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1. Responses of the Martian Magnetosphere to Changes in the Solar Wind Velocity and the IMF Orientation

Author

Romanelli, Norberto, Modolo, Ronan, Leblanc, François, Chaufray, Jean-Yves, Martinez, Antoine, Dibraccio, Gina A., Espley, Jared R., Brain, David, Connerney, Jack E. P., Halekas, Jasper S., Mcfadden, J. P., Jakosky, Bruce M., 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), University of Michigan [Ann Arbor], University of Michigan System, NASA Goddard Space Flight Center (GSFC), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], University of Iowa [Iowa City], Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)

Subjects
Ionospheres, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Magnetospheres, Physics::Space Physics, Planets, Astrophysics::Earth and Planetary Astrophysics
Abstract

International audience; The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission is currently probing the very complex and dynamic Martian environment. Despite that main structures resulting from the interaction between the solar wind (SW) and the induced magnetosphere of Mars can be characterized using a steady state picture, time-dependent physical processes play a fudamental role modifying the reponse of such obstacle. These processes are the consequence of temporal variabilities in the internal and/or external electromagnetic fields and plasma properties. In this work we study the effects that changes in the IMF orientation and SW speed and the rotation of the crustal magnetic fields (CF) have on the Martian magnetosphere by means of MAVEN magnetic field and plasma measurements and LATMOS Hybrid Simulations (LatHyS) runs. Firstly, we analyze magnetic field and plasma measurements provided by MAVEN on 23 December 2014 between 06:00 UT and 14:20 UT. During this time interval the spacecraft sampled the Martian magnetosphere twice, with highly similar trajectories. MAVEN measurements suggest that the external conditions remained approximately constant when the spacecraft was inside the magnetosphere for the first time. In contrast, MAVEN observed changes in the IMF orientation before visiting the magnetosphere for the second time. Making use of the LatHyS model, we perform a time-dependent simulation to investigate the global response of the Martian plasma environment to the CF rotation and the change of the background magnetic field orientation, taking into account MAVEN observations to set the external conditions. Simulation results are compared with the MAVEN Magnetometer and Solar Wind Ion Analyzer observations obtained in the Martian magnetosphere and show a good agreement. Based on this agreement, we determine associated recovery timescales of the Martian magnetosphere to such event. Secondly, we perform LatHyS runs to characterize the response of the Martian magnetosphere to changes in the SW speed. Particularly, we investigate associated effects on the SW deflection taking place inside the Martian magnetosheath. Finally, we perform estimations of the total planetary proton and oxygen escape fluxes at different times during these events.

Published
2018

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

Author

Jakosky , Bruce, Brain , David, Chaffin , Michael, Curry , Shannon M., Deighan , Justin, Grebowsky , Joseph, Halekas , Jasper, Leblanc , François, Lillis , Robert, Luhmann , Janet, Andersson , Laila, André , Nicolas, Andrews , David, Baird , Darren, Baker , Daniel, Bell , Jared, Benna , Mehdi, Bhattacharyya , Dolon, Bougher , Stephen, Bowers , Charlie, Chamberlin , Phillip, Chaufray , Jean-Yves, Clarke , John, Collinson , Glyn, Combi , Michael, Connerney , Jack, Connour , Kyle, Correira , J., Crabb , Kyle, Crary , Frank, Cravens , Thomas, Crismani , Matteo, Delory , Greg, Dewey , Ryan, DiBraccio , Gina, Dong , Chuanfei, Dong , Yaxue, Dunn , Patrick, Egan , Hilary, Elrod , Meredith K., England , Scott, Eparvier , Frank, Ergun , Robert, Eriksson , Anders, Esman , Teresa, Espley , Jared, Evans , S., Fallows , Kathryn, Fang , Xiaohua, Fillingim , Matthew, Flynn , C., Fogle , A., Fowler , Christopher M., Fox , Jane L., Fujimoto , Masaki, Garnier , Philippe, Girazian , Zachary, Groeller , Hannes, Gruesbeck , Jacob, Hamil , O., Hanley , K., Hara , Takuya, Harada , Yuki, Hermann , Jacob, Holmberg , Mika, Holsclaw , Greg, Houston , S., Inui , S., Jain , Sonal, Jolitz , Rebecca, Kotova , Anna, Kuroda , Takeshi, Larson , Davin, Lee , Yuni, Lee , C., Lefèvre , Franck, Lentz , Christy, Lo , D., Lugo , Rafael, Ma , Yingjuan, Mahaffy , Paul R., Marquette , Melissa, Matsumoto , Y., Mayyasi , Majd, Mazelle , Christian, Mcclintock , William, McFadden , Jim, Medvedev , A., Mendillo , Michael, Meziane , K., Milby , Zachariah, Mitchell , D., Modolo , Ronan, Montmessin , Franck, Nagy , Andrew, Nakagawa , H., Narvaez , Clara, Olsen , Kirk, Pawlowski , D., Peterson , William, Rahmati , Ali, Roeten , Kali, Romanelli , Norberto, Ruhunusiri , Suranga, Russell , Christopher T., Sakai , Shotaro, Schneider , Nicholas, Seki , K., Sharrar , R., Shaver , S., Siskind , David E., Slipski , Marek, Soobiah , Yasir, Steckiewicz , Morgane, Stevens , Michael, Stewart , Ian, Laboratory for Atmospheric and Space Physics [Boulder] ( LASP ), University of Colorado Boulder [Boulder], Space Sciences Laboratory [Berkeley] ( SSL ), University of California [Berkeley], NASA Goddard Space Flight Center ( GSFC ), Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa], HEPPI - 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 ), Institut de recherche en astrophysique et planétologie ( IRAP ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -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], Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] ( AOSS ), Communications and Power Industries ( CPI ), Department of Physics and Astronomy [Lawrence], University of Kansas [Lawrence] ( KU ), Princeton University, University of Arizona, Wright State University [Dayton], Institute of Space and Astronautical Science ( ISAS ), University of Kansas, Department of Physics and Astronomy [Ames, Iowa], Iowa State University ( ISU ), The University of Tokyo, National Institute of Information and Communications Technology ( NICT ), IMPEC - LATMOS, Analytical Mechanics Associates, Inc., University of California at Los Angeles [Los Angeles] ( UCLA ), Max-Planck-Institut für Sonnensystemforschung ( MPS ), Tohoku University [Sendai], Eastern Michigan University, Institute of Geophysics and Planetary Physics [Los Angeles] ( IGPP ), Department of Earth and Planetary Science [Tokyo], and Naval Research Laboratory ( NRL )

Subjects
Mars atmosphere, [ PHYS.PHYS.PHYS-AO-PH ] Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Atmosphere, Magnetospheres, Solar wind, Mars, Mars climate
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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3. On the origins of magnetic flux ropes in near-Mars magnetotail current sheets

Author

Hara, Takuya, Harada, Yuki, Mitchell, David L., Dibraccio, Gina A., Espley, Jared R., Brain, David A., Halekas, Jasper S., Seki, Kanako, Luhmann, Janet G., Mcfadden, James P., Mazelle, Christian, Jakosky, Bruce M., 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
magnetotail, [SDU]Sciences of the Universe [physics], current sheet, Physics::Space Physics, reconnection, Astrophysics::Solar and Stellar Astrophysics, Mars, MAVEN, Astrophysics::Earth and Planetary Astrophysics, flux rope
Abstract

International audience; We analyze Mars Atmosphere and Volatile EvolutioN (MAVEN) observations of magnetic flux ropes embedded in Martian magnetotail current sheets, in order to evaluate the role of magnetotail reconnection in their generations. We conduct a minimum variance analysis to infer the generation processes of magnetotail flux ropes from the geometrical configuration of the individual flux rope axial orientation with respect to the overall current sheet. Of 23 flux ropes detected in current sheets in the near-Mars (∼1-3 Martian radii downstream) magnetotail, only 3 (possibly 4) can be explained by the magnetotail reconnection scenario, while the vast majority of the events (19 events) are more consistent with flux ropes that are originally generated in the dayside ionosphere and subsequently transported into the nightside magnetotail. The mixed origins of the detected flux ropes imply complex nature of generation and transport of Martian magnetotail flux ropes.

Published
2017
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4. Statistical Study of Relations Between the Induced Magnetosphere, Ion Composition, and Pressure Balance Boundaries Around Mars Based On MAVEN Observations

Author

Matsunaga, Kazunari, Seki, Kanako, Brain, David A., Hara, Takuya, Masunaga, Kei, Mcfadden, James P., Halekas, Jasper S., Mitchell, David L., Mazelle, Christian, Espley, J. R., Gruesbeck, Jacob, Jakosky, Bruce M., 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
induced magnetosphere boundary, [SDU]Sciences of the Universe [physics], ion composition boundary, Mars, MAVEN, pressure balance boundary
Abstract

International audience; Direct interaction between the solar wind (SW) and the Martian upper atmosphere forms a characteristic region, called the induced magnetosphere between the magnetosheath and the ionosphere. Since the SW deceleration due to increasing mass loading by heavy ions plays an important role in the induced magnetosphere formation, the ion composition is also expected to change around the induced magnetosphere boundary (IMB). Here we report on relations of the IMB, the ion composition boundary (ICB), and the pressure balance boundary based on a statistical analysis of about 8 months of simultaneous ion, electron, and magnetic field observations by Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. We chose the period when MAVEN observed the SW directly near its apoapsis to investigate their dependence on SW parameters. Results show that IMBs almost coincide with ICBs on the dayside and locations of all three boundaries are affected by the SW dynamic pressure. A remarkable feature is that all boundaries tend to locate at higher altitudes in the southern hemisphere than in the northern hemisphere on the nightside. This clear geographical asymmetry is permanently seen regardless of locations of the strong crustal B fields in the southern hemisphere, while the boundary locations become higher when the crustal B fields locate on the dayside. On the nightside, IMBs usually locate at higher altitude than ICBs. However, ICBs are likely to be located above IMBs in the nightside, southern, and downward ESW hemisphere when the strong crustal B fields locate on the dayside.

Published
2017
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5. MAVEN observations of a giant ionospheric flux rope near Mars resulting from interaction between the crustal and interplanetary draped magnetic fields

Author

Brain, David A., Mitchell, David L., Luhmann, Janet G., Mcfadden, James P., Halekas, Jasper S., Espley, Jared R., Harada, Yuki, Livi, Roberto, DiBraccio, Gina A., Connerney, John E. P., Mazelle, Christian, Andersson, Laila, Jakosky, Bruce M., Hara, Takuya, Seki, Kanako, Hasegawa, Hiroshi, 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), and Université de Toulouse (UT)

Subjects
010504 meteorology & atmospheric sciences, Flux, Mars, MAVEN, ionosphere, 01 natural sciences, flux rope, Physics::Geophysics, ICME, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Grad-Shafranov equation, Pitch angle, Interplanetary magnetic field, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Martian, Physics, Mars Exploration Program, Atmosphere of Mars, Geophysics, Magnetic flux, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Interplanetary spaceflight
Abstract

著者人数: 16名, Accepted: 2016-12-07, 資料番号: SA1160336000

Published
2017
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6. MAVEN observations of atmospheric loss at Mars

Author

Curry, Shannon, Luhmann, Janet, Jakosky, Bruce M., Brain, David, Leblanc, Francis, Modolo, Ronan, Halekas, Jasper S., Schneider, Nicholas M., Deighan, Justin, Mcfadden, James, Espley, Jared R., Mitchell, David L., Connerney, J. E. P., Dong, Yaxue, Dong, Chuanfei, Ma, Yingjuan, Cohen, Ofer, Fränz, Markus, Holmström, Mats, Ramstad, Robin, Hara, Takuya, Lillis, Robert J., Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Département de physique et d'astronomie, Université de Moncton, 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 and Astronomy [Iowa City], University of Iowa [Iowa City], NASA Goddard Space Flight Center (GSFC), Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), Swedish Institute of Space Physics [Kiruna] (IRF), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)

Subjects
Physics::Space Physics, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Physics::Atmospheric and Oceanic Physics
Abstract

International audience; The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission has been making observations of the Martian upper atmosphere and its escape to space since November 2014. The subject of atmospheric loss at terrestrial planets is a subject of intense interest not only because of the implications for past and present water reservoirs, but also for its impacts on the habitability of a planet. Atmospheric escape may have been especially effective at Mars, relative to Earth or Venus, due to its smaller size as well as the lack of a global dynamo magnetic field. Not only is the atmosphere less gravitationally bound, but also the lack of global magnetic field allows the impinging solar wind to interact directly with the Martian atmosphere. When the upper atmosphere is exposed to the solar wind, planetary neutrals can be ionized and 'picked up' by the solar wind and swept away.Both neutral and ion escape have played significant roles the long term climate change of Mars, and the MAVEN mission was designed to directly measure both escaping planetary neutrals and ions with high energy, mass, and time resolution. We will present 1.5 years of observations of atmospheric loss at Mars over a variety of solar and solar wind conditions, including extreme space weather events. We will report the average ion escape rate and the spatial distribution of escaping ions as measured by MAVEN and place them in context both with previous measurements of ion loss by other spacecraft (e.g. Phobos 2 and Mars Express) and with estimates of neutral escape rates by MAVEN. We will then report on the measured variability in ion escape rates with different drivers (e.g. solar EUV, solar wind pressure, etc.) and the implications for the total ion escape from Mars over time. Additionally, we will also discuss the implications for atmospheric escape at exoplanets, particularly weakly magnetized planetary bodies orbiting M-dwarfs, and the dominant escape mechanisms that may drive atmospheric erosion in other stellar systems.

Published
2016

7. Plasma acceleration in the Martian magnetotail

Author

Esteban Hernandez, Rosa, Modolo, Ronan, Leblanc, François, Chaufray, Jean-Yves, Curry, Shannon M., Steckiewicz, Morgane, Connerney, John E. P., Mcfadden, James P., Jakosky, Bruce M., Brain, David A., DiBraccio, Gina A., Romanelli, Norberto, Halekas, Jasper S., Mitchell, David L., 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), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, 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), NASA Goddard Space Flight Center (GSFC), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Instituto de Astronomía y Física del Espacio [Buenos Aires] (IAFE), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad de Buenos Aires [Buenos Aires] (UBA), Department of Physics and Astronomy [Ames, Iowa], Iowa State University (ISU), 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
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; Since November 2014, the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft has been collecting data from Mars’s upper atmosphere and induced magnetosphere (Jakosky et al., 2015). Evidences of escaping planetary ions have been reported from earlier missions as Mars-Express (Barabash et al., 2007) and more recently from MAVEN (e.g. Dong et al., 2015, Brain et al., 2015). Our goal is to determine the acceleration mechanism responsible for the energization of planetary ions in the Martian plasma sheet. MAVEN has a full plasma package with a magnetometer and plasma particles instruments, which allow to address the question of plasma particle acceleration.According to Dubinin et al. (2011), the j x B force due to magnetic shear stresses of the draped field lines is expected to play a major role in such energization process. On MAVEN data, we have first identified and characterized current sheet crossings taking place in Mars’ magnetotail and then tested the Walén relation to infer the significance of the j x B force in the particle’s energization. To characterize the plasma sheet crossing we have worked with MAVEN magnetometer (MAG, Connerney et al., SSR, 2015) and mass spectrometer (STATIC, McFadden et al., SSR, 2015) data, focusing on a particular event. We have performed a minimum variance analysis, on the magnetic field observations which allows to characterize the current sheet. We present results of the Walén test and our conclusions on planetary plasma acceleration in the plasma sheet region.

Published
2016

8. Mars-solar wind interaction: LatHyS, an improved parallel 3-D multispecies hybrid model

Author

Modolo, Ronan, Hess, Sebastien, Mancini, Marco, Leblanc, François, Chaufray, Jean-Yves, Brain, David, Leclercq, Ludivine, Esteban Hernandez, Rosa, Chanteur, Gérard, Weill, Philippe, González-Galindo, Francisco, Forget, François, Yagi, Manabu, Mazelle, Christian, 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), ONERA - The French Aerospace Lab [Toulouse], ONERA, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], 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), 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), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), 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)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Tohoku University [Sendai], 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), Agence Nationale de la Recherche (ANR), Centre National d'Etudes Spatiales (CNES), International Space Science Institute (ISSI), European Commission, ANR-09-BLAN-0223,HELIOSARES,Relation Soleil ? Mars: description et analyse des échanges présents et passés entre magnétosphère et atmosphère(2009), European Project: 262863,EC:FP7:SPA,FP7-SPACE-2010-1,IMPEX(2011), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), 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), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), 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), 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), HEPPI - LATMOS, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-École polytechnique (X)-Sorbonne Universités-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Physics::Space Physics, magnetosphere, interaction, Mars, plasma, Simulation
Abstract

International audience In order to better represent Mars-Solar wind interaction, we present an unprecedented model achieving spatial resolution down to 50 km, a so far unexplored resolution for global kinetic models of the Martian ionized environment. Such resolution approaches the ionospheric plasma scale height. In practice, the model is derived from a first version described in Modolo et al. [2005]. An important effort of parallelization has been conducted and is presented here. A better description of the ionosphere was also implemented including ionospheric chemistry, electrical conductivities and a drag force modelling the ion-neutral collisions in the ionosphere. This new version of the code, named LatHyS (Latmos Hybrid Simulation), is here used to characterize the impact of various spatial resolutions on simulation results. In addition, and following a global model challenge effort [Brain et al., 2010], we present the results of simulation run for three cases which allows addressing the effect of the supra-thermal corona and of the solar EUV activity on the magnetospheric plasma boundaries and on the global escape. Simulation results showed that global patterns are relatively similar for the different spatial resolution runs but finest grid runs provide a better representation of the ionosphere and display more details of the planetary plasma dynamic. Simulation results suggest that a significant fraction of escaping O+ ions is originated from below 1200 km altitude.

Published
2016
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9. Proton cyclotron waves occurrence rate upstream from Mars observed by MAVEN: associated variability of the Martian upper atmosphere

Author

Romanelli, Norberto, Mazelle, Christian, Chaufray, Jean-Yves, Meziane, Karim, Shan, Lican, Ruhunusiri, Suranga, Connerney, Jack E. P., Espley, Jared R., Eparvier, Francis, Thiemann, Edward M. B., Halekas, Jasper S., Mitchell, David L., Mcfadden, James P., Brain, David, Jakosky, Bruce M., 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), 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), Physics Department [UNB], University of New Brunswick (UNB), Institute of Geology and Geophysics [Beijing] (IGG), Chinese Academy of Sciences [Beijing] (CAS), Department of Physics and Astronomy [Ames, Iowa], Iowa State University (ISU), NASA Goddard Space Flight Center (GSFC), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), 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), University of California [Berkeley], and University of California-University of California

Subjects
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], H exosphere, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Temporal variability, Mars, EUV flux, PCWs
Abstract

International audience; Measurements provided by the Magnetometer and the Extreme Ultraviolet Monitor (EUVM) onboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft together with atomic H exospheric densities derived from numerical simulations are studied for the time interval from October 2014 up to March 2016. We determine the proton cyclotron waves (PCWs) occurrence rate observed upstream from Mars at different times. We also study the relationship with temporal variabilities of the high altitude Martian hydrogen exosphere and the solar EUV flux reaching the Martian environment. We find that the abundance of PCWs is higher when Mars is close to perihelion, and decreases to lower and approximately constant values after the Martian Northern Spring Equinox. We also conclude that these variabilities cannot be associated with biases in MAVEN's spatial coverage or changes in the background magnetic field orientation. Higher H exospheric densities on the Martian day side are also found when Mars is closer to perihelion, as a result of changes in the thermospheric response to variability in the ultraviolet flux reaching Mars at different orbital distances. A consistent behavior is also observed in the analyzed daily irradiances measured by the MAVEN EUVM. The latter trends point towards an increase in the planetary proton densities upstream from the Martian bow shock near perihelion. These results then suggest a method to indirectly monitor the variability of the H exosphere up to very high altitudes during large time intervals (compared to direct measurements of neutral particles), based on the observed abundance of PCWs.

Published
2016
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10. Two Types of Aurora on Mars as Observed by MAVEN's Imaging UltraViolet Spectrograph

Author

Schneider, Nicholas M., Deighan, Justin, Jain, Sonal K., Stiepen, Arnaud, Larson, Davin, Mitchell, D. L., Lee, Christina O., Lillis, Robert, Brain, David, Mcclintock, William E., Chaffin, Michael Scott, Crismani, Matteo, Holsclaw, Greg M., Jakosky, Bruce M., Mazelle, Christian, Evans, J. Scott, Stewart, A. Ian F., Stevens, M. H., Clarke, John T., Montmessin, Franck, Lefèvre, Franck, Lo, Daniel, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), 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), Computational Physics, Inc., Naval Research Laboratory (NRL), Center for Space Physics [Boston] (CSP), Boston University [Boston] (BU), PLANETO - 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), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, 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
Physics::Space Physics, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics::Earth and Planetary Astrophysics, Physics::Atmospheric and Oceanic Physics, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]
Abstract

International audience; The Imaging UltraViolet Spectrograph (IUVS) on the MAVEN spacecraft has detected two distinct types of auroral emission on Mars. First, we report the discovery of a low altitude, diffuse aurora spanning much of Mars’ northern hemisphere coincident with a solar energetic particle outburst. IUVS observed northerly latitudes during late December 2014, detecting auroral emission in virtually all nightside observations for ~5 days spanning virtually all geographic longitudes. The vertical profile showed emission down to ~70 km altitude (1 microbar), deeper than confirmed at any other planet. The onset and duration of emission coincide with the observed arrival of solar energetic particles up to 200 keV precipitating directly and deeply into the atmosphere. Preliminary modeling of the precipitation, energy deposition and spectral line emission yields good matches to the observations. These observations represent a new class of planetary auroras produced in the Martian middle atmosphere. Given minimal magnetic fields over most of the planet, Mars is likely to exhibit aurora more globally than Earth.Second, we confirm the existence of small patches of discrete aurora near crustal magnetic fields in Mars' southern hemisphere, as observed previously by SPICAM on Mars Express (Bertaux et al., Nature, 435, 790-794 (2005)). IUVS observed southern latitudes in July and August 2015, detecting discrete auroral emission in ~1% of suitable observations. Limb scans resolved both vertically and along-slit indicate this type of auroral emission was patchy on the scale of ~40 km, and located at higher altitudes ~140 km. The higher altitudes imply a lower energy of precipitating particles. The mix of spectral emissions also differed signficiantly from the diffuse aurora, indicating different excitation and quenching processes.We will discuss the observed properties of the aurora and associated charged particle precipitation, as well as the broader implications of this high-energy deposition into Mars' atmopshere.

Published
2015

11. Temporal variability of waves at the proton cyclotron frequency upstream from Mars: Implications for Mars distant hydrogen exosphere

Author

Bertucci, Cesar, Romanelli, Norberto, Chaufray, Jean-Yves, Gomez, Daniel, Mazelle, Christian, Delva, Magda, Modolo, Ronan, Gonzalez-Galindo, Francisco, Brain, David Andrew, Instituto de Astronomía y Física del Espacio [Buenos Aires] (IAFE), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad de Buenos Aires [Buenos Aires] (UBA), Facultad de Ciencias Exactas y Naturales [Buenos Aires] (FCEyN), Universidad de Buenos Aires [Buenos Aires] (UBA), 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), 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), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), University of Colorado [Boulder], 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
EXOSPHERE, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Ciencias Físicas, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, MARS, Mars, purl.org/becyt/ford/1.3 [https], Pick-up, Space Physics (physics.space-ph), Astronomía, purl.org/becyt/ford/1 [https], Physics - Space Physics, Waves, PICK UP, Thermosphere, CIENCIAS NATURALES Y EXACTAS, Exosphere, Hydrogen
Abstract

We report on the temporal variability of the occurrence of waves at the local proton cyclotron frequency upstream from the Martian bow shock from Mars Global Surveyor observations during the first aerobraking and science phasing orbit periods. Observations at high southern latitudes during minimum-to-mean solar activity show that the wave occurrence rate is significantly higher around perihelion southern summer solstice and lower around the same hemisphere's spring and autumn equinoxes. A similar trend is observed in the hydrogen (H) exospheric density profiles over the Martian South Pole obtained from a model including UV thermospheric heating effects. In spite of the complexity in the ion pick-up and plasma wave generation and evolution processes, these results support the idea that variations in the occurrence of waves could be used to study the temporal evolution of the distant Martian H corona and its coupling with the thermosphere at altitudes currently inaccessible to direct measurements., 16 pages, 2 figures, Submitted to Geophysical Research Letters

Published
2013
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