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110 results on '"Ronan Modolo"'

51. On the orbital variability of Ganymede's atmosphere

Author: Ludivine Leclercq, Apurva Oza, T. A. Cassidy, Robert E. Johnson, Carl Schmidt, Jean-Yves Chaufray, François Leblanc, Ronan Modolo, 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), University of Virginia, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], ANR-09-BLAN-0223,HELIOSARES,Relation Soleil ? Mars: description et analyse des échanges présents et passés entre magnétosphère et atmosphère(2009), and University of Virginia [Charlottesville]
Subjects: Rotation period, 010504 meteorology & atmospheric sciences, Terminator (solar), Equator, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, 01 natural sciences, Jovian, Astrobiology, Jupiter, Atmosphere, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy, Astronomy and Astrophysics, Solar wind, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Exosphere
Abstract: Ganymede's atmosphere is produced by radiative interactions with its surface, sourced by the Sun and the Jovian plasma. The sputtered and thermally desorbed molecules are tracked in our Exospheric Global Model (EGM), a 3-D parallelized collisional model. This program was developed to reconstruct the formation of the upper atmosphere/exosphere of planetary bodies interacting with solar photon flux and magnetospheric and/or the solar wind plasmas. Here, we describe the spatial distribution of the H$_2$O and O$_2$ components of Ganymede's atmosphere, and their temporal variability along Ganymede's rotation around Jupiter. In particular, we show that Ganymede's O$_2$ atmosphere is characterized by time scales of the order of Ganymede's rotational period with Jupiter's gravity being a significant driver of the spatial distribution of the heaviest exospheric components. Both the sourcing and the Jovian gravity are needed to explain some of the characteristics of the observed aurora emissions. As an example, the O$_2$ exosphere should peak at the equator with systematic maximum at the dusk equator terminator. The sputtering rate of the H$_2$O exosphere should be maximum on the leading hemisphere because of the shape of the open/close field lines boundary and displays some significant variability with longitude., 14 pages, 9 figures, Accepted to Icarus
Published: 2017

52. Three-dimensional Martian ionosphere model: I. The photochemical ionosphere below 180 km

Author: Sebastien Hess, François Leblanc, Francisco Gonzalez-Galindo, Jean-Yves Chaufray, Gabriella Gilli, M. Yagi, Ronan Modolo, François Forget, and Miguel Lopez-Valverde
Subjects: Martian, 010504 meteorology & atmospheric sciences, Solar zenith angle, Mars Exploration Program, Geophysics, Atmospheric sciences, Photochemistry, 01 natural sciences, Physics::Geophysics, Solar cycle, Mars general circulation model, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Physics::Space Physics, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Solar rotation, Timekeeping on Mars, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract: [1] We describe the Mars ionosphere with unprecedented detail in 3-D, as simulated by a Mars general circulation model (the Laboratoire de Meteorologie Dynamique Mars GCM), and compare it with recent measurements. The model includes a number of recent extensions and improvements. Different simulations for a full Martian year have been performed. The electron density at the main ionospheric peak is shown to vary with the Sun-Mars distance and with the solar variability, both in the long-term (11 year solar cycle) and on shorter temporal scales (solar rotation). The main electronic peak is shown to be located at the same pressure level during all the Martian year. As a consequence, its altitude varies with latitude, local time, and season according to the natural expansions and fluctuations of the neutral atmosphere, in agreement with previous models. The model predicts a nighttime ionosphere due only to photochemistry. The simulated ionosphere close to the evening terminator is in agreement with observations. No effort has been made to explain the patchy ionosphere observed in the deep nightside. We have compared the modeled ionosphere with Mars Global Surveyor and Mars Advanced Radar for Subsurface and Ionosphere Sounding data. The model reproduces the solar zenith angle variability of the electron density and the altitude of the peak, although it underestimates the electron density at the main peak by about 20%. The electron density at the secondary peak is strongly underestimated by the model, probably due to a very crude representation of the X-ray solar flux. This is one of the aspects that needs a revision in future versions of the model.
Published: 2013

53. Extreme densities in Titan's ionosphere during the T85 magnetosheath encounter

Author: David Andrews, Elias Roussos, K. Ågren, Niklas J. T. Edberg, Thomas E. Cravens, Jan-Erik Wahlund, Sarah V. Badman, Philippe Garnier, Ronan Modolo, Hermann Opgenoorth, Cesar Bertucci, Oleg Shebanits, and M. K. Dougherty
Subjects: Physics, 010504 meteorology & atmospheric sciences, Astrophysics, Plasma, Atmospheric sciences, 7. Clean energy, 01 natural sciences, Solar wind, symbols.namesake, Geophysics, Magnetosheath, 13. Climate action, 0103 physical sciences, symbols, Coronal mass ejection, General Earth and Planetary Sciences, Langmuir probe, Ionosphere, Titan (rocket family), 010303 astronomy & astrophysics, Zenith, 0105 earth and related environmental sciences
Abstract: [1] We present Cassini Langmuir probe measurements of the highest electron number densities ever reported from the ionosphere of Titan. The measured density reached 4310 cm−3 during the T85 Titan flyby. This is at least 500 cm−3 higher than ever observed before and at least 50% above the average density for similar solar zenith angles. The peak of the ionospheric density is not reached on this flyby, making the maximum measured density a lower limit. During this flyby, we also report that an impacting coronal mass ejection (CME) leaves Titan in the magnetosheath of Saturn, where it is exposed to shocked solar wind plasma for at least 2 h 45 min. We suggest that the solar wind plasma in the magnetosheath during the CME conditions significantly modifies Titan's ionosphere by an addition of particle impact ionization by precipitating protons.
Published: 2013

54. Nature of the MHD and kinetic scale turbulence in the magnetosheath of Saturn: Cassini observations

Author: Alessandro Retinò, Ronan Modolo, Patrick Canu, Fouad Sahraoui, Adam Masters, Khurom Kiyani, Michele K. Dougherty, Lina Hadid, Laboratoire de Physique des Plasmas (LPP), PSL Research University (PSL)-Sorbonne Université (SU)-Observatoire de Paris, PSL Research University (PSL)-École polytechnique (X)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Universités-Université Paris-Saclay, Centre for Fusion Space and Astrophysics [Coventry] (CFSA), University of Warwick [Coventry], Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Sorbonne Université (SU), Space and Atmospheric Physics Group [London], Blackett Laboratory, Imperial College London-Imperial College London, Japan Aerospace Exploration Agency [Sagamihara] (JAXA), 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), Centre for Fusion, Space and Astrophysics (CFSA), Department of Physics [Coventry], University of Warwick [Coventry]-University of Warwick [Coventry], HELIOS - 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), Institute of Space and Astronautical Science (ISAS), Imperial College London, Science and Technology Facilities Council (STFC), The Royal Society, Science and Technology Facilities Council, and 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)
Subjects: 010504 meteorology & atmospheric sciences, planets and satellites: individual (Saturn), [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], WEAKLY COLLISIONAL PLASMAS, magnetic fields, 7. Clean energy, 01 natural sciences, Magnetosheath, Physics - Space Physics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Saturn, 010303 astronomy & astrophysics, ASTROPHYSICAL GYROKINETICS, ComputingMilieux_MISCELLANEOUS, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Turbulence, Bow shocks in astrophysics, Solar wind, Physical Sciences, Physics::Space Physics, ALFVEN WAVES, Astrophysical plasma, Astrophysics::Earth and Planetary Astrophysics, CLUSTER OBSERVATIONS, BOW SHOCK, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astronomy & Astrophysics, SOLAR-WIND TURBULENCE, 0103 physical sciences, waves, 0105 earth and related environmental sciences, Science & Technology, IDENTIFICATION, Magnetic energy, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], turbulence, Astronomy and Astrophysics, MAGNETIC-FIELD FLUCTUATIONS, plasmas, Space Physics (physics.space-ph), Physics - Plasma Physics, TERRESTRIAL MAGNETOSHEATH, Computational physics, Plasma Physics (physics.plasm-ph), 0201 Astronomical And Space Sciences, 13. Climate action, Space and Planetary Science, Magnetohydrodynamics, DISSIPATION RANGE, Astrophysics - Earth and Planetary Astrophysics
Abstract: Low frequency turbulence in Saturn's magnetosheath is investigated using in-situ measurements of the Cassini spacecraft. Focus is put on the magnetic energy spectra computed in the frequency range $\sim[10^{-4}, 1]$Hz. A set of 42 time intervals in the magnetosheath were analyzed and three main results that contrast with known features of solar wind turbulence are reported: 1) The magnetic energy spectra showed a $\sim f^{-1}$ scaling at MHD scales followed by an $\sim f^{-2.6}$ scaling at the sub-ion scales without forming the so-called inertial range; 2) The magnetic compressibility and the cross-correlation between the parallel component of the magnetic field and density fluctuations $ C(\delta n,\delta B_{||}) $ indicates the dominance of the compressible magnetosonic slow-like modes at MHD scales rather than the Alfv\'en mode; 3) Higher order statistics revealed a monofractal (resp. multifractal) behaviour of the turbulent flow downstream of a quasi-perpendicular (resp. quasi-parallel) shock at the sub-ion scales. Implications of these results on theoretical modeling of space plasma turbulence are discussed.
Published: 2016

55. 3D magnetospheric parallel hybrid multi-grid method applied to planet-plasma interactions

Author: Ludivine Leclercq, Marco Mancini, Ronan Modolo, François Leblanc, Sebastien Hess, 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)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), CNES, ANR-09-BLAN-0223,HELIOSARES,Relation Soleil ? Mars: description et analyse des échanges présents et passés entre magnétosphère et atmosphère(2009), HEPPI - LATMOS, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and 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)
Subjects: Physics, Numerical Analysis, 010504 meteorology & atmospheric sciences, Physics and Astronomy (miscellaneous), [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Applied Mathematics, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mechanics, Plasma, Electron, Grid, 01 natural sciences, Jovian, Computer Science Applications, Ion, Alfvén wave, Computational Mathematics, Distribution function, Planet, Modeling and Simulation, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: International audience; We present a new method to exploit multiple refinement levels within a 3D parallel hybrid model, developed to study planet-plasma interactions. This model is based on the hybrid formalism: ions are kinetically treated whereas electrons are considered as a inertia-less fluid. Generally, ions are represented by numerical particles whose size equals the volume of the cells. Particles that leave a coarse grid subsequently entering a refined region are split into particles whose volume corresponds to the volume of the refined cells. The number of refined particles created from a coarse particle depends on the grid refinement rate. In order to conserve velocity distribution functions and to avoid calculations of average velocities, particles are not coalesced. Moreover, to ensure the constancy of particles' shape function sizes, the hybrid method is adapted to allow refined particles to move within a coarse region. Another innovation of this approach is the method developed to compute grid moments at interfaces between two refinement levels. Indeed, the hybrid method is adapted to accurately account for the special grid structure at the interfaces, avoiding any overlapping grid considerations. Some fundamental test runs were performed to validate our approach (e.g quiet plasma flow, Alfven wave propagation). Lastly, we also show a planetary application of the model, simulating the interaction between Jupiter's moon Ganymede and the Jovian plasma.
Published: 2016

56. Mars exospheric thermal and non-thermal components: Seasonal and local variations

Author: Ronan Modolo, Francisco Gonzalez-Galindo, Manabu Yagi, Sebastien Hess, Jean-Yves Chaufray, François Leblanc, Solar-Terrestrial Environment Laboratory [Nagoya] (STEL), Nagoya University, 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), 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), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, Flux, chemistry.chemical_element, Atmospheric sciences, 7. Clean energy, 01 natural sciences, Oxygen, Planet, Atmospheric Evolution, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Martian, Astronomy and Astrophysics, Scale height, Atmosphere of Mars, Mars Exploration Program, chemistry, 13. Climate action, Space and Planetary Science, Simulation, Exosphere
Abstract: A model of the martian exosphere is built for average solar conditions. A Chamberlain’s approach (Chamberlain, J.W. [1963]. Planet. Space Sci. 11, 901) is used to describe the O, CO, CO 2 , and O 2 thermal exospheric components. The average thermal oxygen density at 300 km in altitude varies by about one order of magnitude with seasons. A Monte-Carlo test particle simulation is also developed in order to estimate the non-thermal oxygen component of the exosphere. The seasonal variation of the non-thermal oxygen average density is much less than the thermal component but displays clear seasonal variations of its spatial distribution. The neutral oxygen atomic escaping flux varies from 2.9 to 5.3 × 10 25 s −1 in good agreement with Valeille et al. (Valeille, A., Combi, M.R., Bougher, S.W., Tenishev, V., Nagy, A.F. [2009a]. J. Geophys. Res. (Planets) 114, 11006; Valeille, A., Tenishev, V., Bougher, S.W., Combi, M.R., Nagy, A.F. [2009b]. J. Geophys. Res. (Planets) 114, 11005). Mars’s oxygen exosphere is thermal below 600 km and non-thermal above 700 km at all seasons. The typical scale height is ∼45 km for thermal O and ∼500 km for the non-thermal oxygen density. The total photoionization rate above 300 km corresponds to a CO 2 + / O + total production ratio between 0.004 and 0.02. When compared to the composition of the escaping flux measured by ASPERA-3/Mars Express, this suggests that ions formed below 300 km should significantly contribute to the escaping ion flux and/or that a significant part of the newly O + ions reimpacts Mars. The simulated oxygen density profile is also compared to the recent observed profile by Alice/Rosetta (Feldman, P.D. et al. [2011]. Icarus 214, 394–399). Although the scale height of our simulated non-thermal oxygen exosphere and the transition from thermal to non-thermal dominated exospheres are slightly higher than suggested by Feldman et al. (Feldman, P.D. et al. [2011]. Icarus 214, 394–399), a good agreement is found when taking into account the uncertainties of Alice/Rosetta observations.
Published: 2012

57. Modeling of Venus, Mars, and Titan

Author: Darci Snowden, Jean-Yves Chaufray, Ronan Modolo, Robert Winglee, Esa Kallio, Finnish Meteorological Institute (FMI), 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), 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), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], European Union (EU), Agence Nationale de la Recherche (ANR), ANR-09-JCJC-0038,CAT,Physico-Chimie organique de l'atmosphère de Titan(2009), ANR-09-BLAN-0223,HELIOSARES,Relation Soleil ? Mars: description et analyse des échanges présents et passés entre magnétosphère et atmosphère(2009), European Project: 228319,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2008-1,EUROPLANET RI(2009), 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), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: Magnetohydrodynamic model, Planetary exospheres, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Monte Carlo method, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, Venus, Planetary magnetospheres, 7. Clean energy, 01 natural sciences, Astrobiology, symbols.namesake, Full kinetic model, Physics::Plasma Physics, Numerical modeling, 0103 physical sciences, Exosphere model, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Martian, Physics, biology, Astronomy and Astrophysics, Mars Exploration Program, biology.organism_classification, Planetary science, Space and Planetary Science, Physics::Space Physics, symbols, Astrophysics::Earth and Planetary Astrophysics, Magnetohydrodynamics, Titan, Titan (rocket family), Hybrid model, Exosphere
Abstract: International audience Increased computer capacity has made it possible to model the global plasma and neutral dynamics near Venus, Mars and Saturn's moon Titan. The plasma interactions at Venus, Mars, and Titan are similar because each possess a substantial atmosphere but lacks a global internally generated magnetic field. In this article three self-consistent plasma models are described: the magnetohydrodynamic (MHD) model, the hybrid model and the fully kinetic plasma model. Chamberlain and Monte Carlo models of the Martian exosphere are also described. In particular, we describe the pros and cons of each model approach. Results from simulations are presented to demonstrate the ability of the models to capture the known plasma and neutral dynamics near the three objects.
Published: 2011

58. Titan's ionosphere in the magnetosheath: Cassini RPWS results during the T32 flyby

Author: Stamatios M. Krimigis, K. Ågren, Ronan Modolo, Nick Sergis, J. H. Waite, M. K. Dougherty, D. A. Gurnett, Lisa Rosenqvist, Mats André, P. Canu, Philippe Garnier, William S. Kurth, Andrew J. Coates, Jan-Erik Wahlund, Centre d'étude spatiale des rayonnements (CESR), 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)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Swedish Institute of Space Physics [Uppsala] (IRF), 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), Office for Space Research and Applications [Athens], Academy of Athens, 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), Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Space and Atmospheric Physics Group [London], Blackett Laboratory, Imperial College London-Imperial College London, Space Science and Engineering Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), 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 Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Magnetosphere, 01 natural sciences, Astrobiology, symbols.namesake, Magnetosheath, Physics::Plasma Physics, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Langmuir probe, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Waves in plasmas, lcsh:QC801-809, Geology, Astronomy and Astrophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, Space and Planetary Science, Physics::Space Physics, symbols, Magnetopause, lcsh:Q, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Titan (rocket family), lcsh:Physics, Radio wave
Abstract: The Cassini mission has provided much information about the Titan environment, with numerous low altitude encounters with the moon being always inside the magnetosphere. The only encounter taking place outside the magnetopause, in the magnetosheath, occurred the 13 June 2007 (T32 flyby). This paper is dedicated to the analysis of the Radio and Plasma Wave investigation data during this specific encounter, in particular with the Langmuir probe, providing a detailed picture of the cold plasma environment and of Titan's ionosphere with these unique plasma conditions. The various pressure terms were also calculated during the flyby. The comparison with the T30 flyby, whose geometry was very similar to the T32 encounter but where Titan was immersed in the kronian magnetosphere, reveals that the evolution of the incident plasma has a significant influence on the structure of the ionosphere, with in particular a change of the exo-ionospheric shape. The electrical conductivities are given along the trajectory of the spacecraft and the discovery of a polar plasma cavity is reported.
Published: 2009

59. Plasma boundary variability at Mars as observed by Mars Global Surveyor and Mars Express

Author: Ronan Modolo, Niklas J. T. Edberg, S. Barabash, Mark Lester, David Brain, Markus Fränz, Stanley W. H. Cowley, Department of Physics and Astronomy [Leicester], University of Leicester, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), 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), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, and Swedish Institute of Space Physics [Kiruna] (IRF)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Flux, 01 natural sciences, Physics::Geophysics, Magnetosheath, Electric field, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Interplanetary magnetic field, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Martian, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Mars Exploration Program, Geophysics, Bow shocks in astrophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, Solar wind, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Physics::Space Physics, lcsh:Q, Astrophysics::Earth and Planetary Astrophysics, lcsh:Physics
Abstract: We have used Mars Express (MEX) and Mars Global Surveyor (MGS) simultaneous and non-simultaneous measurements to study the Martian plasma environment. In particular, we have derived quantitative expressions for the altitude of the terminator bow shock (BS) and magnetic pileup boundary (MPB) as functions of solar wind dynamic pressure, crustal magnetic fields and solar EUV flux. We have also studied the influence of the interplanetary magnetic field (IMF) direction. Through simultaneous two-spacecraft case studies we have shown that the dynamic pressure has a strong influence on the location and shape of these boundaries, which is also confirmed through a large statistical study. A higher dynamic pressure pushes the boundaries downward. The IMF direction has a weaker but still significant influence on both boundaries and causes them to move outward in the hemisphere of locally upward electric field. However, the MPB in the Southern Hemisphere is found to actually move inward when the electric field is directed locally upward. The crustal magnetic fields in the Southern Hemisphere have a strong influence on the MPB and cause it to move to higher altitudes over strong crustal magnetic fields. The influence of the crustal magnetic fields on the BS is more ambiguous since there are few crossings over the strongest crustal fields, but there appears to be at least a small trend of a higher BS for stronger crustal fields. An increased solar EUV flux has been found to cause the BS to move outward and the MPB to move inward.
Published: 2009

60. The electron density of Saturn's magnetosphere

Author: Krishan K. Khurana, Ronan Modolo, Gethyn R. Lewis, Andrew J. Coates, Jan-Erik Wahlund, A. M. Persoon, Anders Eriksson, Donald A. Gurnett, William S. Kurth, Mats André, M. K. Dougherty, Michiko Morooka, Swedish Institute of Space Physics [Uppsala] (IRF), 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], Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), University of California (UC)-University of California (UC), Space and Atmospheric Physics Group [London], Blackett Laboratory, Imperial College London-Imperial College London, and University of California-University of California
Subjects: Rotation period, Atmospheric Science, Electron density, 010504 meteorology & atmospheric sciences, Magnetosphere, Astrophysics, 01 natural sciences, Saturn, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), lcsh:Science, 010303 astronomy & astrophysics, Ring current, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], lcsh:QC801-809, Plasma sheet, Geology, Astronomy and Astrophysics, Geophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, Solar wind, 13. Climate action, Space and Planetary Science, Magnetosphere of Saturn, Physics::Space Physics, lcsh:Q, Astrophysics::Earth and Planetary Astrophysics, lcsh:Physics
Abstract: We have investigated statistically the electron density below 5 cm−3 in the magnetosphere of Saturn (7–80 RS, Saturn radii) using 44 orbits of the floating potential data from the RPWS Langmuir probe (LP) onboard Cassini. The density distribution shows a clear dependence on the distance from the Saturnian rotation axis (√X2+Y2) as well as on the distance from the equatorial plane (|Z|), indicating a disc-like structure. From the characteristics of the density distribution, we have identified three regions: the extension of the plasma disc, the magnetodisc region, and the lobe regions. The plasma disc region is at LL is the radial distance to the equatorial crossing of the dipole magnetic field line, and confined to |Z|RS. The magnetodisc is located beyond L=15, and its density has a large variability. The variability has quasi-periodic characteristics with a periodicity corresponding to the planetary rotation. For Z>15 RS, the magnetospheric density distribution becomes constant in Z. However, the density still varies quasi-periodically with the planetary rotation also in this region. In fact, the quasi-periodic variation has been observed all over the magnetosphere beyond L=15. The region above Z=15 RS is identified as the lobe region. We also found that the magnetosphere can occasionally move latitudinally under the control of the density in the magnetosphere and the solar wind. From the empirical distributions of the electron densities obtained in this study, we have constructed an electron density model of the Saturnian nightside magnetosphere beyond 7 RS. The obtained model can well reproduce the observed density distribution, and can thus be useful for magnetospheric modelling studies.
Published: 2009

61. Simultaneous measurements of Martian plasma boundaries by Rosetta and Mars Express

Author: Raymond Goldstein, Markus Fränz, U. Auster, Anders Eriksson, Mark Lester, Niklas J. T. Edberg, A. Bößwetter, Stanley W. H. Cowley, S. Barabash, Emanuele Cupido, Chris Carr, Jean-Gabriel Trotignon, Karl-Heinz Glassmeier, Ronan Modolo, Ingo Richter, M. Samara, Rickard Lundin, and Holger Nilsson
Subjects: Martian, Physics, Spacecraft, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Flux, Astronomy and Astrophysics, Mars Exploration Program, Bow shocks in astrophysics, Solar wind, Magnetosheath, Space and Planetary Science, Planet, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, business
Abstract: We present the first two-spacecraft near-simultaneous observations of the Martian bow shock (BS), magnetic pileup boundary (MPB) and photo-electron boundary (PEB) obtained by the plasma instruments onboard Rosetta and Mars Express during the Rosetta Mars flyby on February 25, 2007. Our observations are compared with shape models for the BS and MPB derived from previous statistical studies. The MPB is found at its expected position but the BS for this event is found significantly closer to the planet than expected for the rather slow and moderately dense solar wind. Cross-calibration of the density measurements on the two spacecraft gives a density profile through the magnetosheath, indicating an increasing solar wind flux during the Rosetta passage which is consistent with the multiple BS crossings at the Rosetta exit.
Published: 2009

62. TandEM: Titan and Enceladus mission

Author: J. E. Blamont, Tobias Owen, Michael Küppers, Xenophon Moussas, Robert H. Brown, Nicole Schmitz, Sascha Kempf, C. Menor Salvan, T. W. Haltigin, Olivier Grasset, Roger V. Yelle, Wayne H. Pollard, Daniel Gautier, Paul R. Mahaffy, Joe Pitman, Iannis Dandouras, Daphne Stam, John C. Zarnecki, Bruno Sicardy, Georges Durry, Jesús Martínez-Frías, Norbert Krupp, S. Le Mouélic, Matthias Grott, Sébastien Lebonnois, T. Krimigis, Elizabeth P. Turtle, Alain Herique, Linda Spilker, Ralph D. Lorenz, Maria Teresa Capria, M. Combes, John F. Cooper, O. Mousis, Joachim Saur, Wlodek Kofman, J. Bouman, M. Paetzold, Hojatollah Vali, C. Dunford, Sushil K. Atreya, Eric Chassefière, I. de Pater, T. B. McCord, Bruno Bézard, Gabriel Tobie, Catherine D. Neish, M. Ruiz Bermejo, Sergei Pogrebenko, Kim Reh, Athena Coustenis, Ralf Jaumann, Angioletta Coradini, Leonid I. Gurvits, Andrew J. Coates, Tibor S. Balint, H. Hussmann, E. Choi, Ioannis A. Daglis, Edward C. Sittler, Emmanuel Lellouch, Robert A. West, L. Boireau, E.F. Young, Timothy A. Livengood, Cesar Bertucci, Martin G. Tomasko, M. Fujimoto, Ingo Müller-Wodarg, Yves Bénilan, Wing-Huen Ip, Marina Galand, Darrell F. Strobel, Cyril Szopa, Pascal Rannou, D. G. Mitchell, Mark Leese, Véronique Vuitton, P. Annan, Tetsuya Tokano, Caitlin A. Griffith, Conor A. Nixon, Stephen A. Ledvina, Karoly Szego, Andrew Morse, Panayotis Lavvas, Luisa Lara, C. de Bergh, Jonathan I. Lunine, R. A. Gowen, Katrin Stephan, Jianping Li, Glenn S. Orton, Michel Blanc, Esa Kallio, Ronan Modolo, M. Hirtzig, Helmut Lammer, Nicholas Achilleos, D. Nna Mvondo, Frank Sohl, M. Nakamura, Andrew Steele, C. C. Porco, Marcello Fulchignoni, Gordon L. Bjoraker, Olga Prieto-Ballesteros, J. J. López-Moreno, Andrew Dominic Fortes, Rafael Rodrigo, Patrice Coll, Francesca Ferri, François Raulin, Tom Spilker, F. J. Crary, J. H. Waite, Dirk Schulze-Makuch, Thomas E. Cravens, Kevin H. Baines, C. P. McKay, L. Richter, D. Luz, David H. Atkinson, Martin Knapmeyer, Robert E. Johnson, D. Fairbrother, F. M. Flasar, Roland Thissen, Paul N. Romani, Sebastien Rodriguez, Urs Mall, Paul M. Schenk, Franck Hersant, R. Koop, Odile Dutuit, I. Vardavas, T. Kostiuk, Ricardo Amils, Konrad Schwingenschuh, Robert V. Frampton, Fritz M. Neubauer, Jan-Erik Wahlund, L. A. Soderblom, Michele K. Dougherty, Anna Milillo, Frank T. Robb, Bernard Schmitt, Christophe Sotin, Michel Cabane, A. Selig, Bernard Marty, Yves Langevin, Rosaly M. C. Lopes, Emmanuel T. Sarris, E. De Angelis, D. Toublanc, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Space and Atmospheric Physics Group [London], Blackett Laboratory, Imperial College London-Imperial College London, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Joint Institute for VLBI in Europe (JIVE ERIC), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), The Open University [Milton Keynes] (OU), NASA Ames Research Center (ARC), Department of Physics [Athens], National and Kapodistrian University of Athens (NKUA), University of Cologne, Institute for Astronomy [Honolulu], University of Hawai‘i [Mānoa] (UHM), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Swedish Institute of Space Physics [Uppsala] (IRF), Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), Centre National d'Études Spatiales [Toulouse] (CNES), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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 Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Academy of Athens, Observatoire de Paris - Site de Paris (OP), 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), Space Science Institute [Boulder] (SSI), Bombardier Aerospace, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Sensors and Software, University of Idaho [Moscow, USA], SRON Netherlands Institute for Space Research (SRON), 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), Istituto Nazionale di Astrofisica (INAF), University of Kansas [Lawrence] (KU), National Observatory of Athens (NOA), Department of Astronomy [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Service d'aéronomie (SA), 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), Laboratoire de Planétologie de Grenoble (LPG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), McGill University = Université McGill [Montréal, Canada], FORMATION STELLAIRE 2009, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), University of Virginia [Charlottesville], Finnish Meteorological Institute (FMI), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), 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), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), 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), Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics [Beijing] (IAP), Chinese Academy of Sciences [Beijing] (CAS)-Chinese Academy of Sciences [Beijing] (CAS), National Center for Earth and Space Science Education (NCESSE), Observatório Astronómico de Lisboa, Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Bear Fight Center, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Lockheed Martin Space, Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), University of Maryland Biotechnology Institute Baltimore, University of Maryland [Baltimore], Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Democritus University of Thrace (DUTH), Lunar and Planetary Institute [Houston] (LPI), School of Earth and Environmental Sciences [Pullman], Washington State University (WSU), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Universita degli Studi di Padova, National and Kapodistrian University of Athens = University of Athens (NKUA | UoA), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), IMPEC - LATMOS, University of California [Berkeley], University of California-University of California, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), McGill University, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), 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 Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), University of Virginia, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), 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)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - 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)-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), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: Exploration of Saturn, Solar System, Cosmic Vision, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Computer science, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], TandEM, 01 natural sciences, law.invention, Astrobiology, Enceladus, Orbiter, symbols.namesake, law, Saturnian system, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Spacecraft, Tandem, business.industry, Astronomy and Astrophysics, Landing probes, Space and Planetary Science, symbols, Titan, business, Titan (rocket family)
Abstract: 著者人数：156名, Accepted: 2008-05-27, 資料番号: SA1000998000
Published: 2009

63. Asymmetry of plasma fluxes at Mars. ASPERA-3 observations and hybrid simulations

Author: Gérard Chanteur, Eduard Dubinin, Ronan Modolo, J. D. Winningham, Markus Fraenz, Elias Roussos, S. Barabash, Joachim Woch, and Rickard Lundin
Subjects: Martian, Physics, Astrophysics::High Energy Astrophysical Phenomena, Magnetosphere, Astronomy and Astrophysics, Mars Exploration Program, Plasma, Geophysics, Magnetic field, Magnetization, Solar wind, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Interplanetary spaceflight
Abstract: The asymmetry of fluxes of solar wind and planetary ions is studied by using the ASPERA-3 observations onboard the Mars Express spacecraft in February 2004 to March 2006. Due to the small scale of the Martian magnetosphere and its induced origin, the flow pattern near Mars is sensitive to the directions of the interplanetary magnetic and electric ( - V × B ) fields. Asymmetry of the magnetic field draping produces an asymmetry in plasma flows in the plane containing the IMF. The crustal magnetic fields on Mars also influence the flow pattern. Scavenging of planetary ions is less efficient in the regions of strong crustal magnetization and therefore the escape fluxes of planetary ions in the southern hemisphere are smaller. The results of the observations are compared to simulations based on a 3D hybrid model with several ion species.
Published: 2008

64. On magnetospheric electron impact ionisation and dynamics in Titan's ram-side and polar ionosphere – a Cassini case study

Author: Ronan Modolo, Dirk Lummerzheim, J. H. Waite, Roger V. Yelle, Andrew J. Coates, Thomas E. Cravens, P. Canu, Ingo Müller-Wodarg, D. T. Young, Gethyn R. Lewis, Jan-Erik Wahlund, M. K. Dougherty, Marina Galand, K. Ågren, William S. Kurth, Cesar Bertucci, Swedish Institute of Space Physics [Uppsala] (IRF), Geophysical Institute [Fairbanks], University of Alaska [Fairbanks] (UAF), Space and Atmospheric Physics Group [London], Blackett Laboratory, Imperial College London-Imperial College London, Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-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], Department of Physics and Astronomy [Lawrence Kansas], University of Kansas [Lawrence] (KU), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), and Southwest Research Institute [San Antonio] (SwRI)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Magnetosphere, Astrophysics, Electron, 01 natural sciences, 7. Clean energy, Astrobiology, Physics::Geophysics, symbols.namesake, Ionization, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), lcsh:Science, 010303 astronomy & astrophysics, Electron ionization, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], lcsh:QC801-809, Geology, Astronomy and Astrophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, 13. Climate action, Space and Planetary Science, Physics::Space Physics, symbols, Polar, lcsh:Q, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Titan (rocket family), lcsh:Physics, Exosphere
Abstract: We present data from the sixth Cassini flyby of Titan (T5), showing that the magnetosphere of Saturn strongly interacts with the moon's ionosphere and exo-ionosphere. A simple electron ionisation model provides a reasonable agreement with the altitude structure of the ionosphere. Furthermore, we suggest that the dense and cold exo-ionosphere (from the exobase at 1430 km and outward to several Titan radii from the surface) can be explained by magnetospheric forcing and other transport processes whereas exospheric ionisation by impacting low energy electrons seems to play a minor role.
Published: 2007

65. 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

66. 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

67. 3D hybrid simulations of the interaction of a magnetic cloud with a bow shock

Author: Ronan Modolo, Lucile Turc, P. Savoini, Dominique Fontaine, 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), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), 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), 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 Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: Physics, Shock wave, Astrophysics::High Energy Astrophysical Phenomena, Magnetosphere, Geophysics, Computational physics, Foreshock, Shock (mechanics), Magnetosheath, 13. Climate action, Space and Planetary Science, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Physics::Space Physics, Magnetopause, Bow shock (aerodynamics), Magnetic cloud, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract: International audience; In this paper, we investigate the interaction of a magnetic cloud (MC) with a planetary bow shock using hybrid simulations. It is the first time to our knowledge that this interaction is studied using kinetic simulations which include self-consistently both the ion foreshock and the shock wave dynamics. We show that when the shock is in a quasi-perpendicular configuration, the MC's magnetic structure in the magnetosheath remains similar to that in the solar wind, whereas it is strongly altered downstream of a quasi-parallel shock. The latter can result in a reversal of the magnetic field north-south component in some parts of the magnetosheath. We also investigate how the MC affects in turn the outer parts of the planetary environment, i.e., from the foreshock to the magnetopause. We find the following: (i) The decrease of the Alfvén Mach number at the MC's arrival causes an attenuation of the foreshock region because of the weakening of the bow shock. (ii) The foreshock moves along the bow shock's surface, following the rotation of the MC's magnetic field. (iii) Owing to the low plasma beta, asymmetric flows arise inside the magnetosheath, due to the magnetic tension force which accelerates the particles in some parts of the magnetosheath and slows them down in others. (iv) The quasi-parallel region forms a depression in the shock's surface. Other deformations of the magnetopause and the bow shock are also highlighted. All these effects can contribute to significantly modify the solar wind/magnetosphere coupling during MC events.
Published: 2015

68. 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

69. Variability of the hydrogen in the martian upper atmosphere as simulated by a 3D atmosphere–exosphere coupling

Author: Francisco Gonzalez-Galindo, François Leblanc, Miguel Lopez-Valverde, François Forget, Ronan Modolo, Jean-Yves Chaufray, Sebastien Hess, 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), 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), 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), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], 010504 meteorology & atmospheric sciences, Hydrogen, Atmosphere, Northern Hemisphere, chemistry.chemical_element, Mars, Astronomy and Astrophysics, Atmospheric sciences, 01 natural sciences, Corona, Solar cycle, chemistry, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Environmental science, Solstice, Thermosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Exosphere
Abstract: International audience; We present the temporal variability of the atomic and molecular hydrogen density derived from a 3D General Circulation Model describing the Martian atmosphere from the surface to the exobase. A kinetic exospheric model is used to compute the hydrogen density above the exobase. We use these models to study the diurnal and seasonal variations of the hydrogen density and the Jeans escape rate as well as their variations with solar activity, assuming a classic dust scenario. We find that the diurnal variations of the hydrogen density are important with a peak in the dawn region during equinoxes and a peak on the nightside during solstices. These features result from the dynamics of the Martian upper atmosphere. The variations of the atomic hydrogen Jeans escape with seasons and solar activity are in the range 1.3x1025 s-1 – 4.4x1026 s-1. A factor ∼8 is due to the seasonal variations with a maximum during the winter solstice in the northern hemisphere and a minimum during the summer solstice in the northern hemisphere that we attribute to the variation of the Mars-Sun distance. A factor ∼5 is due to the solar cycle with a maximum escape rate at high solar activity. The variations of the molecular hydrogen Jeans escape with seasons and solar activity are in the range 3x1022 s-1 – 6x1024 s-1. A factor ∼10 is due to the seasonal variations with a maximum during the winter solstice in the northern hemisphere and a minimum during the summer solstice in the northern hemisphere. A factor ∼20 is due to the solar cycle with a maximum escape rate at high solar activity. If Jeans escape is the major escape channel for hydrogen, the hydrogen escape is never limited by diffusion. The hydrogen density above 10,000 km presents seasonal and solar cycle variations similar to the Jeans escape rate at all latitudes and local times. This 3D temporal model of the hydrogen thermosphere/exosphere will be useful to interpret future MAVEN observations and the consequences of the hydrogen corona variability on the Martian plasma environment.
Published: 2015

70. Response of Mars O+ pickup ions to the 8 March 2015 ICME: Inferences from MAVEN data-based models

Author: Yuki Harada, Shannon Curry, Yaxue Dong, Janet G. Luhmann, Chuanfei Dong, Jared Espley, Yingjuan J. Ma, James P. McFadden, David Brain, Ronan Modolo, Xiaohua Fang, Bruce M. Jakosky, Takuya Hara, John E. P. Connerney, Jasper Halekas, François Leblanc, Christina O. Lee, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), 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], 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 [Ames, Iowa], Iowa State University (ISU), NASA Goddard Space Flight Center (GSFC), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)
Subjects: Physics, pickup ions, [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], Mars, Mars Exploration Program, Atmosphere of Mars, Astrophysics, precipitation, Kinetic energy, Atmospheric sciences, Plume, ICME, Solar wind, Geophysics, 13. Climate action, General Earth and Planetary Sciences, escape, Magnetohydrodynamics, Test particle, Ejecta
Abstract: International audience; We simulate and compare three phases of the Mars-solar wind interaction with the 8 March interplanetary coronal mass ejection (ICME) event using Mars Atmosphere and Volatile EvolutioN (MAVEN) mission observations in order to derive heavy ion precipitation and escape rates. The MAVEN observations provide the initial conditions for three steady state MHD model cases, which reproduce the observed features in the solar wind density, velocity, and magnetic field seen along the MAVEN orbit. Applying the MHD results to a kinetic test particle model, we simulate global precipitation and escape maps of O+ during the (1) pre-ICME phase, (2) sheath phase, and (3) ejecta phase. We find that the Case 1 had the lowest precipitation and escape rates of 9.5 × 1025 and 4.1 × 1025 s−1, Case 2 had the highest rates of 9.5 × 1025 and 4.1 × 1025 s−1, and Case 3 had rates of 3.2 × 1025 and 1.3 × 1025 s−1, respectively. Additionally, Case 2 produced a high-energy escaping plume >10 keV, which mirrored corresponding STATIC observations.
Published: 2015

71. 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

72. Simulated solar wind plasma interaction with the Martian exosphere: influence of the solar EUV flux on the bow shock and the magnetic pile-up boundary

Author: Ronan Modolo, Gérard Chanteur, Eduard Dubinin, A. P. Matthews, Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, School of Pure and Applied Physics [Durban], and University of KwaZulu-Natal (UKZN)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Photoionization, Atmospheric sciences, 7. Clean energy, 01 natural sciences, Ionization, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, Interplanetary magnetic field, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Physics, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Plasma, lcsh:QC1-999, Computational physics, lcsh:Geophysics. Cosmic physics, Solar wind, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Magnetopause, lcsh:Q, Astrophysics::Earth and Planetary Astrophysics, lcsh:Physics, Exosphere
Abstract: The solar wind plasma interaction with the Martian exosphere is investigated by means of 3-D multi-species hybrid simulations. The influence of the solar EUV flux on the bow shock and the magnetic pile-up boundary is examined by comparing two simulations describing the two extreme states of the solar cycle. The hybrid formalism allows a kinetic description of each ions species and a fluid description of electrons. The ionization processes (photoionization, electron impact and charge exchange) are included self-consistently in the model where the production rate is computed locally, separately for each ionization act and for each neutral species. The results of simulations are in a reasonable agreement with the observations made by Phobos 2 and Mars Global Surveyor spacecraft. The position of the bow shock and the magnetic pile-up boundary is weakly dependent of the solar EUV flux. The motional electric field creates strong asymmetries for the two plasma boundaries.
Published: 2006

73. Influence of the solar EUV flux on the Martian plasma environment

Author: Gérard Chanteur, Eduard Dubinin, Ronan Modolo, A. P. Matthews, Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Aeronomie (MPI Aeronomie), Max-Planck-Gesellschaft, School of Pure and Applied Physics [Durban], and University of KwaZulu-Natal (UKZN)
Subjects: Solar minimum, Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Atmospheric sciences, Solar irradiance, 7. Clean energy, 01 natural sciences, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, Interplanetary magnetic field, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Solar maximum, lcsh:QC1-999, Solar cycle, Computational physics, lcsh:Geophysics. Cosmic physics, Polar wind, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Magnetopause, lcsh:Q, Astrophysics::Earth and Planetary Astrophysics, lcsh:Physics
Abstract: The interaction of the solar wind with the Martian atmosphere and ionosphere is investigated by using three-dimensional, global and multi-species hybrid simulations. In the present work we focus on the influence of the solar EUV flux on the Martian plasma environment by comparing simulations done for conditions representative of the extrema of the solar cycle. The dynamics of four ionic species (H+, He++, O+, O2+), originating either from the solar wind or from the planetary plasma, is treated fully kinetically in the simulation model in order to characterize the distribution of each component of the plasma, both at solar maximum and at solar minimum. The solar EUV flux controls the ionization frequencies of the exospheric species, atomic hydrogen and oxygen, as well as the density, the temperature, and thus the extension of the exosphere. Ionization by photons and by electron impacts, and the main charge exchange reactions are self-consistently included in the simulation model. Simulation results are in reasonable agreement with the observations made by Phobos-2 and Mars Global Surveyor (MGS) spacecraft: 1) the interaction creates a cavity, void of solar wind ions (H+, He++), which depends weakly upon the phase of the solar cycle, 2) the motional electric field of the solar wind flow creates strong asymmetries in the Martian environment, 3) the spatial distribution of the different components of the planetary plasma depends strongly upon the phase of the solar cycle. The fluxes of the escaping planetary ions are computed from the simulated data and results for solar maximum are compared with estimates based on the measurements made by experiments ASPERA and TAUS on board Phobos-2.
Published: 2005

74. Magnetic reconnection at mercury and impacts of solar wind ions on the surface of the planet from global hybrid simulations

Author: Ronan Modolo, François Leblanc, and Gérard Chanteur
Subjects: Physics, Magnetosphere, Magnetic reconnection, Geophysics, Astrobiology, Nanoflares, Solar wind, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Interplanetary magnetic field, Mercury's magnetic field, Magnetosphere of Jupiter
Abstract: Global and three-dimensional hybrid simulations of the ionized environment of Mercury are used to investigate the effect of the quadrupolar component of the intrinsic planetary field on magnetic reconnection with the Interplanetary Magnetic Field (IMF), on the entry of solar wind ions in the Hermean magnetosphere and eventually their impacts on the planetary gound.
Published: 2014

75. Titan's magnetospheric and plasma environment

Author: Jan-Erik Wahlund, Andrew J. Coates, Ronan Modolo, and Cesar Bertucci
Subjects: Physics, symbols.namesake, Planetary science, Plasma sheet, symbols, Magnetopause, Atmosphere of Titan, Ionosphere, Titan (rocket family), Enceladus, Exosphere, Astrobiology
Published: 2014

76. Modelling Ganymede's neutral environment: A 3D test-particle simulation

Author: Ludivine Leclercq, Jean-Yves Chaufray, François Leblanc, Ronan Modolo, Lucile Turc, 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), 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), and 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)
Subjects: Physics, Atmospheres, Satellites, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Plasma sheet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Subsolar point, Astronomy and Astrophysics, Atmospheric sciences, Latitude, Atmosphere, 13. Climate action, Space and Planetary Science, Sputtering, Ganymede, Polar, Sublimation (phase transition), Test particle
Abstract: International audience; In this paper, we present a 3D parallelized test-particle model of Ganymede's neutral environment. The atmosphere sources are assumed to be the sputtering and the sublimation of water-ice, the former taking place in the polar regions and the latter near the subsolar point. It appears that Ganymede's atmosphere is deeply structured by these two processes, leading to a strong dichotomy between polar and subsolar regions. The densest part of the atmosphere is found in the vicinity of the subsolar point, where sublimated H2O is the predominant species near the surface. At higher latitudes and on the nightside, O2 prevails at low altitude, whereas the high altitudes are primarily populated by H2 everywhere in the atmosphere. An estimation of the number of collisions shows that the atmosphere is mostly collisionless, except a small region near the subsolar point. The O2 column density in our model is in good agreement with the observations. However, it appears that we underestimate the H density. This could suggest that the sublimation rates are significantly underestimated but not the sputtering. The escape rates of the different species are essentially lower than those previously obtained by Marconi (2007). The effects of varying surface emission fluxes are investigated in order to simulate Ganymede's passing into the shadow of Jupiter or in the plasma sheet. We estimate that the sublimated H2O peak in the subsolar region would disappear within one hour in the shadow of Jupiter. Likewise, the variation of the sputtering fluxes alters the atmospheric structure in a similar time scale.
Published: 2014

77. Three-dimensional Martian ionosphere model: II. Effect of transport processes due to pressure gradients

Author: François Forget, Jean-Yves Chaufray, Miguel Lopez-Valverde, Ronan Modolo, Olivier Witasse, Pierre-Louis Blelly, F. Gonzalez-Galindo, Sebastien Hess, Manabu Yagi, François Leblanc, 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), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), 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), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut Pierre-Simon-Laplace (IPSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC), Planetary Plasma and Atmospheric Research Center [Sendai] (PPARC), Tohoku University [Sendai], 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), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), 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), 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), and European Space Agency (ESA)
Subjects: Martian, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Mars, Mars Exploration Program, Atmospheric sciences, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Solar cycle, Physics::Geophysics, Dynamics, Atmosphere, Solar wind, Geophysics, Flow velocity, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Physics::Space Physics, Earth and Planetary Sciences (miscellaneous), Environmental science, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Pressure gradient, Physics::Atmospheric and Oceanic Physics
Abstract: International audience; To study the transport of the ionospheric plasma on Mars, we have included a 3D multifluid dynamical core in a Martian General Circulation Model (GCM). Vertical transport modifies the ion density above ~160 km on the dayside, especially the ions produced at high altitudes like O+, N+ and C+. Near the exobase, the dayside to nightside flow velocity reaches few hundreds of m/s, due to a large horizontal pressure gradient. Comparison with MEX/ASPERA-3 measurements between 290 - 500 km, suggests this flow could account for at least 20% of the flow produced by the solar wind. This flow is not sufficient to populate substantially the nightside ionosphere at high altitudes, in agreement with recent observations, because of a strong nightside downward flow produced by vertical pressure gradient. The O2+ and NO+ ion densities on the nightside at low altitudes (~130 km) are modified by this downward flow, compared to simulated densities without ion dynamics, while other ions are lost by chemical reactions. Variability at different time scales (diurnal, seasonal and solar cycle) are studied. We simulate diurnal and seasonal variations of the ionospheric composition due to the variability of the neutral atmosphere and solar flux at the top of the atmosphere. The ionospheric dynamics are not strongly affected by seasons and solar cycles and the retroaction of the ionosphere on the neutral atmosphere temperature and velocity is negligible compared to other physical processes below the exobase.
Published: 2014

78. Outflow and plasma acceleration in Titan's induced magnetotail: Evidence of magnetic tension forces

Author: François Leblanc, Jean-Jacques Berthelier, Andrew J. Coates, D. A. Gurnett, Niklas J. T. Edberg, Jan-Erik Wahlund, Cesar Bertucci, Norberto Romanelli, H. Waite, P. Canu, William S. Kurth, Eduard Dubinin, M. K. Dougherty, Ronan Modolo, 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), 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), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Swedish Institute of Space Physics [Uppsala] (IRF), 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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Southwest Research Institute [San Antonio] (SwRI), Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Space and Atmospheric Physics Group [London], Blackett Laboratory, Imperial College London-Imperial College London, Max-Planck-Institut für Sonnensystemforschung (MPS), and 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)
Subjects: Magnetometer, Ciencias Físicas, Electron, Ionospheric plasma is observed in Titan's wake, 7. Clean energy, law.invention, purl.org/becyt/ford/1 [https], Acceleration, symbols.namesake, law, Physics::Plasma Physics, Physics, Plasma acceleration, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Waves in plasmas, The plasma acceleration is analyzed through Walen tests, purl.org/becyt/ford/1.3 [https], Geophysics, Plasma, This acceleration can be understood in terms of magnetic tension forces, Astronomía, Space and Planetary Science, Physics::Space Physics, symbols, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Atomic physics, Titan (rocket family), Titan, CIENCIAS NATURALES Y EXACTAS
Abstract: Cassini plasma wave and particle observations are combined with magnetometer measurements to study Titan´s induced magnetic tail. In this study, we report and analyze the plasma acceleration in Titan´s induced magnetotail observed in flybys T17, T19, and T40. Radio and Plasma Wave Science observations show regions of cold plasma with electron densities between 0.1 and a few tens of electrons per cubic centimeter. The Cassini Plasma Spectrometer (CAPS)-ion mass spectrometer (IMS) measurements suggest that ionospheric plasma in this region is composed of ions with masses ranging from 15 to 17 amu and from 28 to 31 amu. From these measurements, we determine the bulk velocity of the plasma and the Alfvén velocity in Titan's tail region. Finally, a Walén test of such measurements suggest that the progressive acceleration of the ionospheric plasma shown by CAPS can be interpreted in terms of magnetic tension forces. Fil: Romanelli, Norberto Julio. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina Fil: Modolo, R.. Latmos; Francia Fil: Dubinin, E.. Max Planck Institut; Alemania Fil: Berthelier, J. J.. Latmos; Francia Fil: Bertucci, Cesar. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina Fil: Wahlund, J. E.. Swedish Institute Of Space Physics; Suecia Fil: Leblanc, F.. Latmos; Francia Fil: Canu, P.. Ecole Polytechnique; Francia Fil: Edberg, N. J. T.. Swedish Institute Of Space Physics; Suecia Fil: Waite, H.. Southwest Research Institute; Estados Unidos Fil: Kurth, W. S.. University of Iowa; Estados Unidos Fil: Gurnett, D.. University of Iowa; Estados Unidos Fil: Coates, A.. University College London; Estados Unidos Fil: Dougherty, M.. Imperial College London; Reino Unido
Published: 2014

79. A global hybrid model for Mercury's interaction with the solar wind: Case study of the dipole representation

Author: Gérard Chanteur, François Leblanc, Ronan Modolo, Emilie Richer, and Sebastien Hess
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Field line, Soil Science, Magnetosphere, Aquatic Science, Oceanography, 01 natural sciences, Magnetosheath, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Mercury's magnetic field, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Physics, Ecology, Paleontology, Forestry, Geophysics, Dipole model of the Earth's magnetic field, Computational physics, Magnetic field, Solar wind, Dipole, Space and Planetary Science, Physics::Space Physics
Abstract: The interaction of the solar wind (SW) with the magnetic field of Mercury is investigated by means of a three dimensional parallelized multispecies hybrid model. A comparison between two mathematical representations of Mercury's intrinsic magnetic field is studied. The first model is an Offset Dipole (OD) having the offset and dipolar moment reported by Anderson et al. (2011). The second model is a combination of a Dipole and a Quadrupole (DQ), the total field is fitted to the offset dipolar field, for northern latitudes greater than 50°. Simulations reproduce the features which characterize Mercury's interaction with the SW, encompassing the Bow Shock (BS), the magnetosheath, the magnetotail, the "cusps" region and the neutral current sheet. Global hybrid simulations of the Hermean magnetosphere run for the OD and DQ models demonstrate that the southern parts of the magnetospheres produced by the OD and DQ models differ greatly in topology and volume meanwhile their northern parts-are quite similar. In particular the DQ model exhibits a dome of closed field lines around the south pole in contrast to the OD. Without further information on the intrinsic magnetic field of the planet in the southern region which should be provided by BepiColombo after year 2020, we can only speculate on the influence of the different magnetic topologies on the magnetospheric dynamics.
Published: 2012

80. Reflection of solar wind protons on the Martian bow shock: Investigations by means of 3-dimensional simulations

Author: Eduard Dubinin, Emilie Richer, Gérard Chanteur, and Ronan Modolo
Subjects: Electromagnetic field, Physics, education.field_of_study, 010504 meteorology & atmospheric sciences, Population, Flux, Geophysics, Bow shocks in astrophysics, 01 natural sciences, 010305 fluids & plasmas, Foreshock, Computational physics, Shock (mechanics), Solar wind, Physics::Space Physics, 0103 physical sciences, Reflection (physics), General Earth and Planetary Sciences, education, 0105 earth and related environmental sciences
Abstract: [1] The reflection of solar wind protons on the Martian bow shock (BS) is investigated by means of three-dimensional simulation models. A two steps approach is adopted to allow a detailed analysis of the reflected population. Firstly, the 3-dimensional hybrid model of Modolo et al. (2005) is used to compute a stationary state of the interaction of the solar wind (SW) with Mars. Secondly, the motion of test particles is followed in the electromagnetic field computed by the hybrid simulation meanwhile detection criteria defined to identify reflected protons are applied. This study demonstrates some effects of the large curvature of a planetary BS on the structure of the foreshock. Reflected protons encounter the BS in a region encompassing parts of the quasi-perpendicular and quasi-parallel shocks, and exit the shock mainly from the quasi-parallel region. The energy spectrum of all reflected protons extends from 0 to almost 15keV. A virtual omnidirectional detector (VOD) is used to compute the local omnidirectional flux of reflected protons at various locations upstream of the BS. Spatial variations of this omnidirectional flux indicate the location and spatial extent of the proton foreshock and demonstrate its shift, increasing with the distance downstream, in the direction opposite to the motional electric field of the SW. Local energy spectra computed from the VOD observations demonstrate the existence of an energy gradient along the direction of the convection electric field.
Published: 2012

81. Solar wind charge exchange X-ray emission from Mars

Author: Vasili Kharchenko, Jean-Yves Chaufray, Ronan Modolo, Rosine Lallement, Gérard Chanteur, Dimitra Koutroumpa, 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), 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), University of Connecticut (UCONN), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), and 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)
Subjects: 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Solar wind, planets and satellites: individual: Mars, FOS: Physical sciences, Astrophysics, X-rays: individuals: Mars, 7. Clean energy, 01 natural sciences, Ion, Luminosity, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Martian, Physics, planets and satellites: atmospheres, Energetic neutral atom, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Plasma, Mars Exploration Program, Atomic processes, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], 13. Climate action, Space and Planetary Science, Physics::Space Physics, Halo, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: Aims. We study the soft X-ray emission induced by charge exchange (CX) collisions between solar-wind, highly charged ions and neutral atoms of the Martian exosphere. Methods. A 3D multi species hybrid simulation model with improved spatial resolution (130 km) is used to describe the interaction between the solar wind and the Martian neutrals. We calculated velocity and density distributions of the solar wind plasma in the Martian environment with realistic planetary ions description, using spherically symmetric exospheric H and O profiles. Following that, a 3D test-particle model was developed to compute the X-ray emission produced by CX collisions between neutrals and solar wind minor ions. The model results are compared to XMM-Newton observations of Mars. Results. We calculate projected X-ray emission maps for the XMM-Newton observing conditions and demonstrate how the X-ray emission reflects the Martian electromagnetic structure in accordance with the observed X-ray images. Our maps confirm that X-ray images are a powerful tool for the study of solar wind - planetary interfaces. However, the simulation results reveal several quantitative discrepancies compared to the observations. Typical solar wind and neutral coronae conditions corresponding to the 2003 observation period of Mars cannot reproduce the high luminosity or the corresponding very extended halo observed with XMM-Newton. Potential explanations of these discrepancies are discussed., 10 pages, 5 figures, accepted for publication in Astron. Astrophysics
Published: 2012

82. Upper ionosphere of Mars is not axially symmetrical

Author: Ronan Modolo, Rickard Lundin, D. A. Gurnett, Firdevs Duru, Joachim Woch, Eduard Dubinin, Gérard Chanteur, Markus Fraenz, S. Barabash, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, 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), 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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Swedish Institute of Space Physics [Kiruna] (IRF), Max-Planck-Institut für Sonnensystemforschung (MPS), and 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)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, MARSIS, ionosphere, 01 natural sciences, Physics::Geophysics, crustal magnetization, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Electric field, 0103 physical sciences, Interplanetary magnetic field, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Martian, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Geology, Geophysics, Mars Exploration Program, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Magnetic field, Solar wind, solar wind, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Ionosphere
Abstract: International audience; The measurements carried out by the ASPERA-3 and MARSIS experiments on board the Mars Express (MEX) spacecraft show that the upper Martian ionosphere (h ≥ 400 km) is strongly azimuthally asymmetrical. There are several factors, e.g., the crustal magnetization on Mars and the orientation of the interplanetary magnetic field (IMF) which can give rise to formation of ionospheric swells and valleys. It is shown that expansion of the ionospheric plasma along the magnetic field lines of crustal origin can produce bulges in the plasma density. The absense of a magnetometer on MEX makes the retrieval of an asymmetry caused by the IMF more difficult. However hybrid simulations give a hint that the ionosphere in the hemisphere (E-) to which the motional electric field is pointed occurs more inflated than the ionosphere in the opposite (E+) hemisphere.
Published: 2012

83. Dynamic Martian magnetosphere: Transient twist induced by a rotation of the IMF

Author: Ronan Modolo, Gérard Chanteur, and Eduard Dubinin
Subjects: Physics, 010504 meteorology & atmospheric sciences, Geophysics, Bow shocks in astrophysics, 7. Clean energy, 01 natural sciences, Computational physics, Solar wind, Polar wind, 13. Climate action, Magnetosphere of Saturn, Physics::Space Physics, 0103 physical sciences, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, General Earth and Planetary Sciences, Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Interplanetary magnetic field, Magnetosphere of Jupiter, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: [1] Simulation studies of the Martian environment are usually restricted to stationary situations under various steady conditions of the solar wind and solar radiation. Dynamic transients and their implications have so far attracted little attention although global simulation models can provide valuable insights to understand disagreements between simulations and in situ observations. We make use of a three dimensional multispecies hybrid simulation model to investigate the response of the Martian plasma environment to a sudden rotation of the IMF. The simulation model couples charged and neutral species via three ionisation mechanisms: the absorption of solar extreme ultraviolet radiation, the impact of solar wind electrons, and the charge exchange between ions and neutral atoms. When a rotational discontinuity conveyed by the solar wind reaches the Martian environment the bow shock adapts quickly to the new solar wind conditions in contrast to the induced magnetosphere, especially the magnetic lobes in the wake. Timescales necessary to recover a stationary state can be estimated from such simulations and have some implications for space observations especially in the use of magnetic field proxies and for organizing particle measurements made by a spacecraft like Mars Express without an onboard magnetometer.
Published: 2012

84. Detection of currents and associated electric fields in Titan's ionosphere from Cassini data

Author: Jan-Erik Wahlund, Stanley W. H. Cowley, Niklas J. T. Edberg, L. Rosenqvist, Hermann Opgenoorth, Andrew J. Coates, Ronan Modolo, Michele K. Dougherty, Philippe Garnier, Stephan Buchert, Gethyn R. Lewis, Anne Wellbrock, Gabrielle Provan, D. L. Talboys, David Andrews, and K. Ågren
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Magnetometer, Soil Science, Magnetosphere, Aquatic Science, Oceanography, 01 natural sciences, 7. Clean energy, law.invention, symbols.namesake, Physics::Plasma Physics, Geochemistry and Petrology, law, Electric field, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Physics::Atomic Physics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Physics, Ecology, Spectrometer, Waves in plasmas, Paleontology, Astronomy, Forestry, Geophysics, Plasma, Space and Planetary Science, Physics::Space Physics, symbols, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Titan (rocket family)
Abstract: We present observations from three Cassini flybys of Titan using data from the radio and plasma wave science, magnetometer and plasma spectrometer instruments. We combine magnetic field and cold pl ...
Published: 2011

85. Modeling of Venus, Mars, and Titan

Author: Ronan Modolo, Darci Snowden, Robert Winglee, Jean-Yves Chaufray, and Esa Kallio
Subjects: Martian, Physics, 010504 meteorology & atmospheric sciences, biology, Monte Carlo method, Venus, Mars Exploration Program, Plasma, biology.organism_classification, 7. Clean energy, 01 natural sciences, Astrobiology, symbols.namesake, Physics::Plasma Physics, 13. Climate action, Physics::Space Physics, 0103 physical sciences, symbols, Astrophysics::Earth and Planetary Astrophysics, Magnetohydrodynamics, Titan (rocket family), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Exosphere
Abstract: Increased computer capacity has made it possible to model the global plasma and neutral dynamics near Venus, Mars and Saturn’s moon Titan. The plasma interactions at Venus, Mars, and Titan are similar because each possess a substantial atmosphere but lacks a global internally generated magnetic field. In this article three self-consistent plasma models are described: the magnetohydrodynamic (MHD) model, the hybrid model and the fully kinetic plasma model. Chamberlain and Monte Carlo models of the Martian exosphere are also described. In particular, we describe the pros and cons of each model approach. Results from simulations are presented to demonstrate the ability of the models to capture the known plasma and neutral dynamics near the three objects.
Published: 2011

86. A model of interaction of Phobos' surface with the martian environment

Author: Olivier Witasse, Robert E. Johnson, Ronan Modolo, François Leblanc, Fabrice Cipriani, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), 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), HELIOS - LATMOS, Department of Materials Science and Engineering [Charlottesville] (MS), University of Virginia [Charlottesville], Agence Spatiale Européenne = European Space Agency (ESA), and University of Virginia
Subjects: Materials science, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Solar wind, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, 01 natural sciences, Space weathering, Astrobiology, Phobos, 0103 physical sciences, Emission spectrum, Ejecta, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Martian, Micrometeoroid, Astronomy and Astrophysics, Radius, Regolith, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Atomic physics
Abstract: International audience; We simulate space weathering of Phobos' surface due to both sputtering by solar wind ions (H+ and He2+) and planetary protons, and surface material vaporization by micrometeoroids impact. Assuming an Iron-rich composition of Phobos' regolith, we find that densities of neutral species (Fe, O, Al, Ca, Mg, Na) in the martian environment are in the range (10-4 -- 10-1 cm-3), and observe an ejecta disk with a radius of 6 martian radii in the equatorial plane and a thickness of 3 martian radii in the perpendicular plane. In order to determine the observability of such species from space based instruments, we also estimate their solar scattering emission line intensities. We conclude that Magnesium would be the only potential candidate suitable for spectral detection.
Published: 2011

87. Titan's induced magnetosphere from plasma wave and magnetometer observations

Author: Ronan Modolo, Bertucci, C., Patrick Canu, Rodrigue Piberne, Edberg, N. J., Kurth, W. S., Gurnett, D. A., Dougherty, M. K., 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), 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), Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Swedish Institute of Space Physics [Uppsala] (IRF), Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Imperial College London, Université Paris-Sud - Paris 11 (UP11)-Observatoire de Paris, and 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)
Subjects: [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Plasma wave observations are combined with the magnetometer measurements to investigate Titan's induced magnetosphere. Electric field emissions close to Titan are identified as upper hybrid resonance emissions and therefore can provide a density estimate of Titan's cold plasma. Some of Titan's flybys show a very strong asymmetry between two flybys performed in similar geographical conditions. Good examples are the Ta and Tb flybys, which have a similar trajectory in the Titan interaction coordinate system and even though they have the same illumination conditions, the density profiles present major differences. Thermal plasma observations are displayed for the nominal mission flybys in a draping coordinate system where the average ambient magnetic field, the ideal flow direction and the motional electric field correspond to the main axis of the system. This coordinate system organizes the cold plasma observations and provides information on the envelop of the induced magnetosphere and its global asymmetry.
Published: 2010

88. Electron density and temperature measurements in the cold plasma environment of Titan: Implications for atmospheric escape

Author: Michiko Morooka, K. Ågren, M. K. Dougherty, Ronan Modolo, Cesar Bertucci, Jan-Erik Wahlund, and Niklas J. T. Edberg
Subjects: Physics, Electron density, 010504 meteorology & atmospheric sciences, Atmospheric escape, Plasma, Atmospheric sciences, 7. Clean energy, 01 natural sciences, Computational physics, symbols.namesake, Geophysics, 13. Climate action, Physics::Space Physics, 0103 physical sciences, symbols, General Earth and Planetary Sciences, Electron temperature, Langmuir probe, Magnetic pressure, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Titan (rocket family), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: We present electron temperature and density measurements of Titan's cold ionospheric plasma from the Langmuir probe instrument on Cassini from 52 flybys. An expression of the density as a function of temperature is presented for altitudes below two Titan radii. The density falls off exponentially with increased temperature as log(ne) = −2.0log(Te) + 0.6 on average around Titan. We show that this relation varies with location around Titan as well as with the solar illumination direction. Significant heating of the electrons appears to take place on the night/wake side of Titan as the density-temperature relation is less steep there. Furthermore, we show that the magnetospheric ram pressure is not balanced by the thermal and magnetic pressure in the topside ionosphere and discuss its implications for plasma escape. The cold ionospheric plasma of Titan extends to higher altitudes in the wake region, indicating the loss of atmosphere down the induced magnetospheric tail.
Published: 2010

89. A plasma flow velocity boundary at Mars from the disappearance of electron plasma oscillations

Author: Ronan Modolo, R. A. Frahm, J. D. Winningham, D. A. Gurnett, Firdevs Duru, Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Southwest Research Institute [San Antonio] (SwRI), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), and 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)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Solar wind, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, MARSIS, Plasma oscillation, 01 natural sciences, Magnetosheath, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, Mars Exploration Program, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Ionospheric sounding, Computational physics, Ionospheres, Flow velocity, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Astrophysical plasma, Astrophysics::Earth and Planetary Astrophysics
Abstract: International audience; The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) on the Mars Express (MEX) spacecraft is capable of measuring ionospheric electron density by the use of two main methods: remote radar sounding and from the excitation of local plasma oscillations. The frequency of the locally excited electron plasma oscillations is used to measure the local electron density. However, plasma oscillations are not observed when the plasma flow velocity is higher than about 160 km/s, which occurs mainly in the solar wind and magnetosheath. As a consequence, in many passes, there is a sudden disappearance of the plasma oscillations as the spacecraft enters into the magnetosheath. This fact allows us to identify a flow velocity boundary on the dayside, between the ionosphere of Mars and the shocked solar wind. This paper summarizes the results of the measurement of 552 orbits mostly over a period from August 4, 2005 to August 17, 2007. The boundary points found using MARSIS have been verified by measurements from the Analyzer of Space Plasma and Energetic Atoms (ASPERA-3) Electron Spectrometer (ELS) instrument on Mars Express. The average position of the flow velocity boundary is compared to flow velocity simulations computed using hybrid model and other boundaries. The boundary altitude is slightly lower than the magnetic pile-up boundary determined using Phobos 2 and Mars Global Surveyor (MGS) crossings, but it is in good agreement with the induced magnetospheric boundary determined by ASPERA-3. Investigation of the effect of the crustal magnetic field revealed that the flow velocity boundary is raised at the locations with strong crustal magnetic fields.
Published: 2010

90. Dayside induced magnetic field of the ionosphere of Mars

Author: D. A. Gurnett, David Brain, D. L. Kirchner, Ronan Modolo, David Morgan, F. Akalin, Mario H. Acuña, Jared Espley, Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), 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), NASA Goddard Space Flight Center (GSFC), University of California [Berkeley], and University of California-University of California
Subjects: 010504 meteorology & atmospheric sciences, Field (physics), Magnetometer, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Solar zenith angle, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, MARSIS, 01 natural sciences, law.invention, law, 0103 physical sciences, Ionosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Physics, Astronomy and Astrophysics, Mars Exploration Program, Geophysics, Ionospheric sounding, Magnetic field, Space and Planetary Science, Magnetic fields, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics
Abstract: International audience; The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) onboard the Mars Express spacecraft has occasionally displayed surprising features. One such feature is the occurrence of a series of broadband, low-frequency echoes at equally spaced delay times after the sounder transmitter pulse. The interval between the echoes has been shown to be at the cyclotron period of electrons orbiting in the local magnetic field. The electrons are believed to be accelerated by the large voltages applied to the antenna by the sounder transmitter. Measurements of the period of these “electron cyclotron echoes” provide a simple technique for determining the magnitude of the magnetic field near the spacecraft. These measurements are particularly useful because Mars Express carries no magnetometer, so this is the only method available for measuring the magnetic field magnitude. Using this technique, results are presented showing the large scale structure of the draped field inside the magnetic pile-up boundary. The magnitude of the draped field is shown to vary from about 40 nT at a solar zenith angle of about 25°, to about 25 nT at a solar zenith angle of 90°. The results compare favorably with similar results from the Mars Global Surveyor spacecraft. A fitting technique is developed to derive the vector direction and magnitude of the draped magnetic field in cases where the spacecraft passes through regions with significant variation in the crustal field. The magnetic field directions are consistent with current knowledge of the draping geometry of the magnetic field around Mars.
Published: 2010

91. 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

92. Capture of solar wind alpha-particles by the Martian atmosphere

Author: Gérard Chanteur, E. Dubinin, Ronan Modolo, Markus Fraenz, Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-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 = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, 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), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Max-Planck-Institut für Sonnensystemforschung (MPS), 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)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), CNES, and Max Planck Institute for Solar System Research (MPS)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, 7. Clean energy, Atmosphere of Mercury, Atmosphere, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Energetic neutral atom, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Geophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Solar wind, Polar wind, 13. Climate action, Physics::Space Physics, General Earth and Planetary Sciences, Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Exosphere
Abstract: International audience; Integration along He++ test-particle trajectories in the self-consistent electromagnetic fields generated by three-dimensional hybrid simulations of the solar wind/Mars interaction is used to evaluate the removal of solar wind α-particles due to charge-exchange processes with neutral species of the Martian exosphere. The total removal rate of solar wind He++ ions, transformed into either singly ionised or neutral helium, is equal to 6.7 × 1023 s−1, which corresponds approximately to 30% of the flux of solar α-particles through the planetary cross-section. The deposition rate of helium neutral atoms, created by double electronic capture on exospheric oxygen, impacting the exobase, and penetrating below where it can be trapped, is about 1.5 × 1023 s−1. That means an important contribution of the solar wind source to the helium balance of the Martian atmosphere. The implantation of the solar helium into the Martian atmosphere shows an asymmetry related to the orientation of the motional electric field of the solar wind, −VSW × BIMF.
Published: 2009

93. Titan ionospheric conductivities from Cassini measurements

Author: Jan-Erik Wahlund, K. Ågren, Lisa Rosenqvist, Darrell F. Strobel, Ingo Müller-Wodarg, H. J. Opgenoorth, Philippe Garnier, Ronan Modolo, Cesar Bertucci, Swedish Institute of Space Physics [Uppsala] (IRF), 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), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Johns Hopkins University (JHU), Space and Atmospheric Physics Group [London], Blackett Laboratory, Imperial College London-Imperial College London, Centre d'étude spatiale des rayonnements (CESR), 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)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Agence Spatiale Européenne = European Space Agency (ESA), 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: Electron density, 010504 meteorology & atmospheric sciences, [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], Venus, 01 natural sciences, 7. Clean energy, Dynamo region, symbols.namesake, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, Ionosphere, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Conductivity, biology, Conductance, Astronomy and Astrophysics, Geophysics, Mars Exploration Program, biology.organism_classification, Computational physics, Magnetic field, Astronomía, Space and Planetary Science, symbols, Cassini, Electrodynamical coupling, Titan (rocket family), Titan, CIENCIAS NATURALES Y EXACTAS, Order of magnitude
Abstract: (approximately the location of the exobase) to approximately 1000 km where electrical currents perpendicular to the magnetic field may become important. In this region the ionosphere is highly conductive with peak Pedersen conductivities of 0.002–0.05 S/m and peak Hall conductivities of 0.01–0.3 S/m depending on Solar illumination and magnetospheric conditions. Ionospheric conductivities are found to be typically higher on the sunlit side of Titan. However, Hall and Pedersen conductivities depend strongly on the magnetic field magnitude which is highly variable, both in altitude and with respect to the draping configuration of Saturn's magnetic field around Titan. Furthermore, a consistent double peak nature is found in the altitude profile of the Pedersen conductivity. A high altitude peak is found to be located between 1300 and 1400 km. A second and typically more conductive region is observed below 1000 km, where the magnetic field strength drops sharply while the electron density still remains high. This nature of the Pedersen conductivity profile may give rise to complicated ionospheric–atmospheric dynamics and may be expected also at other unmagnetized objects with a substantial atmosphere, such as e.g. Mars and Venus. Estimates of the total Pedersen conductance are found to range between 1300 and 22,000 S. The Pedersen conductance is always higher than the local Alfvén conductance but the difference varies by two orders of magnitude (from a factor 4 to 100). Thus, the conditions for reflection or absorption of Alfvén waves in Titans ionosphere are highly variable and depends strongly on the magnetic field strength. Fil: Rosenqvist, L.. Swedish Institute of Space Physics; Suecia Fil: Wahlund, J. E.. Swedish Institute of Space Physics; Suecia Fil: Ågren, K.. Swedish Institute of Space Physics; Suecia Fil: Modolo, R.. Swedish Institute of Space Physics; Suecia Fil: Opgenoorth, H. J.. Solar System Mission Division; Países Bajos Fil: Strobel, D.. University Johns Hopkins; Estados Unidos Fil: Müller Wodarg, I.. Imperial College London; Reino Unido Fil: Garnier, P.. Swedish Institute of Space Physics; Suecia Fil: Bertucci, Cesar. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Published: 2009

94. Ionospheric storms on Mars: Impact of the corotating interaction region

Author: S. Barabash, Joachim Woch, Eduard Dubinin, D. A. Gurnett, Firdevs Duru, Ronan Modolo, Rickard Lundin, Markus Fraenz, Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], 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), Swedish Institute of Space Physics [Kiruna] (IRF), and Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics::High Energy Astrophysical Phenomena, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Magnetosphere, Mars, ionosphere, Space weather, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Interplanetary magnetic field, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Geophysics, Mars Exploration Program, Solar wind, Polar wind, solar wind, 13. Climate action, Physics::Space Physics, General Earth and Planetary Sciences, Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Geology
Abstract: International audience; Measurements made by the ASPERA-3 and MARSIS experiments on Mars Express have shown, for the first time, that space weather effects related to the impact of a dense and high pressure solar wind (corotating interaction region) on Mars cause strong perturbations in the martian induced magnetosphere and ionosphere. The magnetic barrier formed by pile-up of the draped interplanetary magnetic field ceases to be a shield for the incoming solar wind. Large blobs of solar wind plasma penetrate to the magnetosphere and sweep out dense plasma from the ionosphere. The topside martian ionosphere becomes very fragmented consisting of intermittent cold/low energy and energized plasmas. The scavenging effect caused by the intrusions of solar wind plasma clouds enhances significantly (by a factor of ≥10) the losses of volatile material from Mars.
Published: 2009

95. Ionization processes in the atmosphere of Titan. II. Electron precipitation along magnetic field lines

Author: Jean Lilensten, Ronan Modolo, Guillaume Gronoff, Laboratoire de Planétologie de Grenoble (LPG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), and 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)
Subjects: Ionization, 010504 meteorology & atmospheric sciences, Field line, Satellites, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Electron precipitation, Planets, Electron, Astrophysics, Atmospheric sciences, 7. Clean energy, 01 natural sciences, symbols.namesake, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, Atmosphere of Titan, Ionosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Astronomy and Astrophysics, Computational physics, Magnetic field, 13. Climate action, Space and Planetary Science, symbols, Astrophysics::Earth and Planetary Astrophysics, Titan (rocket family), Titan
Abstract: International audience; The Cassini probe regularly passes the vicinity of Titan, providing new insights into particle precipitation by use of its electron and ion spectrometers. A discrepancy between precipitation models and observations of electron fluxes has been found. This discrepancy was suspected to be caused by the geometry of the magnetic field. Aims. In this article, we compute the electron impact ionization in the nightside ionosphere of Titan, assuming non-trivial geometry for the magnetic field lines. Methods. We use the TransTitan model, modified to take into account the magnetic field line geometry in the nightside, and we compare these results with the electron flux measurements during the T5 fly-by of Cassini. We use several magnetic field line geometries, including one produced by hybrid simulations. Results. The geometry of the lines implies a longer path of the electron inside the atmosphere of Titan. The electron fluxes are therefore modified considerably compared to the vertical precipitation hypothesis. At an altitude of 1200 km, the electron flux can be divided up to ten times with a field line resulting from hybrid simulation. Thanks to the use of more accurate field lines, the model reproduces the experiment well without any further adjustment of the precipitated measured electron flux. Conclusions. Several hypothesis had been suggested to explain the discrepancies between the different models and the observation of the electron flux during the T5 fly-by of Cassini. Our approach shows that the most probable explanation is the magnetic field line geometry. This work shows that the computation of ion production by electron impact in the atmosphere of Titan needs the consideration of both magnetic field and the input electron fluxes. Based on these considerations, our model can compute the conditions for future fly-by, and could be used to compare models with experiments.
Published: 2009

96. Rosetta and Mars Express observations of the influence of high solar wind pressure on the Martian plasma environment

Author: Niklas J. T. Edberg, David Brain, Stanley W. H. Cowley, Markus Fränz, A. Bößwetter, James L. Burch, Rickard Lundin, Jean-Gabriel Trotignon, S. Barabash, U. Auster, Hans Nilsson, Karl-Heinz Glassmeier, Firdevs Duru, M. Samara, Ronan Modolo, Emanuele Cupido, Anders Eriksson, Ingo Richter, Raymond Goldstein, Mark Lester, Chris Carr, Swedish Institute of Space Physics [Uppsala] (IRF), Department of Physics and Astronomy [Leicester], University of Leicester, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Swedish Institute of Space Physics [Kiruna] (IRF), Institut für Theoretische Physik [Braunschweig], Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Southwest Research Institute [San Antonio] (SwRI), Blackett Laboratory, Imperial College London, Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, 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), Laboratoire de physique et chimie de l'environnement (LPCE), Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Planetary bow shocks, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics::High Energy Astrophysical Phenomena, Magnetosphere, 01 natural sciences, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Astrophysics::Solar and Stellar Astrophysics, Interplanetary physics, Interplanetary magnetic field, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Martian, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Geophysics, Mars Exploration Program, Magnetosheath, Bow shocks in astrophysics, lcsh:QC1-999, Solar wind, lcsh:Geophysics. Cosmic physics, Polar wind, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Physics::Space Physics, Magnetospheric physics, Magnetopause, lcsh:Q, Astrophysics::Earth and Planetary Astrophysics, lcsh:Physics, Solar wind interactions
Abstract: We report on new simultaneous in-situ observations at Mars from Rosetta and Mars Express (MEX) on how the Martian plasma environment is affected by high pressure solar wind. A significant sharp increase in solar wind density, magnetic field strength and turbulence followed by a gradual increase in solar wind velocity is observed during ~24 h in the combined data set from both spacecraft after Rosetta's closest approach to Mars on 25 February 2007. The bow shock and magnetic pileup boundary are coincidently observed by MEX to become asymmetric in their shapes. The fortunate orbit of MEX at this time allows a study of the inbound boundary crossings on one side of the planet and the outbound crossings on almost the opposite side, both very close to the terminator plane. The solar wind and interplanetary magnetic field (IMF) downstream of Mars are monitored through simultaneous measurements provided by Rosetta. Possible explanations for the asymmetries are discussed, such as crustal magnetic fields and IMF direction. In the same interval, during the high solar wind pressure pulse, MEX observations show an increased amount of escaping planetary ions from the polar region of Mars. We link the high pressure solar wind with the observed simultaneous ion outflow and discuss how the pressure pulse could also be associated with the observed boundary shape asymmetry.
Published: 2009

97. The Magnetic Memory of Titan's Ionized Atmosphere

Author: Michele K. Dougherty, Ronan Modolo, Nicholas Achilleos, Cesar Bertucci, D. T. Young, Fritz M. Neubauer, Andrew J. Coates, P. Garnier, Jan-Erik Wahlund, Adam Masters, Karoly Szego, and Yingjuan Ma
Subjects: Physics, Multidisciplinary, Astrophysics::High Energy Astrophysical Phenomena, Ciencias Físicas, Magnetosphere, Magnetic reconnection, Astrobiology, Astronomía, symbols.namesake, Solar wind, Magnetosphere of Saturn, Physics::Space Physics, symbols, Titan's magnetic field, Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Atmosphere of Titan, Interplanetary magnetic field, Titan (rocket family), CIENCIAS NATURALES Y EXACTAS
Abstract: After 3 years and 31 close flybys of Titan by the Cassini Orbiter, Titan was finally observed in the shocked solar wind, outside of Saturn’s magnetosphere. These observations revealed that Titan’s flow-induced magnetosphere was populated by “fossil” fields originating from Saturn, to which the satellite was exposed before its excursion through the magnetopause. In addition, strong magnetic shear observed at the edge of Titan's induced magnetosphere suggests that reconnection may have been involved in the replacement of the fossil fields by the interplanetary magnetic field. Fil: Bertucci, Cesar. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina Fil: Achilleos, N.. University College London; Estados Unidos Fil: Dougherty, M. K.. Imperial College London; Reino Unido Fil: Modolo, R.. University of Iowa; Estados Unidos Fil: Coates, A. J.. University College London; Estados Unidos Fil: Szego, K.. Research Institute for Particle and Nuclear Physics; Hungría Fil: Masters, A.. Imperial College London; Reino Unido Fil: Ma, Y.. University of California; Estados Unidos Fil: Neubauer, F. M.. Köln University; Alemania Fil: Garnier, P.. Swedish Institute of Space Physics; Suecia Fil: Wahlund, J. E.. Swedish Institute of Space Physics; Suecia Fil: Young, D. T.. Southwest Research Institute; Estados Unidos
Published: 2008

98. Plasma environment of Mars as observed by simultaneous MEX-ASPERA-3 and MEX-MARSIS observations

Author: Joachim Woch, R. A. Frahm, Markus Fraenz, J. J. Plaut, Firdevs Duru, Rickard Lundin, Gérard Chanteur, Eduard Dubinin, Ronan Modolo, S. Barabash, Giovanni Picardi, D. A. Gurnett, J. D. Winningham, and F. Akalin
Subjects: Physics, Atmospheric Science, Ionospheric dynamo region, Ecology, Plasma sheet, Paleontology, Soil Science, Magnetosphere, Forestry, Geophysics, Aquatic Science, Oceanography, Bow shocks in astrophysics, Solar wind, Polar wind, Space and Planetary Science, Geochemistry and Petrology, Physics::Space Physics, Earth and Planetary Sciences (miscellaneous), Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Interplanetary magnetic field, Earth-Surface Processes, Water Science and Technology
Abstract: [1] Simultaneous in situ measurements carried out by the Analyzer of Space Plasma and Energetic Atoms (ASPERA-3) and Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instruments on board the Mars Express (MEX) spacecraft for the first time provide us with the local parameters of cold ionospheric and hot solar wind plasma components in the different regions of the Martian magnetosphere and ionosphere. On the dayside, plasma of ionospheric and exospheric origin expands to large altitudes and gets in touch with the solar wind plasma. Formation of the magnetic field barrier which terminates the solar wind flow is governed by solar wind. The magnetic field rises up to the value which is just sufficient to balance the solar wind pressure while the position of the magnetospheric boundary varies insignificantly. Although, within the magnetic barrier, solar wind plasma is depleted, the total electron density increases owing to the enhanced contribution of planetary plasma. In some cases, a load caused by a planetaiy plasma becomes so strong that a pileup of the magnetic field occurs in a manner which forms a discontinuity (the magnetic pileup boundary). Generally, the structure of the magnetospheric boundary on the dayside varies considerably, and this variability is probably controlled by the magnetic field orientation. Inside the magnetospheric boundaiy, the electron density continues to increase and forms the photoelectron boundary which sometimes almost coincides with the magnetospheric boundary. The magnetic field strength also increases in this region, implying that the planetary plasma driven into the bulk motion transports the magnetic field inward. A cold and denser ionospheric plasma at lower altitudes reveals a tailward cometary-like expansion. Large-amplitude oscillations in the number density of the ionospheric plasma are another typical feature. Crossings of plasma sheet at low altitudes in the terminator region are characterized by depletions in the density of the ionospheric component. In some cases, density depletions correlate with large vertical components of the crustal magnetic field. Such anticorrelation in the variations of the densities of the cold ionospheric and hot magnetosheath/plasma sheet plasmas is also rather typical for localized aurora-type events on the nightside.
Published: 2008

99. Electron densities in the upper ionosphere of Mars from the excitation of electron plasma oscillations

Author: Dalal Najib, Firdevs Duru, Ronan Modolo, D. A. Gurnett, David Morgan, and A. F. Nagy
Subjects: Atmospheric Science, Electron density, Soil Science, MARSIS, Aquatic Science, Oceanography, Plasma oscillation, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Earth-Surface Processes, Water Science and Technology, Physics, Ecology, Paleontology, Forestry, Scale height, Geophysics, Mars Exploration Program, Ionospheric sounding, Computational physics, Solar wind, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Ionosphere
Abstract: [1] In addition to remote radio sounding of the ionosphere of Mars, the MARSIS (Mars Advanced Radar for Subsurface and Ionospheric Sounding) instrument on the Mars Express spacecraft is also able to measure the in situ electron density from the excitation of local electron plasma oscillations. This paper presents an investigation of the electron density in the upper ionosphere of Mars based on the frequency of these oscillations. The advantage of this method is that electron densities can be measured at much higher altitudes than can be determined from remote radio soundings. Using this technique electron densities from 503 orbits have been analyzed over the period from 4 August 2005 to 31 July 2007 for altitudes ranging from about 275 to 1300 km. Although there is considerable variability from orbit to orbit, the median electron density at a given solar zenith angle (SZA) on the dayside of Mars decreases systematically with increasing altitude with a characteristic plasma scale height varying from about 80 to 145 km. At a fixed altitude, the electron density remains almost constant for SZAs less than about 80°. For SZAs greater than about 80° the electron density decreases rapidly with increasing SZA, approaching very low values on the nightside. Simulations performed using both magnetohydrodynamic and hybrid codes show that the nearly constant density at a given altitude is caused by the horizontal transport of plasma from the dayside toward the nightside due to interaction with the solar wind.
Published: 2008

100. Structure and dynamics of the solar wind/ionosphere interface on Mars: MEX-ASPERA-3 and MEX-MARSIS observations

Author: Joachim Woch, Markus Fraenz, Eduard Dubinin, Giovanni Picardi, S. Barabash, Firdevs Duru, Ronan Modolo, D. A. Gurnett, J. J. Plaut, Rickard Lundin, and F. Akalin
Subjects: Geomagnetic storm, Physics, Ionospheric dynamo region, Geophysics, Bow shocks in astrophysics, Solar wind, Polar wind, Physics::Space Physics, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, General Earth and Planetary Sciences, Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Interplanetary magnetic field
Abstract: [1] The measurements of the local plasma parameters of the ionospheric and solar wind plasmas and the magnetic field strength carried out by the ASPERA-3 and MARSIS experiments onboard Mars Express (MEX) in the subsolar region of the induced Martian magnetosphere provide us with a first test of the pressure balance across the solar wind/ionosphere interface. The structure of this transition is very dynamic and is controlled by the solar wind. For a broad range of the solar wind dynamic pressures, the magnetic field in the boundary layer raises to the values just sufficient to balance the solar wind pressure. The magnetic field frozen into the electrons is transported across the magnetospheric boundary (MB) where solar wind terminates and the planetary plasma begins to prevail. The dense ionospheric plasma has a sharp outer boundary the position of which is usually a little closer to the planet than the MB. Although the number density reaches on this boundary ∼103 cm−3 the contribution of the ionospheric thermal pressure is rather small and the ionosphere is magnetized. There are also cases when the magnetic field almost does not vary across both boundaries.
Published: 2008

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