Exploring the Complex Heliotail Boundary by an Extended Level Set Approach
There is an ongoing debate regarding the shape of the heliotail. Studies have shown that the heliotail may be “comet-like,” extending for thousands of au. Some previous works defined the heliopause using magnetohydrodynamic variables, which only serve as an approximation to capture the heliopause in...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/ada68e |
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| author | C. Onubogu M. Opher M. Kornbleuth G. Tóth V. Florinski |
| author_facet | C. Onubogu M. Opher M. Kornbleuth G. Tóth V. Florinski |
| author_sort | C. Onubogu |
| collection | DOAJ |
| description | There is an ongoing debate regarding the shape of the heliotail. Studies have shown that the heliotail may be “comet-like,” extending for thousands of au. Some previous works defined the heliopause using magnetohydrodynamic variables, which only serve as an approximation to capture the heliopause in all directions. Here we use a level set method in our heliospheric model to constrain the location of the heliopause. The level set function, f _HP , is defined by boundary conditions, having a value of +1 at the inner boundary and −1 at the outer boundary. We find that the f _HP = 0 criterion, the standard heliopause definition used by other models to determine where solar wind and interstellar plasma meet, is impacted in the heliotail, where there is a broad mixing region of solar wind and interstellar medium plasma, by the nature of turbulent flows in the heliotail. We explore a different isosurface, defined by f _HP = 0.99, where the interface is composed of 99.5% solar wind and 0.50% interstellar medium. This determines the limits of the heliosphere by the region of solar wind flow that is minimally influenced by the interstellar flow. This region also contains magnetic field lines with at least one end anchored to the Sun. We obtain a split heliotail structure using the f _HP = 0.99 criterion. |
| format | Article |
| id | doaj-art-805415a8e3084e4d9cdc09c33cc2ff2d |
| institution | Kabale University |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal Letters |
| spelling | doaj-art-805415a8e3084e4d9cdc09c33cc2ff2d2025-02-11T13:26:08ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019802L1910.3847/2041-8213/ada68eExploring the Complex Heliotail Boundary by an Extended Level Set ApproachC. Onubogu0https://orcid.org/0009-0001-7254-917XM. Opher1https://orcid.org/0000-0002-8767-8273M. Kornbleuth2https://orcid.org/0000-0002-3479-1766G. Tóth3https://orcid.org/0000-0001-8459-2100V. Florinski4https://orcid.org/0000-0001-5485-2872Astronomy Department, Boston University , Boston, MA 02115, USAAstronomy Department, Boston University , Boston, MA 02115, USAAstronomy Department, Boston University , Boston, MA 02115, USAUniversity of Michigan , Ann Arbor, MI 48109, USADepartment of Space Science and Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville , Huntsville, AL 35899, USAThere is an ongoing debate regarding the shape of the heliotail. Studies have shown that the heliotail may be “comet-like,” extending for thousands of au. Some previous works defined the heliopause using magnetohydrodynamic variables, which only serve as an approximation to capture the heliopause in all directions. Here we use a level set method in our heliospheric model to constrain the location of the heliopause. The level set function, f _HP , is defined by boundary conditions, having a value of +1 at the inner boundary and −1 at the outer boundary. We find that the f _HP = 0 criterion, the standard heliopause definition used by other models to determine where solar wind and interstellar plasma meet, is impacted in the heliotail, where there is a broad mixing region of solar wind and interstellar medium plasma, by the nature of turbulent flows in the heliotail. We explore a different isosurface, defined by f _HP = 0.99, where the interface is composed of 99.5% solar wind and 0.50% interstellar medium. This determines the limits of the heliosphere by the region of solar wind flow that is minimally influenced by the interstellar flow. This region also contains magnetic field lines with at least one end anchored to the Sun. We obtain a split heliotail structure using the f _HP = 0.99 criterion.https://doi.org/10.3847/2041-8213/ada68eHeliosphereSolar windInterstellar mediumHeliopauseHeliosheathMagnetohydrodynamics |
| spellingShingle | C. Onubogu M. Opher M. Kornbleuth G. Tóth V. Florinski Exploring the Complex Heliotail Boundary by an Extended Level Set Approach The Astrophysical Journal Letters Heliosphere Solar wind Interstellar medium Heliopause Heliosheath Magnetohydrodynamics |
| title | Exploring the Complex Heliotail Boundary by an Extended Level Set Approach |
| title_full | Exploring the Complex Heliotail Boundary by an Extended Level Set Approach |
| title_fullStr | Exploring the Complex Heliotail Boundary by an Extended Level Set Approach |
| title_full_unstemmed | Exploring the Complex Heliotail Boundary by an Extended Level Set Approach |
| title_short | Exploring the Complex Heliotail Boundary by an Extended Level Set Approach |
| title_sort | exploring the complex heliotail boundary by an extended level set approach |
| topic | Heliosphere Solar wind Interstellar medium Heliopause Heliosheath Magnetohydrodynamics |
| url | https://doi.org/10.3847/2041-8213/ada68e |
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