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Interplanetary shocks are some of the main drivers of geomagnetic storms. Before they can impact the geomagnetic environment, they propagate through the magnetosheath where their properties and geometry can be modified. What is the velocity of interplanetary shocks propagating through the magnetosheath? Previous numerical simulations and observations have given a wide range of apparently contradictory answers to this question, but they seem to all agree that interplanetary shocks generally slow down as they enter the magnetosheath: the interplanetary shocks’ velocity in the magnetosheath have been reported to be between 0.25 and 0.93 times their velocity in the solar wind. In this work, we offer two competing simple models to predict the propagation velocity of shocks through the magnetosheath. These models are applied to a list of shocks detected by currently operational spacecraft (e.g. Wind, MMS) as well as to results obtained from a hybrid PIC simulation. We show that our models both reconcile previous results and imply that interplanetary shocks could - in certain space weather-relevant situations - travel faster in the magnetosheath than they did in the solar wind.

The escape and precipitation of planetary ions at Mercury under different solar wind conditions have been examined using a global hybrid simulation. The combination of Mercury’s weak intrinsic magnetic field and solar wind conditions at Mercury’s location results in the formation of a relatively small magnetosphere compared to that of Earth. Its magnetosphere is strongly compressed and may disappear when solar wind conditions are extreme. Under these circumstances, the solar wind can directly interact with its exosphere and surface and the escape of planetary ions is expected to be enhanced. By focusing on the dynamic pressure and interplanetary magnetic field dependence, three different solar wind conditions are used in this study. Under the extreme solar wind planetary protons shows the highest escape rates while planetary sodium ions show the smallest, indicating that the distribution of sodium ions around the planet is controlled by the size of the magnetosphere. As the Larmor radius of planetary sodium ions is larger than that of planetary protons, they cannot escape and instead precipitate onto surface during extreme solar wind conditions, when the dayside magnetosphere is well compressed. Precipitation maps of three components (solar wind protons, planetary protons, and planetary sodium ions) show that the flux from planetary plasmas is sometimes higher than solar wind plasmas, suggesting that the precipitation of planetary plasmas should be considered for the space weathering of Mercury’s surface.

The D/H ratio is a key parameter to understand the atmospheric evolution of a planet. On Mars a D/H ~ 5 times larger than the ratio on Earth is measured. This large ratio can be explained by a preferential escape of the hydrogen compared to the deuterium due to its lower mass. However, while the thermal escape (Jeans escape) is strongly mass dependent other non-thermal processes are less mass dependent and would impact the time needed to fractionate the water from the terrestrial value to the current value. After the first detections of the deuterium Lyman-α emission from Earth (Bertaux et al. 1992, Krasnopolsky et al. 1998), the mission MAVEN performed the first systematic observations of the atomic deuterium Lyman-α emission around Mars showing a brightness of several hundreds of Rayleigh near Mars winter solstice (Clarke et al. 2017, Mayyasi et al. 2017), much larger than the Earth detections done near aphelion (~ 20 – 50 Rayleighs). This seasonal variation of the deuterium Lyman-α brightness is consistent with the variations of the hydrogen Lyman-α brightness observed from Mars Express (Chaffin et al. 2014, Chaufray et al. 2021), HST (Clarke et al. 2014), and MAVEN/IUVS (Clarke et al. 2017, Chaffin et al. 2018) and should result from the processes transporting the water vapor from the lower atmosphere to the upper atmosphere (Vals et al. 2022). In this work we will present preliminary simulations of the 3D deuterium abundance in the Martian upper atmosphere (Fig. 1) using a 3D time dependent global circulation model, including the chemical reactions between HD and HDO with the ions in the upper atmosphere, its extension in the exosphere, and a comparison of the simulated D Lyman-α brightness with the brightness measured by MAVEN/IUVS (Mayyasi et al. 2017) for the Martian year 33. Fig. 1 Simulated average dayside and nightside D density at different altitudes in the thermosphere and exosphere along one Martian year. We will also present first results of the simulated non-thermal escape of H and D produced by collisions between hot oxygen with H, D, H2 and HD as well as the escape of planetary H+ and D+ driven by the solar wind interaction. We will compare the D and H thermal escape rate with the non-thermal escape rates. References: Bertaux et al. (1992), in ESOC conference and workshop proceedings, 44, 459. Chaffin, M. et al. (2014), Geophys. Res. Lett., 41, 314-320 Chaffin, M. et al. (2018), J. Geophys. Res., 123, 2192-2210 Chaufray et al., (2021), Icarus, 353,113498 Clarke et al. (2014), Geophys. Res. Lett., 41, 8013-8020 Clarke et al. (2017), J. Geophys. Res., 122, 2336-2344 Krasnopolsky et al., (1998), Science, 280, 1576 Mayyasi et al., (2017), J. Geophys. Res., 122, 10811-10823 Vals et al. (2022), J. Geophys. Res., under revisions

JUICE is the first large mission chosen in the framework of ESA’s Cosmic Vision 2015-2025 program. The focus of JUICE is to characterize the conditions that might have led to the emergence of habitable environments among the Jovian icy satellites, in particular Europa, Callisto and Ganymede. In addition, JUICE will also perform a multidisciplinary investigation of the Jupiter system as an archetype for gas giants. To address those key science objectives, the spacecraft payload consists of 10 state-of-the-art instruments (and one experiment that use the spacecraft telecommunication system with ground-based instruments) that will perform remote and in-situ measurements of Jupiter, its moon and their environment. From a trajectory’s point of view, the mission calls for a three-year orbital survey of the Jupiter System designed as a sequence of 67 orbits around the planet of different periods and inclinations, and includes 35 flybys of Europa (2), Ganymede (12) and Callisto (21). The second part of the mission will devote an additional 9 months in orbit around Ganymede for an in-depth characterization of Ganymede as a planetary object and possible habitat. By its touring nature and due to the diversity of science targets and different disciplines involved in the mission, the development of an observation plan will often face conflicting observations opportunities, also limited in resources as a consequence of the large helio- and geo-centric distances at play. The Science Operations Center, together with the Project Scientist and the Science Working Team, are in charge of setting up and developing a science planning strategy for the mission to ensure that the prime science objectives of the mission are addressed while remaining compatible with the mission constraints. The JUICE Science Planning Process for the Jupiter tour consists of two main pillars: Segmentation of the trajectory. Based on the Cassini heritage, this activity relies on the analysis of all science opportunities along the tour to subsequently support the decision on selecting a prime scientific objective that will get priority in terms of resources (data volume, power and pointing) for a specific time window (a.k.a segment). Taking into account known operational activities’ constraints (navigation, wheel off-loading etc) and high-level resources’ estimate, an analysis of the expected scientific coverage and resource status along the tour is performed, and several iterations between the different disciplines experts (through the science working groups) take place to converge towards a plan that should ensure that prime science objectives of the mission are fulfilled within the operational constraints of the mission. Detailed sizing case analysis for science operations: For specific operationally of scientifically challenging sections of the segmentation, in-depth analysis is needed in order to refine resources assumptions (attitude, power and data volume) made at segmentation level. Those detailed analysis, performed down to observation level, is done in collaboration with the instrument teams. The present work will describe the different steps and groups involved in the science planning, the current status of the segmentation, and the detailed analysis of the first JUICE Europa flybys will be presented.

Unlike Earth, Venus doesn’t have an intrinsic magnetic field shielding it from the solar wind. However, an inducedmagnetic field is generated from the interaction of solar wind and the dense atmosphere of the planet. RecentVenus flybys by the BepiColombo mission in October 2020 and August 2021, and by Parker Solar Probe and SolarOrbiter, are unique opportunities to further study the interaction between Venus and the Sun. Observational data are essential in the study of this interaction but they are limited by the mission’s trajectory,offering a constrained view of the processes that take place. On the other hand, simulations offer a global viewof the interactions, allowing us to get results with physical significance that would not have been possible fromobservational data only. LatHyS is a three-dimensional parallel multi-species model using the hybrid formalism,that represents the electrons as a massless fluid conserving the neutrality of the plasma, and the ions by numericalmacroparticles with variable weights. Ions and electrons are coupled together using the Maxwell equations, and themacroscopic plasma parameters determine the evolution of the magnetic field (Ledvina et al. 2008). It was initiallydeveloped at LATMOS, Paris, France, for Mars (Modolo et al. 2005) and later parallelized (Modolo et al. 2016) forperformance and optimization purposes. It has the advantage of having a self consistently calculated ionosphere.LatHyS was recently adapted to the simulations of the interaction between the solar wind and Venus at IRAP,Toulouse, France (Aizawa et al. 2022). The work conducted aims at adapting a multi-grid method, initially adapted to LatHyS by Leclercq et al. 2016for the study of Mars and Ganymede, to the case of Venus. The multi-grid refinement allows a more efficient useof computing resources and an improved accuracy of the simulation thanks to a spatial resolution equivalent to orlower than the ionospheric plasma scale height. First, the multi-grid method is presented. Then, simulations using the multi-grid method on the solar wind’sinteraction with Venus are conducted, and their results are compared to simulations made using LatHyS with asingle homogeneous grid.Finally the outputs of the numerical simulations are compared to data on the magnetic field and charged particlesfrom recent flybys and from the Venus Express mission, that orbited the planet from 2006 to 2014. References: Aizawa et al. 2022. https://doi.org/10.1016/j.pss.2022.105499 Leclercq et al. 2016. http://dx.doi.org/10.1016/j.jcp.2016.01.005 Ledvina et al. 2008. http://dx.doi.org/10.1007/s11214-008-9384-6 Modolo et al. 2005. https://doi.org/10.5194/angeo-23-433-2005 Modolo et al. 2016. http://dx.doi.org/10.1002/2015JA022324

Venus lacks an intrinsic magnetic filed, as a result, the incoming solar wind interacts directly with its atmosphere, creating an induced magnetosphere. Venus is believed to have once held a significant amount of water, which has since then disappeared from the planet as evidence by the increased, compared to Earth's, Deuterium-Hydrogen ratio measured by Pioneer Venus (Donahue et al. 1982). Its disappearance is mainly contributed to the interaction of the solar wind with the planet's induced magnetosphere. This interaction is the primary cause of atmospheric escape for elements heavier than Hydrogen, such as Oxygen (Futaana et al. 2017). Measurements from Venus Express have shown that the majority of the escape is taking place at the magnetotail, with the ration of Hydrogen to Oxygen escape being approximately equal to two during solar minimum and equal to one during solar maximum (Persson et al. 2018), indicating the escape of water from the nightside. This effect can bring rise to the question: what happens to the atmospheric loss under extreme solar wind conditions, such as under the influence of Interplanetary Coronal Mass Ejections (ICMEs)? Understanding those processes can give us valuable information on the evolution of the planet. Previous works have provided answers by investigating the impact of ICMEs on the Venusian atmospheric escape compared to nominal conditions with observations (Luhmann et al. 2007, McEnulty et al. 2010, Edberg et al. 2011, Collinson et al. 2015) and simulations (Luhmann et al. 2008, Dimmock et al. 2017) to name a few. In this study, we contribute to this subject by using observations taken from Venus Express and simulations to explore the influence of different ICME parameters on the escape. The simulation used is a global hybrid model, called LatHyS, first developed for Mars (Modolo et al. 2017) and adapted for Venus (Aizawa et al. 2022), that has the advantage of having a self consistently calculated ionosphere. Magnetic field and particle data taken from Venus Express upstream of the bowshock are used as reference for the initial conditions of the simulations. Two ICME events are selected. The first impacted Venus on the 5th of November 2011 and created the highest observed magnetic obstacle at the planet. Upstream of the bowshock it had a temperature of 200 eV and a velocity of 900 km/s. The second event occurred on the 27th of October 2013 and had similar plasma and magnetic field parameters to the first one, but had significantly different temperature of 35 eV and velocity of 600 km/s. Idealized models of the events are simulated and compared. In order to discuss the parameter dependence, for each comparison the simulation inputs of the two events are forced to be the same, imposing either temperature or velocity to be identical, and leaving the studied variable as the only difference. We find an increase of the dayside Oxygen escape for the event with the higher velocity, but a decrease on the nightside outgoing ion flux. Since both of the selected events can be considered as fast solar wind, to better investigate the dependency of the velocity we perform an additional simulation with a much lower solar wind speed of 300 km/s. To study further the effect of the ICME parameters, in a more model driven approach, the second selected event is kept as a reference and additional simulations are performed to examine variables such as the magnetic field strength and cone angle. Finally, the results are compared with statistical data of the mean solar wind conditions on Venus and their corresponding calculated atmospheric escape. References: Aizawa et al. 2022, doi: https://doi.org/10.1016/j.pss.2022.105499 Collinson et al. 2015, doi: https://doi.org/10.1002/2014JA020616 Dimmock et al. 2018, doi: https://doi.org/10.1029/2017JA024852 Donahue et al. 1982, doi: https://doi.org/10.1126/science.216.4546.630 Edberg et al. 2011, doi: https://doi.org/10.1029/2011JA016749 Futaana et al. 2017, doi: https://doi.org/10.1007/s11214-017-0362-8 Luhmann et al. 2007, doi: https://doi.org/10.1029/2006JE002820 Luhmann et al. 2008, doi: https://doi.org/10.1029/2008JE003092 McEnulty et al. 2010, doi: https://doi.org/10.1016/j.pss.2010.07.019 Modolo et al. 2016, doi: https://doi.org/10.1002/2015JA022324 Persson et al. 2018, doi: https://doi.org/10.1029/2018GL079454

During the last decade, MAVEN space mission have emphasized a widespread spatial distribution of escaping O+ ions (Brain et al., 2015; Dong et al., 2015; Curry et al., 2015). Statistical studies have demonstrated that such structure is constant and present an asymmetry with respect to the solar wind convective electric field direction. In the Mars Solar Ecliptic coordinate system, continuous large O+ ion fluxes have been observed from the Martian wake to the Northward hemisphere. Global hybrid models have been developed since more than fiffteen years (Modolo et al., 2005, 2016; Brecht and Ledvina, 2006; Kallio et al., 2006) predicting and reproducing successfully the main characteristics of these escaping ion signatures. To further characterize this heavy-ion escape and its variability due to the solar wind forcing, global hybrid simulations have been performed with different set of upstream solar wind parameters. The impact of the solar wind drivers on the dynamics of O+ ion fluxes are reported and compared to the statistical ion fluxes maps derived from MAVEN/STATIC observations (Dong et al., 2015).Brain, D. A., McFadden, J. P., Halekas, J. S., Connerney, J. E. P., Bougher, S. W., Curry, S., et al. (2015). The spatial distribution of planetary ion fluxes near Mars observed by MAVEN. Geophys. Res. Lett. 42, 9142–9148. doi:10.1002/2015GL065293Dong, Y., Fang, X., Brain, D. A., McFadden, J. P., Halekas, J. S., Connerney, J. E., et al. (2015). Strong plume fluxes at Mars observed by MAVEN: An important planetary ion escape channel. Geophys. Res. Lett. 42, 8942–8950. doi:10.1002/2015GL065346Curry, S. M., Luhmann, J. G., Ma, Y. J., Dong, C. F., Brain, D., Leblanc, F., et al. (2015). Response of Mars O+ pickup ions to the 8 March 2015 ICME: Inferences from MAVEN data-based models. Geophys. Res. Lett. 42, 9095–9102. doi:10.1002/2015GL065304Modolo, R., Chanteur, G. M., Dubinin, E., and Matthews, A. P. (2005). Influence of the solar EUV flux on the Martian plasma environment. Annales Geophysicae 23, 433–444. doi:10.5194/angeo-23-433-2005 Brecht, S. H. and Ledvina, S. A. (2006). The Solar Wind Interaction With the Martian Ionosphere/Atmosphere 126, 15–38. doi:10.1007/s11214-006-9084-zKallio, E., Fedorov, A., Budnik, E., Sa¨les, T., Janhunen, P., Schmidt, W., et al. (2006). Ion escape at Mars: Comparison of a 3-D hybrid simulation with Mars Express IMA/ASPERA-3 measurements 182, 350–359. doi:10.1016/j.icarus.2005.09.018

The 2nd Venus flyby of BepiColombo has been examined and compared by the newly developed global hybrid simulation LatHyS for the Venusian environment. The LatHyS has been first validated by comparison with Venus Express observations, then using the observation from Solar Orbiter, which was located in the upstream region and both observed the same solar wind, it is applied for the Venus flyby. The simulation successfully reproduced the observed signatures and it shows that BepiColombo passed through the stagnation region of Venus, which supports the results obtained by data-analysis. In addition, we have sampled the plasma information along the trajectory and constructed the energy spectrum for three species (solar wind proton, planetary proton, and planetary oxygen ion) and possible effect due to the limited field of view is discussed. Moreover, ion escape from Venus for planetary species have been discussed and the escape rate is estimated.

Photo-ionization of Mercury’s tenuous exosphere contributes to the heavy ion population in the Hermean environment. Observations with the MESSENGER Fast Imaging Plasma Spectrometer (FIPS) have revealed the ion density and spatial distribution of the three most abundant planetary ions or ion groups around Mercury: The Na+-group (mass-per-charge ratio m / q = 21 – 30 amu / e ), O+-group ( m / q = 16 – 20 amu / e ) and He+. We developed a test-particle model coupled to a neutral exosphere model and two different models of the magnetosphere to simulate the ion density distribution of Na+, He+ and O+. We compare the modeled ion density distribution at aphelion for northward interplanetary magnetic field (IMF) with FIPS observations from the entire orbital phase (23 March 2011 to 30 April 2015). Our model reproduces several observed features but the average ion density is up to 18x too high. However, we find that the discrepancy is less than 3x for other solar wind and exosphere conditions. Comparison with previous simulation studies of the Na+ ion density and magnetic field line resonance observations give an average Na+ density which is on the same order as our estimate. Finally, we model the phase space density (PSD) distribution in four different regions. We find that in three out of four regions only a fraction of the PSD distribution can typically be observed by FIPS. This is mainly due the obstruction of the field-of-view caused by the spacecraft’s sun shield, which blocks plasma with a high v x / v z ratio from entering the instrument.

Galilean moons are embedded in Jupiter’s giant magnetosphere. The Jovian plasma particles interact with the atmosphere of the moons, exchanging momentum and energy, and generate different phenomena such as aurora, electric current, etc.The exploration of the Galilean moons, and in particular Ganymede and Europa, considered as potential habitats, are listed among the main objectives of the ESA JUpiter ICy moon Explorer (JUICE) mission. In preparation for future observations, a modelling effort is conducted to describe the Europa moon-magnetosphere system. We have used the LATMOS Hybrid Simulation (LatHyS) model to characterize the Jovian plasma and magnetic field interaction with the moon and its atmosphere. The model is a hybrid 3D, multi-species and parallel simulation model which is based on a kinetic description of ions and a fluid description of electrons. The model is based on the CAM-CL algorithm and various physical processes has been implemented to describe the solar wind (or a magnetospheric plasma) interaction with Mars, Mercury, Titan, Ganymede, Earth-like body etc… (Matthews, 1994, Modolo et al, 2016, Richer et al, 2012, Modolo et al, 2008, Leclercq et al, 2015, Turc et al, 2015). This simulation model depicts the dynamic and the structure of the ionized environment in the neighborhood of these bodies. Recently, the model has been adapted to Europa-Jupiter interaction. Global simulation results are compared to Galileo observations and will be used to illustrate the conditions that JUICE might encounter during its flybys. References :Alan P. Matthews, Current Advance Method and Cyclic Leapfrog for 2D Multispecies Hybrid Plasma Simulations, Journal of Computational Physics, Volume 112, Issue 1, 1994, Pages 102-116, ISSN 0021-9991, https://doi.org/10.1006/jcph.1994.1084.Turc L., Fontaine D., Savoini P., Modolo R., 3D hybrid simulations of the interaction of a magnetic cloud with a bow shock, JGR, 2015Richer E, Modolo R, Chanteur GM, Hess S and Leblanc F, A Global Hybrid Model for Mercury's Interaction With the Solar Wind: Case Study of the Dipole Representation, Journ. Geophys. Res., doi:10.1029/2012JA017898, 2012Leclercq L., Modolo R., Leblanc F., Hess S., Mancini M. ,3D Magnetospheric parallel hybrid multi-grid method applied to planet-plasma interactions, Journal of Computational Physics, 309, pp.295-313, 10.1016/j.jcp.2016.01.005, 2016Modolo R., Hess S., Mancini M., Leblanc F., Chaufray J.-Y., Brain D., Leclercq L., Esteban Hernandez R., Chanteur G., Weill P., Gonzalez-Galindo F. et al., Mars-solar wind interaction: LatHyS, an improved parallel 3-D multispecies hybrid model, Journal of Geophysical Research : Space Physics, American Geophysical Union/Wiley, 2016, 121 (7), pp.6378-6399.10.1002/2015JA022324, 2016

The JUICE (JUpiter ICy moon Explorer) mission, selected by the European Space Agency in May 2012 to be the first large mission within the Cosmic Vision Program 2015–2025, will provide the most comprehensive exploration to date of the Jovian system in all its complexity, with particular emphasis on Ganymede as a planetary body and potential habitat (JUICE Red Book, 2014). The Galilean satellites are known to have thin atmospheres, technically exospheres (McGrath et al., 2004), produced by ion-induced sputtering and sublimation of the surface materials. These moons and tenuous atmosphere are embedded in the flowing plasma of the jovian. The interaction between the neutral environments of the Galilean satellites and the jovian plasma changes the plasma momentum, the temperature and generates strong electrical currents. In order to prepare the scientific return of the mission and the optimization of operation modes of plasma instruments, a modeling effort has been carried out at LATMOS (PhD R. Allioux, IRAP, 2012; L. Leclercq, LATMOS, 2015; O. Apurva, LATMOS, 2017). A 3D parallel multi-species hybrid model (Latmos Hybrid Simulation, LatHyS) has been developed to model and characterize the plasma environment of Ganymede (Leclercq et al, 2016; Modolo et al, 2016) and a 3D parallel multi-species exospheric model (Exospheric Global Model, EGM) to pattern the dynamic of the neutral envelopes of Ganymede (Turc et al, 2014; Leblanc et al, 2017). The presentation will examine the global structure of the interaction with the jovian plasma, to describe the formation of Alfvén wings, and to emphasize the phenomena related to the multi-species nature of the plasma. The simulation model supports the preparation of the JUICE mission and its Ganymede phase by characterizing boundary crossings.

International audience; We study the influence of the solar extreme ultraviolet (EUV) flux intensity on the precipitating ion fluxes as seen by the Solar Wind Ion Analyzer, an energy and angular ion spectrometer aboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. We defined three periods with significantly different EUV flux intensity (1.6 and 3.2 times the lowest EUV intensity) and compare the precipitating ion flux measured by MAVEN/Solar Wind Ion Analyzer during each period. At low energy [30–650] eV, we find that the median (average) precipitating ion flux during the medium and low EUV periods are, respectively, 1.7 (2.1) and 3 (3.5) times more intense than the flux during the high EUV period. At high energy [650–25,000] eV, a similar trend in the intensity of the precipitating ion flux is observed but with an increase by 50% (46%) and 70% (79%), respectively. A larger EUV flux does therefore not seem to favor heavy ion precipitation into Mars's atmosphere, contrary to modeling prediction and overall expectations.

International audience; In this work, we study the influence of the September 2017 solar event on the precipitating heavy ion fluxes towards Mars' atmosphere as seen by MAVEN/SWIA, an energy and angular ion spectrometer and by MAVEN/STATIC, an energy, mass and angular ion spectrometer. After a careful reconstruction of the background induced by the Solar Energetic Particle (SEP) event in the MAVEN/SWIA spectrometer, we investigate the precipitating ion flux responses to the space weather events that took place in September 2017. This period is a unique opportunity to analyze the respective role of various possible drivers of heavy ion precipitation into Mars’ atmosphere with a wide range of different space weather events occurring during the same month. This study shows an increase in the precipitation flux by more than one order of magnitude during the arrival of the September Interplanetary Coronal Mass Ejection (ICME) compared to the average flux during quiet solar conditions. We also showed that among the possible solar drivers, the solar wind dynamic pressure is the most significant during September 2017.

The Mercury plasma environment is enriched in planetary ions from the tenuous neutral exosphere. We have developed a test-particle model which describes the full equation of motion for planetary ions produced from photo-ionization of the neutral exosphere. The new test-particle model is coupled to a Monte Carlo test-particle model of the neutral exosphere (Exospheric Global Model; EGM; Leblanc et al. 2017) and two hybrid-kinetic models: LatHyS (Modolo et al. 2016) and AIKEF (Müller et al. 2011). This coupling will allow us to consider the impact of non-adiabatic energization on the ion density distribution as well as the connection to seasonal asymmetries in the neutral exosphere.We compare the density, energy and phase space density distribution of He+, O+ and Na+ from our model with observations from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) time-of-flight spectrometer Fast Imaging Plasma Spectrometer (FIPS; Raines et al. 2013). Our results indicate the presence of several interesting high-density structures both inside and outside FIPS observable energy range (E = 0.05 -13 keV), the properties of which are likely very sensitive to the upstream solar wind conditions. We present how these results may aid the interpretation of FIPS data and future measurements by BepiColombo.

International audience; Accessing, visualizing and analyzing heterogeneous plasma datasets has always been a tedious task that hindered students and senior researchers as well. Offering user friendly and versatile tools to perform basic research tasks is therefore pivotal for data centres including the Centre de Données de la Physique des Plasmas (CDPP http://www.cdpp.eu/) which holds a large variety of plasma data from various Earth, planetary and heliophysics missions and observatories in plasma physics. This clearly helps gaining increased attention, relevant feedback, and enhanced science return on data. These are the key ideas that crystallized at CDPP more than 15 years ago and resulted in the lay-out of the concepts, and then development, of AMDA, the Automated Multi-Dataset Analysis software (http://amda.cdpp.eu/). This paper gives a description of the architecture of AMDA, describes its functionalities, presents some use cases taken from the literature or fruitful collaborations and shows how it offers unique capabilities for educational purposes.

It is well known that in the magnetosphere of the outer planets (eg. Saturn, Jupiter, Neptune), even in the absence of an electric current, a polarization electric field develops as a consequence of charge separation in a plasma, providing a restoring force to maintain charge neutrality. It is also well established that certain regions of these planetary systems (ionosphere, icy moons, rings) are populated by significant amount of charged dust that play an important role in the physical and chemical processes in the surrounding plasma environment.In the present work, we study the effect of the charged dust grains on the polarization electric field using Saturn’s F-ring region as a case study. We derive a general expression for E parallel to the magnetic field (E_para) and then using the Cassini RPWS/LP measurements we estimate for the first time in situ E_para close to Janus/Epimetheus ring during the F ring grazing orbits. We further demonstrate that the presence of charged dust, as small as nanometers in size, can significantly influence the plasma transport processes, in particular the ambipolar diffusion along the magnetic field lines. We show that, close to the ring plane (Z

Cassini plasma wave and charged particle observations are combined with magnetometer measurements to investigate Titan's induced magnetosphere. Electric field emissions close to Titan are identifie...

Multi-spacecraft missions after 2000 (Cluster II, THEMIS, Van Allen Probes, and MMS) have revolutionized our understanding of the causes, patterns and variability of a wide array of plasma phenomena in the terrestrial magnetospheric environment. ESCAPADE is a twin-spacecraft Mars mission concept that will similarly revolutionize our understanding of how solar wind momentum and energy flows throughout Mars’ magnetosphere to drive ion and sputtering escape, two processes which have helped shape Mars’ climate evolution over solar system history. ESCAPADE will measure magnetic field strength and topology, ion plasma distributions (separated into light and heavy masses), as well as suprathermal electron flows and thermal electron and ion densities, from coordinated elliptical, 200 km x ~7000 km orbits. ESCAPADE are small spacecraft ( ESCAPADE is due to complete its preliminary design review in August 2020, thereafter moving toward build, test, integration and launch two years later. We will report on science goals and objectives, mission design challenges, and provide a status update.

The highly compressed magnetosphere (HCM) events at Mercury observed by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft have been investigated using the global hybrid simulation LatHyS. The HCM events occur due to the interactions with coronal mass ejections (CMEs) or high-speed streams (HSSs) and previous studies indicate that not only the reconnection-driven erosion but also the induced currents in the inner core have an important role in the variation of the dayside magnetosphere of Mercury. However, the effects of the presence of planetary ions on Mercury’s system have not been well discussed. In this study, we mainly focus on the presence of planetary ions that are self-consistently produced from the exosphere by several ionization processes under extreme solar wind conditions and discuss their role on the structure and dynamics of Mercury’s magnetosphere.

Abstract In this work, we compare simulation of the precipitating flux for different solar wind dynamic pressure with MAVEN observations. In particular, we focus on the fluxes of precipitating ion towards Mars' atmosphere as seen by MAVEN/SWIA (cs product), an energy and angular ion spectrometer [1]. We also use LatHyS, which is a 3D multispecies parallelized hybrid model that describes the formation of Mars electromagnetic environment induced by its interaction with the solar wind [2]. 1. Introduction Although atmospheric sputtering is a minor component of atmospheric escape today, it is thought to have been much more important four billion years ago [3]. Heavy ion precipitation is the primary driver of atmospheric sputtering. At the present epoch, the efficiency of Mars' atmospheric sputtering by precipitating heavy ions to induce atmospheric escape is expected to be small compared to other mechanisms of atmospheric erosion. However, since the main driver of sputtering is ion precipitation, it is crucial to constrain the dependence of the precipitating ion flux on present solar wind conditions, before any extrapolation to past solar conditions. By comparing simulation results and MAVEN observations, we here investigate the mechanisms controlling the precipitation when the solar wind dynamic pressure change. We will present how the precipitating ion flux, measured by MAVEN/SWIA, is influenced by the solar wind dynamic pressure and will analyze these observations by comparison with simulation results. 2. Observations and simulations results We define two sets of different solar wind dynamic pressure from the set of MAVEN observations of the precipitating flux and simulate Mars’ interaction with the solar wind for the average values of the solar parameters (Extreme Ultraviolet irradiance, Interplanetary magnetic field, solar wind density, solar wind speed...) for both sets. We then reconstruct map of the precipitating heavy ion flux at 250km in altitude and the simulated precipitating flux along each MAVEN trajectory used in our analysis. 3. Summary Comparing MAVEN observations with models improves our understanding of the parameters that control the precipitating ion flux. By defining two sets, characterized by different solar wind dynamic pressure and modelling them, we present the comparison between models and observations. Acknowledgements This work was supported by the DIM ACAV and the ESA/ESTEC faculty. This work was also supported by CNES “Système Solaire” program and by the “Programme National de Planétologie” and “Programme National Soleil-Terre”. This work is also part of HELIOSARES Project supported by the ANR (ANR-09-BLAN-0223), ANR MARMITE (ANR-13-BS05-0012-02) and ANR TEMPETE (ANR-17-CE31-0016). Spacecraft data used in this paper are archived and available in the Planetary Data System Archive (https://pds.nasa.gov/). Numerical simulation results used in this article can be found in the simulation database (http://impex.latmos.ipsl.fr). References [1] Leblanc F., R. Modolo and al. (2015), Geophys. Res. Lett, 42, 9135-9141, doi : 10.1002/2015GL066170. [2] Modolo, R., et al. (2016), J. Geophys. Res. Space Physics, 121, 6378–6399, doi: 10.1002/2015JA022324. [3] Luhmann, J.G., Johnson, R.E., Zhang, M.H.G., (1992), Geophys. Res. Lett., 19, 21, 2151-2154.

International audience; Ganymede's surface is subject to constant bombardment by Jovian magnetospheric and Ganymede's ionospheric ions. These populations sputter the surface and contribute to the replenishment of the moon's exosphere.Thus far, estimates for sputtering on the moon's surface have included only the contribution from Jovian ions. In this work, we have used our recent model of Ganymede's ionosphere (Carnielli et al., 2019) to evaluate the contribution of ionospheric ions for the first time. In addition, we have made new estimates for the contribution from Jovian ions, including both thermal and energetic components.For Jovian ions, we find a total sputtering rate of 2.2x1027s-1, typically an order of magnitude higher compared to previous estimates. For ionospheric ions, produced through photo- and electron-impact ionization, we find values in the range 2.7x1026-5.2x1027s when the moon is located above the Jovian plasma sheet. Hence, Ganymede's ionospheric ions provide a contribution of at least 10% to the sputtering rate, and under certain conditions they dominate the process. This finding indicates that the ionospheric population is an important source to consider in the context of exospheric models.

The Mercury plasma environment is enriched in heavy ions (mass-per-charge ratio m/q > 4) from photo-ionization of the tenuous exosphere. The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) time-of-flight spectrometer Fast Imaging Plasma Spectrometer (FIPS) has detected many planetary ion species of which He+, the Na+-group (including Na+, Mg+ and Si+) and the O+-group (including O+ and several water group ions) are the most abundant. The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) UltraViolet and Visible Spectrometer (UVVS) has also detected Ca+ ions in the nightside plasma sheet. Models of the planetary ion distribution inside Mercury's magnetosphere have mostly concentrated on the abundant Na+ and H+ ion populations. Comparison with FIPS data has been limited to the first two MESSENGER flybys and no comparison has been made with MASCS/UVVS observations. We have developed a Monte Carlo test-particle model which describes the ion density distribution produced from photo-ionization of several neutral species in Mercury's exosphere. The global ion density and energy distribution of Ca+, Mg+, Na+, O+ and He+ will be presented here. We will review the influence of the interplanetary magnetic field (IMF) Bx and By components on the global structure of the ion density distribution, the composition of the nightside plasma sheet and the evolution of the Na+ ion density along the Mercury year.

Multi-spacecraft missions after 2000 (Cluster II, THEMIS, Van Allen Probes, and MMS) have revolutionized our understanding of the causes, patterns and variability of a wide array of plasma phenomena in the terrestrial magnetospheric environment. ESCAPADE is a twin-spacecraft Mars mission concept that will similarly revolutionize our understanding of how solar wind momentum and energy flows throughout Mars’ magnetosphere to drive ion and sputtering escape, two processes which have helped shape Mars’ climate evolution over solar system history. ESCAPADE will measure magnetic field strength and topology, ion plasma distributions (separated into light and heavy masses), as well as suprathermal electron flows and thermal electron and ion densities, from elliptical, 200 km x 7000 km orbits. ESCAPADE are small spacecraft (ESCAPADE has been selected for Phase A and B study by NASA as one of three finalists in the SIMPLEX-II program. We will report on science goals, engineering and mission design challenges, and provide a status update.

International audience; Ganymede's neutral and plasma environments are poorly constrained by observations. Carnielli et al. (2019) developed the first 3D ionospheric model aimed at understanding the dynamics of the present ion species and at quantifying the presence of each component in the moon's magnetosphere. The model outputs were compared with Galileo measurements of the ion energy flux, ion bulk velocity and electron number density made during the G2 flyby. A good agreement was found in terms of ion energy distribution and bulk velocity, but not in terms of electron number density.In this work, we present some improvements to our model (Carnielli et al., 2019) and quantitatively address the possible sources of the discrepancy found in the electron number density between the Galileo observations and our ionospheric model. We have improved the ion model by developing a collision scheme to simulate the charge-exchange interaction between the exosphere and the ionosphere. We have simulated the energetic component of the O2 population, which is missing in the exospheric model of Leblanc et al. (2017) and added it to the original distribution, hence improving its description at high altitudes. These improvements are found to be insufficient to explain the discrepancy in the electron number density. We provide arguments that the input O2 exosphere is underestimated and that the plasma production acts asymmetrically between the Jovian and anti-Jovian hemispheres. In particular, we estimate that the O2 column density should be greater than 1015 cm−2, i.e., higher than previously derived upper limits (and a factor 10 higher than the values from Leblanc et al. (2017)), and that the ionization frequency from electron impact must be higher in the anti-Jovian hemisphere for the G2 flyby conditions.

International audience; We discuss the influence of the solar wind dynamic pressure on the ion precipitation using observations performed by MAVEN from the 04 June 2014 to the 20 July 2017. The increase of the dynamic pressure from 0.63 to 1.44nPa is clearly associated with an increase of the same order of magnitude of the precipitating oxygen ion energy flux measured by MAVEN/STATIC from 9.9 to 20.6 × 106eV. cm−2. sr−1. s−1at low energy (from 30 to 650 eV). In the same way, from 650 eV to 25000 eV, MAVEN/SWIA (all species) observed an increase from 22.4 to 42.8 × 107eV. cm−2. sr−1. s−1 of the precipitating ion energy flux.Performing two simulations using the average solar wind conditions for both solar dynamic pressure regimes observed by MAVEN as input of the LatHyS model (LATMOS Hybrid Simulation), we reproduce some of the key characteristics of the observed oxygen ion precipitation. We characterize the oxygen ions simulated by LatHyS by their energy and time of impact, their time of injection in the simulation and initial position and the mechanism by which these ions were created. The model suggests that the main cause of the increase of the heavy ion precipitation during an increase of the solar dynamic pressure is the increase of the ion production by charge exchange, proportional to the increase of the solar wind flux, which becomes the main contribution to the ion precipitation at high energy.

Krasnopolsky (2017) makes a careful review of our recent results about the Martian hydrogen content of the Martian upper atmosphere (Chaufray et al., 2015). We comment here on his two major points. First, he suggests that the non-thermal escape of H, and particularly collisions with hot oxygen, not taken into account in our general circulation model (GCM), should modify our reported H and H density profiles. This is an important issue; we acknowledge that future effective coupling of our GCM with comprehensive models of the Martian solar wind interaction, ideally after being validated with the latest plasma observations of H , would allow for better estimations of the relative importance of the H non-thermal and thermal escape processes. For the time being we need assumptions in the GCM, with proper and regular updates. According to a recent and detailed study of the anisotropic elastic and inelastic collision cross sections between O and H (Gacesa et al., 2012), the escape rates used by Krasnopolsky (2010) for this process might be overestimated. We therefore do not include non thermal escape of H in the model. And secondly, in response to Krasnopolsky's comment on the H escape variability with the solar cycle, we revised our calculations and found a small bug in the computation of the Jeans effusion velocity. Our revised computed H escape rates are included here. They have a small impact on our key conclusions: similar seasonal variations, a reduced variation with the solar cycle but still larger than Krasnopolsky (2017), and again a hydrogen scape systematically lower than the diffusion-limited flux. This bug does not affect the latest Mars Climate Database v5.2. © 2017 Elsevier Inc., This work has been partially funded by the European Union Horizon 2020 Programme (H2020 Compet -08-2014) under grant agreement UPWARDS-633127. We thank Programme National de Planetologie (PNP) and Programme National Soleil-Terre (PNST) for their support.

The first measurements of the emission brightness of the oxygen atomic exosphere by Mars Atmosphere and Volatile EvolutioN (MAVEN) mission have clearly shown that it is composed of a thermal component produced by the extension of the upper atmosphere and of a non-thermal component. Modeling these measurements allows us to constrain the origins of the exospheric O and, as a consequence, to estimate Mars' present oxygen escape rate. We here propose an analysis of three periods of MAVEN observations based on a set of three coupled models: a hybrid magnetospheric model (LatHyS), an Exospheric General Model (EGM) and the Global Martian Circulation model of the Laboratoire de Meteorologie Dynamique (LMD-GCM), which provide a description of Mars' environment from the surface up to the solar wind. The simulated magnetosphere by LatHyS is in good agreement with MAVEN Plasma and Field Package instruments data. The LMD-GCM modeled upper atmospheric profiles for the main neutral and ion species are compared to NGIMS/MAVEN data showing that the LMD-GCM can provide a satisfactory global view of Mars' upper atmosphere. Finally, we were able to reconstruct the expected emission brightness intensity from the oxygen exosphere using EGM. The good agreement with the averaged measured profiles by IUVS during these three periods suggests that Mars' exospheric non-thermal component can be fully explained by the reactions of dissociative recombination of the O2+ ion in Mars' ionosphere, limiting significantly our ability to extract information from MAVEN observations of the O exosphere on other non-thermal processes, such as sputtering.

International audience; An asymmetrical pileup of the interplanetary magnetic field (IMF) leads to an additional draping of the field lines in the opposite direction to the motional electric field. Such a draping and the associated magnetic field forces push the ionosphere plasma in the transverse direction opening a passage for an ion trail which contains dense and slowly moving plasma. We found that wrapping of the field lines around Mars starts in the hemisphere pointing in the direction of the motional electric field and propagates to the opposite hemisphere where the cross‐flow component of the draped IMF changes sign in a broad area accompanied by the formation of loops of closed field lines. Reconnection near Mars accompanied by the generation of plasma vortices imposes serious constraints on the ion dynamics and their escape through the tail. The existence of all these features is confirmed by hybrid simulations.

International audience; A combination of statistical studies and 18 case studies have been used to investigate the structure of the induced Martian magnetosphere. The different plasma and magnetic pressure forces on the dayside of the induced magnetosphere of Mars have been studied using 3.5 years of Mars Atmosphere and Volatile Evolution (MAVEN) and Mars Express (MEX) observations. We present estimates of typical values for the dominant pressure terms, i.e., the thermal pressures of the ionosphere and the magnetosheath, the magnetic pressure of the magnetic pile‐up region, and the solar wind dynamic pressure. For 18 typical orbits the altitudes and relative distances of the pressure balance boundaries, the photoelectron boundary (PEB), the ion composition boundary (ICB), and the induced magnetosphere boundary (IMB) are estimated. The Magnetic Pile‐up Boundary (MPB) is discussed but not further studied since earlier characterisations of the MPB do not agree with our results.This study focuses on the transition region between the ionosphere and the magnetosheath on the dayside of Mars. We show that earlier definitions of the PEB, ICB, and IMB do not characterise the transition region well, mainly because each boundary is based on measurements from only one or two instruments. In order to characterise the transition region correctly changes in magnetic field strength and fluctuations, dominant ion species, electron and ion densities and energy distributions, need to be considered. This article confirms a complex interaction between Mars and the solar wind and can explain why previous studies have had difficulties to describe the force balance.

International audience; In this work we revisit an event observed by Mars Atmosphere and Volatile Evolution MissioN (MAVEN) in the solar wind where the Interplanetary Magnetic Field (IMF) rotates around the Mars‐Sun axis during approximately 6 minutes. Based on a time‐dependent LATMOS Hybrid Simulation, we determine recovery timescales of the dayside Martian magnetosphere normalized by the IMF variability timescale. Particularly, we find that such recovery timescales range between 8 s and 11 min for an ~90° IMF rotation that lasted 50 s (observed as part of the 6 minutes time interval), depending on the considered magnetospheric region. We also find that the O+ plume recovery timescales range between 40 s and 120 s, taking greater values for further downstream distances (at least up to 1 RM downstream from the terminator plane). This range is on the order of the magnetosheath O+ gyroperiod, showing the kinetic nature of the plume recovery process.

International audience; We present the first three-dimensional multi-species ionospheric model for Ganymede, based on a test particle Monte Carlo approach. Inputs include the electromagnetic field configuration around the moon from the magnetospheric models developed by Leclercq et al. (2016) and by Jia et al. (2009), and the number density, bulk velocity and temperature distributions of the neutral exosphere simulated by Leblanc et al. (2017). According to our simulations, O2+ is the most abundant ion species, followed by O+, H2+ and H2O+. For O+ and O2+, the majority of ions produced impact the moon's surface, while for the other species the majority escapes Ganymede's magnetosphere. For all ion species, the escape occurs either in the direction of corotation of the Jovian plasma or through the Alfvén wings.To validate our model, the output of our simulations, performed under the Galileo G2 flyby conditions, are compared to the observations. These include the electron density derived by the plasma wave instrument (PWS), the ion energy spectrogram measured by the plasma analyzer (PLS) and the associated plasma moments (Frank et al., 1997a).On the one hand, the electron density found by our model is consistently underestimated throughout the flyby, being at least one order of magnitude lower compared to observations. We argue that the prime reason for this discrepancy comes from the exospheric density, which may be underestimated. On the other hand, we find a remarkably good agreement between the modeled ion energy spectrogram and that recorded by PLS, providing a validation of the test particle model. Finally, we compare the modeled plasma moments along the G2 flyby with those analyzed by Frank et al. (1997a). The data seems to be more consistent with an ionosphere dominated by O2+ instead of H+ or O+, as suggested previously in the literature. This supports our finding that O2+ is the dominant ion species close to the surface.

International audience; Dedicated in‐situ measurements of Mars' exospheric Ar density by NGIMS/MAVEN highlight profiles displaying two slopes altitude variation. Below 230 km, the Ar density is characterized by scale height of 13.5 ± 1.7 km and above 400 km by scale height of 156 ± 25 km. A comparison with the model HELIOSARES suggests that the most probable origin of the Ar non‐thermal component is the collisional interaction, below the exobase, between the atmospheric Ar and the non‐thermal O atoms produced by the dissociative recombination of O2+. These measurements therefore provide a new approach to constrain one of the main source of Mars' atmospheric escape. They also lead to set up an upper limit on the efficiency of pickup ion sputtering at Mars. The comparison with HELIOSARES suggests that NGIMS detection sensitivity might allow a positive detection of this mechanism if more measurements at high altitude deep in the nightside are performed.

We have simulated the 3D atomic hydrogen density in the Martian upper atmosphere and associated Jeans escape rate during Martian years 28 and 29. The coronal Lyman-α brightness is computed using a 3D radiative transfer model which accounts for the monthly average hydrogen density for these two years and is compared to a large set of observations by Mars Express/SPICAM. The simulated brightness is generally in good agreement with the observations for Ls 330° for Martian year 28 and Ls < 270°, Ls > 340° for Martian year 29, but the model strongly underestimated the brightness for 230 < Ls < 330° for Martian year 28 and 270 < Ls < 340° for Martian year 29. In these simulations the transport of water vapor contributes to the production of hydrogen at high altitudes during southern summer. A possible explanation for the model discrepancy is an underestimate of this water transport, associated with an underestimate of the hygropause altitude and/or an underestimate of the supersaturation of the mesosphere. Considering this discrepancy, we estimate the hydrogen escape rate during these two Martian years to vary by almost two orders of magnitude, between ~10 to 6 × 10 s (equivalent to a global layer of water ~33 to 2000 mm deep every billion years), in agreement with the seasonal variations estimated directly from the fit of the SPICAM observations during the Martian year 28 by Chaffin et al. (2014). Our analysis suggests that episodic dust storms and associated enhancements at high altitude near perihelion are a major factor in the H escape estimates averaged over one martian year or longer periods, but the accumulated water lost at this rate for 4 billion years is much lower than the amount of water needed to form the flow channels observed on Mars.© 2019 Elsevier Inc., This project was partially funded by the Programme National de Planetologie and Programme National Soleil Terre and by the Centre National d'Etudes Spatiales. This work has been partially funded by the European Union Horizon 2020 Programme (H2020 Compet -08-2014) under grant agreement UPWARDS-633127. FGG has been partly funded by the Spanish Ministerio de Ciencia e Innovación , the Agencia Estatal de Investigacion and EC FEDER funds under projects ESP2017-87143-R and RTI2018-100920-J-I00 . We would like to thank G. Lacombe and L. Baggio for their support on the calibration. We thank Allyson Leffler for her careful review of grammatical aspects of this paper. The SPICAM/MEX data used in this study are available through the ESA Planetary Science Archive (PSA, https://archives.esac.esa.int/psa/ ). The monthly average 3D simulated hydrogen exosphere can be found on: https://owncloud.latmos.ipsl.fr/index.php/s/AdUgv9PdipA2rim Appendix A, With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.

A one-dimensional full-particle model of the Martian upper thermosphere-exosphere has been developed, where the Direct Simulation Monte Carlo (DSMC) method is applied to both thermal and non-thermal components. Our full-particle model can self-consistently solve the transition from collisional to collisionless domains in the upper thermosphere, so that the energy deposition from non-thermal energetic components to thermal components in the transition region is properly described. For the solar EUV condition during the Viking-1 measurement (1 EUV case), computed density profiles are in good agreement with those observed by Viking 1 and with the conventional model. For a solar EUV flux six times the Viking-1 condition (6 EUV case), the computed heating efficiency is essentially the same as 1 EUV case but slightly increases by about 10 % below the exobase, and temperature deviates from the conventional model in and above the transition region. This result suggests that the conventional heating efficiency of 0.18 is a good approximation for low (1 EUV case) to moderately strong (6 EUV case) solar EUV conditions but would be inappropriate for an extremely strong solar EUV (up to ~100 times stronger flux) environment. We also find that applying different models of the CO2-O collisional energy transfer rate results in a difference in the calculated exobase temperature by 150 K for 6 EUV case.

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

International audience; In its Grand Finale phase, Cassini traversed a region of the Saturnian system not explored in the preceding 12 years in orbit. These high inclination, highly eccentric orbits took Cassini through the source regions of Saturn kilometric radiation (SKR) on auroral magnetic eld lines, across eld lines that tie the planet to its magnetosphere, the ring system, and through the topside ionosphere near the sub- solar equator just below the ring system. The Radio and Plasma Wave Science (RPWS) instrument studied the conditions in the SKR source region that had only been traversed twice in the entire preceding mission. Near 5 kHz intense narrowband emissions are observed in the Z mode at latitudes above about 10°. Plasma wave phenomena known as VLF saucers were observed on eld lines threading both Enceladus and the ring system, providing evidence of electron beams and quite possibly currents connecting these members of the Saturnian system to the planet. The RPWS found only very small numbers of micronsized dust grains in the region between the rings and the atmosphere. Perhaps some of the most important measurements were of plasma densities and temperatures in Saturn’s equatorial topside ionosphere, providing important information for understanding how the ring system and the ionosphere interact. These observations revealed small- scale structures in the ionospheric densities and large-scale asymmetries associated with ring shadowing. The ionosphere revealed a new plasma wave phenomenon apparently driven by a lower hybrid instability. This paper will summarize evidence of coupling between Saturn, the rings, and the more distant magnetosphere a orded by Cassini’s Grand Finale orbits.

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

International audience; The Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft observed a strong interplanetary coronal mass ejection (ICME) reaching Mars on 13 September 2017. In this work we analyze the interaction between such an extreme event and the Martian induced magnetosphere by means of LATMOS Hybrid Simulation (LatHyS) stationary runs and magnetic field and plasma observations obtained by MAVEN in a time interval from ∼ 5 h before the ICME shock arrival to about 5.5 h after the impact. Detailed comparisons between simulation results and such MAVEN measurements are performed and show that several stages during this interaction can be described through a combination of steady states. LatHyS results show the simulated bow shock is closer to the planet for higher magnetosonic Mach number and solar wind dynamic pressure conditions, in agreement with previous observational studies. MAVEN observations and LatHyS results also suggest a compression on the flanks of the magnetic pile‐up boundary. Finally, simulated H+ and O+ planetary escape rates increase by a factor ∼10 and ∼2.4, respectively, due to the ICME passage through the Martian magnetosphere.

International audience; We study oxygen ion energization in the Mars-solar wind interaction by comparing particle and magnetic field observations on the Mars Atmosphere and Volatile EvolutioN (MAVEN) and Mars Express missions to a global hybrid simulation. We find that large-scale structures of the Martian-induced magnetosphere and plasma environment as well as the Mars heavy ion plume as seen by multispacecraft observations are reproduced by the model. Using the simulation, we estimate the dynamics of escaping oxygen ions by analyzing their distance and time of flight as a function of the gained kinetic energy along spacecraft trajectories. In the upstream region the heavy ion energization resembles single-particle solar wind ion pickup acceleration as expected, while within the induced magnetosphere the energization displays other features including the heavy ion plume from the ionosphere. Oxygen ions take up to 80 s and travel the distance of 20,000 km after their emission from the ionosphere to the induced magnetosphere or photoionization from the neutral exosphere before they have reached energies of 10 keV in the plume along the analyzed spacecraft orbits. Lower oxygen ion energies of 100 eV are reached faster in 10-20 s over the distance of 100-200 km in the plume. Our finding suggests that oxygen ions are typically observed within the first half of their gyrophase if the spacecraft periapsis is on the hemisphere where the solar wind convection electric field points away from Mars.

International audience; The Mars Atmosphere and Volatile EvolutioN Mission (MAVEN) is currently probing the complex Martian environment. Although main structures arising from the interaction between the solar wind (SW) and the induced magnetosphere of Mars can be described using a steady state picture, time‐dependent physical processes modify the response of this obstacle. These processes result from temporal variabilities in the internal and/or external electromagnetic fields and plasma properties. Indeed, the crustal magnetic fields (CF) rotation constantly modifies the intrinsic magnetic field topology relative to the SW. Moreover, the magnetosphere's state is also modified by changes in the interplanetary magnetic field (IMF). In this work we analyze MAVEN magnetic field and plasma measurements obtained on 23 December 2014, between 06:00 UT ‐ 14:15 UT. These measurements suggest the external conditions remained approximately constant when MAVEN was inside the magnetosphere during the first orbit. In contrast, MAVEN observed changes in the IMF orientation before visiting the magnetosphere during the second orbit. To investigate the response of the Martian plasma environment to the CF rotation and IMF variability, we also perform hybrid simulations, using MAVEN observations to set SW external conditions. Simulation results are compared with the MAVEN measurements and show good agreement. Associated recovery timescales of different magnetospheric regions are found to range between ∼ 10 s and ∼ 10 min. Finally, we do not observe large variability in the total planetary H+ and O+ escape rates at different times during this event, although a correlation between the latter and the CFs location is identified.

We simulate the hydrogen density near the exobase of Mars, using the 3-D Martian Global Circulation Model of Laboratoire de Météorologie Dynamique, coupled to an exospheric ballistic model to compute the downward ballistic flux. The simulated hydrogen distribution near the exobase obtained at two different seasons—Ls = 180° and Ls = 270°—is close to Zero Net Ballistic Flux equilibrium. In other words, the hydrogen density near the exobase adjusts to have a balance between the local upward ballistic and the downward ballistic flux due to a short lateral migration time in the exosphere compared to the vertical diffusion time. This equilibrium leads to a hydrogen density n near the exobase directly controlled by the exospheric temperature T by the relation nT5/2 = constant. This relation could be used to extend 1-D hydrogen exospheric model of Mars used to derive the hydrogen density and escape flux at Mars from Lyman-α observations to 3-D model based on observed or modeled exospheric temperature near the exobase, without increasing the number of free parameters. ©2018. American Geophysical Union. All Rights Reserved., This project was partly funded by the Programme National de Planetologie and Programme National Soleil Terre and by the Centre National d'Etudes Spatiales. This work has been partially funded by the European Union Horizon 2020 Programme (H2020 Compet-082014) under grant agreement UPWARDS-633127.

International audience; We present a 3D orbit viewer application capable of displaying science data. 3DView, a web tool designed by the French Plasma Physics Data Centre (CDPP) for the planetology and heliophysics community, has extended functionalities to render space physics data (observations and models alike) in their original 3D context. Time series, vectors, dynamic spectra, celestial body maps, magnetic field or flow lines, 2D cuts in simulation cubes, etc, are among the variety of data representation enabled by 3DView. The direct connection to several large databases, the use of VO standards and the possibility to upload user data makes 3DView a versatile tool able to cover a wide range of space physics contexts. The code is open source and the software is regularly used at Masters Degree level or summer school for pedagogical purposes. The present paper describes the general architecture and all major functionalities, and offers several science cases (simulation rendering, mission preparation, etc.) which can be easily replayed by the interested readers. Future developments are finally outlined.

International audience; We present the Latmos Hybrid Simulation (LatHyS) database, which is dedicated to the investigations of planetary plasma environment. Simulation results of several planetary objects (Mars, Mercury, Ganymede) are available in an online catalogue. The full description of the simulations and their results is compliant with a data model developped in the framework of the FP7 IMPEx project. The catalogue is interfaced with VO-visualization tools such AMDA, 3DView, TOPCAT, CLweb or the IMPEx portal. Web services ensure the possibilities of accessing and extracting simulated quantities/data. We illustrate the interoperability between the simulation database and VO-tools using a detailed science case that focuses on a three-dimensional representation of the solar wind interaction with the Martian upper atmosphere, combining MAVEN and Mars Express observations and simulation results.

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

In the absence of an intrinsic dipole magnetic field, Mars' O+ planetary ions are accelerated by the solar wind. Because of their large gyroradius, a population of these planetary ions can precipitate back into Mars' upper atmosphere with enough energy to eject neutrals into space via collision. This process, referred to as sputtering, may have been a dominant atmospheric loss process during earlier stages of our Sun. Yet until now, a limited number of observations have been possible; Analyzer of Space Plasmas and Energetic Atoms-3/Mars Express observed such a precipitation only during extreme conditions, suggesting that sputtering might be not as intense as theoretically predicted. Here we describe one example of precipitation of heavy ions during quiet solar conditions. Between November 2014 and April 2015, the average precipitating flux is significant and in agreement with predictions. From these measured precipitating fluxes, we estimate that a maximum of 1.0 × 1024 O/s could have been lost due to sputtering.

International audience; The French Plasma Physics Data Centre (CDPP, http://www.cdpp.eu/ ) has been addressing for almost the past 20 years all issues pertaining to natural plasma data distribution and valorization. Initially established by CNES and CNRS on the ground of a solid data archive, CDPP activities diversified with the advent of broader networks and interoperability standards, and through fruitful collaborations (e.g. with NASA/PDS). Providing access to remote data, designing and building science driven analysis tools then became at the forefront of CDPP developments. In the frame of data distribution, the CDPP has provided to the Rosetta Plasma Consortium (RPC), a suite of five different plasma sensors, with the possibility to visualize plasma data acquired by the Rosetta mission through its data analysis tool AMDA. AMDA was used during the operational phase of the Rosetta mission, facilitating data access between different Rosetta PI sensor teams, thus allowing 1/ a more efficient instruments operation planning and 2/ a better understanding of single instrument observations in the context of other sensor measurements and of more global observations. The data are now getting open to the public via the AMDA tool as they are released to the ESA/PSA. These in-situ data are complemented by model data, for instance, a solar wind propagation model (see http://heliopropa.irap.omp.eu ) or illumination maps of 67P (available through http://vespa.obspm.fr ). The CDPP also proposes 3D visualization tool for planetary / heliospheric environments which helps putting data in context (http://3dview.cdpp.eu ); for instance all comets and asteroids in a given volume and for a given time interval can be searched and displayed. From this fruitful experience the CDPP intends to play a similar role for the forthcoming data of the Solar Orbiter, Bepi-Colombo and JUICE missions as it is officially part of several instrument consortia. Beside highlighting the current database and products, the presentation will show how these future data could be presented and valorized through a combined use of the tools and models provided by the CDPP.

International audience