The art of Knowing the Surface Potential in an Ionosphere and the Effect of Atomic Oxygen
Abstract
Knowing the electrostatic potential of a surface over a wide range of space plasma environments can be challenging. MAVEN is one of the few recent missions that moves from tenuous hot plasma to high-density cold plasma, and... [ view full abstract ]
Knowing the electrostatic potential of a surface over a wide range of space plasma environments can be challenging. MAVEN is one of the few recent missions that moves from tenuous hot plasma to high-density cold plasma, and the periapsis of the orbit is located in an atomic oxygen (AO) rich atmosphere. One key objective near periapsis is to observe cold ionospheric plasma, and therefore one needs to know the electrostatic potentials of various surfaces, which can significantly perturb low-energy measurements. The MAVEN Particles and Fields Package includes three instruments that measure low-energy plasma, and as a result several aspects of the space environment can be analyzed. This presentation will cover two aspects: (1) the spacecraft potential and (2) AO effects on surface characteristics and instrument performance. The instruments on board can monitor the potential over most of this range, but as will be shown, potentials near zero are difficult to determine. The effect on spacecraft potential of thruster firing is well known this presentation will also discuss the impact of dust grains. The science payload was designed to tolerate exposure to AO, but some unforeseen effects on sensitive measurements will be discussed. Non-uniform AO exposure on internal surfaces of the ESA resulted in de-tuned optics and the Langmuir probe surfaces to AO seems to have changed the characteristics of the material. The MAVEN mission provides an excellent opportunity to analyze these space environment effects in detail.
Authors
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laila andersson
(LASP, University of Colorado)
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Bob Ergun
(LASP, University of Colorado)
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Jim P. Mcfadden
(SSL University of California)
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Dave Mitchell
(SSL University of California)
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Chris Fowler
(LASP, University of Colorado)
Topic Areas
Observations , Ionosphere, Neutral Atmosphere, Planetary , Atmospheric Effects (e.g., drag, AO, sputtering, glow)
Session
Session 8 » Observations (Invited) (08:30 - Thursday, 18th May)
Paper
ASEC_2017_Andersson_v4.doc
Presentation Files
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