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| Titel |
Nitrogen and Oxygen Budget ExpLoration (NOBEL) for ESA M5-call: Measurement requirements to understand the atmospheric escape/budget |
| VerfasserIn |
Masatoshi Yamauchi, Iannis Dandouras, Henri Rème, Octav Marghitu |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250125878
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| Publikation (Nr.) |
 EGU/EGU2016-5530.pdf |
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| Zusammenfassung |
| The NOBEL mission aims to study the thermal and non-thermal escape of major atmospheric
components (nitrogen, oxygen, and their isotopes) from the Earth, a magnetized planet. This
requires the first-time exploration of the Earth’s entire exosphere as well as the first-time
examination of isotope ratios in an extended altitude range from the upper ionosphere (800
km high) up to the magnetosphere.
The measurement quality should allow connecting the various types of escape from the
Earth to the different gravity mass-filtering and chemical reactions on a geological
time scale, such that the result will be used as a good reference to understand the
atmospheric/ionospheric evolution of magnetized planets based on their 17,18O/16O isotope
ratio and N/O ratio. Since the solar EUV and solar wind conditions during solar maximum at
present are comparable to the solar minimum conditions 1-2 billion years ago, the
escaping amount and the isotope and N/O ratios should be obtained as a function
of external forcing (solar and geomagnetic conditions) to allow a scaling to the
past.
To achieve these goals, the ion measurements in this mission should be able to separate
nitrogen species (N, N2, N+ and N2+) from oxygen (O, O+), near the exobase, in the
exosphere (for modelling thermal escape, hydrodynamics escape, and the pre-acceleration
amount of non-thermal escape) and up in the magnetosphere (for modelling non-thermal
escape and circulation of all ions). Furthermore, these aims require the capability to measure
isotope ratios of cold oxygen ions and neutrals. We briefly discuss why we focus on the
exosphere, on isotope ratios, and nitrogen measurements, and finally describe the current idea
of a mission profile using a spinning satellite in a 500 km × 33000 km altitude
high-inclination orbit. |
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