén-wave and electron-beam heating cases due to their different energy-damping patterns. However, there seem to be no unique features in the Ly α and H α line profiles that can be used to distinguish the wave-heated models. In the jointly heated cases, the heating effect of waves and that of energetic electron beams can affect each other during the evolution of flares. Our simulations provide some references for interpreting the observed line profiles as well as the continuum emissions in solar white-light flares. |
| format | Article |
| id | doaj-art-383b404bd8a443399787e21bae5d4579 |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
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| series | The Astrophysical Journal |
| spelling | doaj-art-383b404bd8a443399787e21bae5d45792025-08-20T03:50:12ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01987216310.3847/1538-4357/addd0eContinuum Enhancement and Line Asymmetries of Solar Flares in Different Heating Models: Alfvén Waves, Nonthermal Electron Beams, and Their Joint EffectJun Tian0https://orcid.org/0000-0002-1068-4835Ying Li1https://orcid.org/0000-0002-8258-4892Jie Hong2https://orcid.org/0000-0002-8002-7785M. D. Ding3https://orcid.org/0000-0002-4978-4972Key Laboratory of Dark Matter and Space Astronomy , Purple Mountain Observatory, CAS, Nanjing 210023, People’s Republic of China ; yingli@pmo.ac.cn; School of Astronomy and Space Science, University of Science and Technology of China , Hefei 230026, People’s Republic of ChinaKey Laboratory of Dark Matter and Space Astronomy , Purple Mountain Observatory, CAS, Nanjing 210023, People’s Republic of China ; yingli@pmo.ac.cn; School of Astronomy and Space Science, University of Science and Technology of China , Hefei 230026, People’s Republic of ChinaInstitute for Solar Physics, Department of Astronomy, Stockholm University , AlbaNova University Centre, SE-106 91 Stockholm, SwedenSchool of Astronomy and Space Science, Nanjing University , Nanjing 210023, People’s Republic of China; Key Laboratory for Modern Astronomy and Astrophysics (Nanjing University) , Ministry of Education, Nanjing 210023, People’s Republic of ChinaHow the plasma in the atmosphere is heated during a solar flare remains inconclusive. Nonthermal electron beams are usually considered as an essential heating source, yet Alfvén waves have also been proposed as a promising heating mechanism. Based on radiative hydrodynamic simulations, we explored the performance of different heating mechanisms, including nonthermal electron beams, Alfvén waves, and their joint effects. We studied the parameter space of Alfvén waves, focusing on the heating depth and the continuum emissions at 3600 and 6170 Å. We compared the atmospheric structures, continuum enhancements, and line profiles of hydrogen Ly α and H α in beam-heated, wave-heated, and jointly heated flare models. We find that the heating location of waves is strongly dependent on the wavenumber and frequency. The Alfvén wave can penetrate into the lower chromosphere and even the photosphere, causing a prominent continuum emission. There are different atmospheric responses in the Alfvén-wave and electron-beam heating cases due to their different energy-damping patterns. However, there seem to be no unique features in the Ly α and H α line profiles that can be used to distinguish the wave-heated models. In the jointly heated cases, the heating effect of waves and that of energetic electron beams can affect each other during the evolution of flares. Our simulations provide some references for interpreting the observed line profiles as well as the continuum emissions in solar white-light flares.https://doi.org/10.3847/1538-4357/addd0eRadiative transferSolar flaresAlfvén wavesSolar flare spectra |
| spellingShingle | Jun Tian Ying Li Jie Hong M. D. Ding Continuum Enhancement and Line Asymmetries of Solar Flares in Different Heating Models: Alfvén Waves, Nonthermal Electron Beams, and Their Joint Effect The Astrophysical Journal Radiative transfer Solar flares Alfvén waves Solar flare spectra |
| title | Continuum Enhancement and Line Asymmetries of Solar Flares in Different Heating Models: Alfvén Waves, Nonthermal Electron Beams, and Their Joint Effect |
| title_full | Continuum Enhancement and Line Asymmetries of Solar Flares in Different Heating Models: Alfvén Waves, Nonthermal Electron Beams, and Their Joint Effect |
| title_fullStr | Continuum Enhancement and Line Asymmetries of Solar Flares in Different Heating Models: Alfvén Waves, Nonthermal Electron Beams, and Their Joint Effect |
| title_full_unstemmed | Continuum Enhancement and Line Asymmetries of Solar Flares in Different Heating Models: Alfvén Waves, Nonthermal Electron Beams, and Their Joint Effect |
| title_short | Continuum Enhancement and Line Asymmetries of Solar Flares in Different Heating Models: Alfvén Waves, Nonthermal Electron Beams, and Their Joint Effect |
| title_sort | continuum enhancement and line asymmetries of solar flares in different heating models alfven waves nonthermal electron beams and their joint effect |
| topic | Radiative transfer Solar flares Alfvén waves Solar flare spectra |
| url | https://doi.org/10.3847/1538-4357/addd0e |
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