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On June 23rd 2022, BepiColombo performed its second gravity assist maneuver (MFB2) at Mercury. Just like the first encounter with Mercury that took place on October 1st 2021, the spacecraft approached the planet from dusk-nightside to dawn-dayside down to an extremely close distance (within about 200 km altitude from the planet surface). Even though BepiColombo is in a so-called “stacked configuration” during cruise, meaning that the instruments cannot be fully operated yet, these instruments can still make interesting observations. Particularly, despite their limited field-of-view, the particle sensors allow us to get a hint on the ion composition and dynamics very close to the planet well before the forthcoming orbit insertion around Mercury in December 2025. In this study, we present observations of the Mass Spectrum Analyzer (MSA) at Mercury during MFB2. MSA is part of the low energy sensors of the Mercury Plasma Particle Experiment (MPPE) consortium (PI: Y. Saito), which is a comprehensive instrumental suite for plasma, high-energy particle and energetic neutral atom measurements (Saito et al., 2021) onboard the Mercury Magnetospheric Orbiter (Mio). MSA is a “reflectron” time-of-flight spectrometer that provides information on the plasma composition and the three-dimensional distribution functions of ions with energies up to ~ 38 keV/q and masses up to ~ 60 amu (Delcourt et al., 2016). In this study, we show that both H+ and He2+ ions in the 1-10 keV range are present throughout the innermost magnetosphere near closest approach. In addition, during this MFB2 sequence, MSA observations provide evidences of He+ ions with energies of several hundreds of eVs. These ions likely originate from the planet exosphere and are rapidly circulated within the magnetosphere. During the outbound sequence of MFB2, MSA measurements also reveal copious amounts of keV protons of solar wind origin that propagate upstream after being reflected from the bow shock.

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 sheath regions driven by coronal mass ejections (CMEs) are large-scale heliospheric structures where magnetic field fluctuations are observed over various temporal scales. Their internal structure and nature of embedded fluctuations are currently poorly understood. We report here the key characteristics of magnetic field fluctuations in CME-driven sheaths, including their spectral index, intermittency, amplitude and compressibility. The results highlight the gradual formation of sheaths over several days as they propagate through interplanetary and the presence of intermittent coherent structures such as strong current sheets. The Jensen-Shannon permutation entropy and complexity analysis suggest that sheath fluctuations are stochastic, but have lower entropy and higher complexity than the preceding wind. We also show the analysis results during the slow sheath at ~0.5 AU detected by Parker Solar Probe, highlighting that slow CMEs can have prominent sheaths with distinct fluctuation properties.

In this work we present some results from 3D hybrid simulations of the interaction between extreme solar events, such as Coronal Mass Ejections (CMEs) or Co-rotating Interaction Regions (CIRs), and a 3D Earth-like geo-environment. The events are generated and let evolve self-consistently in order to represent their typical realistic Earth-hitting characteristics as described by the averaged profiles obtained from decades of observations at 1 AU. Both shock-less and shock-driven configurations are considered to highlight the differences between the two scenarios in terms of their kinetic dynamics, as well as in terms of the effects on the Bow-Shock / Magnetosheath / Magnetosphere system.

This work illustrates the use of three different digitization techniques to study and valorize a 15th-century engraved tablet discovered during a preventive archaeological excavation in the area of a former convent. The tablet is covered with engraved inscriptions on both sides and includes a musical score. Digitization allowed for an advanced analysis of the inscriptions, and to generate a complete and precise 3D model of the artifact that was used to produce an interactive application deployed both on tactile tablets and websites. The interactive application integrates a musical interpretation of the score that gives access to a testimony of intangible heritage. This interdisciplinary work gathered archaeologists, researchers from computer science and physics, and a professional musician.

Plusieurs plaques de schiste gravees ont ete mises au jour lors de la fouille du couvent des Jacobins de Rennes qui s’est deroulee entre 2011 et 2013. Parmi les noms, les dessins ou les caricatures, une portee musicale a retenu l’attention des archeologues, peu accoutumes a ce genre de decouverte. Une soprano specialisee en chants religieux anciens a donc ete sollicitee afin d’approfondir l’analyse de ce temoignage rare date du XVe siecle. Cette collaboration a permis de decrypter la petite œuvre et d’en proposer une interpretation qui enrichit d’une dimension inhabituelle les nombreux resultats de la fouille (http://www.irisa.fr/immersia/tablette-jacobins/).

We present an automatic classification method of the three near-Earth regions, the magnetosphere, the magnetosheath and the solar wind from their in-situ data measurement by multiple spacecraft. Ba...

Glioblastomas (GBM) are Grade IV gliomas that are highly aggressive, lethal primary brain tumors. They are extremely heterogenous tumors both at a cellular and molecular level, harboring diverse oncogenes and mutated tumor suppressor genes with both inter- and intra-tumor variability in expression patterns. Currently, the presence of GBM cannot be predicted and they are diagnosed post-surgical resection by histologic evaluation of tumor tissue. There is an urgent, unmet need for the discovery of GBM-specific biomarkers that could precisely predict and monitor the presence of tumors in GBM patients. Over the last seven years we have carried out a prospective, multi-center, clinical study to longitudinally analyze tumor and plasma samples from GBM patients. We have characterized expression levels of microRNAs, mRNAs and proteins isolated from plasma samples collected from GBM patients throughout their treatment and compared these data to clinical and pathological reports for each patient. Our research has identified a set of systemic microRNAs and their targets that can be correlated to tumor burden in GBM patients. Data will be presented to demonstrate how specific sets of molecular markers and secreted proteins can track disease in GBM patients. This study provides insights into how systemically expressed biomarkers in GBM patients can be used in the development of methods for the precise assessment of disease progression and treatment efficacy while being minimally invasive and cost-effective. Combining clinicopathological findings and biomarker profiling will predict treatment outcomes and provide oncologists precise readouts for tumor burden and response to treatment. Furthermore, this research will also provide critically needed criteria for rigorous monitoring of efficacy of all new therapeutic trials for GBM.

International audience; BepiColombo Mio (previously called MMO: Mercury Magnetospheric Orbiter) was successfully launched by Ariane 5 from Kourou, French Guiana on October 20, 2018. The Mercury Plasma/Particle Experiment (MPPE) is a comprehensive instrument package onboard Mio spacecraft used for plasma, high-energy particle and energetic neutral atom measurements. It consists of seven sensors including two Mercury Electron Analyzers (MEA1 and MEA2), Mercury Ion Analyzer (MIA), Mass Spectrum Analyzer (MSA), High Energy Particle instrument for electron (HEP-ele), High Energy Particle instrument for ion (HEP-ion), and Energetic Neutrals Analyzer (ENA). Significant efforts were made pre-flight to calibrate all of the MPPE sensors at the appropriate facilities on the ground. High voltage commissioning of MPPE analyzers was successfully performed between June and August 2019 and in February 2020 following the completion of the low voltage commissioning in November 2018. Although all of the MPPE analyzers are now ready to begin observation, the full service performance has been delayed until Mio’s arrival at Mercury. Most of the fields of view (FOVs) of the MPPE analyzers are blocked by the thermal shield surrounding the Mio spacecraft during the cruising phase. Together with other instruments on Mio including Magnetic Field Investigation (MGF) and Plasma Wave Investigation (PWI) that measure plasma field parameters, MPPE will contribute to the comprehensive understanding of the plasma environment around Mercury when BepiColombo/Mio begins observation after arriving at the planet Mercury in December 2025.

This work will be giving new insights into the global Quasi-Perpendicular interaction effects of the Solar Wind with a realistic three-dimensional terrestrial-like curved Bow Shock (BS) by means of hybrid computer simulations.The Bow-Shock profoundly changes its behavior for different incoming Solar Wind conditions. For Alfvénic Mach numbers greater than a specific threshold, the Bow-Shock shows an intense rippling phenomenon propagating along its surface, as well as the formation of a set of waves in the near-Earth flanks.A similar rippling has been observed from different independent in-situ satellite crossings, as well as studied with ad-hoc computer simulations configured with 2D-planar shocks, conclusively confirming the highly kinetic nature of this phenomenon. Yet, the possible effects of a global three-dimensional curved interaction are still poorly described.As such, we have performed a series of 3D simulations at different Alfvénic Mach numbers, different plasma beta - ratio between the thermal to the magnetic pressures - and different incoming Interplanetary Magnetic Field (IMF) configurations with the hybrid code LatHyS, which was already successfully used for similar past analyses.Particularly, we have found that the ripples follow a pattern not directly driven by the IMF direction as initially expected, but rather a Nose-to-Flanks propagation with the rippling onset region being significantly displaced from the nose position. Additionally, this phenomenon seems to be mainly confined to the plane on where the IMF direction lies, with the perpendicular cross-sections showing only a slight oscillation.Finally, we have observes a significant ions acceleration in the local perpendicular directions along the flanks modulations, which is most likely related to the local IMF-BS normal fluctuations occurring in the ripples boundary.

Solar transients impinging on Earth’s magnetosphere often present a larger velocity than the surrounding solar wind, leading to a different response of the bow shock-magnetosheath system. As such, ...

International audience; A clear understanding of storm-time magnetospheric dynamics is essential for a reliable storm forecasting capability. The dayside magnetospheric response to an interplanetary coronal mass ejection (ICME; dynamic pressure P dyn > 20 nPa and storm-time index SYM-H < −150 nT) is investigated using in situ OMNI, Geotail, Cluster, MMS, GOES, Van Allen Probes, and THEMIS measurements. The dayside magnetic flux content is directly quantified from in situ magnetic field measurements at different radial distances. The arrival of the ICME, consisting of shock and sheath regions preceding a magnetic cloud, initiated a storm sudden commencement (SSC) phase (SYM-H~+50 nT). At SSC, the magnetopause standoff distance was compressed earthward at ICME shock encounter at an average rate~−10.8 Earth radii per hour for~10 min, resulting in a rapid 40% reduction in the magnetospheric volume. The "closed" magnetic flux content remained constant at 170 ± 30 kWb inside the compressed dayside magnetosphere, even in the presence of dayside reconnection, as evident by an outsized flux transfer event containing 160 MWb. During the storm main and recovery phases, the magnetosphere expanded. The dayside magnetic flux did not remain constant within the expanding magnetosphere (110 ± 30 kWb), resulting in a 35% reduction in pre-storm flux content during the magnetic cloud encounter. At that stage, the magnetospheric magnetic flux was eroded resulting in a weakened dayside magnetospheric field strength at radial distances R ≥ 5 R E. It is concluded that the inadequate replenishment of the eroded dayside magnetospheric flux during the magnetosphere expansion phase is due to a time lag in storm-time Dungey cycle. Plain Language Summary A clear understanding of Earth's magnetospheric dynamics is essential for a reliable space weather forecasting capability. To achieve this, we take advantage of the Heliophysics System Observatory's (HSO) multitude of in situ observations in order to, for the first time, quantify the amount of magnetic flux stored in the dayside magnetosphere. The stored magnetic flux shields our ground-based and space-borne assets from adverse space weather events. We examine the dayside magnetic flux content during an encounter with an interplanetary coronal mass ejection (ICME). ICME is a large-scale bundle of magnetic flux and charged particles originating from the Sun. Upon arrival, the ICME which occupied nearly one third of the space between the Sun and Earth forced the dayside magnetosphere to rapidly shrink down to geosynchronous orbit where most communications and weather satellites are located. Though the dayside magnetosphere significantly shrunk, its magnetic flux content remained constant. It was only when the dayside magnetosphere started to expand that the dayside magnetospheric flux content gradually reduced by 35%. It is concluded that, during large ICME encounters, the rate at which dayside magnetic flux is transported to the magnetotail is faster than the rate at which magnetic flux is recycled, via a process known as the Dungey cycle. In addition to the observed loss in magnetic flux, this time lag in Dungey cycle can further cause magnetopause shadowing, wherein significant population of magnetospheric charged particles is lost to solar wind.

The most geoeffective storms in the Space Age have been driven solely by the sheath preceding an interplanetary coronal mass ejection (ICME) or by a combination of the sheath and an ICME magnetic cloud. In the present study, the magnetospheric response to a chain of three independent and well-spaced ICMEs (Pdyn > 15 nPa and Sym-H < -50 nT) spanning one month (December 12, 2015 – January 12, 2016) is investigated using WIND, Cluster, and MMS fields and plasma measurements. The first of the three ICMEs consists of a sheath preceding an ICME (ICME-SH). The latter two ICMEs are preceded by a combination of the sheath and an ICME magnetic cloud (ICME-SH-MC).Following the passage of the first ICMEs (ICME-SH) the interplanetary environment was made up of moderate Alfvenic Mach number (MA ~ 10) and average magnetopause standoff distance (RMP ~ 11 RE). The arrival of the ICME-SH-MC then initiated a sudden storm commencement (SSC) phase. During the SSC, the storm index (Sym-H ~ +50 nT) remained positive through the ICME shock and sheath regions. The storm index and the Alfvenic Mach number sharply declined (Sym-H~ -200 nT and MA ~ 1.0, respectively) with the arrival of the leading edge of the magnetic cloud (BIMF, core ~ 20 nT) and the associated sharp IMF Bz reversal (Bzz are found to directly correlate with the Sym-H index. ICME-SH-MC compressed the magnetopause standoff distance (∂RMP/∂t ~ -1 RE/min), resulting in a sudden reduction in the total magnetospheric volume (∂VMP/∂t ~ -3×102 RE3/min), as determined by cross-scale observations. In particular, the sharp drops in the magnetospheric volume (relative change in volume >30%) with the arrival of each of the three independent ICMEs are shown to start with the SSC and remain low through the main phase, before slowly recovering (∂VMP/∂t ~ +1 RE3/min) to the pre-ICME conditions during the recovery phase.

Full list of authors: Blanc, Michel; Prieto-Ballesteros, Olga; André, Nicolas; Gomez-Elvira, Javier; Jones, Geraint; Sterken, Veerle; Desprats, William; Gurvits, Leonid I.; Khurana, Krishan; Balmino, Georges; Blöcker, Aljona; Broquet, Renaud; Bunce, Emma; Cavel, Cyril; Choblet, Gaël; Colins, Geoffrey; Coradini, Marcello; Cooper, John; Dirkx, Dominic; Fontaine, Dominique; Garnier, Philippe; Gaudin, David; Hartogh, Paul; Hussmann, Hauke; Genova, Antonio; Iess, Luciano; Jäggi, Adrian; Kempf, Sascha; Krupp, Norbert; Lara, Luisa; Lasue, Jérémie; Lainey, Valéry; Leblanc, François; Lebreton, Jean-Pierre; Longobardo, Andrea; Lorenz, Ralph; Martins, Philippe; Martins, Zita; Marty, Jean-Charles; Masters, Adam; Mimoun, David; Palumba, Ernesto; Parro, Victor; Regnier, Pascal; Saur, Joachim; Schutte, Adriaan; Sittler, Edward C.; Spohn, Tilman; Srama, Ralf; Stephan, Katrin; Szegő, Károly; Tosi, Federico; Vance, Steve; Wagner, Roland; Van Hoolst, Tim; Volwerk, Martin; Wahlund, Jan-Erik; Westall, Frances; Wurz, Peter, Europa is the closest and probably the most promising target to search for extant life in the Solar System, based on complementary evidence that it may fulfil the key criteria for habitability: the Galileo discovery of a sub-surface ocean; the many indications that the ice shell is active and may be partly permeable to transfer of chemical species, biomolecules and elementary forms of life; the identification of candidate thermal and chemical energy sources necessary to drive a metabolic activity near the ocean floor. In this article we are proposing that ESA collaborates with NASA to design and fly jointly an ambitious and exciting planetary mission, which we call the Joint Europa Mission (JEM), to reach two objectives: perform a full characterization of Europa's habitability with the capabilities of a Europa orbiter, and search for bio-signatures in the environment of Europa (surface, subsurface and exosphere) by the combination of an orbiter and a lander. JEM can build on the advanced understanding of this system which the missions preceding JEM will provide: Juno, JUICE and Europa Clipper, and on the Europa lander concept currently designed by NASA (Maize, report to OPAG, 2019). We propose the following overarching goals for our Joint Europa Mission (JEM): Understand Europa as a complex system responding to Jupiter system forcing, characterize the habitability of its potential biosphere, and search for life at its surface and in its sub-surface and exosphere. We address these goals by a combination of five Priority Scientific Objectives, each with focused measurement objectives providing detailed constraints on the science payloads and on the platforms used by the mission. The JEM observation strategy will combine three types of scientific measurement sequences: measurements on a high-latitude, low-altitude Europan orbit; in-situ measurements to be performed at the surface, using a soft lander; and measurements during the final descent to Europa's surface. The implementation of these three observation sequences will rest on the combination of two science platforms: a soft lander to perform all scientific measurements at the surface and sub-surface at a selected landing site, and an orbiter to perform the orbital survey and descent sequences. We describe a science payload for the lander and orbiter that will meet our science objectives. We propose an innovative distribution of roles for NASA and ESA; while NASA would provide an SLS launcher, the lander stack and most of the mission operations, ESA would provide the carrier-orbiter-relay platform and a stand-alone astrobiology module for the characterization of life at Europa's surface: the Astrobiology Wet Laboratory (AWL). Following this approach, JEM will be a major exciting joint venture to the outer Solar System of NASA and ESA, working together toward one of the most exciting scientific endeavours of the 21st century: to search for life beyond our own planet. © 2020, The authors received support from the sponsors of their home institutions during the development of their projects, particularly at the two institutes leading this effort: at IRAP, Toulouse, MB and NA acknowledge the support of CNRS, University Toulouse III - Paul Sabatier and CNES. At CAB, Madrid, OPB and JGE acknowledge the support of INTA and Spanish MINECO project ESP2014-55811-C2-1-P and ESP2017-89053-C2-1-P and the AEI project MDM-2017-0737 Unidad de Excelencia "Maria de Maeztu". We would also like to extend special thanks to the PASO of CNES for its precious assistance and expertise in the design of the mission scenario.

We have analysed magnetic field fluctuations in sheath regions ahead of interplanetary coronal mass ejections (CMEs). CME sheaths are one of the key drivers of space weather disturbances, but their detailed structure and formation are relatively poorly understood. The level of magnetic field fluctuations in sheaths is generally much higher than in the ambient solar wind. We compare fluctuation properties in different parts of a sheath observed at the orbit of Earth using by the Wind spacecraft. Our findings show that in general the transition from the preceding solar wind to the sheath generates new fluctuations that are mostly compressive and which increase intermittency. Spectral indices are mostly steeper than the -5/3 Kolmogorov index. The standard p-model did not show a good fit (in either the Kraichnan or Kolmogorov form), but the extended p-model was in a very good agreement. This suggests that turbulence may not be fully developed in CME sheaths in general. Our study also reveals that turbulent properties can vary considerably between different sheaths and in different subregions of the sheath, and can be significantly modified by the presence of small coherent structures. The findings support the view that sheath formation is a complex process with multiple physical mechanisms playing a role in generating the turbulence.

The 21st century is marked by an increasing number of brilliant technological inventions, simulation in the context of virtuality being one of them. Nowadays, the entering of virtual landscapes in various domains of everyday life is quite substantial and that is why interactions between virtuality and landscape constitute both an interesting and legitimate field of research. While focusing on virtuality and landscape against the background of postmodernity and social constructivism, the complexity of the interplay between landscape, aesthetics and atmosphere becomes obvious. To what extend landscape can be artificially manipulated is shown in any kind of computer games. The link to escapism gives proof of social needs and pictures socio-cultural structures. The following article gives a synopsis about the interdependence of postmodernity and social constructivism with regard to landscape and draws conclusions on how cultural and social backgrounds are reflected in virtuality.

In view of the present and still ongoing virtual gaming boom, it seems appropriate to focus on the recent understanding of landscape. Based on observations of physical landscapes in ‘real’ life (in contrast to the virtual one), artificial landscapes are produced in order to make computer games as realistic as possible. Virtual effects in combination to a sophisticated storytelling (which is typical for the postmodern times) favor escapism and bring landscaping up to a new level. The chosen examples of GTA V and Watchdogs 2 are representative for computer games having an accent on the landscaping part. The simulations of Los Angeles and San Francisco show how urban landscape is perceived and in what way it can be manipulated in order to fulfill several actions in the game. From a scientific point of view, the active creation (and designing) of landscape goes back to the social constructivist approach pronating that landscape has to be understood as a dynamic sociocultural product. Social constructivism is rather a contemporary phenomenon rooted in the paradigm shift towards postmodernity.

International audience; Decades of studies have suggested several criteria to detect Interplanetary coronal mass ejections (ICME) in time series from in-situ spacecraft measurements. Among them the most common are an enhanced and smoothly rotating magnetic field, a low proton temperature and a low plasma beta. However, these features are not all observed for each ICME due to their strong variability. Visual detection is time-consuming and biased by the observer interpretation leading to non exhaustive, subjective and thus hardly reproducible catalogs. Using convolutional neural networks on sliding windows and peak detection, we provide a fast, automatic and multi-scale detection of ICMEs. The method has been tested on the in-situ data from WIND between 1997 and 2015 and on the 657 ICMEs that were recorded during this period. The method offers an unambiguous visual proxy of ICMEs that gives an interpretation of the data similar to what an expert observer would give. We found at a maximum 197 of the 232 ICMEs of the 2010-2015 period (recall 84 +-4.5 % including 90% of the ICMEs present in the lists of Nieves-Chinchilla et al. (2015) and Chi et al. (2016). The minimal number of False Positives was 25 out of 158 predicted ICMEs (precision 84+-2.6%). Although less accurate, the method also works with one or several missing input parameters. The method has the advantage of improving its performance by just increasing the amount of input data. The generality of the method paves the way for automatic detection of many different event signatures in spacecraft in-situ measurements.

International audience; The electromagnetic radio emissions known as 'continuum radiation' are widelyobserved for decades in planetary magnetospheres. Although their main sourcelocation is well identified for Earth in the vicinity of the equatorial plasmapause andits generation mechanism generally associated with electrostatic emissions arisingbetween half harmonics of the electron gyro harmonics, many details of theircharacteristics and source are still missing. Recent observations had suggested newfeatures in their description. For example, studies based on the Whisperinstruments have shown that continuum sources can also be located at mid latitudesand can be generated at exact harmonics of the electron frequency. The higherperigee of the present phase of the Cluster extended mission allows the spacecraftto skim the sources regions close to the plasmapause and to explore their latitudinalextension thanks to its polar orbit. This higher perigee also allows to get Peace data,seldom available at the lower perigees earlier in the mission, to characterize theelectrons populations at the origin of these emissions. We present here the firstanalysis of the best events observed so far.

Das Thema ‚Landschaft‘ befasst die Kulturgeographie aus essentialistischer Perspektive seit jeher. Gegenwartig ruckt die Landschaftsthematik insbesondere in den Fokus des Sozialkonstruktivismus. Da Landschaften den Rahmen fur samtliche Lebensbereiche bilden, sehen sich die Bildungseinrichtungen in der Pflicht, das Konstrukt ‚Landschaft‘ mit all ihren Facetten naher auseinanderzusetzen. Auch in den saarlandischen Lehrplanen und Gymnasiallehrwerken sind Landschaftsbetrachtungen Bestandteil des Geographiekonzepts, wobei die aktuelle Schwerpunktsetzung starker dem physisch-geographischen als dem kulturgeographischen Ansatz zuzuordnen ist.

Observations from the MESSENGER spacecraft have considerably enhanced our understanding of the plasma environment at Mercury. In particular, measurements from the Fast Imaging Plasma Spectrometer (FIPS) provide evidences of a variety of ion species of planetary origin (He+, O+, Na+) in the northern dayside cusp and in the nightside plasma sheet. A more comprehensive view of Mercury's plasma environment will be provided by the Bepi Colombo mission that will be launched in 2018. Onboard the Bepi Colombo MMO spacecraft, the MPPE (Mercury Plasma/Particle Experiment) consortium gathers different sensors dedicated to particle measurements. Among these sensors, the Mass Spectrum Analyzer (MSA) is the instrument dedicated to plasma composition analysis. It consists of a top-hat for energy analysis followed by a Time-Of-Flight (TOF) chamber to derive the ion mass. Taking advantage of the spacecraft rotation, MSA will measure three-dimensional distribution functions in one spin (4 s), from energies characteristic of exospheric populations (in the eV range) up to plasma sheet energies (up to ~38 keV/q). A notable feature of the MSA instrument is that the TOF chamber is polarized with a linear electric field that leads to isochronous TOFs and enhanced mass resolution (typically, m/∆m ≈ 40 for ions with energies up to 13 keV/q). At Mercury, this capability is of paramount importance to thoroughly characterize the wide variety of ion species originating from the planet surface. It is thus anticipated that MSA will provide unprecedented information on ion populations in the Hermean environment and hence improve our understanding of the coupling processes at work.

From data of the European incoherent scatter radar EISCAT, and mainly from its tristatic capabilities, statistical models of steady convection in the auroral ionosphere were achieved for various levels of magnetic activity. We propose here to consistently extend these models to the polar cap, by avoiding the use of a pre-defined convection pattern. Basically, we solve the second-order differential equation governing the polar cap convection potential with the boundary conditions provided by these models. The results display the classical twin-vortex convection pattern, with the cell centres around 17 MLT for the evening cell and largely shifted towards midnight (3–3.5 MLT) for the morning cell, both slightly moving equatorward with activity. For moderate magnetic activities, the convection flow appears approximately oriented along the meridian from 10:00 MLT to 22:00 MLT, while in more active situations, it enters the polar cap at prenoon times following the antisunward direction, and then turns to exit around 21:00 MLT. Finally, from these polar cap patterns combined with the auroral statistical models, we build analytical models of the auroral and polar convection expected in steady magnetic conditions.