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  • Journal article
    Phillips C, Bandyopadhyay R, McComas DJ, Bale SDet al., 2023,

    Association of intermittency with electron heating in the near-Sun solar wind

    , MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 519, Pages: L1-L4, ISSN: 0035-8711
  • Journal article
    Trotta D, Hietala H, Horbury T, Dresing N, Vainio R, Wilson L, Plotnikov I, Kilpua Eet al., 2023,

    Multi-spacecraft observations of shocklets at an interplanetary shock

    , MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 520, Pages: 437-445, ISSN: 0035-8711
  • Journal article
    Zomerdijk-Russell S, Masters A, Korth H, Heyner Det al., 2023,

    Modelling the time-dependent magnetic fields that BepiColombo will use to probe down into Mercury’s mantle

    , Geophysical Research Letters, Vol: 50, ISSN: 0094-8276

    External solar wind variability causes motion of the magnetopause and changes of this boundary's current structure, and the resulting inductive processes, may be exploited to determine the interior structure of magnetized planets. In preparation for the arrival of the BepiColombo spacecraft at Mercury, we here assess solar wind ram pressure forcing in this planet's environment, through analysis of data acquired by the Helios spacecraft, and the impact on the magnetopause's inducing field. These measurements suggest that BepiColombo will see highly unpredictable solar wind conditions and that the inducing field generated in response to variable solar wind ram pressure is non-uniform across the planet's surface. The inducing magnetic field spectrum, with frequencies in the range of ∼5.5 x10¯⁵ -1.5 x 10¯²Hz, suggests that the transfer functions derived from the two BepiColombo spacecraft could allow us to obtain a profile of conductivity through Mercury's crust and mantle.
  • Journal article
    De Marco R, Bruno R, Jagarlamudi VK, D'Amicis R, Marcucci MF, Fortunato V, Perrone D, Telloni D, Owen CJ, Louarn P, Fedorov A, Livi S, Horbury Tet al., 2023,

    Innovative technique for separating proton core, proton beam, and alpha particles in solar wind 3D velocity distribution functions

    , ASTRONOMY & ASTROPHYSICS, Vol: 669, ISSN: 0004-6361
  • Journal article
    Maffei S, Eggington JWB, Livermore PW, Mound JE, Sanchez S, Eastwood JP, Freeman MPet al., 2023,

    Climatological predictions of the auroral zone locations driven by moderate and severe space weather events

    , Scientific Reports, Vol: 13, Pages: 1-11, ISSN: 2045-2322

    Auroral zones are regions where, in an average sense, aurorae due to solar activity are most likely spotted. Their shape and, similarly, the geographical locations most vulnerable to extreme space weather events (which we term ‘danger zones’) are modulated by Earth’s time-dependent internal magnetic field whose structure changes on yearly to decadal timescales. Strategies for mitigating ground-based space weather impacts over the next few decades can benefit from accurate forecasts of this evolution. Existing auroral zone forecasts use simplified assumptions of geomagnetic field variations. By harnessing the capability of modern geomagnetic field forecasts based on the dynamics of Earth’s core we estimate the evolution of the auroral zones and of the danger zones over the next 50 years. Our results predict that space-weather related risk will not change significantly in Europe, Australia and New Zealand. Mid-to-high latitude cities such as Edinburgh, Copenhagen and Dunedin will remain in high-risk regions. However, northward change of the auroral and danger zones over North America will likely cause urban centres such as Edmonton and Labrador City to be exposed by 2070 to the potential impact of severe solar activity.
  • Journal article
    Clear CP, Uylings P, Raassen T, Nave G, Pickering JCet al., 2023,

    New Ritz wavelengths and transition probabilities for parity-forbidden, singly ionized nickel [Ni II] lines of astrophysical interest

    , Monthly Notices of the Royal Astronomical Society, Vol: 519, Pages: 4040-4046, ISSN: 0035-8711

    We report accurate Ritz wavelengths for parity-forbidden [Ni II] transitions, derived from energy levels determined using high-resolution Fourier transform spectroscopy. Transitions between the 18 lowest Ni II energy levels of even-parity produced Ritz wavelengths for 126 parity-forbidden lines. Uncertainties for the Ritz wavelengths derived in this work are up to two orders of magnitude lower than previously published values. Transition probabilities were calculated using the semi-empirical orthogonal operator method, with uncertainties ranging from approximately 1 per cent for strong M1 lines and up to 10 per cent for weak E2 lines. Accurate forbidden line wavelengths and transition probabilities, particularly for lines in the infrared, are important in the analyses of low-density astrophysical plasmas, such as supernova remnants, planetary nebulae, and active galactic nuclei.
  • Journal article
    Breul P, Ceppi P, Shepherd TG, 2023,

    Revisiting the wintertime emergent constraint of the southern hemispheric midlatitude jet response to global warming

    , Weather and Climate Dynamics, Vol: 4, Pages: 39-47, ISSN: 2698-4016

    Most climate models show a poleward shift of the southern hemispheric zonal-mean jet in response to climate change, but the inter-model spread is large. In an attempt to constrain future jet responses, past studies have identified an emergent constraint between the climatological jet latitude and the future jet shift in austral winter. However, we show that the emergent constraint only arises in the zonal mean and not in separate halves of the hemisphere, which questions the physicality of the emergent constraint. We further find that the zonal-mean jet latitude does not represent the latitude of a zonally coherent structure, due to the presence of a double-jet structure in the Pacific region during this season. The zonal asymmetry causes the previously noted large spread in the zonal-mean climatology but not in the response, which underlies the emergent constraint. We therefore argue that the emergent constraint on the zonal-mean jet cannot narrow down the spread in future wind responses, and we propose that emergent constraints on the jet response in austral winter should be based on regional rather than zonal-mean circulation features.
  • Journal article
    Vuorinen L, Lamoury A, Masongsong E, Hietala Het al., 2023,

    SPACE RAINDROPS SPLASHING ON EARTH’S MAGNETIC UMBRELLA

    , Eos (United States), Vol: 104, Pages: 35-39, ISSN: 0096-3941

    Every few minutes, enormous “droplets” of plasma rain down from space toward Earth. Instead of crashing catastrophically to the ground, these droplets, called magnetosheath jets, are deflected by the outer reaches of Earth’s magnetic field. Despite the frequent occurrence of magnetosheath jets near Earth and their likely ubiquity across the solar system, their study is young and there is much we do not know about their origins and behavior. Specifi-cally, their potential effects on space weather—the phenomena we experience on Earth due to the ever changing stream of plasma that flows through our solar system—are unclear and still being investigated. Therefore, these jets are currently not factored into space weather models or predictions. Here we dis-cuss recent findings in this field and important questions that remain to be answered.
  • Journal article
    Lotz S, Nel AE, Wicks RT, Roberts OW, Engelbrecht NE, Strauss RD, Botha GJJ, Kontar EP, Pitna A, Bale SDet al., 2023,

    The Radial Variation of the Solar Wind Turbulence Spectra near the Kinetic Break Scale from Parker Solar Probe Measurements

    , ASTROPHYSICAL JOURNAL, Vol: 942, ISSN: 0004-637X
  • Conference paper
    Eckersley S, Rowe S, Hill W, Forsyth C, Wicks R, Eastwood J, Brown P, Dániel V, Gromeš J, Junas M, Ryden K, Heil M, Terzo S, Gonzalo AR, Jiggens Pet al., 2023,

    An ESA Nanosatellite Constellation to Monitor Space Weather Effects

    , ISSN: 0074-1795

    Major space weather events have the potential to cause significant damage and disruption to critical terrestrial and space-based infrastructure, including radio communication networks, Global Navigation Satellite Systems (GNSS) and the electricity grid. The continuous monitoring of space weather is therefore crucial for providing advanced warning of potentially destructive events. The European Space Agency (ESA) is in the process of developing the Enhanced Space Weather Monitoring System, which will utilise spacecraft to monitor space weather on and away from the Sun-Earth line (e.g., the ESA Vigil mission). The Distributed Space Weather Sensor System (D3S) will form part of this Enhanced Space Weather Monitoring System and focus on making measurements in the vicinity of the Earth. In early 2021, SSTL was selected to lead an ESA-funded Phase 0/A study titled “SSA P3-SWE-LIII Nanosatellites for D3S”. The aim of the study was to establish the role that nanosatellites can play as part of the D3S space weather monitoring system. Nanosatellite technologies have seen significant performance and capability improvements in recent years, and this was one of the reasons that nanosatellites were of particular interest for this study, along with the benefit of their small size and lower costs. The objective of the Phase 0 study was to analyse the space weather measurement requirements for the mission and identify potential space weather instruments that could be accommodated on a nanosatellite mission. A trade-off of a range of different mission architecture concepts was conducted, and the two most promising concepts were selected for more detailed analysis in the latter half of the Phase 0 study. At the end of Phase 0, ESA selected a concept comprising 6x 16U SSTL CubeSats in a 500-600km Sun-Synchronous Orbit to take forward into Phase A for further definition. The Phase A study focussed on the more detailed design of a precursor demonstration mission comprised of
  • Journal article
    Sioulas N, Huang Z, Shi C, Velli M, Tenerani A, Bowen TA, Bale SD, Huang J, Vlahos L, Woodham LD, Horbury TS, de Wit TD, Larson D, Kasper J, Owen CJ, Stevens ML, Case A, Pulupa M, Malaspina DM, Bonnell JW, Livi R, Goetz K, Harvey PR, MacDowall RJ, Maksimovic M, Louarn P, Fedorov Aet al., 2023,

    Magnetic field spectral evolution in the inner heliosphere

    , Letters of the Astrophysical Journal, Vol: 943, Pages: 1-7, ISSN: 2041-8205

    Parker Solar Probe and Solar Orbiter data are used to investigate the radial evolution of magnetic turbulence between 0.06 ≲ R ≲ 1 au. The spectrum is studied as a function of scale, normalized to the ion inertial scale di. In the vicinity of the Sun, the inertial range is limited to a narrow range of scales and exhibits a power-law exponent of, αB = −3/2, independent of plasma parameters. The inertial range grows with distance, progressively extending to larger spatial scales, while steepening toward a αB = −5/3 scaling. It is observed that spectra for intervals with large magnetic energy excesses and low Alfvénic content steepen significantly with distance, in contrast to highly Alfvénic intervals that retain their near-Sun scaling. The occurrence of steeper spectra in slower wind streams may be attributed to the observed positive correlation between solar wind speed and Alfvénicity.
  • Journal article
    Gingell I, Schwartz SJ, Kucharek H, Farrugia CJ, Fryer LJ, Plank J, Trattner KJet al., 2023,

    Hybrid simulations of the decay of reconnected structures downstream of the bow shock

    , PHYSICS OF PLASMAS, Vol: 30, ISSN: 1070-664X
  • Journal article
    Sun J, Vasko IY, Bale SD, Wang R, Mozer FSet al., 2022,

    Double Layers in the Earth's Bow Shock

    , GEOPHYSICAL RESEARCH LETTERS, Vol: 49, ISSN: 0094-8276
  • Journal article
    Xie X, Myhre G, Shindell D, Faluvegi G, Takemura T, Voulgarakis A, Shi Z, Li X, Xie X, Liu H, Liu X, Liu Yet al., 2022,

    Anthropogenic sulfate aerosol pollution in South and East Asia induces increased summer precipitation over arid Central Asia

    , COMMUNICATIONS EARTH & ENVIRONMENT, Vol: 3
  • Journal article
    Perrone D, Perri S, Bruno R, Stansby D, D'Amicis R, Jagarlamudi VK, Laker R, Toledo-Redondo S, Stawarz JE, Telloni D, De Marco R, Owen CJ, Raines JM, Settino A, Lavraud B, Maksimovic M, Vaivads A, Phan TD, Fargette N, Louarn P, Zouganelis Iet al., 2022,

    Evolution of coronal hole solar wind in the inner heliosphere: Combined observations by Solar Orbiter and Parker Solar Probe

    , ASTRONOMY & ASTROPHYSICS, Vol: 668, ISSN: 0004-6361
  • Journal article
    Koehn G, Desai R, Davies E, Forsyth R, Eastwood J, Poedts Set al., 2022,

    Successive interacting coronal mass ejections: How to create a perfect storm?

    , The Astrophysical Journal: an international review of astronomy and astronomical physics, Vol: 941, ISSN: 0004-637X

    Coronal mass ejections (CMEs) are the largest type of eruptions on the Sun and the main driver of severe space weather at the Earth. In this study, we implement a force-free spheromak CME description within 3D magnetohydrodynamic simulations to parametrically evaluate successive interacting CMEs within a representative heliosphere. We explore CME–CME interactions for a range of orientations, launch time variations, and CME handedness and quantify their geo-effectiveness via the primary solar wind variables and empirical measures of the disturbance storm time index and subsolar magnetopause standoff distance. We show how the interaction of two moderate CMEs between the Sun and the Earth can translate into extreme conditions at the Earth and how CME–CME interactions at different radial distances can maximize different solar wind variables that induce different geophysical impacts. In particular, we demonstrate how the orientation and handedness of a given CME can have a significant impact on the conservation and loss of magnetic flux, and consequently Bz, due to magnetic reconnection with the interplanetary magnetic field. This study thus implicates the identification of CME chirality in the solar corona as an early diagnostic for forecasting geomagnetic storms involving multiple CMEs.
  • Journal article
    Paranicas C, Mauk B, Kollmann P, Clark G, Haggerty D, Westlake J, Liuzzo L, Masters A, Cassidy T, Bagenal F, Bolton Set al., 2022,

    Energetic charged particle fluxes relevant to Ganymede's polar region

    , Geophysical Research Letters, Vol: 49, ISSN: 0094-8276

    The JEDI instrument made measurements of energetic charged particles near Ganymede during a close encounter with that moon. Here we find ion flux levels are similar close to Ganymede itself but outside its magnetosphere and on near wake and open field lines. But energetic electron flux levels are more than a factor of 2 lower on polar and near-wake field lines than on nearby Jovian field lines at all energies reported here. Flux levels are relevant to the weathering of the surface, particularly processes that affect the distribution of ice, since surface brightness has been linked to the open-closed field line boundary. For this reason, we estimate the sputtering rates expected in the polar regions due to energetic heavy ions. Other rates, such as those related to radiolysis by plasma and particles that can reach the surface, need to be added to complete the picture of charged particle weathering.
  • Journal article
    Masters A, Ioannou C, Rayns N, 2022,

    Does Uranus’ asymmetric magnetic field produce a relatively weak proton radiation belt?

    , Geophysical Research Letters, Vol: 49, ISSN: 0094-8276

    Since the Voyager 2 flyby in 1986 the radiation belts of Uranus have presented a problem for physicists. The observations indicate the electron radiation belt is far more intense than the proton radiation belt, and while the electron intensities are close to the upper theoretical limit, proton intensities are well below. Here we propose the relatively weak proton radiation belt could be due to Uranus' asymmetric magnetic field. We model test particle motion through the field to show that perturbations arising from asymmetry are greater the larger the particle gyroradius, predominantly affecting urn:x-wiley:00948276:media:grl65197:grl65197-math-0001100-keV protons. For these particles, more rapid changes in maximum distance from the planet during a bounce motion promote trajectory evolution into regions where they could be lost through impact with the rings, impact with the atmosphere, or to the distant magnetosphere and solar wind. We suggest this could explain a relatively weak proton radiation belt at Uranus.
  • Journal article
    Page B, Bassett N, Lecacheux A, Pulupa M, Rapetti D, Bale SDet al., 2022,

    The <i>l</i>=2 spherical harmonic expansion coefficients of the sky brightness distribution between 0.5 and 7 MHz

    , ASTRONOMY & ASTROPHYSICS, Vol: 668, ISSN: 0004-6361
  • Journal article
    Persson M, Aizawa S, Andre N, Barabash S, Saito Y, Harada Y, Heyner D, Orsini S, Fedorov A, Mazelle C, Futaana Y, Hadid LZ, Volwerk M, Collinson G, Sanchez-Cano B, Barthe A, Penou E, Yokota S, Genot V, Sauvaud JA, Delcourt D, Fraenz M, Modolo R, Milillo A, Auster H-U, Richter I, Mieth JZD, Louarn P, Owen CJ, Horbury TS, Asamura K, Matsuda S, Nilsson H, Wieser M, Alberti T, Varsani A, Mangano V, Mura A, Lichtenegger H, Laky G, Jeszenszky H, Masunaga K, Signoles C, Rojo M, Murakami Get al., 2022,

    BepiColombo mission confirms stagnation region of Venus and reveals its large extent

    , NATURE COMMUNICATIONS, Vol: 13
  • Journal article
    Pathak N, Ergun RE, Qi Y, Schwartz SJ, Vo T, Usanova ME, Hesse M, Phan TD, Drake JF, Eriksson S, Ahmadi N, Chasapis A, Wilder FD, Stawarz JE, Burch JL, Genestreti KJ, Torbert RB, Nakamura Ret al., 2022,

    Evidence of a Nonorthogonal X-line in Guide-field Magnetic Reconnection

    , ASTROPHYSICAL JOURNAL LETTERS, Vol: 941, ISSN: 2041-8205
  • Journal article
    Mousis O, Bouquet A, Langevin Y, Andre N, Boithias H, Durry G, Faye F, Hartogh P, Helbert J, Iess L, Kempf S, Masters A, Postberg F, Renard J-B, Vernazza P, Vorburger A, Wurz P, Atkinson DH, Barabash S, Berthomier M, Brucato J, Cable M, Carter J, Cazaux S, Coustenis A, Danger G, Dehant V, Fornaro T, Garnier P, Gautier T, Groussin O, Hadid LZ, Ize J-C, Kolmasova I, Lebreton J-P, Le Maistre S, Lellouch E, Lunine JI, Mandt KE, Martins Z, Mimoun D, Nenon Q, Munoz Caro GM, Rannou P, Rauer H, Schmitt-Kopplin P, Schneeberger A, Simons M, Stephan K, Van Hoolst T, Vaverka J, Wieser M, Woerner Let al., 2022,

    Moonraker: Enceladus Multiple Flyby Mission

    , PLANETARY SCIENCE JOURNAL, Vol: 3
  • Journal article
    Retino A, Khotyaintsev Y, Le Contel O, Marcucci MF, Plaschke F, Vaivads A, Angelopoulos V, Blasi P, Burch J, De Keyser J, Dunlop M, Dai L, Eastwood J, Fu H, Haaland S, Hoshino M, Johlander A, Kepko L, Kucharek H, Lapenta G, Lavraud B, Malandraki O, Matthaeus W, McWilliams K, Petrukovich A, Pincon J-L, Saito Y, Sorriso-Valvo L, Vainio R, Wimmer-Schweingruber Ret al., 2022,

    Particle energization in space plasmas: towards a multi-point, multi-scale plasma observatory

    , Experimental Astronomy: an international journal on astronomical instrumentation and data analysis, Vol: 54, Pages: 427-471, ISSN: 0922-6435

    This White Paper outlines the importance of addressing the fundamental science theme “How are charged particles energized in space plasmas” through a future ESA mission. The White Paper presents five compelling science questions related to particle energization by shocks, reconnection, waves and turbulence, jets and their combinations. Answering these questions requires resolving scale coupling, nonlinearity, and nonstationarity, which cannot be done with existing multi-point observations. In situ measurements from a multi-point, multi-scale L-class Plasma Observatory consisting of at least seven spacecraft covering fluid, ion, and electron scales are needed. The Plasma Observatory will enable a paradigm shift in our comprehension of particle energization and space plasma physics in general, with a very important impact on solar and astrophysical plasmas. It will be the next logical step following Cluster, THEMIS, and MMS for the very large and active European space plasmas community. Being one of the cornerstone missions of the future ESA Voyage 2050 science programme, it would further strengthen the European scientific and technical leadership in this important field.
  • Journal article
    Roussos E, Allanson O, Andre N, Bertucci B, Branduardi-Raymont G, Clark G, Dialynas K, Dandouras I, Desai RT, Futaana Y, Gkioulidou M, Jones GH, Kollmann P, Kotova A, Kronberg EA, Krupp N, Murakami G, Nenon Q, Nordheim T, Palmaerts B, Plainaki C, Rae J, Santos-Costa D, Sarris T, Shprits Y, Sulaiman A, Woodfield E, Wu X, Yao Zet al., 2022,

    The in-situ exploration of Jupiter's radiation belts

    , Experimental Astronomy: an international journal on astronomical instrumentation and data analysis, Vol: 54, Pages: 745-789, ISSN: 0922-6435

    Jupiter has the most complex and energetic radiation belts in our Solar System and one of the most challenging space environments to measure and characterize in-depth. Their hazardous environment is also a reason why so many spacecraft avoid flying directly through their most intense regions, thus explaining how Jupiter’s radiation belts have kept many of their secrets so well hidden, despite having been studied for decades. In this paper we argue why these secrets are worth unveiling. Jupiter’s radiation belts and the vast magnetosphere that encloses them constitute an unprecedented physical laboratory, suitable for interdisciplinary and novel scientific investigations: from studying fundamental high energy plasma physics processes which operate throughout the Universe, such as adiabatic charged particle acceleration and nonlinear wave-particle interactions, to exploiting the astrobiological consequences of energetic particle radiation. The in-situ exploration of the uninviting environment of Jupiter’s radiation belts presents us with many challenges in mission design, science planning, instrumentation, and technology. We address these challenges by reviewing the different options that exist for direct and indirect observations of this unique system. We stress the need for new instruments, the value of synergistic Earth and Jupiter-based remote sensing and in-situ investigations, and the vital importance of multi-spacecraft in-situ measurements. While simultaneous, multi-point in-situ observations have long become the standard for exploring electromagnetic interactions in the inner Solar System, they have never taken place at Jupiter or any strongly magnetized planet besides Earth. We conclude that a dedicated multi-spacecraft mission to Jupiter is an essential and obvious way forward for exploring the planet’s radiation belts. Besides guaranteeing numerous discoveries and huge leaps in our understanding of radiation belt systems, such a mis
  • Journal article
    Rodriguez S, Vinatier S, Cordier D, Tobie G, Achterberg RK, Anderson CM, Badman SV, Barnes JW, Barth EL, Bézard B, Carrasco N, Charnay B, Clark RN, Coll P, Cornet T, Coustenis A, Couturier-Tamburelli I, Dobrijevic M, Flasar FM, Kok RD, Freissinet C, Galand M, Gautier T, Geppert WD, Griffith CA, Gudipati MS, Hadid LZ, Hayes AG, Hendrix AR, Jauman R, Jennings DE, Jolly A, Kalousova K, Koskinen TT, Lavvas P, Lebonnois S, Lebreton J-P, Gall AL, Lellouch E, Mouélic SL, Lopes RMC, Lora JM, Lorenz RD, Lucas A, MacKenzie S, Malaska MJ, Mandt K, Mastrogiuseppe M, Newman CE, Nixon CA, Radebaugh J, Rafkin SC, Rannou P, Sciamma-O-Brien EM, Soderblom JM, Solomonidou A, Sotin C, Stephan K, Strobel D, Szopa C, Teanby NA, Turtle EP, Vuitton V, West RAet al., 2022,

    Science goals and new mission concepts for future exploration of Titan's atmosphere geology and habitability: Titan POlar Scout/orbitEr and In situ lake lander and DrONe explorer (POSEIDON)

    , Experimental Astronomy: an international journal on astronomical instrumentation and data analysis, Vol: 54, Pages: 911-973, ISSN: 0922-6435

    In response to ESA’s “Voyage 2050” announcement of opportunity, we propose an ambitious L-class mission to explore one of the most exciting bodies in the Solar System, Saturn’s largest moon Titan. Titan, a “world with two oceans”, is an organic-rich body with interior-surface-atmosphere interactions that are comparable in complexity to the Earth. Titan is also one of the few places in the Solar System with habitability potential. Titan’s remarkable nature was only partly revealed by the Cassini-Huygens mission and still holds mysteries requiring a complete exploration using a variety of vehicles and instruments. The proposed mission concept POSEIDON (Titan POlar Scout/orbitEr and In situ lake lander DrONe explorer) would perform joint orbital and in situ investigations of Titan. It is designed to build on and exceed the scope and scientific/technological accomplishments of Cassini-Huygens, exploring Titan in ways that were not previously possible, in particular through full close-up and in situ coverage over long periods of time. In the proposed mission architecture, POSEIDON consists of two major elements: a spacecraft with a large set of instruments that would orbit Titan, preferably in a low-eccentricity polar orbit, and a suite of in situ investigation components, i.e. a lake lander, a “heavy” drone (possibly amphibious) and/or a fleet of mini-drones, dedicated to the exploration of the polar regions. The ideal arrival time at Titan would be slightly before the next northern Spring equinox (2039), as equinoxes are the most active periods to monitor still largely unknown atmospheric and surface seasonal changes. The exploration of Titan’s northern latitudes with an orbiter and in situ element(s) would be highly complementary in terms of timing (with possible mission timing overlap), locations, and science goals with the upcoming NASA New Frontiers Dragonfly mission that will provide in situ exploration o
  • Journal article
    Goetz C, Gunell H, Volwerk M, Beth A, Eriksson A, Galand M, Henri P, Nilsson H, Wedlund CS, Alho M, Andersson L, Andre N, De Keyser J, Deca J, Ge Y, Glassmeier K-H, Hajra R, Karlsson T, Kasahara S, Kolmasova I, LLera K, Madanian H, Mann I, Mazelle C, Odelstad E, Plaschke F, Rubin M, Sanchez-Cano B, Snodgrass C, Vigren Eet al., 2022,

    Cometary plasma science Open science questions for future space missions

    , Experimental Astronomy: an international journal on astronomical instrumentation and data analysis, Vol: 54, Pages: 1129-1167, ISSN: 0922-6435

    Comets hold the key to the understanding of our Solar System, its formation and its evolution, and to the fundamental plasma processes at work both in it and beyond it. A comet nucleus emits gas as it is heated by the sunlight. The gas forms the coma, where it is ionised, becomes a plasma, and eventually interacts with the solar wind. Besides these neutral and ionised gases, the coma also contains dust grains, released from the comet nucleus. As a cometary atmosphere develops when the comet travels through the Solar System, large-scale structures, such as the plasma boundaries, develop and disappear, while at planets such large-scale structures are only accessible in their fully grown, quasi-steady state. In situ measurements at comets enable us to learn both how such large-scale structures are formed or reformed and how small-scale processes in the plasma affect the formation and properties of these large scale structures. Furthermore, a comet goes through a wide range of parameter regimes during its life cycle, where either collisional processes, involving neutrals and charged particles, or collisionless processes are at play, and might even compete in complicated transitional regimes. Thus a comet presents a unique opportunity to study this parameter space, from an asteroid-like to a Mars- and Venus-like interaction. The Rosetta mission and previous fast flybys of comets have together made many new discoveries, but the most important breakthroughs in the understanding of cometary plasmas are yet to come. The Comet Interceptor mission will provide a sample of multi-point measurements at a comet, setting the stage for a multi-spacecraft mission to accompany a comet on its journey through the Solar System. This White Paper, submitted in response to the European Space Agency’s Voyage 2050 call, reviews the present-day knowledge of cometary plasmas, discusses the many questions that remain unanswered, and outlines a multi-spacecraft European Space Agency mission
  • Journal article
    Bockelée-Morvan D, Filacchione G, Altwegg K, Bianchi E, Bizzarro M, Blum J, Bonal L, Capaccioni F, Choukroun M, Codella C, Cottin H, Davidsson B, De Sanctis MC, Drozdovskaya MN, Engrand C, Galand M, Güttler C, Henri P, Herique A, Ivanovski S, Kokotanekova R, Levasseur-Regourd A-C, Miller KE, Rotundi A, Schönbächler M, Snodgrass C, Thomas N, Tubiana C, Ulamec S, Vincent J-Bet al., 2022,

    AMBITION – comet nucleus cryogenic sample return

    , Experimental Astronomy, Vol: 54, Pages: 1077-1128, ISSN: 0922-6435

    We describe the AMBITION project, a mission to return the first-ever cryogenicallystored sample of a cometary nucleus, that has been proposed for the ESA ScienceProgramme Voyage 2050. Comets are the leftover building blocks of giant planetcores and other planetary bodies, and fingerprints of Solar System’s formation processes. We summarise some of the most important questions still open in cometaryscience and Solar System formation after the successful Rosetta mission. We showthat many of these scientific questions require sample analysis using techniques thatare only possible in laboratories on Earth. We summarize measurements, instrumentation and mission scenarios that can address these questions. We emphasize the needfor returning a sample collected at depth or, still more challenging, at cryogenic temperatures while preserving the stratigraphy of the comet nucleus surface layers. Weprovide requirements for the next generation of landers, for cryogenic sample acquisition and storage during the return to Earth. Rendezvous missions to the main beltcomets and Centaurs, expanding our knowledge by exploring new classes of comets,are also discussed. The AMBITION project is discussed in the international contextof comet and asteroid space exploration.
  • Journal article
    Yamauchi M, De Keyser J, Parks G, Oyama S-I, Wurz P, Abe T, Beth A, Daglis IA, Dandouras I, Dunlop M, Henri P, Ivchenko N, Kallio E, Kucharek H, Liu YC-M, Mann I, Marghitu O, Nicolaou G, Rong Z, Sakanoi T, Saur J, Shimoyama M, Taguchi S, Tian F, Tsuda T, Tsurutani B, Turner D, Ulich T, Yau A, Yoshikawa Iet al., 2022,

    Plasma-neutral gas interactions in various space environments: Assessment beyond simplified approximations as a Voyage 2050 theme

    , Experimental Astronomy: an international journal on astronomical instrumentation and data analysis, Vol: 54, Pages: 521-559, ISSN: 0922-6435

    In the White Paper, submitted in response to the European Space Agency (ESA) Voyage 2050 Call, we present the importance of advancing our knowledge of plasma-neutral gas interactions, and of deepening our understanding of the partially ionized environments that are ubiquitous in the upper atmospheres of planets and moons, and elsewhere in space. In future space missions, the above task requires addressing the following fundamental questions: (A) How and by how much do plasma-neutral gas interactions influence the re-distribution of externally provided energy to the composing species? (B) How and by how much do plasma-neutral gas interactions contribute toward the growth of heavy complex molecules and biomolecules? Answering these questions is an absolute prerequisite for addressing the long-standing questions of atmospheric escape, the origin of biomolecules, and their role in the evolution of planets, moons, or comets, under the influence of energy sources in the form of electromagnetic and corpuscular radiation, because low-energy ion-neutral cross-sections in space cannot be reproduced quantitatively in laboratories for conditions of satisfying, particularly, (1) low-temperatures, (2) tenuous or strong gradients or layered media, and (3) in low-gravity plasma. Measurements with a minimum core instrument package (< 15 kg) can be used to perform such investigations in many different conditions and should be included in all deep-space missions. These investigations, if specific ranges of background parameters are considered, can also be pursued for Earth, Mars, and Venus.
  • Journal article
    Verscharen D, Wicks RT, Alexandrova O, Bruno R, Burgess D, Chen CHK, D'Amicis R, De Keyser J, de Wit TD, Franci L, He J, Henri P, Kasahara S, Khotyaintsev Y, Klein KG, Lavraud B, Maruca BA, Maksimovic M, Plaschke F, Poedts S, Reynolds CS, Roberts O, Sahraoui F, Saito S, Salem CS, Saur J, Servidio S, Stawarz JE, Stverak S, Told Det al., 2022,

    A case for electron-astrophysics

    , Experimental Astronomy: an international journal on astronomical instrumentation and data analysis, Vol: 54, Pages: 473-519, ISSN: 0922-6435

    The smallest characteristic scales, at which electron dynamics determines the plasma behaviour, are the next frontier in space and astrophysical plasma research. The analysis of astrophysical processes at these scales lies at the heart of the research theme of electron-astrophysics. Electron scales are the ultimate bottleneck for dissipation of plasma turbulence, which is a fundamental process not understood in the electron-kinetic regime. In addition, plasma electrons often play an important role for the spatial transfer of thermal energy due to the high heat flux associated with their velocity distribution. The regulation of this electron heat flux is likewise not understood. By focussing on these and other fundamental electron processes, the research theme of electron-astrophysics links outstanding science questions of great importance to the fields of space physics, astrophysics, and laboratory plasma physics. In this White Paper, submitted to ESA in response to the Voyage 2050 call, we review a selection of these outstanding questions, discuss their importance, and present a roadmap for answering them through novel space-mission concepts.
  • Journal article
    Fletcher LN, Helled R, Roussos E, Jones G, Charnoz S, André N, Andrews D, Bannister M, Bunce E, Cavalié T, Ferri F, Fortney J, Grassi D, Griton L, Hartogh P, Hueso R, Kaspi Y, Lamy L, Masters A, Melin H, Moses J, Mousis O, Nettleman N, Plainaki C, Schmidt J, Simon A, Tobie G, Tortora P, Tosi F, Turrini Det al., 2022,

    Ice giant system exploration within ESA’s Voyage 2050

    , Experimental Astronomy, Vol: 54, Pages: 1015-1025, ISSN: 0922-6435

    Of all the myriad environments in our Solar System, the least explored are the distant Ice Giants Uranus and Neptune, and their diverse satellite and ring systems. These ‘intermediate-sized’ worlds are the last remaining class of Solar System planet to be characterised by a dedicated robotic mission, and may shape the paradigm for the most common outcome of planetary formation throughout our galaxy. In response to the 2019 European Space Agency call for scientific themes in the 2030s and 2040s (known as Voyage 2050), we advocated that an international partnership mission to explore an Ice Giant should be a cornerstone of ESA’s science planning in the coming decade, targeting launch opportunities in the early 2030s. This article summarises the inter-disciplinary science opportunities presented in that White Paper [1], and briefly describes developments since 2019.

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