[en] The Mars Atmosphere and Volatile Evolution (MAVEN) mission, during the second of its Deep Dip campaigns, made comprehensive measurements of martian thermosphere and ionosphere composition, structure, and variability at altitudes down to ~130 kilometers in the subsolar region. This altitude range contains the diffusively separated upper atmosphere just above the well-mixed atmosphere, the layer of peak extreme ultraviolet heating and primary reservoir for atmospheric escape. In situ measurements of the upper atmosphere reveal previously unmeasured populations of neutral and charged particles, the homopause altitude at approximately 130 kilometers, and an unexpected level of variability both on an orbit-To-orbit basis and within individual orbits. These observations help constrain volatile escape processes controlled by thermosphere and ionosphere structure and variability.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Bougher, Stephen W.; CLaSP Department, University of Michigan, Ann Arbor, MI, United States
Jakosky, Bruce M.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Halekas, J.; Department of Physics and Astronomy, University of Iowa, Iowa City, IA, United States
Grebowsky, Joseph M.; NASA/Goddard Space Flight Center, Greenbelt, MD, United States
Luhmann, Janet G.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Mahaffy, P.; NASA/Goddard Space Flight Center, Greenbelt, MD, United States
Connerney, J.; NASA/Goddard Space Flight Center, Greenbelt, MD, United States
Eparvier, F.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Ergun, R.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Larson, D.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
McFadden, J.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Mitchell, D.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Schneider, N.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Zurek, R.; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
Mazelle, C.; CNRS/Institut de Recherche en Astrophysique et Planétologie, Toulouse, France, University Paul Sabatier, Toulouse, France
Andersson, L.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Andrews, D.; Swedish Institute of Space Physics, Kiruna, Sweden
Baird, D.; NASA/Johnson Space Center, Houston, TX, United States
N. Baker, D.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
M. Bell, J.; National Institute of Aerospace, Hampton, VA, United States
Benna, M.; NASA/Goddard Space Flight Center, Greenbelt, MD, United States
Brain, D.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Chaffin, M.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Chamberlin, P.; NASA/Goddard Space Flight Center, Greenbelt, MD, United States
Chaufray, Y.; Laboratoire Atmosphères, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France
Clarke, J.; Department of Astronomy, Boston University, Boston, MA, United States
Collinson, G.; NASA/Goddard Space Flight Center, Greenbelt, MD, United States
Combi, M.; CLaSP Department, University of Michigan, Ann Arbor, MI, United States
Crary, F.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Cravens, T.; Department of Physics and Astronomy, University of Kansas, Lawrence, KS, United States
Crismani, M.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Curry, S.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Curtis, D.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Deighan, J.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Delory, G.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Dewey, R.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
DiBraccio, G.; NASA/Goddard Space Flight Center, Greenbelt, MD, United States
Dong, C.; CLaSP Department, University of Michigan, Ann Arbor, MI, United States
Dong, Y.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Dunn, P.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Elrod, M.; NASA/Goddard Space Flight Center, Greenbelt, MD, United States
England, S.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Eriksson, A.; Swedish Institute of Space Physics, Kiruna, Sweden
Espley, J.; NASA/Goddard Space Flight Center, Greenbelt, MD, United States
Evans, S.; Computational Physics, Springfield, VA, United States
Fang, X.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Fillingim, M.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Fortier, K.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Fowler, C. M.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Fox, J.; Department of Physics, Wright State University, Fairborn, OH, United States
Gröller, H.; Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, United States
Guzewich, S.; NASA/Goddard Space Flight Center, Greenbelt, MD, United States
Hara, T.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Harada, Y.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Holsclaw, G.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
K. Jain, S.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Jolitz, R.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
LeBlanc, F.; Laboratoire Atmosphères, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France
Lee, C. O.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Lee, Y.; CLaSP Department, University of Michigan, Ann Arbor, MI, United States
Lefevre, F.; Laboratoire Atmosphères, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France
Lillis, R.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Livi, R.; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, United States
Lo, D.; Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, United States
Ma, Y.; Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA, United States
Mayyasi, M.; Department of Astronomy, Boston University, Boston, MA, United States
McClintock, W.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
McEnulty, T.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Modolo, R.; Laboratoire Atmosphères, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France
Montmessin, F.; Laboratoire Atmosphères, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France
Morooka, M.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Nagy, A.; CLaSP Department, University of Michigan, Ann Arbor, MI, United States
Olsen, K.; CLaSP Department, University of Michigan, Ann Arbor, MI, United States
Peterson, W.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Rahmati, A.; Department of Physics and Astronomy, University of Kansas, Lawrence, KS, United States
Ruhunusiri, S.; Department of Physics and Astronomy, University of Iowa, Iowa City, IA, United States
Russell, T. C.; Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA, United States
Sakai, S.; Department of Physics and Astronomy, University of Kansas, Lawrence, KS, United States
Sauvaud, J.-A.; CNRS/Institut de Recherche en Astrophysique et Planétologie, Toulouse, France, University Paul Sabatier, Toulouse, France
Seki, K.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Aichi, Japan
Steckiewicz, M.; CNRS/Institut de Recherche en Astrophysique et Planétologie, Toulouse, France, University Paul Sabatier, Toulouse, France
Stevens, M.; Naval Research Laboratory, Washington, DC, United States
Stewart, A. I. F.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Stiepen, Arnaud ; University of Colorado at Boulder - CU > Laboratory for Atmospheric and Space Physics
Stone, S.; Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, United States
Tenishev, V.; CLaSP Department, University of Michigan, Ann Arbor, MI, United States
Thiemann, E.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Tolson, R.; National Institute of Aerospace, Hampton, VA, United States
Toublanc, D.; CNRS/Institut de Recherche en Astrophysique et Planétologie, Toulouse, France, University Paul Sabatier, Toulouse, France
Vogt, M.; Department of Astronomy, Boston University, Boston, MA, United States
Weber, T.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Withers, P.; Department of Astronomy, Boston University, Boston, MA, United States
Woods, T.; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, United States
Yelle, R.; Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, United States
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The homopause altitude of a given planetary upper atmosphere is commonly estimated as the altitude at which a given species diffusion coefficient matches the specified eddy diffusion coefficient. This altitude represents that level in the atmosphere below which this species is well mixed (homosphere) and above which molecular diffusion serves to separate species according to their individual scale heights (heterosphere). Each species has its particular homopause altitude, owing to the slight variation of molecular diffusion coefficients by species. In reality, the homopause is not a single altitude level, but a transition region across which these molecular and eddy diffusion processes gradually exchange their dominant roles. For Mars, a common mixed-Atmosphere scale height is revealed by CO2, Ar, and N2 below their homopauses. However, photochemically active species (such as O) do not conform to this mixed-Atmosphere scale height.
The MAVEN in situ instruments are the Accelerometer (ACC), Langmuir Probe and Waves (LPW), Magnetometer (MAG), Neutral Gas and Ion Mass Spectrometer (NGIMS), Solar Wind Electron Analyzer (SWEA), Solar Wind Ion Analyzer (SWIA), and Supra-Thermal and Thermal Ion Composition (STATIC).
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