The temporal and latitudinal dependences of turbulence driven by pickup ions in the outer heliosphere
The distribution of turbulence in the heliosphere remains a mystery, due to the complexity in not only modeling the turbulence transport equations but also identifying the drivers of turbulence that vary with time and spatial location. Beyond the ionization cavity (a few astronomical units (AU) from...
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Frontiers Media S.A.
2023-12-01
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| Series: | Frontiers in Astronomy and Space Sciences |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fspas.2023.1298577/full |
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| author | Bingbing Wang Lingling Zhao Lingling Zhao Paria Abouhamzeh Paria Abouhamzeh Gary P. Zank Gary P. Zank Laxman Adhikari Laxman Adhikari |
| author_facet | Bingbing Wang Lingling Zhao Lingling Zhao Paria Abouhamzeh Paria Abouhamzeh Gary P. Zank Gary P. Zank Laxman Adhikari Laxman Adhikari |
| author_sort | Bingbing Wang |
| collection | DOAJ |
| description | The distribution of turbulence in the heliosphere remains a mystery, due to the complexity in not only modeling the turbulence transport equations but also identifying the drivers of turbulence that vary with time and spatial location. Beyond the ionization cavity (a few astronomical units (AU) from the Sun), the turbulence is driven predominantly by freshly created pickup ions (PUIs), in contrast to the driving by stream shear and compression. Understanding the source characteristics is necessary to refine turbulence transport models and interpret measurements of turbulence and solar wind temperature in the outer heliosphere. Using a recent latitude-dependent solar wind speed model and the ionization rate of neutral interstellar hydrogen (H), we investigate the temporal and spatial variation in the strength of low-frequency turbulence driven by PUIs from 1998 to 2020. We find that the driving rate is stronger during periods of high solar activity and at lower latitudes in the outer heliosphere. The driving rates for parallel and anti-parallel propagating (relative to the background magnetic field) slab turbulence have different spatial and latitude dependences. The calculated generation rate of turbulence by PUIs is an essential ingredient to investigate the latitude dependence of turbulence in the outer heliosphere, which is important to understand the heating of the distant solar wind and the modulation of cosmic rays. |
| first_indexed | 2024-03-09T10:40:09Z |
| format | Article |
| id | doaj.art-ec63571516834b40aa56a558f84e9549 |
| institution | Directory Open Access Journal |
| issn | 2296-987X |
| language | English |
| last_indexed | 2024-03-09T10:40:09Z |
| publishDate | 2023-12-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Astronomy and Space Sciences |
| spelling | doaj.art-ec63571516834b40aa56a558f84e95492023-12-01T16:37:24ZengFrontiers Media S.A.Frontiers in Astronomy and Space Sciences2296-987X2023-12-011010.3389/fspas.2023.12985771298577The temporal and latitudinal dependences of turbulence driven by pickup ions in the outer heliosphereBingbing Wang0Lingling Zhao1Lingling Zhao2Paria Abouhamzeh3Paria Abouhamzeh4Gary P. Zank5Gary P. Zank6Laxman Adhikari7Laxman Adhikari8Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL, United StatesCenter for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL, United StatesDepartment of Space Science, University of Alabama in Huntsville, Huntsville, AL, United StatesCenter for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL, United StatesDepartment of Space Science, University of Alabama in Huntsville, Huntsville, AL, United StatesCenter for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL, United StatesDepartment of Space Science, University of Alabama in Huntsville, Huntsville, AL, United StatesCenter for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL, United StatesDepartment of Space Science, University of Alabama in Huntsville, Huntsville, AL, United StatesThe distribution of turbulence in the heliosphere remains a mystery, due to the complexity in not only modeling the turbulence transport equations but also identifying the drivers of turbulence that vary with time and spatial location. Beyond the ionization cavity (a few astronomical units (AU) from the Sun), the turbulence is driven predominantly by freshly created pickup ions (PUIs), in contrast to the driving by stream shear and compression. Understanding the source characteristics is necessary to refine turbulence transport models and interpret measurements of turbulence and solar wind temperature in the outer heliosphere. Using a recent latitude-dependent solar wind speed model and the ionization rate of neutral interstellar hydrogen (H), we investigate the temporal and spatial variation in the strength of low-frequency turbulence driven by PUIs from 1998 to 2020. We find that the driving rate is stronger during periods of high solar activity and at lower latitudes in the outer heliosphere. The driving rates for parallel and anti-parallel propagating (relative to the background magnetic field) slab turbulence have different spatial and latitude dependences. The calculated generation rate of turbulence by PUIs is an essential ingredient to investigate the latitude dependence of turbulence in the outer heliosphere, which is important to understand the heating of the distant solar wind and the modulation of cosmic rays.https://www.frontiersin.org/articles/10.3389/fspas.2023.1298577/fullmagnetohydrodynamic turbulenceheliospheresolar windwaves and instabilitiespickup ions |
| spellingShingle | Bingbing Wang Lingling Zhao Lingling Zhao Paria Abouhamzeh Paria Abouhamzeh Gary P. Zank Gary P. Zank Laxman Adhikari Laxman Adhikari The temporal and latitudinal dependences of turbulence driven by pickup ions in the outer heliosphere Frontiers in Astronomy and Space Sciences magnetohydrodynamic turbulence heliosphere solar wind waves and instabilities pickup ions |
| title | The temporal and latitudinal dependences of turbulence driven by pickup ions in the outer heliosphere |
| title_full | The temporal and latitudinal dependences of turbulence driven by pickup ions in the outer heliosphere |
| title_fullStr | The temporal and latitudinal dependences of turbulence driven by pickup ions in the outer heliosphere |
| title_full_unstemmed | The temporal and latitudinal dependences of turbulence driven by pickup ions in the outer heliosphere |
| title_short | The temporal and latitudinal dependences of turbulence driven by pickup ions in the outer heliosphere |
| title_sort | temporal and latitudinal dependences of turbulence driven by pickup ions in the outer heliosphere |
| topic | magnetohydrodynamic turbulence heliosphere solar wind waves and instabilities pickup ions |
| url | https://www.frontiersin.org/articles/10.3389/fspas.2023.1298577/full |
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