A Numerical Study of the Effects of a Corotating Interaction Region on Cosmic-Ray Transport. II. Features of Cosmic-Ray Composition and Rigidity
We continue the numerical modeling of a corotating interaction region (CIR) and the effects it has on solar-rotational recurrent variations of galactic cosmic rays (GCRs). A magnetohydrodynamic model is adapted to simulate the background solar wind plasma with a CIR structure in the inner heliospher...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad0cb6 |
| _version_ | 1797357491701415936 |
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| author | Xi Luo Marius S. Potgieter Ming Zhang Fang Shen |
| author_facet | Xi Luo Marius S. Potgieter Ming Zhang Fang Shen |
| author_sort | Xi Luo |
| collection | DOAJ |
| description | We continue the numerical modeling of a corotating interaction region (CIR) and the effects it has on solar-rotational recurrent variations of galactic cosmic rays (GCRs). A magnetohydrodynamic model is adapted to simulate the background solar wind plasma with a CIR structure in the inner heliosphere, which is incorporated into a comprehensive Parker-type transport model. The focus is on the simulation of the effects of a CIR on GCR protons and the two helium isotopes as a function of heliolongitude. This is to establish whether the difference in composition affects how they are modulated by the CIR in terms of their distribution in longitude. It is demonstrated that particle diffusion and drift influence the effects of the CIR with increasing rigidity from 100 MV up to 15 GV. It is found that protons and helium isotopes are modulated differently with longitude by the CIR and that particle drift influences the modulation effects in longitude. These differences dissipate with increasing rigidity. The final results are focused on the simulated amplitude of these GCR flux variations as a function of rigidity. The amplitude displays a power-law behavior above ∼1 GV with an index similar to the power index of the rigidity dependence of the assumed diffusion coefficients. The simulations further show that below this rigidity, the amplitude at first flattens off, displaying a plateau-like profile, but it then increases systematically with decreasing rigidity below ∼0.3 GV. Again, a power-law behavior is displayed, but it is completely different from that above 1 GV. |
| first_indexed | 2024-03-08T14:45:55Z |
| format | Article |
| id | doaj.art-5448823ed3a24ce98bce16c5beff0dfe |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-08T14:45:55Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-5448823ed3a24ce98bce16c5beff0dfe2024-01-11T09:50:22ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0196112110.3847/1538-4357/ad0cb6A Numerical Study of the Effects of a Corotating Interaction Region on Cosmic-Ray Transport. II. Features of Cosmic-Ray Composition and RigidityXi Luo0https://orcid.org/0000-0002-4508-6042Marius S. Potgieter1https://orcid.org/0000-0003-0793-7333Ming Zhang2https://orcid.org/0000-0003-3529-8743Fang Shen3https://orcid.org/0000-0002-4935-6679Shandong Institute of Advanced Technology (SDIAT) , 250100 Jinan, Shandong, People’s Republic of China ; xi.luo@iat.cnShandong Institute of Advanced Technology (SDIAT) , 250100 Jinan, Shandong, People’s Republic of China ; xi.luo@iat.cn; Institute for Experimental and Applied Physics (IEAP), Christian-Albrechts University in Kiel , D-24118 Kiel, GermanyDepartment of Physics and Space Sciences, Florida Institute of Technology , Melbourne, FL 32901, USASIGMA Weather Group, State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences , Beijing 100190, People’s Republic of ChinaWe continue the numerical modeling of a corotating interaction region (CIR) and the effects it has on solar-rotational recurrent variations of galactic cosmic rays (GCRs). A magnetohydrodynamic model is adapted to simulate the background solar wind plasma with a CIR structure in the inner heliosphere, which is incorporated into a comprehensive Parker-type transport model. The focus is on the simulation of the effects of a CIR on GCR protons and the two helium isotopes as a function of heliolongitude. This is to establish whether the difference in composition affects how they are modulated by the CIR in terms of their distribution in longitude. It is demonstrated that particle diffusion and drift influence the effects of the CIR with increasing rigidity from 100 MV up to 15 GV. It is found that protons and helium isotopes are modulated differently with longitude by the CIR and that particle drift influences the modulation effects in longitude. These differences dissipate with increasing rigidity. The final results are focused on the simulated amplitude of these GCR flux variations as a function of rigidity. The amplitude displays a power-law behavior above ∼1 GV with an index similar to the power index of the rigidity dependence of the assumed diffusion coefficients. The simulations further show that below this rigidity, the amplitude at first flattens off, displaying a plateau-like profile, but it then increases systematically with decreasing rigidity below ∼0.3 GV. Again, a power-law behavior is displayed, but it is completely different from that above 1 GV.https://doi.org/10.3847/1538-4357/ad0cb6Galactic cosmic raysHeliosphereSolar activitySolar wind |
| spellingShingle | Xi Luo Marius S. Potgieter Ming Zhang Fang Shen A Numerical Study of the Effects of a Corotating Interaction Region on Cosmic-Ray Transport. II. Features of Cosmic-Ray Composition and Rigidity The Astrophysical Journal Galactic cosmic rays Heliosphere Solar activity Solar wind |
| title | A Numerical Study of the Effects of a Corotating Interaction Region on Cosmic-Ray Transport. II. Features of Cosmic-Ray Composition and Rigidity |
| title_full | A Numerical Study of the Effects of a Corotating Interaction Region on Cosmic-Ray Transport. II. Features of Cosmic-Ray Composition and Rigidity |
| title_fullStr | A Numerical Study of the Effects of a Corotating Interaction Region on Cosmic-Ray Transport. II. Features of Cosmic-Ray Composition and Rigidity |
| title_full_unstemmed | A Numerical Study of the Effects of a Corotating Interaction Region on Cosmic-Ray Transport. II. Features of Cosmic-Ray Composition and Rigidity |
| title_short | A Numerical Study of the Effects of a Corotating Interaction Region on Cosmic-Ray Transport. II. Features of Cosmic-Ray Composition and Rigidity |
| title_sort | numerical study of the effects of a corotating interaction region on cosmic ray transport ii features of cosmic ray composition and rigidity |
| topic | Galactic cosmic rays Heliosphere Solar activity Solar wind |
| url | https://doi.org/10.3847/1538-4357/ad0cb6 |
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