Generation of Sunward Ion Cyclotron Waves and the Nature of Right-handed Polarized Ion-scale Waves in the Near-Sun Solar Wind
Observations from the Parker Solar Probe have revealed the ubiquitous presence of right-handed polarized waves in the near-Sun solar wind. While antisunward fast-magnetosonic whistler waves have been commonly considered as their source, sunward ion cyclotron waves (ICWs) are another plausible candid...
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2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adf43d |
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| author | Chen Shi Jinsong Zhao Yifan Wu Si Liu Fuliang Xiao Huasheng Xie |
| author_facet | Chen Shi Jinsong Zhao Yifan Wu Si Liu Fuliang Xiao Huasheng Xie |
| author_sort | Chen Shi |
| collection | DOAJ |
| description | Observations from the Parker Solar Probe have revealed the ubiquitous presence of right-handed polarized waves in the near-Sun solar wind. While antisunward fast-magnetosonic whistler waves have been commonly considered as their source, sunward ion cyclotron waves (ICWs) are another plausible candidate. Sunward ICWs can directly interact with antisunward ions via cyclotron resonant interactions, suggesting they may play an important role in particle energization processes in the solar wind. However, the generation of sunward ICWs remains poorly understood. In this study, we perform a theoretical instability survey over a broad parameter space to investigate the conditions that favor the generation of sunward ICWs, focusing on two key plasma properties: the temperature anisotropy and the relative streaming speed of the proton beam component. Our results show that sunward ICWs can be excited by proton beams with slow streaming speeds but significant temperature anisotropy. Additionally, the analysis reveals that the growth of this instability is strongly suppressed in environments with high alpha particle concentrations, indicating that sunward ICWs preferentially arise in plasmas with low alpha particle abundance. These findings offer new insights into the generation and nature of ion-scale waves in the near-Sun solar wind. |
| format | Article |
| id | doaj-art-4f597bbc79f1429c8d294dbb6bb88c9d |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-4f597bbc79f1429c8d294dbb6bb88c9d2025-08-20T03:36:14ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01989216410.3847/1538-4357/adf43dGeneration of Sunward Ion Cyclotron Waves and the Nature of Right-handed Polarized Ion-scale Waves in the Near-Sun Solar WindChen Shi0https://orcid.org/0000-0002-9166-1036Jinsong Zhao1https://orcid.org/0000-0002-3859-6394Yifan Wu2https://orcid.org/0000-0002-2039-0590Si Liu3https://orcid.org/0000-0001-8465-9395Fuliang Xiao4https://orcid.org/0000-0003-1487-6620Huasheng Xie5https://orcid.org/0000-0001-9204-135XSchool of Physics and Electronic Sciences, Changsha University of Science and Technology , Changsha, People’s Republic of China ; flxiao@126.comPurple Mountain Observatory, Chinese Academy of Sciences , Nanjing 210023, People’s Republic of China ; zhaojs82@gmail.comCAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China , Hefei, People’s Republic of ChinaSchool of Physics and Electronic Sciences, Changsha University of Science and Technology , Changsha, People’s Republic of China ; flxiao@126.comSchool of Physics and Electronic Sciences, Changsha University of Science and Technology , Changsha, People’s Republic of China ; flxiao@126.comHebei Key Laboratory of Compact Fusion , Langfang 065001, People’s Republic of China; ENN Science and Technology Development Co. , Ltd., Langfang 065001, People’s Republic of ChinaObservations from the Parker Solar Probe have revealed the ubiquitous presence of right-handed polarized waves in the near-Sun solar wind. While antisunward fast-magnetosonic whistler waves have been commonly considered as their source, sunward ion cyclotron waves (ICWs) are another plausible candidate. Sunward ICWs can directly interact with antisunward ions via cyclotron resonant interactions, suggesting they may play an important role in particle energization processes in the solar wind. However, the generation of sunward ICWs remains poorly understood. In this study, we perform a theoretical instability survey over a broad parameter space to investigate the conditions that favor the generation of sunward ICWs, focusing on two key plasma properties: the temperature anisotropy and the relative streaming speed of the proton beam component. Our results show that sunward ICWs can be excited by proton beams with slow streaming speeds but significant temperature anisotropy. Additionally, the analysis reveals that the growth of this instability is strongly suppressed in environments with high alpha particle concentrations, indicating that sunward ICWs preferentially arise in plasmas with low alpha particle abundance. These findings offer new insights into the generation and nature of ion-scale waves in the near-Sun solar wind.https://doi.org/10.3847/1538-4357/adf43dSpace plasmasPlasma physicsSolar wind |
| spellingShingle | Chen Shi Jinsong Zhao Yifan Wu Si Liu Fuliang Xiao Huasheng Xie Generation of Sunward Ion Cyclotron Waves and the Nature of Right-handed Polarized Ion-scale Waves in the Near-Sun Solar Wind The Astrophysical Journal Space plasmas Plasma physics Solar wind |
| title | Generation of Sunward Ion Cyclotron Waves and the Nature of Right-handed Polarized Ion-scale Waves in the Near-Sun Solar Wind |
| title_full | Generation of Sunward Ion Cyclotron Waves and the Nature of Right-handed Polarized Ion-scale Waves in the Near-Sun Solar Wind |
| title_fullStr | Generation of Sunward Ion Cyclotron Waves and the Nature of Right-handed Polarized Ion-scale Waves in the Near-Sun Solar Wind |
| title_full_unstemmed | Generation of Sunward Ion Cyclotron Waves and the Nature of Right-handed Polarized Ion-scale Waves in the Near-Sun Solar Wind |
| title_short | Generation of Sunward Ion Cyclotron Waves and the Nature of Right-handed Polarized Ion-scale Waves in the Near-Sun Solar Wind |
| title_sort | generation of sunward ion cyclotron waves and the nature of right handed polarized ion scale waves in the near sun solar wind |
| topic | Space plasmas Plasma physics Solar wind |
| url | https://doi.org/10.3847/1538-4357/adf43d |
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