MAGNETIC FLUX CONSERVATION IN THE HELIOSHEATH INCLUDING SOLAR CYCLE VARIATIONS OF MAGNETIC FIELD INTENSITY
In the heliosheath (HS), Voyager 2 has observed a flow with constant radial velocity and magnetic flux conservation. Voyager 1, however, has observed a decrease in the flow's radial velocity and an order of magnitude decrease in magnetic flux. We investigate the role of the 11 yr solar cycle va...
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| Format: | Article |
| Language: | en_US |
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IOP Publishing
2015
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| Online Access: | http://hdl.handle.net/1721.1/97093 |
| _version_ | 1826206334626824192 |
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| author | Michael, A. T. Opher, M. Provornikova, E. Richardson, John D. Toth, G. |
| author2 | MIT Kavli Institute for Astrophysics and Space Research |
| author_facet | MIT Kavli Institute for Astrophysics and Space Research Michael, A. T. Opher, M. Provornikova, E. Richardson, John D. Toth, G. |
| author_sort | Michael, A. T. |
| collection | MIT |
| description | In the heliosheath (HS), Voyager 2 has observed a flow with constant radial velocity and magnetic flux conservation. Voyager 1, however, has observed a decrease in the flow's radial velocity and an order of magnitude decrease in magnetic flux. We investigate the role of the 11 yr solar cycle variation of the magnetic field strength on the magnetic flux within the HS using a global 3D magnetohydrodynamic model of the heliosphere. We use time and latitude-dependent solar wind velocity and density inferred from Solar and Heliospheric Observatory/SWAN and interplanetary scintillations data and implemented solar cycle variations of the magnetic field derived from 27 day averages of the field magnitude average of the magnetic field at 1 AU from the OMNI database. With the inclusion of the solar cycle time-dependent magnetic field intensity, the model matches the observed intensity of the magnetic field in the HS along both Voyager 1 and 2. This is a significant improvement from the same model without magnetic field solar cycle variations, which was over a factor of two larger. The model accurately predicts the radial velocity observed by Voyager 2; however, the model predicts a flow speed ~100 km s[superscript −1] larger than that derived from LECP measurements at Voyager 1. In the model, magnetic flux is conserved along both Voyager trajectories, contrary to observations. This implies that the solar cycle variations in solar wind magnetic field observed at 1 AU does not cause the order of magnitude decrease in magnetic flux observed in the Voyager 1 data. |
| first_indexed | 2024-09-23T13:27:51Z |
| format | Article |
| id | mit-1721.1/97093 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T13:27:51Z |
| publishDate | 2015 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/970932022-10-01T15:26:32Z MAGNETIC FLUX CONSERVATION IN THE HELIOSHEATH INCLUDING SOLAR CYCLE VARIATIONS OF MAGNETIC FIELD INTENSITY Michael, A. T. Opher, M. Provornikova, E. Richardson, John D. Toth, G. MIT Kavli Institute for Astrophysics and Space Research Richardson, John D. In the heliosheath (HS), Voyager 2 has observed a flow with constant radial velocity and magnetic flux conservation. Voyager 1, however, has observed a decrease in the flow's radial velocity and an order of magnitude decrease in magnetic flux. We investigate the role of the 11 yr solar cycle variation of the magnetic field strength on the magnetic flux within the HS using a global 3D magnetohydrodynamic model of the heliosphere. We use time and latitude-dependent solar wind velocity and density inferred from Solar and Heliospheric Observatory/SWAN and interplanetary scintillations data and implemented solar cycle variations of the magnetic field derived from 27 day averages of the field magnitude average of the magnetic field at 1 AU from the OMNI database. With the inclusion of the solar cycle time-dependent magnetic field intensity, the model matches the observed intensity of the magnetic field in the HS along both Voyager 1 and 2. This is a significant improvement from the same model without magnetic field solar cycle variations, which was over a factor of two larger. The model accurately predicts the radial velocity observed by Voyager 2; however, the model predicts a flow speed ~100 km s[superscript −1] larger than that derived from LECP measurements at Voyager 1. In the model, magnetic flux is conserved along both Voyager trajectories, contrary to observations. This implies that the solar cycle variations in solar wind magnetic field observed at 1 AU does not cause the order of magnitude decrease in magnetic flux observed in the Voyager 1 data. United States. National Aeronautics and Space Administration (Earth and Space Science Fellowship Program Grant NNX14AO14H) 2015-05-28T17:19:22Z 2015-05-28T17:19:22Z 2015-04 2015-02 Article http://purl.org/eprint/type/JournalArticle 2041-8213 2041-8205 http://hdl.handle.net/1721.1/97093 Michael, A. T., M. Opher, E. Provornikova, J. D. Richardson, and G. Toth. “MAGNETIC FLUX CONSERVATION IN THE HELIOSHEATH INCLUDING SOLAR CYCLE VARIATIONS OF MAGNETIC FIELD INTENSITY.” The Astrophysical Journal 803, no. 1 (April 6, 2015): L6. © 2015 The American Astronomical Society en_US http://dx.doi.org/10.1088/2041-8205/803/1/l6 The Astrophysical Journal. Letters Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf IOP Publishing IOP Publishing |
| spellingShingle | Michael, A. T. Opher, M. Provornikova, E. Richardson, John D. Toth, G. MAGNETIC FLUX CONSERVATION IN THE HELIOSHEATH INCLUDING SOLAR CYCLE VARIATIONS OF MAGNETIC FIELD INTENSITY |
| title | MAGNETIC FLUX CONSERVATION IN THE HELIOSHEATH INCLUDING SOLAR CYCLE VARIATIONS OF MAGNETIC FIELD INTENSITY |
| title_full | MAGNETIC FLUX CONSERVATION IN THE HELIOSHEATH INCLUDING SOLAR CYCLE VARIATIONS OF MAGNETIC FIELD INTENSITY |
| title_fullStr | MAGNETIC FLUX CONSERVATION IN THE HELIOSHEATH INCLUDING SOLAR CYCLE VARIATIONS OF MAGNETIC FIELD INTENSITY |
| title_full_unstemmed | MAGNETIC FLUX CONSERVATION IN THE HELIOSHEATH INCLUDING SOLAR CYCLE VARIATIONS OF MAGNETIC FIELD INTENSITY |
| title_short | MAGNETIC FLUX CONSERVATION IN THE HELIOSHEATH INCLUDING SOLAR CYCLE VARIATIONS OF MAGNETIC FIELD INTENSITY |
| title_sort | magnetic flux conservation in the heliosheath including solar cycle variations of magnetic field intensity |
| url | http://hdl.handle.net/1721.1/97093 |
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