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| Titel |
Day-to-night transport in the Martian ionosphere |
| VerfasserIn |
Jun Cui, Marina Galand, Roger Yelle, Yong Wei |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250101035
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| Publikation (Nr.) |
 EGU/EGU2015-52.pdf |
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| Zusammenfassung |
| The nightisde Martian ionosphere is thought to be contributed by day-to-night transport and
electron precipitation, of which the former has not been well studied. In this work, we
evaluate the role of day-to-night transport based on the total electron content (TEC)
measurements made by the Mars Advanced Radar for Subsurface and Ionospheric Sounding
(MARSIS) onboard Mars Express (MEx). This is accomplished by an examination of the
variation of nightside TEC in the time domain rather than the traditional solar zenith angle
(SZA) domain. Our analyses here, being constrained to the northern hemisphere where the
effects of crustal magnetic fields can be neglected, reveal that day-to-night transport serves as
the dominant source for the nightside Martian ionosphere from terminator crossing up to
time in darkness, TD, of ≈ 5.3 x 103 s, beyond which it is surpassed by electron
precipitation. We also compare the observations with predictions from a simplified
time-dependent ionosphere model. We conclude that the solid body rotation of Mars is
insufficient to account for the observed depletion of nightside TEC but the data
could be reasonably reproduced by the zonal transport model with a zonal electron
flow velocity of ≈ 1.9 km s-1. Such a velocity corresponds to a day-to-night
electron transport rate of ≈ 2.6 x 1025 s-1, of which the driving force is unclear. |
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