The Effect of Angular Scattering Imposed by Charge Exchange and Elastic Collisions on Interstellar Neutral Hydrogen Atoms
Angular scattering (AS) in charge exchange and elastic collisions between interstellar ions and neutral (ISN) atoms has been assumed to be negligible in previous studies. Here, we investigate the momentum transfer associated with the AS of H atoms using Monte Carlo calculations to simulate their tra...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad0be1 |
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| author | F. Rahmanifard P. Swaczyna E. J. Zirnstein J. Heerikhuisen A. Galli J. M. Sokół N. A. Schwadron E. Möbius D. J. McComas S. A. Fuselier |
| author_facet | F. Rahmanifard P. Swaczyna E. J. Zirnstein J. Heerikhuisen A. Galli J. M. Sokół N. A. Schwadron E. Möbius D. J. McComas S. A. Fuselier |
| author_sort | F. Rahmanifard |
| collection | DOAJ |
| description | Angular scattering (AS) in charge exchange and elastic collisions between interstellar ions and neutral (ISN) atoms has been assumed to be negligible in previous studies. Here, we investigate the momentum transfer associated with the AS of H atoms using Monte Carlo calculations to simulate their transport through the outer heliosheath. We consider two cases where charge exchange and elastic collisions between ISN H atoms and protons occur with and without AS in the outer heliosheath. We show that considering AS decelerates and heats primary ISN H, reducing the effect of selective charge exchange in the outer heliosheath. Secondary ISN H atoms, on the other hand, are not significantly affected by AS. We then simulate the transport of ISN H atoms inside the heliosphere to simulate count rates observed in the lowest energy bin of IBEX-Lo. We study the effect of radiation pressure on the ISN H measurements for the cases with and without AS and compare them with our previous findings. We find an effective radiation parameter ( μ _eff , which represents force associated with radiation pressure relative to gravity) for the years 2009–2018 based on the longitudinal shift of the ISN H signal. The two cases with and without AS reproduce the longitudinal shift in accordance with variations in solar activity, in agreement with our previous results, and they result in similar values for the μ _eff , which is ∼22%–23% larger than the value found based on solar Ly α profile observations. |
| first_indexed | 2024-03-08T23:33:05Z |
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| id | doaj.art-b653b7ada4254719b6759de2eb71a470 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-08T23:33:05Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj.art-b653b7ada4254719b6759de2eb71a4702023-12-14T10:13:41ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01959212910.3847/1538-4357/ad0be1The Effect of Angular Scattering Imposed by Charge Exchange and Elastic Collisions on Interstellar Neutral Hydrogen AtomsF. Rahmanifard0https://orcid.org/0000-0001-9316-0553P. Swaczyna1https://orcid.org/0000-0002-9033-0809E. J. Zirnstein2https://orcid.org/0000-0001-7240-0618J. Heerikhuisen3https://orcid.org/0000-0001-7867-3633A. Galli4https://orcid.org/0000-0003-2425-3793J. M. Sokół5https://orcid.org/0000-0002-4173-3601N. A. Schwadron6https://orcid.org/0000-0002-3737-9283E. Möbius7https://orcid.org/0000-0002-2745-6978D. J. McComas8https://orcid.org/0000-0001-6160-1158S. A. Fuselier9https://orcid.org/0000-0003-4101-7901Physics Department, Space Science Center, University of New Hampshire , Durham, NH 03824, USADepartment of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USA; Space Research Centre PAS (CBK PAN) , 00-716 Warsaw, PolandDepartment of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USADepartment of Mathematics and Statistics, University of Waikato , Hamilton, New ZealandPhysics Institute, University of Bern , Bern, 3012, SwitzerlandSouthwest Research Institute , San Antonio, TX 78228, USAPhysics Department, Space Science Center, University of New Hampshire , Durham, NH 03824, USAPhysics Department, Space Science Center, University of New Hampshire , Durham, NH 03824, USADepartment of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USASouthwest Research Institute , San Antonio, TX 78228, USA; University of Texas at San Antonio , San Antonio, TX 78228, USAAngular scattering (AS) in charge exchange and elastic collisions between interstellar ions and neutral (ISN) atoms has been assumed to be negligible in previous studies. Here, we investigate the momentum transfer associated with the AS of H atoms using Monte Carlo calculations to simulate their transport through the outer heliosheath. We consider two cases where charge exchange and elastic collisions between ISN H atoms and protons occur with and without AS in the outer heliosheath. We show that considering AS decelerates and heats primary ISN H, reducing the effect of selective charge exchange in the outer heliosheath. Secondary ISN H atoms, on the other hand, are not significantly affected by AS. We then simulate the transport of ISN H atoms inside the heliosphere to simulate count rates observed in the lowest energy bin of IBEX-Lo. We study the effect of radiation pressure on the ISN H measurements for the cases with and without AS and compare them with our previous findings. We find an effective radiation parameter ( μ _eff , which represents force associated with radiation pressure relative to gravity) for the years 2009–2018 based on the longitudinal shift of the ISN H signal. The two cases with and without AS reproduce the longitudinal shift in accordance with variations in solar activity, in agreement with our previous results, and they result in similar values for the μ _eff , which is ∼22%–23% larger than the value found based on solar Ly α profile observations.https://doi.org/10.3847/1538-4357/ad0be1HeliosphereHeliosheathSolar activityInterstellar mediumInterstellar medium windSolar wind |
| spellingShingle | F. Rahmanifard P. Swaczyna E. J. Zirnstein J. Heerikhuisen A. Galli J. M. Sokół N. A. Schwadron E. Möbius D. J. McComas S. A. Fuselier The Effect of Angular Scattering Imposed by Charge Exchange and Elastic Collisions on Interstellar Neutral Hydrogen Atoms The Astrophysical Journal Heliosphere Heliosheath Solar activity Interstellar medium Interstellar medium wind Solar wind |
| title | The Effect of Angular Scattering Imposed by Charge Exchange and Elastic Collisions on Interstellar Neutral Hydrogen Atoms |
| title_full | The Effect of Angular Scattering Imposed by Charge Exchange and Elastic Collisions on Interstellar Neutral Hydrogen Atoms |
| title_fullStr | The Effect of Angular Scattering Imposed by Charge Exchange and Elastic Collisions on Interstellar Neutral Hydrogen Atoms |
| title_full_unstemmed | The Effect of Angular Scattering Imposed by Charge Exchange and Elastic Collisions on Interstellar Neutral Hydrogen Atoms |
| title_short | The Effect of Angular Scattering Imposed by Charge Exchange and Elastic Collisions on Interstellar Neutral Hydrogen Atoms |
| title_sort | effect of angular scattering imposed by charge exchange and elastic collisions on interstellar neutral hydrogen atoms |
| topic | Heliosphere Heliosheath Solar activity Interstellar medium Interstellar medium wind Solar wind |
| url | https://doi.org/10.3847/1538-4357/ad0be1 |
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