Scientific publications

2026

• Statistical Noise Removal Method for the Mass Spectrum Analyzer onboard BepiColombo/Mio
  
  • Verkercke Sebastien
  • Hadid Lina
  • Aizawa Sae
  • Delcourt Dominique
  • Raines Jim
  • Fränz Markus
  • Saito Yoshifumi
  • Yokota Shoichiro
  • Rojo Mathias
  • Harada Yuki
  • Fontaine Dominique
  • André Nicolas
  • Katra Bruno
  • Verdeil Christophe
  • Modolo Ronan
  • Krupp Norbert
  • Leblanc François
  • Fiethe Björn
  • Fischer Henning
  , 2026. Mercury is one of the two terrestrial planets in our Solar System possessing an intrinsic magnetic field. Being the closest planet to the Sun and having a weak magnetic field, the Hermean magnetic environment is rapidly changing and forms a tightly coupled system with the planet's core and surface. Its closeness to the Sun causes Mercury's surface to undergo extreme conditions, with continuous space weathering that can eject atoms from the surface to form a tenuous atmosphere called an exosphere (Potter & Morgan 1985). As these atoms become ionized, they drift along the magnetic field lines and populate the magnetosphere of Mercury. Part of these ions can re-impact the surface and eject surface atoms, forming a strong coupling between the magnetosphere, the exosphere, and the surface (Potter & Morgan 1990, Leblanc et al. 2003). More than fifty years after the Mariner 10 mission confirmed the presence of Mercury's magnetic field (Ness et al. 1974), the structure of Mercury's magnetosphere and its ionic composition remain poorly understood. The ESA/JAXA BepiColombo mission is currently cruising towards Mercury to study the Hermean environment, from the planet's surface up to its magnetosphere (Benkhoff et al. 2021). The Mass Spectrum Analyzer (MSA) (Delcourt et al. 2016) on board the ESA/JAXA BepiColombo mission collected some data during its cruise phase and during the different planetary swing-bys. The instrument measures the ions' energy, and the Time-Of-Flight (TOF) of the ions entering MSA TOF chamber. A striking feature observed in the data is a large band of detection counts present at similar energies than protons, when a large number of protons are detected by the instrument. This features was attributed to energy straggling, causing a delay in the ions' detection with respect to their theoretical TOF, and accidental counts generated by true start signals and stop signals caused by random noise. As protons are the most abundant ionic species of the solar wind (SW), this straggler induced noise is nearly always present, and contaminates strongly the rest of the measurements. Using the data acquired by MSA in the SW, we derive a generic statistical fit of the noise induced by the proton stragglers, connecting the proton counts to the noise level. By applying our method to re-analyze some of the data collected by MSA during the Mercury swing-bys (MSB), we demonstrate that : 1) the stragglers play an important role in the determination of the spacecraft outgassing rate and confirm that the outgassing follows an exponential decrease; 2) the MSB3 data collected in Mercury's magnetosphere are heavily affected by the stragglers' noise. Using our noise subtraction method provides a refined constraint on the heavy ion populations during MSB3 and further strengthens the evidence ions detections from the O+, Na+, K+-groups. With our results, we try to infer the spatial distributions of the planetary ions during different Mercury flybys. (10.5194/epsc2026-327)
  DOI : 10.5194/epsc2026-327
• Evidence of a cold and dense plasma in the northern polar cap of Mercury
  
  • Rojo Mathias
  • Dandouras Iannis
  • Aizawa Sae
  • Dewey Ryan
  • Raines Jim
  • Liu Zhi-Yang
  • Le Liboux Thomas
  • Coustillet Camille
  • Gonnet Anderson
  • Hadid Lina
  • Harada Yuki
  • Varsani Ali
  • Williamson Hayley
  • Millilo Anna
  • André Nicolas
  • Saito Yoshifumi
  • Murakami Go
  , 2026. The northern polar cap region of Mercury remains poorly explored, as the MESSENGER orbits were close to the surface. Moreover, this region appears to bepopulated by tenuous plasma. The northern polar cap of Mercury was crossed twice during the 4th and 6th flybys of BepiColombo. The Mercury Electron Ana-lyzer onboard BepiColombo allowed the probing of low-energy electrons for the first time in this region since the third flyby of Mariner 10. We show that thenorthern polar cap is populated with dense and cold electrons. Simultaneously, the four ion sensors did not detect any particles. This lack of detection suggests the presence of very cold ions of exospheric origin. Such a measurement challenges current models of Mercury’s exosphere and could be compatible with a closure of Region 1 field aligned currents above the surface. (10.5194/epsc2026-896)
  DOI : 10.5194/epsc2026-896
• Three-dimensional simulations of thermal and non-thermal hydrogen and deuterium escape from Venus
  
  • Li Dan
  • Martinez Antoine
  • Modolo Ronan
  • Chaufray Jean-Yves
  • Aizawa Sae
  • Xu Qiuyu
  • Montmessin Franck
  • Lefèvre Franck
  • Lebonnois Sébastien
  , 2026. The enrichment of Venusian atmospheric D/H ratio is commonly interpreted as evidence for substantial water loss, but its connection to present-day atmospheric escape remains uncertain. Because hydrogen and deuterium can escape through different thermal and non-thermal pathways, quantifying their relative escape rates is essential for assessing the escape fractionation of Venusian water. We present new developments of the LMDZ Venus Planetary Climate Model for the study of H and D escape. Building on the recent thermospheric and ionospheric extension of the model, we have introduced deuterium-bearing species and reactions, allowing the H- and D-bearing species to be followed from the lower atmosphere to the thermosphere. The model is used to compute the thermal escape of H and D and to provide a self-consistent three-dimensional atmospheric and ionospheric background for non-thermal escape calculations. Photochemical escape is investigated with a Monte Carlo test-particle model, while solar-wind-driven ion escape is studied by coupling the Venus PCM outputs to the LatHyS Venus hybrid model. This work provides a unified framework for comparing the main escape channels of H and D at Venus and for estimating the present-day D/H escape fractionation factor. It offers a step toward linking current upper-atmospheric loss processes to the long-term isotopic evolution history of Venusian water. (10.5194/epsc2026-535)
  DOI : 10.5194/epsc2026-535
• A Combined Computational and Experimental Approach to Investigating Volatile-Surface Interactions on Airless Planetary Bodies
  
  • Ricketts Amanda
  • Mclain Jason
  • Yeo Li Hsia
  • Sarantos Menelaos
  • Verkercke Sébastien
  • Morrissey Liam
  , 2026. The surfaces of airless, planetary bodies like the Moon and Mercury are constantly exposed to several processes that eject atoms into the exosphere1,2. While the composition and densities of these exospheres are partially known based on observational data from exploratory missions3, the source of each component is not well understood. This uncertainty necessitates better constraints for accurately interpreting the observed exospheric data, which requires both experimentally constrained measurement and atomistic-level physical insight.Laboratory studies provide valuable measurements of adsorption and desorption behavior, while molecular dynamics (MD) simulations enable direct investigation of the atomic-scale interactions that cannot be resolved experimentally. By combining these approaches, it becomes possible to better constrain the physical mechanisms controlling surface-exosphere interactions on bodies such as Mercury and the Moon.In this work, MD simulations of Na and K adsorption on silica surfaces are combined with thermal stimulated desorption (TSD) experiments of Na and K adsorbed onto silica. The study focuses on understanding how surface coverage and environmental hydroxylation influence adsorption energetics and desorption behavior4. The combined computational and experimental approach not only provides validation between methods, but also demonstrates how MD simulations can explain experimentally observed trends and identify surface processes relevant to planetary environments. Methodology: MD simulations were performed to investigate Na and K adsorption on silica surfaces under varying surface coverages and surface chemistries. Surface binding energies (SBEs) were calculated for adsorbed Na and K atoms to quantify the strength of adsorbate-surface interactions and to identify how adsorption behavior evolves from isolated adsorbates to high-coverage surfaces5. Additional simulations examined H covered silica surfaces to evaluate the effect of hydroxylation on adsorbed Na SBEs.TSD experiments were conducted by collaborators using Na- and K-dosed Apollo samples6. Following adsorbate deposition, samples were heated to approximately 1000K while monitoring desorption behavior to derive activation energies associated with adsorbate release from the surface. The experimental desorption energetics were compared directly with the MD-derived SBEs to investigate the physical origins of the experimentally observed desorption behavior. Results: The combined MD and experimental results demonstrate strong agreement between stimulated adsorption energetics and experimentally observed desorption behavior. Figure 1 displays the SBE distributions of adsorbed Na on a bare silica surface, Na covered surface, and hydroxylated surface.MD simulations show that isolated Na atoms adsorbed directly onto bare silica surfaces form strongly bound adsorption states with SBEs exceeding 5 eV. These energies are larger than the effective experimental detection range of the TSD studies, which are insensitive to adsorption energies above approximately 3.5 eV at the maximum experimental temperature of 1000K. Consequently, strongly bound adsorbates detected in the MD results are unlikely to desorb during experimental heating cycles.This provides important insight into the physical experiments, suggesting that residual adsorbates likely remain on the silica surface between experimental runs despite minimal dosing conditions. Over time, this accumulated coverage may produce increasingly significant Na-Na or K-K interactions and lower-energy adsorption states, consistent with the experimentally observed desorption energies. In this way, the MD simulations provide a physical explanation for experimental behavior that cannot be directly measured.Further MD simulations demonstrate that hydroxylated silica surface significantly reduce adsorbate SBEs relative to bare silica (by ~2.9 eV). This suggests that exposure of experimental samples to ambient atmospheric water or H during sample transfer may hydroxylate undercoordinated surface oxygens, producing weaker adsorption states and lower desorption temperatures in the TSD measurements. Similar hydroxylation processes are also expected on Mercury and the Moon due to solar wind hydrogen implantation, likely resulting in spatially variable adsorption energetics across the planetary surface.Together, these results demonstrate how combining MD simulations with laboratory experiments enables a more reliable interpretation of both datasets while providing improved insight into the surface processes governing volatile behavior on airless planetary bodies. Conclusion: This study demonstrates the strength of integrating MD simulations with laboratory thermal desorption experiments to investigate surface processes on airless planetary bodies. While experiments provide direct measurements of adsorbate desorption behavior, MD simulations reveal the underlying atomic-scale interactions responsible for the observed trends. The combined approach identifies the important roles of surface coverage and hydroxylation in controlling adsorption energetics and explains how experimentally inaccessible strongly bound adsorption states may influence measured desorption behavior.By coupling computational and experimental methods, this work provides a more physically complete understanding of adsorbate-surface interactions and highlights the importance of considering realistic surface environments when interpreting laboratory measurements and modelling planetary surface-exosphere systems. (10.5194/epsc2026-640)
  DOI : 10.5194/epsc2026-640
• On Phase Transition of ITG Turbulence in the Dimits shift
  
  • Marquant Lucien Noël
  • Morel Pierre
  • Gurcan Ozgur
  Plasma Physics and Controlled Fusion, IOP Publishing, 2026. Abstract The transition between turbulent and zonal flow dominated states is investigated by varying the ion temperature gradient in nonlinear gyrokinetic simulations. Independent gradient scans reveal three distinct regimes: a turbulent regime at high gradients, a zonal flow dominated regime with strongly reduced heat transport at low gradients, and an intermediate regime characterized by intermittent switching between these two states. These different regimes can be classified using an order parameter, defined as the fraction of the zonal to total free energy in the system. To assess the memory effects, the temperature gradient is first lowered gradually from high values that result in fully developed turbulence, to lower values in the Dimits shift region that form strong zonal flows, and then is slowly increased back. Once the zonal flows form, and efficiently suppress turbulence, they can persist at higher gradients, leading to an asymmetric response implying a hysteresis loop. It is observed that, in the zonal flow dominated state, the free energy is mostly condensated in the largest radial scale, with a steep slope of the k x spectrum, while in the turbulent state, it exhibits a wider spectrum with two distinct slopes. (10.1088/1361-6587/ae9ac6)
  DOI : 10.1088/1361-6587/ae9ac6
• Occurrence and controls of ~ 1 Hz waves in Mercury’s magnetosphere: insights from MESSENGER observations
  
  • Persson M.
  • Dimmock A.
  • Wahlund J.-E.
  • Morooka M.
  • Yordanova E.
  • Eriksson A.
  • Hadid L. Z.
  • Aizawa S.
  • Khotyaintsev Yu.
  • Edberg N.
  • André M.
  Earth Planets and Space, Springer / Terra Scientific Publishing Company, 2026, 78 (1), pp.180. (10.1186/s40623-026-02516-6)
  DOI : 10.1186/s40623-026-02516-6
• Thermal Non-equilibrium Cycles in a Non-eruptive Pseudo-Streamer
  
  • Froment Clara
  • Masson Sophie
  Solar Physics, Springer Verlag, 2026, 301 (8), pp.118. Thermal non-equilibrium (TNE) is a well-known thermodynamic mechanism, generally studied in coronal loops. These evaporation and condensation cycles are induced by a quasi-steady and stratified heating. Long-period EUV pulsations and coronal rain are two manifestations of TNE. The quasi-periodicity of the cycles is a strong characteristic of TNE as the system dynamically evolves around a thermal equilibrium position that is not reachable. There are recent reports of coronal rain at open-closed boundaries such as fan-spine topologies and pseudo-streamers. However, no definite conclusions were drawn on the physical mechanisms driving these coronal rain events. In this article, we report the detection of long-period EUV pulsations and co-spatial recurring coronal rain showers in a pseudo-streamer observed with the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO). The magnetic topology and evolution of the pseudo-streamer are studied in detail using a combination of potential field source-surface (PFSS) modeling and EUV dynamics. The 2.5-day event exhibits all the characteristic features of previous TNE events reported in coronal loops: periodic EUV pulses appearing sequentially in the different channels, following the ordering of the peaks in their temperature response, and coronal rain showers appearing toward the end of these cycles. We further show that the TNE cycles in the pseudo-streamer occur not only in the closed field but also in the open field. Our observations support the findings of recent numerical studies showing that TNE can also occur in open field regions and at open-closed boundaries. In parallel, interchange reconnection occurs continuously and non-impulsively all along the open-closed boundary as seen in EUV. The interplay between TNE and interchange reconnection may play a role in the release of condensations below the open-closed boundary and should be studied in detail in future works. This observation opens further perspectives for the understanding of TNE in the solar atmosphere and its potential implications for the solar wind. (10.1007/s11207-026-02671-9)
  DOI : 10.1007/s11207-026-02671-9
• Potential Solar Precursors to Magnetic Switchbacks
  
  • Tripathi Durgesh
  • Madjarska Maria S
  • Karpen Judy
  • Velli Marco
  • Froment Clara
  • Pariat Etienne
  • Patsourakos Spiros
  • Raouafi Nour E
  • Rouillard Alexis P
  • Sterling Alphonse C
  • Tziotziou Kostas
  • Wyper Peter F
  Space Science Reviews, Springer Verlag, 2026, 222 (5), pp.60. The origin of magnetic switchbacks-large-amplitude, spherically polarized magnetic-field fluctuations with local polarity inversions shown to be nearly ubiquitous in the inner heliosphere by Parker Solar Probe-is presently one of the most outstanding open questions in solar and heliospheric science. The occurrence of these structures in the young solar wind is a topic of active research, focusing not only on their characteristics and evolution but also on unraveling the puzzle of their origin. We first discuss the potential influence on switchback (SB) formation of large-scale coronal dynamics and restructuring processes that shape and regulate the extended solar corona. Following that, we review the dynamics, physical properties, occurrence rate, and energetics of numerous possible precursor small-scale dynamic events that occur throughout the solar atmosphere, emphasizing their possible roles in creating SBs. Finally, we discuss some recent studies attempting to connect in situ observations of SBs and SB patches with remote-sensing observations, and the related challenges in identifying solar wind source regions precisely and linking in situ observations to transient solar phenomena. We also clarify the terminology used by the solar community to describe small-scale solar phenomena. (10.1007/s11214-026-01312-8)
  DOI : 10.1007/s11214-026-01312-8
• Atomic Simulations of Volatile Coverage on Silicate Surfaces
  
  • Ricketts Amanda
  • Clouter‐gergen Benjamin A
  • Ebel Denton S
  • Georgiou Anastasis
  • Leblanc Francois
  • Sarantos Menelaos
  • Verkercke Sebastien
  • Morrissey Liam S
  Geophysical Research Letters, American Geophysical Union, 2026, 53 (14), pp.e2026GL122334. <div><p>Understanding how surface processes shape exosphere formation on airless bodies is limited by how surface properties influence the ejection of volatiles such as Na. Recent studies show that retention and release are sensitive to surface binding energy (SBE), motivating the need for SBE values as a function of mineral type and surface coverage. Currently, Na SBE values are available only for silica at 0 or 1 monolayer (ML) coverage. Here, we present the first SBE distributions at intermediate coverages (0.1-0.75 ML) on silica, along with the first SBE distributions for Na adsorbed on albite and anorthite from 0 to 1 ML. Increasing coverage shifts SBE distributions to lower energies, with mean SBE decreasing even at 0.1 ML. Results demonstrate that SBE depends nonlinearly on coverage and surface composition. We incorporate findings into sputtering models to quantify their impact on yield and energy distributions, highlighting the importance of coverage-dependent SBEs in exosphere modeling.</p><p>Plain Language Summary Understanding how atoms escape from the surfaces of airless planetary bodies like the Moon and Mercury help scientists explain how their exospheres form. One important factor is how strongly an atom sticks to the surface, known as the surface binding energy (SBE). This sticking strength changes depending on how many atoms are already covering the surface, although past studies have only focused on empty or fully covered surfaces. In our study, we used computer simulations to test several intermediate coverage levels and also examined different types of minerals found on planetary surfaces. We found that when more sodium atoms are already present, newly added atoms stick less strongly. Even a small amount of prior coverage noticeably lowers the SBE. By visualizing where atoms attach, we also saw that sites near already-occupied spots tend to hold atoms less tight. These results can help improve models that predict how atoms are released into exospheres and support better interpretation of upcoming mission data.</p></div> (10.1029/2026GL122334)
  DOI : 10.1029/2026GL122334
• Investigation of homogeneous dielectric barrier discharges sustained in CO2-containing mixtures
  
  • Naudé Nicolas
  • Wang C
  • Bajon C
  • Dap S
  • Guaitella O
  • Guerra V.
  • Silva T
  , 2026.
• Introduction aux Enjeux Environnementaux : le livre
  
  • Rezeau Laurence
  , 2026. Une partie de l’équipe qui a monté l’enseignement obligatoire TEDS (transition écologique pour un développement soutenable) à Sorbonne Université a décidé d’écrire un livre à partir de cette expérience pluridisciplinaire riche. L’objectif de cet ouvrage est de donner à des lecteurs et des lectrices non spécialistes un socle de connaissances pluridisciplinaires pour comprendre les enjeux environnementaux actuels. Il s’agit d’apporter des éléments de réponse aux questions difficiles auxquelles nous devons toutes et tous faire face de façon urgente pour avoir l’espoir de transmettre une planète habitable pour les générations futures. La première partie de l’ouvrage a pour but de consolider les connaissances liées aux enjeux environnementaux : comprendre le fonctionnement de la planète Terre et son évolution, comprendre comment l’accès à une énergie fossile presqu’illimitée impacte ce fonctionnement, analyser les modèles d'évolution possibles pour la société en tenant compte des limites physiques de la planète et en essayant de construire une société juste et équitable. Cette première partie se base sur les connaissances scientifiques bien établies par les spécialistes. Pour autant il n’y a pas de solution simple aux questions posées. La moindre interrogation en matière de transition environnementale débouche sur des problèmes d’acceptabilité sociale, de contestation des résultats scientifiques, de conflits d’intérêt économiques, de conflit de valeurs, d'enjeux politiques de court terme, etc. L’objet de la seconde partie de l’ouvrage est donc de comprendre comment les connaissances scientifiques se construisent et comment nous pouvons y accéder de manière fiable. Des pistes d'appropriation des compétences informationnelles de base nécessaires sont proposées : confrontation des sources, analyse de la pertinence et de la fiabilité d’une source documentaire. Nous proposons ensuite un cadre méthodologique pour analyser une controverse, c'est-à-dire identifier les acteurs, les enjeux, les points de tension, faire une cartographie de la controverse puis envisager les perspectives possibles. Cette partie sera illustrée par une controverse close dont on peut faire le bilan : le tabac est-il dangereux ?
• Analysis of Geomagnetically Induced Currents (GICs) during the May 2024 Gannon storm
  
  • Amaechi Paul O
  • Grodji Franck O
  • Messanga Honore
  • Despirak Irina
  • Ngwira Chigomezyo M
  • Akala Andrew
  • Oyeyemi Elijah
  • Amory-Mazaudier Christine
  • Nishimura Yukitoshi
  • Weygand James M
  Advances in Space Research, Elsevier, 2026. The May 2024 Gannon storm, one of the most intense geomagnetic disturbances (GMDs) in two decades, provides a valuable opportunity to examine geomagnetically induced currents (GICs), their drivers, and impacts on bulk power system resilience. We analyzed GICs over the United States using direct measurements from three North American Electric Reliability Corporation (NERC) monitoring devices, magnetometer-derived proxy indices, and continuous wavelet transform (CWT). The storm featured multiple substorm onsets, supersubstorms (SSSs), and westward electrojet (WEJ). Results show that during the sudden storm commencement on 10 May, magnetic field variations, |dH/dt| reached 80 nT/min at ~54 o MLAT with GICs of up to 70 A recorded by device 10659 (~54 o MLAT) at about 17:08 UT. During the main phase on 10 May, GICs peaked at 128 A at device 10659 around 21:44 UT due to substorm activity in conjunction with Ps6 pulsations. Furthermore, the substorm onset at ~02:00 UT on 11 May was associated with an enhanced |dH/dt| of 437 nT/min at ~56 o MLAT and the largest GIC response to this GMD with a peak of 176 A (device 10659) at 02:04 UT. CWT analysis further suggests that Ps6 magnetic pulsations contributed as secondary driving mechanisms. The recovery phase was characterized by significant GICs up to 120 A at the same device around 08:41 UT, related to coupled magnetospheric drivers, including Pc5 magnetic pulsations and a SSS under magnetic cloud conditions. This storm phase further featured a GIC of 91 A (at 04:32 UT) associated with substorm activity detected during the high-speed stream on 12 May. The study highlights the role of substorms, SSSs, and associated localized magnetic disturbances driven by distinct ICME features, in generating substantial GICs during the recovery phase of intense storms, emphasizing their critical impact on space-weather hazards. (10.1016/j.asr.2026.06.055)
  DOI : 10.1016/j.asr.2026.06.055
• BGES des activités spatiales du LPP, laboratoire en “transition”
  
  • Rezeau Laurence
  • Sahraoui Fouad
  , 2026.
• STAFF Instrument Calibration, Sensitivity, and Performance Evolutions During the Cluster Mission
  
  • Canu P.
  • Bouzid V.
  • Piberne R.
  • Cornilleau-Wehrlin N.
  • Katra R.
  • Carr C.
  • Alconcel L.
  • Yearby K.
  • Robert P.
  • Lacombe C.
  • de Conchy Y.
  • Grison B.
  • Santolik O.
  • Soucek J.
  • Le Contel O.
  • Baraka M.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2026, 131 (6). The Spatio‐Temporal Analysis of Field Fluctuations (STAFF) instruments onboard the Cluster satellites were designed to measure magnetic fluctuations in the 0.2–12 Hz and 0.2–180 Hz frequency ranges from the Search‐Coil Magnetometer (SCM), as well as electromagnetic spectra from the Spectrum Analyzer (SA) in the 8–4,000 Hz range. They provided a considerable amount of data throughout the 24‐year mission. The production and calibration of these data sets were detailed in Robert et al. (2014, https://doi.org/10.5194/gi‐3‐153‐2014 ), which demonstrated its excellent quality and good agreement with the fluxgate magnetometer (FGM) measurements over their common frequency range. The Cluster's 24 years of operation, which far exceed the nominal 2‐year mission, represent the longest flight of search coil magnetometers and offer a unique opportunity to evaluate their performance over such a long period, as well as to compare the results of four initially identical instruments. The present work, based on data now archived at the Cluster Scientific Archive (CSA), examines the evolution of these products after the first 11 years in space, and until the end of the Cluster operations in September 2024. The quality of the measurements, calibration, sensitivities, and their agreement between spacecraft proved to be excellent and remained stable throughout the mission. Comparison of spectra derived from the calibrated waveforms of STAFF (CWF) and FGM shows a very good agreement until the end of operations, a further proof of the high quality of their respective calibrations. (10.1029/2026JA035072)
  DOI : 10.1029/2026JA035072
• BGES des activités spatiales du LPP, laboratoire en “transition”
  
  • Rezeau Laurence
  • Sahraoui Fouad
  , 2026. L’outil GES 1point5 de Labos1point5 permet d’obtenir de manière simple un bilan des émissions de gaz à effet de serre associées aux activités de recherche effectuées hors du laboratoire, ce qui se résume pour le LPP essentiellement à l’exploitation des données des missions spatiales. Le calcul est fait sur la base des publications mentionnant les différentes missions (méthode de Knödelseder et al 2002, 2024). Les résultats obtenus s’avèrent compliqués à exploiter pour envisager une baisse de nos émissions, en particulier parce qu’ils varient de façon considérable d’une année sur l’autre. Nous discuterons de possibles autres instruments de mesure de notre impact, pour essayer de mieux tenir compte de notre activité réelle. Le but des mesures d’impact est de trouver des moyens de baisser cet impact et de vérifier leur efficacité. Dans le contexte actuel de la recherche il est compliqué, voire irréaliste, d’avoir comme seul levier la baisse des publications. Nous discuterons aussi des potentiels leviers de baisse des émissions elles-mêmes.
• Mercury's Eccentric Orbit as a Driver of Significant “Seasonal” Change in Upstream Solar Wind Forcing
  
  • Dewey Ryan M
  • Jackman Caitriona Mary
  • Rojo Mathias
  • Hadid Lina Z
  • Sánchez‐cano Beatriz
  • Bowers Charles F
  • Raines Jim M
  • Lepri Susan T
  • Livi Stefano
  • Coburn Jesse T
  • Aizawa Sae
  • Rivera Yeimy J
  • Sun Weijie
  • Zhao Jiutong
  • Slavin James A
  • Heyner Daniel
  • Hollman Daragh M
  • Shane Alexander D
  Geophysical Research Letters, American Geophysical Union, 2026, 53. <div xmlns="http://www.tei-c.org/ns/1.0"><p>Mercury experiences the most intense and variable solar wind (SW) conditions in the solar system due to its close, eccentric orbit about the Sun. In addition to variation driven by coronal source and solar cycle, the SW arriving at Mercury varies periodically as the planet's heliocentric distance changes by over 50% per orbit. We use 30 years of SW measurements near Earth and scale them to Mercury's orbital distance to determine the importance of this "seasonal" change in the SW. We find the seasonal change to be substantial, systematic, and significant, and that it dominates over other sources of variability (e.g., fast vs. slow SW) and even exceeds the relative change at Earth from ICMEs compared to the ambient SW. As a result, Mercury's magnetosphere is expected to exhibit substantial seasonal effects.</p></div> <div xmlns="http://www.tei-c.org/ns/1.0"><head>Plain Language Summary</head><p>The solar wind (SW) is the outermost extent of the Sun's atmosphere, and it flows out supersonically to fill the solar system. The characteristics of the SW vary due to the region of the Sun that produced it as well as where in the solar system it is measured: as it flows away from the Sun, the SW expands and cools so its density decreases sharply. The planet Mercury experiences a high variation in the SW that arrives at it due to these various effects. Mercury's orbit is non-circular so it experiences the strongest "seasonal" change in the SW as it moves closer and further from the Sun. In this study we compare this seasonal change in the SW at Mercury to other sources of variability. We find that the seasonal change affects the characteristics of the SW more than these other sources.</p></div> (10.1029/2026gl123323)
  DOI : 10.1029/2026gl123323
• Progress and innovations in the TCV tokamak research programme
  
  • Theiler C.
  • Adamek J.
  • Agostini M.
  • Alberti S.
  • Alberti G.
  • Aleiferis S.
  • Alessi E.
  • Anastassiou G.
  • Andrèbe Y.
  • Antonenas Y.
  • Apruzzese G.M.
  • Aucone L.
  • Auriemma F.
  • Ayllon-Guerola J.
  • Aymerich E.
  • Bagnato F.
  • Bairaktaris F.
  • Balestri A.
  • Ball J.
  • Balugani S.
  • Baquero-Ruiz M.
  • Bardsley O.
  • Battey A.F.
  • Bechtle S.
  • Bernert M.
  • Bin W.
  • Blanchard P.
  • Boedo J.
  • Bolzonella T.
  • Bonalumi L.
  • Bonisolli M.
  • Bosman T.
  • Bouffet-Klein R.
  • Boyer M.D.
  • Bramucci L.
  • Braunmüller F.
  • Breizman B.N.
  • Brida D.
  • Brown B.
  • Brunner S.
  • Buchli J.
  • Buermans J.
  • Busi D.
  • Camenen Y.
  • Cardinali A.
  • Carli S.
  • Carnevale D.
  • Carpanese F.
  • Carpita M.
  • Casolari A.
  • Castaldo C.
  • Cavedon M.
  • Cazabonne J.
  • Cerovsky J.
  • Chapman-Oplopoiou B.
  • Chellai O.
  • Chervonyi Y.
  • Chlum J.
  • Chmielewski P.
  • Chomiczewska A.
  • Cicioni R.
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  • Zuin M.
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  Nuclear Fusion, IOP Publishing, 2026, 66 (11), pp.116007. Abstract Research on the Tokamak à Configuration Variable addresses a wide range of key questions relevant to ITER and future fusion power plants. Over the past two years, highly productive experimental campaigns have led to major advances across several areas: the ITER baseline scenario; pedestal properties in low-collisionality, peeling-limited conditions; and the development of high- β N , non-inductive regimes. Alternative high-confinement scenarios have likewise received significant attention, with remarkable progress in quasi-continuous exhaust operation, X-point radiator plasmas, and negative triangularity configurations. Substantial achievements were also made in the mitigation or benign termination of runaway electron beams, in elucidating fast-ion loss mechanisms, and in improving exhaust behaviour in both conventional and alternative divertor geometries. These experimental results have been strongly supported by advances in modelling and their direct application to the experiment, ranging from gyrokinetic simulations of core and pedestal turbulence to fluid-based studies of scrape-off layer and divertor physics in diverse geometries. Plasma control has taken on an increasingly important role, with model-based and data-driven approaches now closely intertwined with physics studies. This article provides a overview of these recent activities, together with a brief outlook on forthcoming upgrades and next steps. (10.1088/1741-4326/ae6d12)
  DOI : 10.1088/1741-4326/ae6d12
• Analyse du bilan (BGES) des activités spatiales du LPP
  
  • Rezeau Laurence
  • Sahraoui Fouad
  , 2026. L'outil GES 1point5 de Labos1point5 permet d'obtenir de manière simple un bilan des émissions de gaz à effet de serre associées aux activités de recherche effectuées hors du laboratoire, ce qui se résume pour le LPP essentiellement à l'exploitation des données des missions spatiales. Le résultat obtenu varie dans des proportions importantes d'une année sur l'autre, ce qui rend l'analyse compliquée puisque l'activité réelle de l'équipe n'est pas si variable. Nous analyserons comment ce résultat est lié à notre activité réelle. Nous comparerons la méthode de calcul, initiée par les collègues de l'IRAP, avec celle qui est utilisée pour les autres « grands instruments » dont les émissions sont prises en compte par Labos1point5. L'objectif de ces calculs de bilan est d'avoir un instrument pour évaluer les évolutions de l'impact de notre activité d'une année sur l'autre dans le but de tenter de diminuer cet impact sans dégrader la qualité de la science produite. Nous nous interrogerons sur ce qui est possible pour améliorer le « thermomètre » et le bilan des missions spatiales.
• Operational space exploration of the X-Point Radiator scenario in WEST
  
  • Rivals N
  • Fedorczak N
  • Geulin E
  • Nouailletas R
  • Moiraf D
  • Yang H
  • Havlickova E
  • Meng L
  • Guillemaut C
  • Gunn J P
  • Hennequin P
  • Morales J
  • Manas P
  • Fevre L
  • Gaspar J
  • Ekedahl A
  • Gerardin J
  • Corre Y
  • Maget P
  • Bernert M
  • Henderson S
  • Reimerdes H
  • Tsitrone E
  • Vianello N
  , 2026. Operational space exploration of the X-Point Radiator scenario in WEST
• Evidence of Langmuir/ Z -mode Wave Decay into Z -mode Electromagnetic Radiation in the Solar Wind
  
  • Polanco-Rodríguez F J
  • Krafft C.
  • Savoini P.
  The Astrophysical Journal Letters, Bristol : IOP Publishing, 2026, 1002 (2), pp.L35. The nonlinear decay of Langmuir/ Z -mode waves into electromagnetic Z -mode wave radiation near the plasma frequency is observed for the first time in the solar wind, during the encounter of the Solar Orbiter satellite with an electron beam associated with a type III radio burst. This result was achieved through the high-resolution electric and magnetic field measurements provided by the Radio Plasma Waves instrument on board the spacecraft. The decay process is identified through multiple lines of evidence: satisfaction of Doppler-shifted frequency resonance conditions, strong phase coherence and temporal coincidence between the interacting waves, dominance over competing mechanisms, and full agreement with theoretical predictions. Two-dimensional particle-in-cell simulations, conducted under close beam-plasma conditions, successfully reproduce the key features of the observations. Notably, they suggest that the wave packet observed by Solar Orbiter may be trapped within an extended, nearly flat-bottomed density well, where the decay process is not overcome by wave scattering on random density fluctuations and subsequent mode conversion effects. (10.3847/2041-8213/ae626f)
  DOI : 10.3847/2041-8213/ae626f
• 3D hybrid simulations of self-consistent IP shocks and their interaction with Earth
  
  • Cazzola Emanuele
  • Fontaine Dominique
  • Savoini Philippe
  , 2026. Interplanetary shocks are ubiquitous in the heliosphere in relation or not with solar events such as Stream Interaction Regions and Coronal Mass Ejections. However, their interactions with planetary environments remain poorly understood. In this study, we performed hybrid-PIC simulations of the interaction between interplanetary shocks and a realistic near-Earth environment system. We firstly focused on two aspects: (i) the self-consistent generation of a realistic bow shock–magnetosheath–magnetopause system, and (ii) a stand-alone analysis of the self-consistent evolution of a high-speed stream throughout an interplanetary medium in different scenarios. The latter included quasi-perpendicular, quasi-parallel, and Parker spiral-based scenarios, in order to highlight their profoundly diverse dynamics, as well as the possible formation of large upstream instabilities, such as foreshocks.Finally, we present preliminary findings on the interaction between the realistic near-Earth environment and an interplanetary shock-front and shock-sheath in a quasi-perpendicular scenario. (10.5194/egusphere-egu26-5366)
  DOI : 10.5194/egusphere-egu26-5366
• In-flight performance and first scientific observations of the Search-Coil Magnetometer (SCM) of the Radio and Plasma Waves Investigation (RPWI) onboard the ESA JUICE mission
  
  • Le Khanh T. N.
  • Retino Alessandro
  • Le Contel Olivier
  • Mansour Malik
  • Faure Thomas
  • Baraka Mohammed
  • Stassen Theo
  • Chust Thomas
  • Mirioni Laurent
  • Piberne Rodrigue
  • Santolik Ondrej
  • Soucek Jan
  • Pisa David
  • Khotyaintsev Yuri
  • Cecconi Baptiste
  • Wahlund Jan-Erik
  • Bergman Jan
  • Brown P.
  • Dougherty Michele
  • Masters Adam
  • Barabash S.
  , 2026. The JUpiter ICy moons Explorer (JUICE) mission is the first large-class (L1) mission of ESA Cosmic Vision. JUICE has been launched in April 2023 with an arrival at Jupiter in 2031 and at least four years making detailed plasma observations of Jupiter's magnetosphere and of three of its largest moons (Ganymede, Callisto and Europa). The Radio and Plasma Wave Investigation (RPWI) consortium will carry the most advanced set of electric and magnetic fields sensors ever flown in Jupiter's magnetosphere, which will allow to characterize the radio emission and plasma wave environment of Jupiter and its icy moons. The Search Coil Magnetometer (SCM) of RPWI, combined with the RPWI Low-Frequency receiver (LF), will provide for the first time three-dimensional measurements of magnetic field fluctuations within Jupiter's magnetosphere, with high sensitivity (~10 fT / √Hz at 1 kHz) in the frequency range 0.1 Hz - 20 kHz. Here we present SCM in-flight performance and first scientific observations obtained during its cruise phase, including those from the Lunar-Earth Gravity Assist (LEGA) in August 2024. These observations show a nominal functioning and performance of SCM, in agreement with ground calibrations, together with a rather good magnetic cleanliness of the JUICE spacecraft. Observations during LEGA have also allowed to properly identify a number of plasma boundaries in the Earth’s magnetosphere, such as the magnetopause and the magnetotail current sheet, successfully testing the SCM capability to study such boundaries at Jupiter’s and of Ganymede's magnetosphere. (10.5194/egusphere-egu26-21140)
  DOI : 10.5194/egusphere-egu26-21140
• Experiments and SOLEDGE modelling of X-Point Radiator regimes in WEST
  
  • Rivals N
  • Fedorczak N
  • Yang H
  • Fèvre L
  • Orlacchio F
  • Havlickova E
  • Team West
  , 2026. <div><p>Particle flux to divertor plate Plasma density "Detachment": reduction of particle flux "XPR": Stable toroidal radiation ring located at the X-Point, (= "stable MARFE"), observed in many machines, associated with divertor heat flux reduction Colloque FR-FCM -N.</p></div>
• Theoretical ion sputtering yields from loose powders using a multiscale Monte Carlo approach
  
  • Verkercke Sébastien
  • Berhanu Deborah
  • Bu Caixia
  • Clouter-Gergen Ben
  • Leblanc François
  • Lewis Jesse R
  • Morrissey Liam S
  • Savin Daniel W
  Journal of Applied Physics, American Institute of Physics, 2026, 139, pp.145302. Ion sputtering from loose powders remains poorly understood despite its relevance to planetary science and industry. We developed a multi-scale Monte Carlo model to simulate sputtering from powders, using a higher-fidelity approach for the target geometry compared to voxel-based methods. Simulating Kr+ ions impacting Cu powders and flat slabs, we show that sputtering from loose powders differs markedly from that of flat slabs or rough surfaces. The main differences are: (1) for incident angles α > 0° relative to the bulk normal, the escaping sputtering yield is dominated by backward-directed ejecta for all ion energies; (2) for α ≤ 60°, the yield peaks toward the ion-beam origin, similar to the opposition effect seen in optical observations of airless bodies; (3) the angular distribution peak is half or less than that of a flat slab as ion energy increases, no evolution occurs from primary to secondary knock-on sputtering in the ejecta angular distribution. We attribute these behaviors to the powder’s interconnected voids. Ions penetrate these voids and sputter underlying grains; the ejecta then preferentially escape toward the ion-beam origin, where shadowing is minimal. We derive two fitting functions: (1) relating the escaping sputtering yield of a powder to that of a flat surface, depending only on porosity, incident angle, mean local incidence angle, and the corresponding flat slab yield; (2) providing the double-differential angular distribution of the escaping ejecta for porosities ≥0.49. These provide a potentially universal fitting function of the absolute doubly differential escaping sputtering yield from loose powders. (10.1063/5.0316828)
  DOI : 10.1063/5.0316828
• Low‐Pressure Microwave Air Plasma Decontamination of Black Pepper ( Piper nigrum ): From Microbial Efficacy to Quality Preservation
  
  • Soulier Manon
  • Kais Abderrahmane
  • Maho Thomas
  • Guillot Philippe
  • Muja Cristina
  Plasma Processes and Polymers, Wiley-VCH Verlag, 2026, 23 (4). ABSTRACT This study investigates low‐pressure microwave air plasma as a non‐thermal decontamination approach for spices, using black peppercorns as a model matrix. At 20 Pa and 80 W, the discharge exhibits electron densities of 10 9 –10 10 cm −3 , effective electron temperatures of 0.7 eV, while keeping the substrate temperature below 60°C. Under these conditions 1.2‐log reduction of native aerobic mesophilic and thermophilic flora is achieved after 60 min. Bacillus subtilis spores on peppercorns show a similar 1.2‐log reduction, versus > 6‐log on flat glass carriers, revealing a strong surface shielding effect. UV radiation drives early spore inactivation, while long‐lived reactive species contribute during prolonged exposures. These antimicrobial effects are achieved without significant compromise of the key quality attributes of black pepper. (10.1002/ppap.70165)
  DOI : 10.1002/ppap.70165