The Response of Saturn's Dawn Field‐Aligned Currents to Magnetospheric and Ring Current Conditions During Cassini's Proximal Orbits: Evidence for a Region 2 Response at Saturn.
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| Title: | The Response of Saturn's Dawn Field‐Aligned Currents to Magnetospheric and Ring Current Conditions During Cassini's Proximal Orbits: Evidence for a Region 2 Response at Saturn. |
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| Authors: | Hunt, G. J.1 (AUTHOR) gregjhunt1@gmail.com, Provan, G.2 (AUTHOR), Bradley, T. J.2 (AUTHOR), Cowley, S. W. H.2 (AUTHOR), Dougherty, M. K.1 (AUTHOR), Roussos, E.3 (AUTHOR) |
| Source: | Journal of Geophysical Research. Space Physics. Jun2022, Vol. 127 Issue 6, p1-15. 15p. |
| Subject Terms: | *Earth currents, Saturn (Planet), Current sheets, Orbits (Astronomy), Magnetosphere |
| Abstract: | Cassini's 2017 proximal orbits provided the opportunity to examine the auroral field‐aligned currents in the northern hemisphere dawn sector in relation to wider magnetospheric conditions. We combine three recent studies to examine the response of the dawn region auroral field‐aligned currents and the azimuthal ring currents to compressions and expansions of the Saturnian magnetosphere. For compressions of Saturn's magnetosphere resulting in tail reconnection, the currents within the downward current sheet, located equatorward of the main auroral oval, increases in strength with increasing total ring current and location of the peak downwards current moves inwards toward Saturn. While the inverse relation occurs during intervals of quiet or expanded magnetospheric conditions. During compression events there is an increase in the energetic particle intensities, in particular in the protons (35–506 keV), within the downward current region. This current system is akin to an Earth‐like "region 2" field aligned current within Saturn's magnetosphere, with tail reconnection occurring when the magnetosphere is compressed resulting in a partial nightside ring current closed by a downward current near to dawn. Within the upward current sheet, mapping to Saturn's main auroral oval, both non‐rotating subcorotating current and the rotating Planetary Period Oscillations (PPOs) currents flow. The upward current is strongly modulated by the PPOs but also increases in strength, with enhanced high‐energy protons, during intervals of magnetospheric compressions and tail reconnection. We conclude that the enhanced plasma injected into the midnight‐dawn sector during tail reconnection events results in an enhanced subcorotation current system. Key Points: We combine datasets for Saturn's northern auroral field‐aligned currents, magnetospheric compression state and total ring currentFor compression events the downward current sheet at dawn increases in strength with the total ring current and higher energy protonsWe conclude that there is an enhanced dawn downward current (∼0.5 MA/rad), which is akin to a Region 2 current system at Earth [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Geophysical Research. Space Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Header | DbId: 8gh DbLabel: GreenFILE An: 157689979 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: The Response of Saturn's Dawn Field‐Aligned Currents to Magnetospheric and Ring Current Conditions During Cassini's Proximal Orbits: Evidence for a Region 2 Response at Saturn. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Hunt%2C+G%2E+J%2E%22">Hunt, G. J.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> gregjhunt1@gmail.com</i><br /><searchLink fieldCode="AR" term="%22Provan%2C+G%2E%22">Provan, G.</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Bradley%2C+T%2E+J%2E%22">Bradley, T. J.</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Cowley%2C+S%2E+W%2E+H%2E%22">Cowley, S. W. H.</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Dougherty%2C+M%2E+K%2E%22">Dougherty, M. K.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Roussos%2C+E%2E%22">Roussos, E.</searchLink><relatesTo>3</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Geophysical+Research%2E+Space+Physics%22">Journal of Geophysical Research. Space Physics</searchLink>. Jun2022, Vol. 127 Issue 6, p1-15. 15p. – Name: Subject Label: Subject Terms Group: Su Data: *<searchLink fieldCode="DE" term="%22Earth+currents%22">Earth currents</searchLink><br /><searchLink fieldCode="DE" term="%22Saturn+%28Planet%29%22">Saturn (Planet)</searchLink><br /><searchLink fieldCode="DE" term="%22Current+sheets%22">Current sheets</searchLink><br /><searchLink fieldCode="DE" term="%22Orbits+%28Astronomy%29%22">Orbits (Astronomy)</searchLink><br /><searchLink fieldCode="DE" term="%22Magnetosphere%22">Magnetosphere</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Cassini's 2017 proximal orbits provided the opportunity to examine the auroral field‐aligned currents in the northern hemisphere dawn sector in relation to wider magnetospheric conditions. We combine three recent studies to examine the response of the dawn region auroral field‐aligned currents and the azimuthal ring currents to compressions and expansions of the Saturnian magnetosphere. For compressions of Saturn's magnetosphere resulting in tail reconnection, the currents within the downward current sheet, located equatorward of the main auroral oval, increases in strength with increasing total ring current and location of the peak downwards current moves inwards toward Saturn. While the inverse relation occurs during intervals of quiet or expanded magnetospheric conditions. During compression events there is an increase in the energetic particle intensities, in particular in the protons (35–506 keV), within the downward current region. This current system is akin to an Earth‐like "region 2" field aligned current within Saturn's magnetosphere, with tail reconnection occurring when the magnetosphere is compressed resulting in a partial nightside ring current closed by a downward current near to dawn. Within the upward current sheet, mapping to Saturn's main auroral oval, both non‐rotating subcorotating current and the rotating Planetary Period Oscillations (PPOs) currents flow. The upward current is strongly modulated by the PPOs but also increases in strength, with enhanced high‐energy protons, during intervals of magnetospheric compressions and tail reconnection. We conclude that the enhanced plasma injected into the midnight‐dawn sector during tail reconnection events results in an enhanced subcorotation current system. Key Points: We combine datasets for Saturn's northern auroral field‐aligned currents, magnetospheric compression state and total ring currentFor compression events the downward current sheet at dawn increases in strength with the total ring current and higher energy protonsWe conclude that there is an enhanced dawn downward current (∼0.5 MA/rad), which is akin to a Region 2 current system at Earth [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Geophysical Research. Space Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1029/2021JA029852 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 15 StartPage: 1 Subjects: – SubjectFull: Earth currents Type: general – SubjectFull: Saturn (Planet) Type: general – SubjectFull: Current sheets Type: general – SubjectFull: Orbits (Astronomy) Type: general – SubjectFull: Magnetosphere Type: general Titles: – TitleFull: The Response of Saturn's Dawn Field‐Aligned Currents to Magnetospheric and Ring Current Conditions During Cassini's Proximal Orbits: Evidence for a Region 2 Response at Saturn. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Hunt, G. J. – PersonEntity: Name: NameFull: Provan, G. – PersonEntity: Name: NameFull: Bradley, T. J. – PersonEntity: Name: NameFull: Cowley, S. W. H. – PersonEntity: Name: NameFull: Dougherty, M. K. – PersonEntity: Name: NameFull: Roussos, E. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 06 Text: Jun2022 Type: published Y: 2022 Identifiers: – Type: issn-print Value: 21699380 Numbering: – Type: volume Value: 127 – Type: issue Value: 6 Titles: – TitleFull: Journal of Geophysical Research. Space Physics Type: main |
| ResultId | 1 |
