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1. Modeling Wind‐Driven Ionospheric Dynamo Currents at Mars: Expectations for InSight Magnetic Field Measurements

Author

Francisco Gonzalez-Galindo, Catherine L. Johnson, François Forget, Anna Mittelholz, Yingjuan Ma, Christopher M. Fowler, Robert Lillis, Matthew Fillingim, Laila Andersson, Christopher T. Russell, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Department of Earth, Ocean and Atmospheric Sciences [Vancouver] (UBC EOAS), University of British Columbia (UBC), Planetary Science Institute [Tucson] (PSI), University of Colorado [Boulder], National Aeronautics and Space Administration (US), Consejo Superior de Investigaciones Científicas (España), Ministerio de Ciencia, Innovación y Universidades (España), and Centre National de la Recherche Scientifique (France)

Subjects
Engineering, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], business.industry, Center of excellence, Mars Exploration Program, 010502 geochemistry & geophysics, 7. Clean energy, 01 natural sciences, Prime (order theory), Physics::Geophysics, Wind driven, Geophysics, Aeronautics, State agency, 13. Climate action, Research council, Physics::Space Physics, General Earth and Planetary Sciences, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, business, 0105 earth and related environmental sciences, Dynamo
Abstract

We model expected dynamo currents above, and resulting magnetic field profiles at, InSight's landing site on Mars, including for the first time the effect of electron-ion collisions. We calculate their diurnal and seasonal variability using inputs from global models of the Martian thermosphere, ionosphere, and magnetosphere. Modeled currents primarily depend on plasma densities and the strength of the neutral wind component perpendicular to the combined crustal and draped magnetic fields that thread the ionosphere. Negligible at night, currents are the strongest in the late morning and near solstices due to stronger winds and near perihelion due to both stronger winds and higher plasma densities from solar EUV photoionization. Resulting surface magnetic fields of tens of nanotesla and occasionally >100 nT may be expected at the InSight landing site. We expect currents and surface fields to vary significantly with changes in the draped magnetic field caused by Mars' dynamic solar wind environment. ©2019. American Geophysical Union. All Rights Reserved., R. J. L., C. M. F., and L. A. were funded by the NASA MAVEN mission prime contract. M. O. F. was funded by the NASA Insight mission prime contract. F. G. G. was funded by the Spanish National Research Council (CSIC) under intramural project CSIC 201450E022 and acknowledges financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia-CSIC (SEV-2017-0709). F. F. was funded by the French Centre National De La Recherche Scientifique.

Published
2019
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2. Investigation of Martian Magnetic Topology Response to 2017 September ICME

Author

Christian Mazelle, Tristan Weber, Christina O. Lee, David Brain, Yingjuan Ma, D. L. Mitchell, Xiaohua Fang, Shaosui Xu, Shannon Curry, Janet G. Luhmann, Gina A. DiBraccio, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Martian, 010504 meteorology & atmospheric sciences, Mars, Mars Exploration Program, 01 natural sciences, ICME, Astrobiology, Geophysics, [SDU]Sciences of the Universe [physics], Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Astrophysics::Earth and Planetary Astrophysics, magnetic topology, 010303 astronomy & astrophysics, Geology, Topology (chemistry), 0105 earth and related environmental sciences
Abstract

International audience; Many aspects of the Sun-Mars interaction have been investigated during solar transient events with measurements from multiple spacecrafts and also simulation efforts. Limited discussion has been paid to magnetic topology response to disturbed upstream conditions. The implications of topology changes include, but are not limited to, the pattern of energetic particle precipitation into the Martian atmosphere and the impact on cold ion escape during solar transient events as low-energy ion escape is dependent on magnetic topology. In this study, we investigate the magnetic topology response to the 2017 September interplanetary coronal mass ejection (ICME) event with measurements collected by the Mars Atmospheric and Volatile EvolutioN spacecraft. It is found that the interface between draped interplanetary magnetic field and closed field lines was moved from 800-1400 km in altitude during quiet conditions to 200-400 km after ICME arrived at Mars and then relaxed back to high altitudes again after the event. To gain insight into magnetic topology response on a global scale, we first validate magnetic topology from a time-dependent simulation with a single-fluid multispecies magnetohydrodynamic (MHD) model by comparing magnetic topology determined from Mars Atmospheric and Volatile EvolutioN data, which shows a good agreement. Then we present MHD predictions of global magnetic topology changes during this ICME event. In addition to a deeper interplanetary magnetic field penetration, MHD results suggest more open field lines in response to the ICME event.

Published
2018
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3. The Impact and Solar Wind Proxy of the 2017 September ICME Event at Mars

Author

Gabor Toth, Jasper Halekas, James P. McFadden, Xiaohua Fang, Shaosui Xu, Christina O. Lee, Christopher T. Russell, David L. Mitchell, Jared Espley, Andrew F. Nagy, Chuanfei Dong, Yingjuan Ma, Bruce M. Jakosky, and Janet G. Luhmann

Subjects
Solar wind, Geophysics, 010504 meteorology & atmospheric sciences, Meteorology, 0103 physical sciences, General Earth and Planetary Sciences, Environmental science, Mars Exploration Program, 010303 astronomy & astrophysics, 01 natural sciences, Proxy (climate), 0105 earth and related environmental sciences
Published
2018
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4. The Twisted Configuration of the Martian Magnetotail: MAVEN Observations

Author

Shaosui Xu, Gina A. DiBraccio, Jasper Halekas, Yuki Harada, David Brain, Shannon Curry, Chuanfei Dong, Bruce M. Jakosky, Suranga Ruhunusiri, Y. I. J. Soobiah, David L. Mitchell, Jacob Gruesbeck, Jared Espley, Takuya Hara, Janet G. Luhmann, Yingjuan Ma, and John E. P. Connerney

Subjects
Physics, Martian, 010504 meteorology & atmospheric sciences, Field line, Ecliptic, Magnetic reconnection, Mars Exploration Program, Atmosphere of Mars, Astrophysics, 01 natural sciences, Current sheet, Geophysics, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Astrophysics::Earth and Planetary Astrophysics, Interplanetary magnetic field, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract

Measurements provided by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft are analyzed to investigate the Martian magnetotail configuration as a function of interplanetary magnetic field (IMF) BY. We find that the magnetotail lobes exhibit a ~45deg twist, either clockwise or counterclockwise from the ecliptic plane, up to a few Mars radii downstream. Moreover, the associated cross-tail current sheet is rotated away from the expected location for a Venus-like induced magnetotail based on nominal IMF draping. Data-model comparisons using magnetohydrodynamic simulations are in good agreement with the observed tail twist. Model field line tracings indicate that a majority of the twisted tail lobes are composed of open field lines, surrounded by draped IMF. We infer that dayside magnetic reconnection between the crustal fields and draped IMF creates these open fields and may be responsible for the twisted tail configuration, similar to what is observed at Earth.

Published
2018
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5. Reconnection in the Martian Magnetotail: Hall‐ <scp>MHD</scp> With Embedded Particle‐in‐Cell Simulations

Author

Yuki Harada, Bruce M. Jakosky, Robert Lillis, Yuxi Chen, Yingjuan Ma, Ivy Bo Peng, Jasper Halekas, Gina A. DiBraccio, John E. P. Connerney, Christopher T. Russell, Stefano Markidis, Xiaohua Fang, Jared Espley, Andrew F. Nagy, James P. McFadden, and Gabor Toth

Subjects
Physics, Martian, 010504 meteorology & atmospheric sciences, Magnetic reconnection, Atmosphere of Mars, Plasma, 01 natural sciences, Astrobiology, Geophysics, Physics::Plasma Physics, Space and Planetary Science, Physics::Space Physics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Particle-in-cell, Magnetohydrodynamics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

Mars Atmosphere and Volatile EvolutioN (MAVEN) mission observations show clear evidence of the occurrence of the magnetic reconnection process in the Martian plasma tail. In this study, we use soph ...

Published
2018
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6. The Morphology of the Solar Wind Magnetic Field Draping on the Dayside of Mars and Its Variability

Author

Yingjuan Ma, Christina O. Lee, Xiaohua Fang, Yaxue Dong, David Brain, Chuanfei Dong, Bruce M. Jakosky, Dana M. Hurley, and Janet G. Luhmann

Subjects
Morphology (linguistics), 010504 meteorology & atmospheric sciences, Geophysics, Mars Exploration Program, 01 natural sciences, Magnetic field, Solar wind, Magnetosheath, 0103 physical sciences, General Earth and Planetary Sciences, Bow shock (aerodynamics), 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Published
2018
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7. The Mars crustal magnetic field control of plasma boundary locations and atmospheric loss: MHD prediction and comparison with MAVEN

Author

Bruce M. Jakosky, Robert Lillis, Yingjuan Ma, Xiaohua Fang, Jasper Halekas, K. Masunaga, Yaxue Dong, Chuanfei Dong, John E. P. Connerney, Joseph M. Grebowsky, and David Brain

Subjects
Physics, 010504 meteorology & atmospheric sciences, Atmosphere of Mars, Geophysics, Mars Exploration Program, Bow shocks in astrophysics, 01 natural sciences, Solar wind, Space and Planetary Science, Physics::Space Physics, 0103 physical sciences, Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Interplanetary magnetic field, Magnetohydrodynamics, 010303 astronomy & astrophysics, Magnetosphere particle motion, 0105 earth and related environmental sciences
Abstract

We present results from a global Mars time-dependent MHD simulation under constant solar wind and solar radiation impact considering inherent magnetic field variations due to continuous planetary rotation. We calculate the 3-D shapes and locations of the bow shock (BS) and the induced magnetospheric boundary (IMB) and then examine their dynamic changes with time. We develop a physics-based, empirical algorithm to effectively summarize the multidimensional crustal field distribution. It is found that by organizing the model results using this new approach, the Mars crustal field shows a clear, significant influence on both the IMB and the BS. Specifically, quantitative relationships have been established between the field distribution and the mean boundary distances and the cross-section areas in the terminator plane for both of the boundaries. The model-predicted relationships are further verified by the observations from the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. Our analysis shows that the boundaries are collectively affected by the global crustal field distribution, which, however, cannot be simply parameterized by a local parameter like the widely used subsolar longitude. Our calculations show that the variability of the intrinsic crustal field distribution in Mars-centered Solar Orbital itself may account for approx.60% of the variation in total atmospheric loss, when external drivers are static. It is found that the crustal field has not only a shielding effect for atmospheric loss but also an escape-fostering effect by positively affecting the transterminator ion flow cross-section area.

Published
2017
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8. Planetary magnetic field control of ion escape from weakly magnetized planets

Author

David Brain, Hilary Egan, Riku Jarvinen, Yingjuan Ma, University of Colorado Boulder, Tuija Pulkkinen Group, University of California, Department of Electronics and Nanoengineering, Aalto-yliopisto, and Aalto University

Subjects
010504 meteorology & atmospheric sciences, Magnetosphere, FOS: Physical sciences, Plasmasphere, 01 natural sciences, magnetic fields [planets and satellites], Planet, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Atmospheric escape, Astronomy and Astrophysics, numerical [methods], Plasma, atmospheres [planets and satellites], plasmas, Magnetic field, Computational physics, Dipole, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Magnetic dipole, Astrophysics - Earth and Planetary Astrophysics
Abstract

Intrinsic magnetic fields have long been thought to shield planets from atmospheric erosion via stellar winds; however, the influence of the plasma environment on atmospheric escape is complex. Here we study the influence of a weak intrinsic dipolar planetary magnetic field on the plasma environment and subsequent ion escape from a Mars sized planet in a global three-dimensional hybrid simulation. We find that increasing the strength of a planet's magnetic field enhances ion escape until the magnetic dipole's standoff distance reaches the induced magnetosphere boundary. After this point increasing the planetary magnetic field begins to inhibit ion escape. This reflects a balance between shielding of the southern hemisphere from ``misaligned" ion pickup forces and trapping of escaping ions by an equatorial plasmasphere. Thus, the planetary magnetic field associated with the peak ion escape rate is critically dependent on the stellar wind pressure. Where possible we have fit power laws for the variation of fundamental parameters (escape rate, escape power, polar cap opening angle and effective interaction area) with magnetic field, and assessed upper and lower limits for the relationships., Comment: Accepted to MNRAS. 17 pages, 10 figures

Published
2019

9. Mars Upper Atmospheric Responses to the 10 September 2017 Solar Flare: A Global, Time-Dependent Simulation

Author

Wenbin Wang, Bruce M. Jakosky, David Pawlowski, Yaxue Dong, Xiaohua Fang, Paul R. Mahaffy, Phillip C. Chamberlin, Chuanfei Dong, Stephen W. Bougher, Francis G. Eparvier, Mehdi Benna, Edward Thiemann, Meredith Elrod, Christina O. Lee, and Yingjuan Ma

Subjects
010504 meteorology & atmospheric sciences, Solar flare, Irradiance, Atmosphere of Mars, Mars Exploration Program, 010502 geochemistry & geophysics, Atmospheric sciences, 01 natural sciences, Article, law.invention, Atmosphere, Geophysics, Altitude, law, Physics::Space Physics, Meteorology & Atmospheric Sciences, General Earth and Planetary Sciences, Environmental science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Flare
Abstract

We report the first global, time-dependent simulation of the Mars upper atmospheric responses to a realistic solar flare event, an X8.2 eruption on 10 September 2017. The Mars Global Ionosphere-Thermosphere Model runs with realistically specified flare irradiance, giving results in reasonably good agreement with the Mars Atmosphere and Volatile EvolutioN spacecraft measurements. It is found that the ionized and neutral regimes of the upper atmosphere are significantly disturbed by the flare but react differently. The ionospheric electron density enhancement is concentrated below ~110-km altitude due to enhanced solar X-rays, closely following the time evolution of the flare. The neutral atmospheric perturbation increases with altitude and is important above ~150-km altitude, in association with atmospheric upwelling driven by solar extreme ultraviolet heating. It takes ~2.5 hr past the flare peak to reach the maximum disturbance and then additional ~10 hr to generally settle down to preflare levels.

Published
2019

10. Pressure and ion composition boundaries at Mars

Author

Michael W. Liemohn, Shaosui Xu, Chuanfei Dong, Yingjuan Ma, David L. Mitchell, and Stephen W. Bougher

Subjects
Geophysics, 010504 meteorology & atmospheric sciences, Space and Planetary Science, 0103 physical sciences, Boundary (topology), Mars Exploration Program, Composition (combinatorics), 010303 astronomy & astrophysics, 01 natural sciences, Geology, 0105 earth and related environmental sciences, Ion
Published
2016
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11. Modeling Martian Atmospheric Losses over Time: Implications for Exoplanetary Climate Evolution and Habitability

Author

David Brain, Valeriy Tenishev, Manasvi Lingam, Yingjuan Ma, Yuni Lee, Janet Luhmann, Bruce M. Jakosky, Xiaohua Fang, D. L. Mitchell, Shannon Curry, Stephen W. Bougher, Andrew F. Nagy, Gabor Toth, and Chuanfei Dong

Subjects
010504 meteorology & atmospheric sciences, FOS: Physical sciences, Context (language use), 01 natural sciences, Astrobiology, Ion, Physics - Space Physics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Martian, Astronomy and Astrophysics, Mars Exploration Program, Space Physics (physics.space-ph), Exoplanet, Solar wind, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Order of magnitude, Astrophysics - Earth and Planetary Astrophysics
Abstract

In this Letter, we make use of sophisticated 3D numerical simulations to assess the extent of atmospheric ion and photochemical losses from Mars over time. We demonstrate that the atmospheric ion escape rates were significantly higher (by more than two orders of magnitude) in the past at $\sim 4$ Ga compared to the present-day value owing to the stronger solar wind and higher ultraviolet fluxes from the young Sun. We found that the photochemical loss of atomic hot oxygen dominates over the total ion loss at the current epoch whilst the atmospheric ion loss is likely much more important at ancient times. We briefly discuss the ensuing implications of high atmospheric ion escape rates in the context of ancient Mars, and exoplanets with similar atmospheric compositions around young solar-type stars and M-dwarfs., 6 pages, 4 figures, 1 table, accepted for publication in ApJ Letters

Published
2018

12. Comparison of Global Martian Plasma Models in the Context of MAVEN Observations

Author

Hilary Egan, James P. McFadden, David Brain, Ronan Modolo, Riku Jarvinen, Bruce M. Jakosky, John E. P. Connerney, Yingjuan Ma, Jasper Halekas, Chuanfei Dong, Stephen W. Bougher, David L. Mitchell, University of Colorado [Boulder], University of California [Los Angeles] (UCLA), University of California, Princeton University, HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Finnish Meteorological Institute (FMI), Department of Electronics and Nanoengineering [Espoo], School of Electrical Engineering [Aalto Univ], Aalto University-Aalto University, Department of Climate and Space Sciences and Engineering (CLaSP), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Department of Physics and Astronomy [Ames, Iowa], Iowa State University (ISU), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, NASA Goddard Space Flight Center (GSFC), University of Colorado Boulder, University of California Los Angeles, Université Paris-Saclay, Department of Electronics and Nanoengineering, University of Michigan, Ann Arbor, University of Iowa, University of California Berkeley, NASA Goddard Space Flight Center, Aalto-yliopisto, and Aalto University

Subjects
Martian, ta115, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Observable, Context (language use), Atmosphere of Mars, Geophysics, 01 natural sciences, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], Atmosphere, Solar wind, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Physics::Space Physics, Orbit (dynamics), Environmental science, Astrophysics::Earth and Planetary Astrophysics, Magnetohydrodynamics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

International audience; Global models of the interaction of the solar wind with the Martian upper atmosphere have proved to be valuable tools for investigating both the escape to space of the Martian atmosphere and the physical processes controlling this complex interaction. The many models currently in use employ different physical assumptions, but it can be difficult to directly compare the effectiveness of the models since they are rarely run for the same input conditions. Here we present the results of a model comparison activity, where five global models (single‐fluid MHD, multi‐fluid MHD, multi‐fluid electron pressure MHD, and two hybrid models) were run for identical conditions corresponding to a single orbit of observations from the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft.We find that low altitude ion densities are very similar across all models, and are comparable to MAVEN ion density measurements from periapsis. Plasma boundaries appear generally symmetric in all models and vary only slightly in extent. Despite these similarities there are clear morphological differences in ion behavior in other regions such as the tail and southern hemisphere. These differences are observable in ion escape loss maps, and are necessary to understand in order to accurately use models in aiding our understanding of the martian plasma environment.

Published
2018
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13. Solar wind interaction with the Martian upper atmosphere: Roles of the cold thermosphere and hot oxygen corona

Author

Valeriy Tenishev, David Pawlowski, Xiaohua Fang, Jasper Halekas, Stephen W. Bougher, Yingjuan Ma, Janet Luhmann, Andrew F. Nagy, Yuni Lee, Michael W. Liemohn, Michael R. Combi, Chuanfei Dong, and Gabor Toth

Subjects
Martian, Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Mars Exploration Program, 01 natural sciences, Corona, Space Physics (physics.space-ph), Computational physics, Physics::Geophysics, Atmosphere, Solar wind, Geophysics, Physics - Space Physics, Space and Planetary Science, 0103 physical sciences, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Thermosphere, 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences, Exosphere
Abstract

We study roles of the thermosphere and exosphere on the Martian ionospheric structure and ion escape rates in the process of the solar wind-Mars interaction. We employ a four-species multifluid MHD (MF-MHD) model to simulate the Martian ionosphere and magnetosphere. The $cold$ thermosphere background is taken from the Mars Global Ionosphere Thermosphere Model (M-GITM) and the $hot$ oxygen exosphere is adopted from the Mars exosphere Monte Carlo model - Adaptive Mesh Particle Simulator (AMPS). A total of four cases with the combination of 1D (globally averaged) and 3D thermospheres and exospheres are studied. The ion escape rates calculated by adopting 1D and 3D atmospheres are similar; however, the latter are required to adequately reproduce MAVEN ionospheric observations. In addition, our simulations show that the 3D hot oxygen corona plays an important role in preventing planetary molecular ions (O$_2^+$ and CO$_2^+$) escaping from Mars, mainly resulting from the mass loading of the high-altitude exospheric O$^+$ ions. The $cold$ thermospheric oxygen atom, however, is demonstrated to be the primary neutral source for O$^+$ ion escape during the relatively weak solar cycle 24., Comment: 21 pages, 10 figures, 4 tables, accepted for publication in Journal of Geophysical Research-Space Physics

Published
2018
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14. Loss of the Martian atmosphere to space: Present-day loss rates determined from MAVEN observations and integrated loss through time

Author

Phillip C. Chamberlin, Jane L. Fox, Jared Espley, Andrew F. Nagy, Daniel Lo, Yuki Harada, Ali Rahmati, Casey L. Flynn, Valeriy Tenishev, Shotaro Sakai, Shannon Curry, Shaosui Xu, Franck Montmessin, Jean-Yves Chaufray, Tristan Weber, Anna Kotova, Michael Mendillo, Christy Lentz, David Brain, Kyle Connour, J. P. McFadden, Nicholas M. Schneider, Roger V. Yelle, Christina O. Lee, Bruce M. Jakosky, F. J. Crary, Matthew Fillingim, Arnaud Stiepen, Michael R. Combi, W. K. Peterson, Thomas E. Cravens, Joseph M. Grebowsky, Jared Bell, Kaori Terada, Anders Eriksson, K. Roeten, Jeffrey Trovato, Frank Eparvier, Zachary Girazian, S. Inui, P. Dunn, Paul Withers, Majd Mayyasi, Scott L. England, Yaxue Dong, Meredith Elrod, Edward Thiemann, David E. Siskind, Paul R. Mahaffy, Robert H. Tolson, François Leblanc, Gina A. DiBraccio, David L. Mitchell, David Andrews, Kirk Olsen, Ronan Modolo, K. Fallows, Dolon Bhattacharyya, Marissa F. Vogt, Masaki Fujimoto, Michael Chaffin, S. Houston, Nicolas André, Mehdi Benna, Chuanfei Dong, Kyle Crabb, Naoki Terada, J. R. Gruesbeck, Takeshi Kuroda, Yingjuan Ma, Yuni Lee, Alexander S. Medvedev, Robert Lillis, Glyn Collinson, Hiromu Nakagawa, Christopher M. Fowler, K. G. Hanley, Richard W. Zurek, R. M. Dewey, Hilary Egan, Robert E. Ergun, S. R. Shaver, Takuya Hara, Sonal Jain, Suranga Ruhunusiri, Jasper Halekas, Morgane Steckiewicz, S. Stone, Stephen W. Bougher, Jacob Hermann, Janet G. Luhmann, Hannes Groeller, Y. I. J. Soobiah, David Pawlowski, Xiaohua Fang, A. Fogle, Davin Larson, Yosuke Matsumoto, T. M. Esman, R. Jolitz, Darren Baird, Karim Meziane, O. Q. Hamil, Clara Narvaez, William E. McClintock, J. Correira, Gabor Toth, John E. P. Connerney, M. Slipski, Melissa L. Marquette, Christopher T. Russell, Kanako Seki, Matteo Crismani, Michael L. Stevens, Greg Holsclaw, John Clarke, Philippe Garnier, Mika Holmberg, Erdal Yiğit, Ian Stewart, Rafael Lugo, G. T. Delory, Laila Andersson, Justin Deighan, C. F. Bowers, Scott Evans, Zachariah Milby, Norberto Romanelli, R. Sharrar, Franck Lefèvre, Christian Mazelle, Daniel N. Baker, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, NASA Goddard Space Flight Center (GSFC), Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Swedish Institute of Space Physics [Uppsala] (IRF), NASA Johnson Space Center (JSC), NASA, National Institute of Aerospace [Hampton] (NIA), Center for Space Physics [Boston] (CSP), Boston University [Boston] (BU), Department of Climate and Space Sciences and Engineering (CLaSP), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), Communications and Power Industries (CPI), Department of Physics and Astronomy [Lawrence Kansas], University of Kansas [Lawrence] (KU), Princeton University, University of Arizona, Wright State University, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), Department of Physics and Astronomy [Ames, Iowa], Iowa State University (ISU), University of Kansas [Kansas City], The University of Tokyo (UTokyo), National Institute of Information and Communications Technology [Tokyo, Japan] (NICT), PLANETO - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Analytical Mechanics Associates, Inc., University of California [Los Angeles] (UCLA), University of California, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, University of New Brunswick (UNB), Tohoku University [Sendai], Eastern Michigan University, University of Michigan System, Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), Department of Earth and Planetary Science [Tokyo], Graduate School of Science [Tokyo], The University of Tokyo (UTokyo)-The University of Tokyo (UTokyo), Naval Research Laboratory (NRL), Laboratoire de Physique Atmosphérique et Planétaire (LPAP), Université de Liège, Graduate School of Information Sciences [Sendai], Lunar and Planetary Laboratory [Tucson] (LPL), Department of Physics and Astronomy [Fairfax], George Mason University [Fairfax], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), and California Institute of Technology (CALTECH)-NASA

Subjects
010504 meteorology & atmospheric sciences, Solar wind, Extrapolation, Mars, Present day, Atmospheric sciences, Mars climate, 01 natural sciences, Atmosphere, Mars atmosphere, Planet, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Spacecraft, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Astronomy and Astrophysics, Atmosphere of Mars, Mars Exploration Program, 13. Climate action, Space and Planetary Science, Magnetospheres, Environmental science, business
Abstract

International audience; Observations of the Mars upper atmosphere made from the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft have been used to determine the loss rates of gas from the upper atmosphere to space for a complete Mars year (16 Nov 2014 – 3 Oct 2016). Loss rates for H and O are sufficient to remove ∼2-3 kg/s to space. By itself, this loss would be significant over the history of the planet. In addition, loss rates would have been greater early in history due to the enhanced solar EUV and more-active Sun. Integrated loss, based on current processes whose escape rates in the past are adjusted according to expected solar evolution, would have been as much as 0.8 bar CO2 or 23 m global equivalent layer of H2O; these losses are likely to be lower limits due to the nature of the extrapolation of loss rates to the earliest times. Combined with the lack of surface or subsurface reservoirs for CO2 that could hold remnants of an early, thick atmosphere, these results suggest that loss of gas to space has been the dominant process responsible for changing the climate of Mars from an early, warmer environment to the cold, dry one that we see today.

Published
2018
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15. High‐Altitude Closed Magnetic Loops at Mars Observed by MAVEN

Author

Janet G. Luhmann, Tristan Weber, Yingjuan Ma, David Brain, Xiaohua Fang, Gina A. DiBraccio, Shaosui Xu, Takuya Hara, Christian Mazelle, David L. Mitchell, Yuki Harada, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Field line, Mars, MAVEN, superthermal electrons, Electron, cold ion escape, 01 natural sciences, 0103 physical sciences, Mars tail topology, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Geophysics, Atmosphere of Mars, Mars Exploration Program, Computational physics, Magnetic field, Solar wind, [SDU]Sciences of the Universe [physics], Physics::Space Physics, reconnection, General Earth and Planetary Sciences, Astrophysics::Earth and Planetary Astrophysics, Magnetohydrodynamics, Ionosphere
Abstract

International audience; With electron and magnetic field data obtained by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, we have identified closed magnetic field lines, with both foot points embedded in the dayside ionosphere, extending up to 6,200 km altitude into the Martian tail. This topology is deduced from photoelectrons produced in the dayside ionosphere being observed traveling both parallel and antiparallel to the magnetic field. At trapped-zone pitch angles (within a range centered on 90° where electrons magnetically reflect before interacting with the atmosphere), cases with either solar wind electrons or photoelectrons have been found, indicating different formation mechanisms for these closed loops. These large closed loops are present in MHD simulations. The case with field-aligned photoelectrons mixed with solar wind electrons having trapped-zone pitch angles is likely to be associated with reconnection, while the case with photoelectrons at all pitch angles is probably due to closed field lines being pulled tailward by the surrounding plasma flow. By utilizing an algorithm for distinguishing photoelectrons from solar wind electrons in pitch angle-resolved energy spectra, we systematically map the spatial distribution and occurrence rate of these closed magnetic loops over the region sampled by the MAVEN orbit. We find that the occurrence rate ranges from a few percent to a few tens of percent outside of the optical shadow and less than one percent within the shadow. These observations can be used to investigate the general magnetic topology in the tail, which is relevant to cold ion escape, reconnection, and flux ropes.

Published
2017
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16. Is Proxima Centauri b habitable? -- A study of atmospheric loss

Author

Manasvi Lingam, Yingjuan Ma, Ofer Cohen, and Chuanfei Dong

Subjects
Solar System, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Venus, 01 natural sciences, Astrobiology, Atmosphere, Physics - Space Physics, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, biology, Astronomy and Astrophysics, Mars Exploration Program, biology.organism_classification, Space Physics (physics.space-ph), Exoplanet, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, Magnetohydrodynamics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We address the important question of whether the newly discovered exoplanet, Proxima Centauri b (PCb), is capable of retaining an atmosphere over long periods of time. This is done by adapting a sophisticated multi-species MHD model originally developed for Venus and Mars, and computing the ion escape losses from PCb. The results suggest that the ion escape rates are about two orders of magnitude higher than the terrestrial planets of our Solar system if PCb is unmagnetized. In contrast, if the planet does have an intrinsic dipole magnetic field, the rates are lowered for certain values of the stellar wind dynamic pressure, but they are still higher than the observed values for our Solar system's terrestrial planets. These results must be interpreted with due caution, since most of the relevant parameters for PCb remain partly or wholly unknown., 7 pages, 2 figures, accepted for publication in ApJL

Published
2017

17. Martian low-altitude magnetic topology deduced from MAVEN/SWEA observations

Author

Morgane Steckiewicz, Xiaohua Fang, Michael W. Liemohn, Yingjuan Ma, Janet Luhmann, David Brain, Bruce M. Jakosky, Christian Mazelle, Shaosui Xu, John E. P. Connerney, David L. Mitchell, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Field line, Mars, MAVEN, Mars Exploration Program, Atmosphere of Mars, Geophysics, superthermal electrons, Topology, 01 natural sciences, Magnetic field, L-shell, Atmosphere, Solar wind, Space and Planetary Science, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, magnetic topology, Ionosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

International audience; The Mars Atmosphere and Volatile Evolution mission has obtained comprehensive particle and magnetic field measurements. The Solar Wind Electron Analyzer provides electron energy-pitch angle distributions along the spacecraft trajectory that can be used to infer magnetic topology. This study presents pitch angle-resolved electron energy shape parameters that can distinguish photoelectrons from solar wind electrons, which we use to deduce the Martian magnetic topology and connectivity to the dayside ionosphere. Magnetic topology in the Mars environment is mapped in three dimensions for the first time. At low altitudes (

Published
2017
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18. Atmospheric escape from the TRAPPIST-1 planets and implications for habitability

Author

Chuanfei Dong, Yingjuan Ma, Manasvi Lingam, Vladimir Airapetian, Meng Jin, and Bart van der Holst

Subjects
Dwarf star, Outer planets, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Context (language use), 01 natural sciences, Astrobiology, Physics - Space Physics, Planet, Natural satellite habitability, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Multidisciplinary, Atmospheric escape, Planetary surface, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Exoplanet, Space Physics (physics.space-ph), Astrophysics - Solar and Stellar Astrophysics, Physical Sciences, Environmental science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The presence of an atmosphere over sufficiently long timescales is widely perceived as one of the most prominent criteria associated with planetary surface habitability. We address the crucial question as to whether the seven Earth-sized planets transiting the recently discovered ultracool dwarf star TRAPPIST-1 are capable of retaining their atmospheres. To this effect, we carry out numerical simulations to characterize the stellar wind of TRAPPIST-1 and the atmospheric ion escape rates for all the seven planets. We also estimate the escape rates analytically and demonstrate that they are in good agreement with the numerical results. We conclude that the outer planets of the TRAPPIST-1 system are capable of retaining their atmospheres over billion-year timescales. The consequences arising from our results are also explored in the context of abiogenesis, biodiversity, and searches for future exoplanets. In light of the many unknowns and assumptions involved, we recommend that these conclusions must be interpreted with due caution., Comment: 19 pages, 4 figures, 3 tables

Published
2017
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19. The Induced Global Looping Magnetic Field on Mars

Author

Uwe Motschmann, Zhaojin Rong, Jasper Halekas, Yong Wei, Markus Fraenz, Yi Li, Yingjuan Ma, Eduard Dubinin, J. Zhong, Tielong Zhang, Lihui Chai, M. Feyerabend, Weixing Wan, and W. Exner

Subjects
Physics, 010504 meteorology & atmospheric sciences, biology, Field line, Astronomy and Astrophysics, Venus, Mars Exploration Program, Geophysics, Atmosphere of Mars, biology.organism_classification, 01 natural sciences, Solar wind, symbols.namesake, Space and Planetary Science, Physics::Space Physics, 0103 physical sciences, symbols, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Titan (rocket family), Interplanetary spaceflight, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

Magnetic fields inconsistent with draped interplanetary magnetic fields and crustal fields have been observed on Mars. Considering the discovery of a global looping magnetic field around the Venusian magnetotail and the similarities in the solar wind interactions between Mars and Venus, we use Mars Atmosphere and Volatile Evolution observations to investigate the global looping field on Mars and its formation mechanism. It is found that a global looping field also exists on Mars; therefore, this type of global looping field is a common feature of unmagnetized planetary bodies with ionospheres, and therefore should also exist on Titan and near-Sun comets. The comparison of the looping fields on Mars and Venus shows that the looping field is stronger on Mars. Solar wind azimuthal flows around the magnetotail toward the − magnetotail polar region () are observed. We illustrate that the looping field can be formed by bending the draped field lines with these azimuthal flows, and that these azimuthal flows are associated with heavy ion plumes along the + direction that are expected to be stronger on Mars than Venus. The current system associated with the looping field and its possible connection with the nightside ionosphere formations and ion escapes on Mars and Venus are discussed.

Published
2019
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20. MAVEN observations of the response of Mars to an interplanetary coronal mass ejection

Author

Jane L. Fox, Joseph M. Grebowsky, D. Larson, Edward Thiemann, François Leblanc, Ali Rahmati, R. M. Dewey, Justin Deighan, Michael Chaffin, Valeriy Tenishev, Jasper Halekas, P. Dunn, A. F. Nagy, Mehdi Benna, Stephen W. Bougher, Arnaud Stiepen, Michael R. Combi, Yingjuan Ma, Yaxue Dong, Chuanfei Dong, Scott D. Guzewich, Richard W. Zurek, Daniel N. Baker, S. Stone, Roberto Livi, D. Baird, Robert Lillis, W. K. Peterson, D. W. Curtis, Tristan Weber, Scott Evans, R. Tolson, Glyn Collinson, William E. McClintock, K. Fortier, Christina O. Lee, Gregory T. Delory, John Clarke, Ronan Modolo, Janet G. Luhmann, Sonal Jain, T. McEnulty, Xiaohua Fang, Jared Espley, Nicholas M. Schneider, John E. P. Connerney, Laila Andersson, Paul Withers, David Andrews, Majd Mayyasi, Daniel Lo, Marissa F. Vogt, David Brain, Kirk Olsen, Y.-Y. Chaufray, Christopher T. Russell, Anders Eriksson, Bruce M. Jakosky, Meredith Elrod, Yuni Lee, Takuya Hara, Paul Mahaffy, Phillip C. Chamberlin, Michiko Morooka, Frank Eparvier, Thomas E. Cravens, Christopher M. Fowler, Kanako Seki, Robert E. Ergun, Scott L. England, Gina A. DiBraccio, A. I. F. Stewart, D. F. Mitchell, J. P. McFadden, Gregory M. Holsclaw, Yuki Harada, F. J. Crary, Matthew Fillingim, Hannes Gröller, Shannon Curry, Franck Montmessin, Matteo Crismani, D. Toublanc, Franck Lefèvre, Christian Mazelle, J. A. Sauvaud, Thomas N. Woods, Roger V. Yelle, Suranga Ruhunusiri, R. Jolitz, Jared Bell, M. Steckiewicz, Michael L. Stevens, Shotaro Sakai, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], NASA Goddard Space Flight Center (GSFC), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Department of Physics and Astronomy [Ames, Iowa], Iowa State University (ISU), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Climate and Space Sciences and Engineering (CLaSP), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Swedish Institute of Space Physics [Uppsala] (IRF), NASA Johnson Space Center (JSC), NASA, National Institute of Aerospace [Hampton] (NIA), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Center for Space Physics [Boston] (CSP), Boston University [Boston] (BU), Department of Physics and Astronomy [Lawrence Kansas], University of Kansas [Lawrence] (KU), Computational Physics, Inc., Department of Physics [Dayton], Wright State University, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, PLANETO - LATMOS, Department of Astronomy [Boston], Solar-Terrestrial Environment Laboratory [Nagoya] (STEL), Nagoya University, Naval Research Laboratory (NRL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Multidisciplinary, Secondary atmosphere, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Atmosphere of Mars, Mars Exploration Program, 01 natural sciences, Astrobiology, Atmosphere, Solar wind, Magnetosheath, 13. Climate action, 0103 physical sciences, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Bow shock (aerodynamics), Astrophysics::Earth and Planetary Astrophysics, Ionosphere, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences
Abstract

International audience; Coupling between the lower and upper atmosphere, combined with loss of gas from the upper atmosphere to space, likely contributed to the thin, cold, dry atmosphere of modern Mars. To help understand ongoing ion loss to space, the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft made comprehensive measurements of the Mars upper atmosphere, ionosphere, and interactions with the Sun and solar wind during an interplanetary coronal mass ejection impact in March 2015. Responses include changes in the bow shock and magnetosheath, formation of widespread diffuse aurora, and enhancement of pick-up ions. Observations and models both show an enhancement in escape rate of ions to space during the event. Ion loss during solar events early in Mars history may have been a major contributor to the long-term evolution of the Mars atmosphere.

Published
2015
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21. Characterizing Atmospheric Escape from Mars Today and Through Time, with MAVEN

Author

Jane L. Fox, John Clarke, Michael R. Combi, Chuanfei Dong, Robert P. Lin, L. Andersson, David Brain, Thomas E. Cravens, Yung-Ching Wang, Ronan Modolo, Yingjuan Ma, Roger V. Yelle, Bruce M. Jakosky, Xiaohua Fang, Robert Lillis, Janet G. Luhmann, I. Stewart, Shannon Curry, J. M. Grebowsky, Justin Deighan, Yuni Lee, Stephen W. Bougher, François Leblanc, David L. Mitchell, Daniel N. Baker, Andrew F. Nagy, Nicholas M. Schneider, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Dayton], Wright State University, Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), Department of Physics and Astronomy [Lawrence Kansas], University of Kansas [Lawrence] (KU), NASA Goddard Space Flight Center (GSFC), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, University of California [Berkeley], and University of California-University of California

Subjects
Solar System, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, MAVEN, Atmospheric sciences, 01 natural sciences, Astrobiology, Atmosphere, Planet, Models, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Martian, Atmospheric escape, Astronomy and Astrophysics, Mars Exploration Program, Planetary science, Escape, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Environmental science, Astrophysics::Earth and Planetary Astrophysics, Exosphere
Abstract

International audience; Two of the primary goals of the MAVEN mission are to determine how the rate of escape of Martian atmospheric gas to space at the current epoch depends upon solar influences and planetary parameters and to estimate the total mass of atmosphere lost to space over the history of the planet. Along with MAVEN’s suite of nine science instruments, a collection of complementary models of the neutral and plasma environments of Mars’ upper atmosphere and near-space environment are an indispensable part of the MAVEN toolkit, for three primary reasons. First, escaping neutrals will not be directly measured by MAVEN and so neutral escape rates must be derived, via models, from in situ measurements of plasma temperatures and neutral and plasma densities and by remote measurements of the extended exosphere. Second, although escaping ions will be directly measured, all MAVEN measurements are limited in spatial coverage, so global models are needed for intelligent interpolation over spherical surfaces to calculate global escape rates. Third, MAVEN measurements will lead to multidimensional parameterizations of global escape rates for a range of solar and planetary parameters, but further global models informed by MAVEN data will be required to extend these parameterizations to the more extreme conditions that likely prevailed in the early solar system, which is essential for determining total integrated atmospheric loss. We describe these modeling tools and the strategies for using them in concert with MAVEN measurements to greater constrain the history of atmospheric loss on Mars.

Published
2015
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22. Early MAVEN Deep Dip campaign reveals thermosphere and ionosphere variability

Author

J. M. Grebowsky, F. Leblanc, Suranga Ruhunusiri, John E. P. Connerney, Xiaohua Fang, Ronan Modolo, Scott D. Guzewich, Richard W. Zurek, Arnaud Stiepen, Michael R. Combi, Davin Larson, Christopher T. Russell, Anders Eriksson, M. Steckiewicz, Yaxue Dong, Franck Lefèvre, Christian Mazelle, J. A. Sauvaud, P. Dunn, Jane L. Fox, Shotaro Sakai, Chuanfei Dong, Yingjuan Ma, S. W. Bougher, S. Stone, R. Jolitz, Gregory M. Holsclaw, T. McEnulty, William E. McClintock, Kirk Olsen, Yuki Harada, A. F. Nagy, Robert Lillis, Thomas N. Woods, Michael L. Stevens, Sonal Jain, Jasper Halekas, Hannes Gröller, Shannon Curry, Franck Montmessin, D. W. Curtis, Tristan Weber, Kanako Seki, Christina O. Lee, Glyn Collinson, Takuya Hara, Paul Mahaffy, D. Baird, Scott L. England, D. Toublanc, Matteo Crismani, Roger V. Yelle, Gina A. DiBraccio, W. K. Peterson, R. M. Dewey, J. P. McFadden, Jared Bell, F. J. Crary, David Brain, Ali Rahmati, Matthew Fillingim, Janet G. Luhmann, John Clarke, Meredith Elrod, Bruce M. Jakosky, Nicholas M. Schneider, A. I. F. Stewart, Paul Withers, Majd Mayyasi, Thomas E. Cravens, Marissa F. Vogt, Edward Thiemann, Michael Chaffin, Phillip C. Chamberlin, Jean-Yves Chaufray, Daniel N. Baker, G. T. Delory, Laila Andersson, Jared Espley, Justin Deighan, Daniel Lo, Christopher M. Fowler, Valeriy Tenishev, Robert E. Ergun, Roberto Livi, Robert H. Tolson, David L. Mitchell, Scott Evans, Michiko Morooka, K. Fortier, Mehdi Benna, Frank Eparvier, David Andrews, Yuni Lee, Department of Climate and Space Sciences and Engineering (CLaSP), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Department of Physics and Astronomy [Ames, Iowa], Iowa State University (ISU), NASA Goddard Space Flight Center (GSFC), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Swedish Institute of Space Physics [Uppsala] (IRF), NASA Johnson Space Center (JSC), NASA, National Institute of Aerospace [Hampton] (NIA), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [Boston], Boston University [Boston] (BU), Department of Physics and Astronomy [Lawrence Kansas], University of Kansas [Lawrence] (KU), Computational Physics, Inc., Department of Physics [Dayton], Wright State University, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, PLANETO - LATMOS, Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), Solar-Terrestrial Environment Laboratory [Nagoya] (STEL), Nagoya University, Naval Research Laboratory (NRL), University of California [Berkeley], University of California-University of California, Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Martian, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Multidisciplinary, 010504 meteorology & atmospheric sciences, Atmospheric escape, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Atmosphere of Mars, Atmospheric sciences, 01 natural sciences, Physics::Geophysics, Atmosphere, Altitude, 13. Climate action, Extreme ultraviolet, 0103 physical sciences, Physics::Space Physics, Environmental science, Astrophysics::Earth and Planetary Astrophysics, Thermosphere, Ionosphere, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences
Abstract

International audience; 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.

Published
2015
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23. The spatial distribution of planetary ion fluxes near Mars observed by MAVEN

Author

Yaxue Dong, Chuanfei Dong, Jasper Halekas, J. P. McFadden, Yingjuan Ma, Stephen W. Bougher, David Brain, Kanako Seki, Frank Eparvier, Xiaohua Fang, Yuki Harada, Bruce M. Jakosky, Takuya Hara, Shannon Curry, Ronan Modolo, John E. P. Connerney, Robert Lillis, Janet G. Luhmann, K. Fortier, Roberto Livi, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Department of Physics and Astronomy [Ames, Iowa], Iowa State University (ISU), NASA Goddard Space Flight Center (GSFC), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Solar-Terrestrial Environment Laboratory [Nagoya] (STEL), Nagoya University, University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)

Subjects
Convection, Physics, 010504 meteorology & atmospheric sciences, Atmospheric escape, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Northern Hemisphere, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], solar wind interaction, Mars Exploration Program, Atmosphere of Mars, Atmospheric sciences, 01 natural sciences, Astrobiology, Ion, Solar wind, Geophysics, 13. Climate action, Planet, 0103 physical sciences, Physics::Space Physics, General Earth and Planetary Sciences, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, atmospheric escape, 0105 earth and related environmental sciences
Abstract

International audience; We present the results of an initial effort to statistically map the fluxes of planetary ions on a closed surface around Mars. Choosing a spherical shell ~1000 km above the planet, we map both outgoing and incoming ion fluxes (with energies >25 eV) over a 4 month period. The results show net escape of planetary ions behind Mars and strong fluxes of escaping ions from the northern hemisphere with respect to the solar wind convection electric field. Planetary ions also travel toward the planet, and return fluxes are particularly strong in the southern electric field hemisphere. We obtain a lower bound estimate for planetary ion escape of ~3 × 1024 s−1, accounting for the ~10% of ions that return toward the planet and assuming that the ~70% of the surface covered so far is representative of the regions not yet visited by Mars Atmosphere and Volatile EvolutioN (MAVEN).

Published
2015
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24. Statistical studies on Mars atmospheric sputtering by precipitating pickup O+: Preparation for the MAVEN mission

Author

Wing-Huen Ip, François Leblanc, Robert E. Johnson, Yung-Ching Wang, Xiaohua Fang, Yingjuan Ma, Janet G. Luhmann, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Birkbeck College [University of London], Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), University of California [Berkeley], and University of California-University of California

Subjects
Materials science, 010504 meteorology & atmospheric sciences, Field (physics), Spectrometer, Extreme ultraviolet lithography, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Atmosphere of Mars, Mars Exploration Program, Atmospheric sciences, 01 natural sciences, Computational physics, Ion, Geophysics, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Sputtering, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Pickup, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

International audience; With the upcoming MAVEN mission, the role of escape in the evolution of the Martian atmosphere is investigated in more detail. This work builds on our previous modeling of the atmospheric impact of the the pickup O+ sputtering effects for varioussolar wind parameters, solar EUV intensities, and the surface crustal field distributions. Relationships between the incident ions properties and the ejected hot neutral components, often referred to as atmospheric sputtering, are derived for application to proposed MAVEN ion spectrometer measurements of precipitating O+. We show how our simulation results can be used to constrain the sputtering effects under present conditions and to interpolate toward estimates of sputtering efficiencies occurring in earlier epochs. Present-day sputtering under typical circumstance is estimated to be weak, but possibly detectable as an exospheric enhancement. The ultimate goal of estimating the importance of atmospheric sputtering effects on the evolution ofthe Martian atmosphere can be better deduced by the combining MAVEN measurements with models, and the sputtering response relations derived here.

Published
2015
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25. A comparison of global models for the solar wind interaction with Mars

Author

Stas Barabash, Esa Kallio, Hans Nilsson, Janet G. Luhmann, Gérard Chanteur, Sunil Simon, Eduard Dubinin, Michael W. Liemohn, Yingjuan Ma, Ronan Modolo, Xiaohua Fang, Markus Fraenz, David Brain, Kaijun Liu, Naoki Terada, Uwe Motschmann, A. Boesswetter, Stephen A. Ledvina, Helmut Lammer, Mats Holmström, Stephen H. Brecht, Andrew F. Nagy, Erika M. Harnett, Jasper Halekas, Stephen W. Bougher, Hiroyuki Shinagawa, Dana M. Hurley, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Swedish Institute of Space Physics [Uppsala] (IRF), Institut für Theoretische Physik [Braunschweig], Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Finnish Meteorological Institute (FMI), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), National Institute of Information and Communications Technology [Tokyo, Japan] (NICT), Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Institute for Geophysics and Meteorology [Köln] (IGM), University of Cologne, University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS)

Subjects
Martian, Physics, Solar System, 010504 meteorology & atmospheric sciences, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Solar wind, Mars, Astronomy and Astrophysics, Mars Exploration Program, Atmospheric sciences, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, Atmosphere, Pickup Ion, Magnetosheath, Ionospheres, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Magnetohydrodynamics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

International audience; We present initial results from the first community-wide effort to compare global plasma interaction model results for Mars. Seven modeling groups participated in this activity, using MHD, multi-fluid, and hybrid assumptions in their simulations. Moderate solar wind and solar EUV conditions were chosen, and the conditions were implemented in the models and run to steady state. Model output was compared in three ways to determine how pressure was partitioned and conserved in each model, the location and asymmetry of plasma boundaries and pathways for planetary ion escape, and the total escape flux of planetary oxygen ions. The two participating MHD models provided similar results, while the five sets of multi-fluid and hybrid results were different in many ways. All hybrid results, however, showed two main channels for oxygen ion escape (a pickup ion 'plume' in the hemisphere toward which the solar wind convection electric field is directed, and a channel in the opposite hemisphere of the central magnetotail), while the MHD models showed one (a roughly symmetric channel in the central magnetotail). Most models showed a transition from an upstream region dominated by plasma dynamic pressure to a magnetosheath region dominated by thermal pressure to a low altitude region dominated by magnetic pressure. However, calculated escape rates for a single ion species varied by roughly an order of magnitude for similar input conditions, suggesting that the uncertainties in both the current and integrated escape over martian history as determined by models are large. These uncertainties are in addition to those associated with the evolution of the Sun, the martian dynamo, and the early atmosphere, highlighting the challenges we face in constructing Mars' past using models.

Published
2010
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