Deep nightside photoelectron observations by MAVEN SWEA: Implications for Martian northern hemispheric magnetic topology and nightside ionosphere source
Abstract The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission samples the Mars ionosphere down to altitudes of ∼150 km over a wide range of local times and solar zenith angles. On 5 January 2015 (Orbit 520) when the spacecraft was in darkness at high northern latitudes (solar zenith angle, SZA...
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Wiley
2016-09-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1002/2016GL070527 |
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| author | Shaosui Xu David Mitchell Michael Liemohn Chuanfei Dong Stephen Bougher Matthew Fillingim Robert Lillis James McFadden Christian Mazelle Jack Connerney Bruce Jakosky |
| author_facet | Shaosui Xu David Mitchell Michael Liemohn Chuanfei Dong Stephen Bougher Matthew Fillingim Robert Lillis James McFadden Christian Mazelle Jack Connerney Bruce Jakosky |
| author_sort | Shaosui Xu |
| collection | DOAJ |
| description | Abstract The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission samples the Mars ionosphere down to altitudes of ∼150 km over a wide range of local times and solar zenith angles. On 5 January 2015 (Orbit 520) when the spacecraft was in darkness at high northern latitudes (solar zenith angle, SZA >120°; latitude >60°), the Solar Wind Electron Analyzer (SWEA) instrument observed photoelectrons at altitudes below 200 km. Such observations imply the presence of closed crustal magnetic field loops that cross the terminator and extend thousands of kilometers to the deep nightside. This occurs over the weak northern crustal magnetic source regions, where the magnetic field has been thought to be dominated by draped interplanetary magnetic fields (IMF). Such a day‐night magnetic connectivity also provides a source of plasma and energy to the deep nightside. Simulations with the SuperThermal Electron Transport (STET) model show that photoelectron fluxes measured by SWEA precipitating onto the nightside atmosphere provide a source of ionization that can account for the O2+ density measured by the Suprathermal and Thermal Ion Composition (STATIC) instrument below 200 km. This finding indicates another channel for Martian energy redistribution to the deep nightside and consequently localized ionosphere patches and potentially aurora. |
| format | Article |
| id | doaj-art-1bc3352335cb402cb3e82dd5ae148ccd |
| institution | DOAJ |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2016-09-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-1bc3352335cb402cb3e82dd5ae148ccd2025-08-20T03:09:52ZengWileyGeophysical Research Letters0094-82761944-80072016-09-0143178876888410.1002/2016GL070527Deep nightside photoelectron observations by MAVEN SWEA: Implications for Martian northern hemispheric magnetic topology and nightside ionosphere sourceShaosui Xu0David Mitchell1Michael Liemohn2Chuanfei Dong3Stephen Bougher4Matthew Fillingim5Robert Lillis6James McFadden7Christian Mazelle8Jack Connerney9Bruce Jakosky10Space Sciences Laboratory University of California Berkeley California USASpace Sciences Laboratory University of California Berkeley California USADepartment of Climate and Space Sciences and Engineering University of Michigan Ann Arbor Michigan USADepartment of Climate and Space Sciences and Engineering University of Michigan Ann Arbor Michigan USADepartment of Climate and Space Sciences and Engineering University of Michigan Ann Arbor Michigan USASpace Sciences Laboratory University of California Berkeley California USASpace Sciences Laboratory University of California Berkeley California USASpace Sciences Laboratory University of California Berkeley California USAIRAP CNRS and University Paul Sabatier Toulouse FranceGSFC Greenbelt Maryland USALASP University of Colorado Boulder Colorado USAAbstract The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission samples the Mars ionosphere down to altitudes of ∼150 km over a wide range of local times and solar zenith angles. On 5 January 2015 (Orbit 520) when the spacecraft was in darkness at high northern latitudes (solar zenith angle, SZA >120°; latitude >60°), the Solar Wind Electron Analyzer (SWEA) instrument observed photoelectrons at altitudes below 200 km. Such observations imply the presence of closed crustal magnetic field loops that cross the terminator and extend thousands of kilometers to the deep nightside. This occurs over the weak northern crustal magnetic source regions, where the magnetic field has been thought to be dominated by draped interplanetary magnetic fields (IMF). Such a day‐night magnetic connectivity also provides a source of plasma and energy to the deep nightside. Simulations with the SuperThermal Electron Transport (STET) model show that photoelectron fluxes measured by SWEA precipitating onto the nightside atmosphere provide a source of ionization that can account for the O2+ density measured by the Suprathermal and Thermal Ion Composition (STATIC) instrument below 200 km. This finding indicates another channel for Martian energy redistribution to the deep nightside and consequently localized ionosphere patches and potentially aurora.https://doi.org/10.1002/2016GL070527Marsphotoelectronsnightside ionospheremagnetic topologyweak crustal fieldsMAVEN |
| spellingShingle | Shaosui Xu David Mitchell Michael Liemohn Chuanfei Dong Stephen Bougher Matthew Fillingim Robert Lillis James McFadden Christian Mazelle Jack Connerney Bruce Jakosky Deep nightside photoelectron observations by MAVEN SWEA: Implications for Martian northern hemispheric magnetic topology and nightside ionosphere source Geophysical Research Letters Mars photoelectrons nightside ionosphere magnetic topology weak crustal fields MAVEN |
| title | Deep nightside photoelectron observations by MAVEN SWEA: Implications for Martian northern hemispheric magnetic topology and nightside ionosphere source |
| title_full | Deep nightside photoelectron observations by MAVEN SWEA: Implications for Martian northern hemispheric magnetic topology and nightside ionosphere source |
| title_fullStr | Deep nightside photoelectron observations by MAVEN SWEA: Implications for Martian northern hemispheric magnetic topology and nightside ionosphere source |
| title_full_unstemmed | Deep nightside photoelectron observations by MAVEN SWEA: Implications for Martian northern hemispheric magnetic topology and nightside ionosphere source |
| title_short | Deep nightside photoelectron observations by MAVEN SWEA: Implications for Martian northern hemispheric magnetic topology and nightside ionosphere source |
| title_sort | deep nightside photoelectron observations by maven swea implications for martian northern hemispheric magnetic topology and nightside ionosphere source |
| topic | Mars photoelectrons nightside ionosphere magnetic topology weak crustal fields MAVEN |
| url | https://doi.org/10.1002/2016GL070527 |
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