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  • Journal article
    Sharan S, Pais A, Amit H, Langlais Bet al., 2025,

    Fluid flow at the top of Jupiter's dynamo region

    , Journal of Geophysical Research: Planets, ISSN: 2169-9097

    The magnetic main field (MF) and secular variation (SV) models for Jupiter can be used to gain insights about the internal dynamo and the flow that drives the field. We use two such models computed from Juno observations up to spherical harmonic degrees 16 and 8 for the MF and SV, respectively. We solve the radial magnetic induction equation in the frozen-flux approximation, at the dynamo region outer boundary assuming zero radial velocity for four large-scale physical flow assumptions- unconstrained, toroidal, tangentially geostrophic and columnar. We find flows with root mean square velocity varying between 100 and 400 km/yr (0.3-1.3 cm/s) when the dynamo region spherical boundary is taken at 0.83 Jupiter radius. Equatorially symmetric, toroidal and non-zonal velocity components are larger than the anti-symmetric, poloidal and zonal components, respectively, for almost all cases. Toroidal and tangentially geostrophic flows display similar velocity values and patterns, despite relying on different physical assumptions. The four inverted solutions indicate that the Jovian interior has dominant eastward flows nearthe Great Blue Spot, in agreement with previous studies. In addition, our more complex flow models shed light on some new features such as a large non-zonal component,meridional flows in the southern hemisphere and field-aligned flows in the north. Finally, our unconstrained flow solution suggests upwelling near the south pole, consistent withn thermal wind theory.
  • Journal article
    Riddell-Young B, Michel SE, Lan X, Tans P, Röckmann T, Dasgupta B, Oh Y, Bruhwiler LMP, Fujita R, Umezawa T, Morimoto S, Miller JBet al., 2025,

    Microbial driver of 2006-2023 CH4 growth indicated by trends in atmospheric δD-CH4 and δ13C-CH4.

    , Proc Natl Acad Sci U S A, Vol: 122

    Methane (CH4) is the second most important greenhouse gas and has been rising following a brief period of stabilization from 1999 to 2006. Determining the cause of this rise is critical for reducing emissions and predicting future climate sensitivity. The carbon and hydrogen stable isotopic composition of atmospheric CH4 is controlled by variability in isotopically distinguishable emission categories and fractionating sink processes. While most studies using atmospheric δ13C-CH4 data suggest a dominantly microbial source for recent CH4 growth, this understanding is not uniform, and uncertainties remain [S. Schwietzke et al., Nature 538, 88-91 (2016), S. Basu et al., Atmos. Chem. Phys. 22, 15351-15377 (2022), J. Thanwerdas, M. Saunois, A. Berchet, I. Pison, P. Bousquet, Atmos. Chem. Phys. 24, 2129-2167 (2024)]. Here, we present a harmonized global measurement record of atmospheric δD-CH4 and estimate emissions from 1999 to 2022 with global isotope mass balance calculations using both carbon and hydrogen isotopic ratios. We conduct thorough uncertainty analyses to separate absolute magnitude and emission trend uncertainties and find with high confidence that trends in δ13C-CH4 and δD-CH4 observations are both consistent with an entirely microbial emission driver of the post-2006 CH4 rise, while fossil fuel emissions have remained relatively stable.
  • Journal article
    Nakamura R, Dudok de wit T, Jones GH, Taylor MGGT, Andre N, Goetz C, Hadid LZ, Hayes LA, Hietala H, Jackman CM, Kepko L, Marchaudon A, Masters A, Owens M, Partamies N, Poedts S, Rae J, Shprits Y, Temmer M, Verscharen D, Wimmer-Schweingruber RFet al., 2025,

    Establishing a European Heliophysics Community (EHC)

    , Annales Geophysicae, Vol: 43, Pages: 855-879, ISSN: 0992-7689

    Europe hosts a large and highly active community of scientists working in the broad domain of Heliophysics. This broad discipline addresses plasmas in the regions of space and atmosphere influenced by the Sun and solar wind. However, this community has historically been fragmented, both geographically and thematically, which has limited the potential for strategic coordination, collaboration, and growth. This has recently prompted a grass-roots community-building effort to foster communication and interactions within the European Heliophysics Community (EHC). This white paper outlines the motivation, priorities, and initial steps towards establishing the EHC, and presents a vision for the future of Heliophysics in Europe. As a crucial first step of this endeavour, a dedicated EHC website is now available: https://www.heliophysics.eu/ (last access: November 2025).
  • Journal article
    Wong HL, Palacios R, Gryspeerdt E, 2025,

    rojak: A Python library and tool for aviation turbulence diagnostics

    , Journal of Open Source Software, Vol: 10, ISSN: 2475-9066

    Aviation turbulence is atmospheric turbulence occurring at length scales large enough (ap proximately 100m to 1km) to affect an aircraft (Sharman, 2016). According to the National Transport Safety Board (NTSB), turbulence experienced whilst onboard an aircraft was theleading cause of accidents from 2009 to 2018 (NTSB, 2021). Clear air turbulence (CAT) is a form of aviation turbulence which cannot be detected by the onboard weather radar. Thus, pilots are unable to preemptively avoid such regions. In order to mitigate this safety risk, CAT diagnostics are used to forecast turbulent regions such that pilots are able to tactically avoidthem.rojak is a parallelised Python library and command-line tool for using meteorological data to forecast CAT and evaluating the effectiveness of CAT diagnostics against turbulence observations. Currently, it supports,1. Computing turbulence diagnostics on meteorological data from the European Centrefor Medium-Range Weather Forecasts’s (ECMWF) ERA5 reanalysis on pressure levels(Hersbach, 2023). Moreover, it is easily extendable through a software update to supportother types of meteorological data.2. Retrieving and processing turbulence observations from Aircraft Meteorological DataRelay (AMDAR) data archived at the National Oceanic and Atmospheric Administration(NOAA)(NCEP Meteorological Assimilation Data Ingest System (MADIS), 2024) andAMDAR data collected via the Met Office MetDB system (Met Office, 2008)3. Computing 27 different turbulence diagnostics, such as the three-dimensional fronto genesis equation (Bluestein, 1993), turbulence index 1 and 2 (Ellrod & Knapp, 1992),negative vorticity advection (Sharman et al., 2006), and Brown’s Richardson tendencyequation (Brown, 1973).4. Converting turbulence diagnostic values into the eddy dissipation rate (EDR) — the International Civil Aviation Organization’s (ICAO) official metric for reporting turbulence (Meteorological Service for International Air Navigati
  • Journal article
    Warwick L, Oetjen H, Murray J, Panditharatne S, Brindley H, Schuettemeyer D, Chen X, Huang Xet al., 2025,

    In situ measurements of ice and snow emissivity in the far-infrared

    , Earth and Space Science, Vol: 12, ISSN: 2333-5084

    This paper describes the first field deployment of the Far INfrarEd Spectrometer for Surface Emissivity far-infrared Fourier transform spectrometer to an Arctic environment and shows retrievals of the emissivity of ice and snow in the wavenumber range 400–1,200 cm−1 at viewing angles of 35° and 50°. The retrieved ice emissivity shows a variation of 0.05 between the peak value at around 950 cm−1 and the minimum value at around 750 cm−1. The emissivity is also between 0.01 and 0.02 lower for the higher viewing angle. The emissivity of snow is higher and shows less variation with both viewing angle and wavenumber but it is 0.01 less than one below 900 cm−1. This has implications for remote sensing and climate modeling in this wavenumber range as it implies that both the spectral and angular variation of emissivity must be taken into account. The retrieved ice emissivity agrees well with the emissivity modeled using Fresnel equations. The retrieved snow emissivity agrees well with modeled snow emissivity but further independent measurements of the snow physical properties are needed to test the performance of the model in the far infrared.
  • Journal article
    Stedman M, Hunt SE, De Vis P, Bantges R, Brindley H, Fox Net al., 2025,

    Impact of characterization on cross-calibration performance for multispectral sensors with SI-traceable satellite mission TRUTHS

    , IEEE Transactions on Geoscience and Remote Sensing, Vol: 63, ISSN: 0196-2892

    A new generation of satellites designed for low-uncertainty, SI-traceable measurements—termed“SITSats”—marks a major advancement in Earth observation (EO) capability. These missions aim to enhance the performance and interoperability of the EO “system of systems.” Among them, the ESA Earth Watch Traceable Radiometry Underpinning Terrestrial- and Helio-Studies (TRUTHS) mission is designedto serve as a “gold-standard” radiometric reference for cross-calibrating EO sensors in the solar reflective domain. In this work, uncertainties in cross-calibration comparisons arising from sensor characterization and design are investigated. A processing chain to prepare collocated data for uncertainty-quantified comparison is presented. This includes steps to perform spectral band adjustment and spatial resampling. Using the TRUTHS hyperspectral imaging spectrometer (HIS)as the reference and Sentinel-2 multispectral imager (MSI) as the target, a simulation study based on high-resolution imagery assesses achievable comparison performance. A subset of uncertainty effects driven by sensor characterization is propagated through the spectral and spatial processing using a Monte Carlo approach. Sentinel-2 data are assumed at 10-m resolution, which is most sensitive to the errors considered. The results highlight the importance of sensor characterization, particularly inherent in-flight wavelength knowledge for target sensors, in such comparisons. Results from the simulation analysis give uncertainty estimates (k = 1) of 0.31% (blue), 0.50% (green), and 0.23% (red) for the combined error effectsarising from sensor characterization and geolocation uncertainty for comparisons over the Libya-4 desert pseudo-invariant calibration sites (PICS) using an instantaneous 205-m square comparison region. Results for more heterogeneous scenes, such as rainforest, still achieve uncertainties of 0.6%–1.2% for the red–green–blue (RGB) ban
  • Journal article
    ,

  • Journal article
    Breul P, Ceppi P, Simpson IR, Woollings Tet al., 2025,

    Seasonal and regional jet stream changes and drivers

    , NATURE REVIEWS EARTH & ENVIRONMENT, Vol: 6, Pages: 824-842
  • Journal article
    Farahat A, Oliveros JCM, Bale SD, 2025,

    Simulation and Design of a CubeSat-Compatible X-Ray Photovoltaic Payload Using Timepix3 Sensors

    , AEROSPACE, Vol: 12
  • Journal article
    Kang H, Choi Y, 2025,

    Estimating Tropical Upper‐Level Cloud Feedback Based on Radiative‐Convective Equilibrium Framework

    , Geophysical Research Letters, Vol: 52, ISSN: 0094-8276

    <jats:title>Abstract</jats:title> <jats:p> Tropical upper‐level cloud (TUC) feedback remains highly uncertain because TUC fraction and its radiative effect respond in complex ways to sea surface temperature (SST) warming. Using a radiative–convective equilibrium (RCE) model, we isolate the radiative impact of TUC changes by adjusting the relative occurrence of clouds and water vapor across the tropics. The resulting TUC feedback parameter, estimated from RCE experiments with observationally constrained versus CMIP6‐derived TUC fractions, is more negative for observational inputs (−1.66 to −1.24 W m <jats:sup>−2</jats:sup>  K <jats:sup>−1</jats:sup> ) and spans a much broader range for CMIP6 inputs (−1.34 to +1.78 W m <jats:sup>−2</jats:sup>  K <jats:sup>−1</jats:sup> ). The stronger negative feedback with observational inputs likely reflects a larger reduction in TUCs with SST warming. In contrast, CMIP6‐based parameters indicate weaker radiative effects of SST‐driven TUC reductions, suggesting that climate models may underestimate this negative feedback. </jats:p>
  • Journal article
    Livadiotis G, Cuesta ME, Khoo LY, Shen MM, Mccomas DJ, Pulupa M, Bale SD, Livi Ret al., 2025,

    Entropy transfer from solar radio bursts to energetic particles

    , SCIENCE ADVANCES, Vol: 11
  • Journal article
    Williams RG, Goodwin P, Ceppi P, Jones CD, MacDougall AHet al., 2025,

    A normalised framework for the Zero Emissions Commitment

    , BIOGEOSCIENCES, Vol: 22, Pages: 7167-7186, ISSN: 1726-4170
  • Journal article
    Lee CO, Christian ER, Sandoval L, Crabtree A, Desai MI, Gkioulidou M, Heber B, Horbury T, Kistler L, Knuth J, Larsen K, Livi S, Lucas GM, Matlin DE, Marbois T, Mccomas DJ, Mitchell JG, Mukherjee J, Rankin JS, Reno C, Schwadron NA, Shrestha BL, Skoug RM, Smith EJ, Starkey MJ, Turner DL, Williams BD, Zirnstein EJet al., 2025,

    Space Weather Science to Enhance Forecasting with the NASA IMAP Active Link for Real-Time (I-ALiRT) System

    , SPACE SCIENCE REVIEWS, Vol: 221, ISSN: 0038-6308
  • Conference paper
    Lin J, Gryspeerdt E, Clark R, 2025,

    Cloud-stereo: a dataset and benchmark for reconstructing atmospheric clouds from stereo images

    , BMVC 2025, Publisher: The British Machine Vision Association and Society for Pattern Recognition

    Obtaining accurate measurements of clouds is a critical problem in atmospheric physics, as accurate modeling of cloud properties allows us to better understand and predict climate change. Stereo camera networks have shown promise in obtaining such measurements, being able to reconstruct detailed cloud fields over multi-km$^2$ domains. However, previous studies on cloud stereo depth estimation have been limited to using traditional (non-learned) matching techniques, due to the absence of suitable training datasets for this challenging domain. In this work, we present a novel dataset (Cloud-Stereo) specifically tailored for cloud depth estimation. The Cloud-Stereo dataset includes: 1) a synthetic dataset for training, comprising 3000 stereo pairs and simulated dense LiDAR depth data, and 2) a high-accuracy real-world dataset consisting of $\approx 120k$ frames acquired from a stereo camera and Doppler Aerosol LiDAR for testing. Using our dataset we benchmark existing learning and non-learning based stereo depth estimation approaches, and demonstrate that fine-tuning on our dataset can lead to significant accuracy improvement for learned methods. We believe this dataset will enable the training of future, more accurate, methods for cloud field reconstruction, enhancing a unique measurement capability for developing and evaluating atmospheric models. The dataset is available at https://cloud-stereo.jacob-lin.com/.
  • Journal article
    Driver OGA, Stettler MEJ, Gryspeerdt E, 2025,

    The ice supersaturation biases limiting contrail modelling are structured around extratropical depressions

    , Atmospheric Chemistry and Physics (ACP), Vol: 25, Pages: 16411-16433, ISSN: 1680-7316

    Contrails are ice clouds formed along aircraft flight tracks, responsible for much of aviation's climate warming impact. Ice-supersaturated regions (ISSRs) provide conditions where contrail ice crystals can persist, but meteorological models often mispredict their occurrence, limiting contrail modelling. This deficiency is often treated by applying local humidity corrections. However, model performance is also affected by synoptic conditions (such as extratropical depressions).Here, composites of ERA5 reanalysis data around North Atlantic extratropical depressions enable a link between their structure and ISSR modelling. ISSRs are structured by these systems: at flight levels, ISSRs occur less frequently in the dry intrusion – descending upper-tropospheric air – than above warm conveyors – where air is lifted. Both ERA5 reanalysis and in situ aircraft observations show this contrast, demonstrating that the model reproduces the fundamental relationship. Individual-ISSR modelling performance (quantified using interpretable metrics) is also structured. Of the rare ISSRs diagnosed in the location associated with the dry intrusion, fewer are confirmed by in situ observations (20 %–25 % precision drop compared to the warm conveyor) and fewer of those observed were diagnosed (13 %–19 % recall drop). Scaling humidity beyond the occurrence rate bias dramatically increases the recall at low precision cost, demonstrating the potential value of scaling approaches designed with different intentions. However, the failure of scaling to improve precision, or the performance in the dry intrusion, implies that there is a need to account for the synoptic weather situation and structure in order to improve ISSR forecasts in support of mitigating aviation's climate impact.
  • Journal article
    Pugsley G, Gryspeerdt E, Nair V, 2025,

    Cloud fraction response to aerosol driven by nighttime processes

    , Proceedings of the National Academy of Sciences of USA, ISSN: 0027-8424
  • Journal article
    Mandikas VG, Voulgarakis A, 2025,

    High-Resolution Numerical Scheme for Simulating Wildland Fire Spread

    , MATHEMATICS, Vol: 13
  • Journal article
    Yufei Y, Timothy H, Domenico T, Lorenzo M, Joseph W, Andrey F, Philippe L, Stuart B, Marc P, Davin L, Michael S, Milan M, Yuri K, Andrea L, Roberto Let al., 2025,

    Ion-scale solitary structures in the solar wind observed by Solar Orbiter and Parker Solar Probe

    , Astrophysical Journal Letters, Vol: 994, ISSN: 2041-8205

    We investigate a class of ion-scale magnetic solitary structures in the solar wind, characterized by distinct magnetic field enhancements and bipolar rotations over spatial scales of several proton inertial lengths. These structures are revisited using high-resolution data from the Solar Orbiter and Parker Solar Probe missions. Using a machine learning-based method, we identified nearly a thousand such structures, providing new insights into their evolution and physical properties. Statistical analysis shows that these structures are more abundant closer to the Sun, with occurrence rates peaking around 30 - 40 Rsun and decreasing farther out. High-cadence measurements reveal that these structures are predominantly found in low-beta (beta <1) environments, with consistent fluctuations in density, velocity, and magnetic field. Magnetic field enhancements are often accompanied by plasma density drops, which, under near pressure balance, limit field increases. This leads to small fractional field enhancements near the Sun (approximately 0.01 at 20 Rsun), making detection challenging. Magnetic field variance analysis indicates that these structures are primarily oblique to the local magnetic field. Alfvénic velocity-magnetic field correlations suggest that most of these structures, unlike most near-Sun solar wind fluctuations, exhibit sunward-directed Alfvenic polarization in the plasma frame. We compare these findings with previous studies, discussing possible generation mechanisms and their implications for the turbulent cascade in the near-Sun Alfvénic solar wind. While these structures might be Alfvénic solitons, vortices, or flux ropes, we refrain from a definitive classification pending further evidence. Further high-resolution observations and simulations are needed to fully understand their origins and impacts.
  • Journal article
    Dasgupta B, Menoud M, van der Veen C, Levin I, Veidt C, Moossen H, Michel SE, Sperlich P, Morimoto S, Fujita R, Umezawa T, Platt S, Zwaaftink CG, Myhre CL, Fisher R, Lowry D, Nisbet EG, France J, Maisch CW, Brailsford G, Moss R, Goto D, Pandey S, Houweling S, Warwick N, Röckmann Tet al., 2025,

    Harmonisation of methane isotope ratio measurements from different laboratories using atmospheric samples

    , Atmospheric Measurement Techniques, Vol: 18, Pages: 6591-6607, ISSN: 1867-1381

    Establishing interlaboratory compatibility among measurements of stable isotope ratios of atmospheric methane (δ<sup>13</sup>C-CH<inf>4</inf> and δD-CH<inf>4</inf>) is challenging. Significant offsets are common because laboratories have different ties to the VPDB or SMOW-SLAP scales. Umezawa et al. (2018) surveyed numerous comparison efforts for CH<inf>4</inf> isotope measurements conducted from 2003 to 2017 and found scale offsets of up to 0.5 ‰ for δ<sup>13</sup>C-CH<inf>4</inf> and 13 ‰ for δD-CH<inf>4</inf> between laboratories. This exceeds the World Meteorological Organisation Global Atmospheric Watch (WMO-GAW) network compatibility targets of 0.02 ‰ and 1 ‰ considerably. We employ a method to establish scale offsets between laboratories using their reported CH<inf>4</inf> isotope measurements on atmospheric samples. Our study includes data from eight laboratories with experience in high-precision isotope ratio mass spectrometry (IRMS) measurements for atmospheric CH<inf>4</inf>. The analysis relies exclusively on routine atmospheric measurements conducted by these laboratories at high-latitude stations in the Northern and Southern Hemispheres, where we assume each measurement represents sufficiently well-mixed air at the latitude for direct comparison. We use two methodologies for interlaboratory comparisons: (I) assessing differences between time-adjacent observation data and (II) smoothing the observed data using polynomial and harmonic functions before comparison. The results of both methods are consistent, and with a few exceptions, the overall average offsets between laboratories align well with those reported by Umezawa et al. (2018). This indicates that interlaboratory offsets remain robust over multi-year periods. The evaluation of routine measurements allows us to calculate the interlaborator
  • Journal article
    Li J-H, Khotyaintsev YV, Graham DB, Horbury T, Louarn Pet al., 2025,

    Solar Orbiter Observations of a Self-Consistent Ion-Scale Magnetic Hole at 0.9AU

    , GEOPHYSICAL RESEARCH LETTERS, Vol: 52, ISSN: 0094-8276
  • Journal article
    Muro GD, Cohen CMS, Xu Z, Leske RA, Cummings AC, Bale S, Berland GD, Christian ER, Cuesta ME, Desai MI, Fraschetti F, Giacalone J, Khoo LY, Labrador A, McComas DJ, Mitchell JG, Pulupa M, Schwadron NA, Shen MMet al., 2025,

    Energy-Dependent SEP Fe/O Abundances During the May 2024 Superstorm

    , SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS, Vol: 23
  • Report
    Clarke B, Barnes C, Keeping T, Sparks N, Heng Lau K, Toumi R, Arrighi J, Singh R, Vahlberg M, Meyer R, Scholz C, Baumgart NJ, Raju E, Koren G, Taylor MA, Stephenson TS, Jones JJ, Campbell JD, Spence JM, Centella-Artola A, Bezanilla-Morlot A, Rubiera J, Bergin C, Yang W, Otto F, Philip S, Kew S, McFarlane B, Douglas K, Vrkic Det al., 2025,

    Climate change enhanced intensity of Hurricane Melissa, testing limits of adaptation in Jamaica and eastern Cuba
  • Journal article
    Von Salzen K, Akingunola A, Cole JNS, Digby RAR, Doherty SJ, Fraser-Leach L, Gryspeerdt E, Sigmond M, Wood Ret al., 2025,

    Reduced aerosol pollution diminished cloud reflectivity over the North Atlantic and Northeast Pacific

    , Nature Communications, Vol: 16, ISSN: 2041-1723

    Over the past several decades, the proportion of solar radiation reflected back into space has declined, accelerating the accumulation of heat within the Earth system. Here we show that the marine cloud reflectivity decreased on average by 2.8 ± 1.2% per decade in the combined North Atlantic and Northeast Pacific regions between 2003 and 2022. The majority of the Earth System Models we analyzed simulated a significantly weaker cloud reflectivity decrease and warming of the sea surface in these regions than observed. In contrast, our simulations using an improved aerosol-climate model reproduce the spatial extent and magnitude of the observed cloud reflectivity decrease. We show that reductions in sulfur dioxide and other aerosol precursors accounted for 69% (range 55−85%) of the cloud reflectivity decrease through aerosol-cloud interactions, consistent with the observed aerosol and cloud trends. This raises the prospect of a continuing cloud reflectivity decrease and an associated warming impact in these regions, given that the emission reductions are projected to persist over the next few decades. Further research is needed to assess whether near-term climate scenarios should be revised to account for the weak cloud reflectivity reductions in the Earth System Models.
  • Journal article
    Sparks N, Toumi R, 2025,

    The impact of global warming on U.S. hurricane landfall: a storyline approach

    , Environmental Research Letters, Vol: 20, ISSN: 1748-9326

    The projection of hurricane activity under climate change is challenging. The Imperial College Storm Model (IRIS) was used to analyse the impact of global warming on North Atlantic hurricane landfall through a storyline approach. The storyline assumes increases of potential intensity (PI) as the cause of change with no changes to tracks or basin frequency. This allows study of both recenttrends and projections for the first time in a consistent way. The observed hurricane intensification is simulated but underestimated. For a +2◦C global warming scenario hurricanes of intensity Category 4 and above become 62% more likely in the basin and nearly twice (92%) more likely at landfall. The future number of hurricanes, their decay and tracks are uncertain and their impact is examined by sensitivity studies. Reduction of the basin count offsets warming driven landfall frequency increases only for weaker hurricanes. The increased frequency and fraction of the most damaging landfalling hurricanes is controlled by changes in PI.
  • Journal article
    Ergun RE, Qi Y, Vo T, Chasapis A, Pathak N, Usanova ME, Sega D, Ahmadi N, George H, Schwartz SJet al., 2025,

    Electron Acceleration in Magnetic Reconnection-driven Turbulence in the Earth's Magnetotail

    , ASTROPHYSICAL JOURNAL, Vol: 993, ISSN: 0004-637X
  • Journal article
    Grimmich N, Settino A, Nykyri HK, Archer MO, Blasl K-A, Pöppelwerth A, Nakamura R, Plaschke Fet al., 2025,

    Comparison of Kelvin–Helmholtz waves observed simultaneously at the dawn and dusk flanks of the Earth’s magnetopause

    , Planetary and Space Science, Vol: 267, ISSN: 0032-0633

    Across the Earth’s magnetopause, unless the magnetic fields stabilise the boundary, the velocity shear between the magnetospheric plasma and the shocked plasma of the solar wind can lead to the Kelvin–Helmholtz instability. This instability can develop into large-scale surface waves and vortices at the magnetopause, causing the different plasma regions to mix, which plays an important role in the transfer of energy across the magnetopause. We know from spacecraft observations and simulations that the way Kelvin–Helmholtz waves grow and evolve can be different at dawn and dusk. However, very few studies have directly observed this phenomenon on both flanks of the magnetopause simultaneously, nor have they provided a consistent explanation for the question of symmetrical or asymmetrical dawn–dusk growth of the waves. By combining measurements from the THEMIS and Cluster missions, we can report here on an event where such a simultaneous observation of the Kelvin–Helmholtz waves is possible.For this event, we investigate and compare the typical wave parameters and the plasma mixing on the two flanks. Our results suggest an asymmetric evolution of the Kelvin–Helmholtz waves at dawn and dusk. Comparing these results with previous studies of simultaneously observed events and linking them to solar wind conditions further shows that this asymmetric growth seems to occur during the Parker spiral IMF, but probably only if the magnetic fields are strong enough to effectively stabilise the boundary at the dusk flank due to field line draping.
  • Journal article
    Cuesta ME, Fraschetti F, Livadiotis G, Farooki HA, Shen MM, Khoo LY, Szalay JR, Rankin JS, Mccomas DJ, Mitchell DG, Christian ER, Mitchell JG, Berland GD, Cohen CMS, Leske RA, Xu Z, Muro GD, Pecora F, Ruffolo D, Matthaeus WH, Giacalone J, Schwadron NA, Desai MI, Dayeh MA, Bale SD, Stevens ML, Livi Ret al., 2025,

    Distinct Solar Energetic Particle Shock Intensity-Diffusion Coefficient Relationships in the Inner Heliosphere

    , ASTROPHYSICAL JOURNAL LETTERS, Vol: 993, ISSN: 2041-8205
  • Journal article
    Halekas JS, Whittlesey P, Larson DE, Stevens ML, Livi R, Bale SDet al., 2025,

    Electrons in the Collisionally Young Solar Wind: Parker Solar Probe Observations

    , ASTROPHYSICAL JOURNAL, Vol: 993, ISSN: 0004-637X
  • Journal article
    Beth A, Galand M, Jia X, Leblanc Fet al., 2025,

    Ion-neutral chemistry at icy moons: the case of Ganymede

    , Monthly Notices of the Royal Astronomical Society, Vol: 544, Pages: 95-112, ISSN: 0035-8711

    Icy moons orbiting giant planets are often described as airless bodies though they host an exosphere where collisions between neutral species are scarce. In the case of Ganymede, the neutral composition is dominated by H2O, H2, and O2. Past observations by Galileo showed that Ganymede hosts an ionosphere and those by Juno revealed the presence of H+3 , an ion species onlystemming from ion-neutral collisions. H+3 detection suggests that ions and neutrals might still collide and be the source of new ion species on icy moons. We examine Ganymede’s ability to host a more diverse ionosphere in terms of ion composition than previously thought and predict its variety. We upgraded our test-particle code of Ganymede’s ionosphere, formerly collisionless,to include ion-neutral collisions in a probabilistic manner. The updated code is applied to three Galileo flybys of Ganymede that were investigated in the absence of chemistry. Both sets of simulations have been compared and the effect of ion-neutral chemistry has been assessed. We show that in the case of an exosphere predominantly composed of H2O, H2, and O2, theionosphere is made not only of their associated cations but also of H+3 , H3O+, and O2H+. Simulations reveal that, depending on the location, the contribution of H+3 and H3O+ to the ion composition may be significant. Strong dayside/nightside and Jovian/anti-Jovian asymmetries in the ion composition are identified. Our findings are key to interpreting Juno and future JUICEion mass spectrometer data sets.
  • Journal article
    McComas DJ, Christian ER, Schwadron NA, Gkioulidou M, Allegrini F, Baker DN, Bzowski M, Clark G, Cohen CMS, Cohen I, Collura C, Cully MJ, Dalla S, Desai MI, Driesman A, Eng D, Fox NJ, Funsten HO, Fuselier SA, Galli A, Giacalone J, Hahn J, Hegarty KP, Horbury T, Horanyi M, Kistler LM, Kubiak MA, Kubota S, Livi S, Lugaz N, Lee CO, Luhmann J, Matthaeus W, Mitchell DG, Mitchell JG, Moebius E, Pope S, Provornikova E, Rankin JS, Reisenfeld DB, Reno C, Richardson JD, Russell CT, Shaw-Lecerf MM, Scherrer J, Skoug RM, Shen MM, Spence HE, Sternovsky Z, Strumik M, Szalay JR, Tapley M, Tokumaru M, Turner DL, Weidner S, Westlake J, Wurz P, Zank GPet al., 2025,

    Interstellar Mapping And Acceleration Probe: The NASA IMAP Mission

    , SPACE SCIENCE REVIEWS, Vol: 221, ISSN: 0038-6308

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