Due to their proximity, these regions provide excellent laboratories in which to study such processes. Near Earth, the ESA/Cluster and NASA/MMS four-point constellations, as well as the large-scale multipoint NASA/THEMIS mission, have greatly improved our understanding of these plasma processes compared to earlier single-point measurements. However, these missions have also revealed that these processes operate across multiple scales, ranging from large fluid scales to smaller kinetic scales. This implies that multi-scale in situ observations are critical. To resolve scale coupling and ultimately fully understand plasma energisation and energy transport processes, simultaneous measurements at both fluid and kinetic scales are required. Building on previous single-scale missions, the Plasma Observatory (PO) mission represents the next generation of space plasma physics investigations. PO is a seven-spacecraft, multi-scale mission concept designed to study plasma energisation and energy transport in the Earth's magnetosphere simultaneously at fluid and ion scales. These are the scales at which the largest amount of electromagnetic energy is converted into energised particles and energy is transported. Any modelling approach, from global to kinetic, can be applied here.
We particularly welcome studies integrating numerical modeling, theoretical investigations and in-situ measurements/remote observations from past, current and future space missions such as Cluster, MMS, PO, Parker Solar Probe, Solar Orbiter, Bepi Colombo, SMILE, HelioSwarm, SPO...
The ESA M7 mission candidate Plasma Observatory (PMO) proposes a seven-spacecraft constellation, to simultaneously measure plasma characteristics and gradients at both fluid and ion scales simultaneously, to investigate multi-scale cross-coupling processes in the Earth’s magnetosphere and around it. The proposal work is supported by several working groups, one of which is the Group on Simulation Numerical Support (GIANNI). The group is tasked with supporting the proposal's Science Study Team with simulation data, to help evaluate the proposal's science impact, assess possible descoping options and their effects on science output, and provide constraints for the PMO constellation parameters. This presentation introduces the group’s models and capabilities, including the wider collaborations with other working groups stemming from the tasks, such as evaluation of multipoint methods from simulation data. Plasma Observatory science objectives are reviewed with a focus towards numerical modelling avenues.
How to cite: Alho, M., Trotta, D., and Valentini, F. and the Plasma Observatory’s Group on Simulation Numerical Support (GIANNI): Numerical Simulations Supporting Plasma Observatory Proposal: Working Group GIANNI, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20725, https://doi.org/10.5194/egusphere-egu26-20725, 2026.
Understanding energy cascades across multiple scales remains challenging in magnetospheric physics, where processes span from large fluid scales down to kinetic scales. Two-fluid simulations employing local Landau-fluid closures offer a computationally efficient alternative to kinetic simulations for modeling the multiscale plasma dynamics. These closures, derived from linear kinetic theory, approximate kinetic effects while maintaining the computational advantages of fluid descriptions. However, their theoretical validity requires the plasma to remain close to local thermodynamic equilibrium (LTE), a condition frequently violated in magnetospheric phenomena such as turbulence in the magnetosheath and reconnection outflows.
We investigate the performance of two-fluid Landau-fluid models in regimes far from LTE through comparison against benchmark Vlasov simulations. Our results demonstrate that despite operating outside their formal regime of applicability, Landau-fluid closures can accurately reproduce kinetic-scale physics (with some limitations that we will highlight) when the local closure parameter is appropriately chosen. The agreement of energy spectra extends across the kinetic range, capturing the essential energy cascade and dissipation mechanisms.
These findings validate Landau-fluid approaches as a robust tool for large-scale magnetospheric simulations where computational constraints prohibit kinetic treatments. This is particularly relevant for interpreting multiscale observations and resolve scale coupling in key magnetospheric regions.
How to cite: Lautenbach, S., Lübke, J., Innocenti, M. E., Kormann, K., and Grauer, R.: Validation of Landau-Fluid Closures for Kinetic-Scale Plasma Turbulence: A Comparison with Fully Kinetic Simulations , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13407, https://doi.org/10.5194/egusphere-egu26-13407, 2026.
Magnetic reconnection in coronal current sheet(s) is widely believed to be the main energy release process powering solar eruptive events, such as flares, coronal mass ejections (CME), and coronal jets. Modeling this process and determining the channels for the energy release, mass motions and heating, has long been a major goal in space science. We present results from a two-fluid MHD simulation of an eruptive flare/CME using a newly developed Strategic Capability, SCEPTER, which is based on the well-validated and widely used Space Weather Modeling Framework. SCEPTER incorporates two major advances in numerical capability. First, we use the STITCH formalism for the energy buildup, so that we start with a potential-field minimum-energy state and slowly form a sheared filament channel over a polarity inversion line as is observed on the Sun. Second, we use a new formulation of the plasma energetics that is explicitly energy conserving while calculating separate electron and ion temperatures and separate parallel and perpendicular pressures, as desired. For this first simulation with our new model, we opted for the non-adiabatic heating to go solely into the protons and for an isotropic pressure. We discuss the resulting energetics of the reconnection and, in particular, the plasma heating in the reconnecting current sheets, mass acceleration, and shock formation. We also discuss the implications of our results for understanding solar eruptions, in general.
This work was supported by the NASA Living With a Star Program.
How to cite: Antiochos, S., Van Der Holst, B., Sachdeva, N., Toth, G., Dahlin, J., Gombosi, T., and Szente, J.: Rigorous Calculation of the Energy Release in Solar Eruptions with the SCEPTER Model, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15373, https://doi.org/10.5194/egusphere-egu26-15373, 2026.
Non-equilibrium ionization (NEI) is a critical physical process in astrophysical environments where the plasma's thermodynamic timescales are shorter than the ionization or recombination timescales, such as in the solar wind and solar eruptions. In such rapidly evolving plasmas, the charge states of ions are governed by time-dependent ionization equations. In this work, we report a package designed to perform fast NEI calculations using the eigenvalue method. A key feature of this package is that it can be applied in various plasma environments with arbitrary non-Maxwellian electron distributions. Furthermore, it supports both post-process analysis by tracking the movement of plasma deduced from MHD simulation and in-line calculation within MHD modeling. Finally, we show one application of this package in investigating solar wind evolution with various Kappa electron distributions. This code is freely available for download from the Web.
How to cite: Shen, C. and Ye, J.: A Package for Non-Equilibrium Ionization Simulations in Plasma with Arbitrary Electron Distributions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2866, https://doi.org/10.5194/egusphere-egu26-2866, 2026.
The fluid behavior of the solar wind is affected by the heat flux carried by the suprathermal electron populations, especially the electron strahl (or beam) that propagates along the magnetic field.
In turn, the electron strahl cannot be stable, and in the absence of collisions, its properties are regulated mainly by self-generated instabilities.
This paper approaches the description of these heat-flux instabilities in a novel manner using regularized Kappa distributions (RKDs) to characterize the electron strahl.
RKDs conform to the velocity distributions with suprathermal tails observed in-situ, and at the same time allow for consistent macromodeling, based on their singularity-free moments.
In contrast, the complexity of RKD models makes the analytical kinetic formalism complicated and still inaccessible, and therefore, here heat-flux instabilities are resolved using the advanced solver ALPS.
Two primary types of instabilities emerge depending on plasma conditions: the whistler and firehose heat-flux instabilities.
The solver is successfully tested for the first time for such instabilities by comparison with previous results for standard distributions, such as Maxwellian and Kappa.
Moreover, the new RKD results show that idealized Maxwellian models can overrate or underestimate the effects of these instabilities, and also show differences from those obtained for the standard Kappa, which, for instance, underestimate the firehose heat-flux growth rates.
How to cite: Schröder, D. L., Lazar, M., López, R. A., and Fichtner, H.: Heat-flux instabilities of regularized Kappa distributed strahl electrons resolved with ALPS, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10866, https://doi.org/10.5194/egusphere-egu26-10866, 2026.
Parameters of solar wind velocity distributions are well constrained by thresholds of ion-driven plasma instabilities derived from linear theory. Surpassing these thresholds results in the transfer of energy from particles to coherent electromagnetic waves as the system is altered toward a more stable configuration. We use linear Vlasov-Maxwell theory to describe an Oblique Drift Instability (ODI) that constrains the limits of stable parametric space for a low-beta plasma that contains a drifting proton beam or helium population. This instability decreases the relative drift of secondary populations and prevents beta from decreasing below a minimum value by heating both the core and drifting populations. Our predictions are of interest for Parker Solar Probe (PSP) observations, as they provide an additional mechanism for perpendicular heating of ions active in the vicinity of Alfven surface. The ODI may explain the discrepancy between long-standing expectations of measurements of very low-beta plasmas in the near-Sun environment and in situ observations, where beta is consistently measured above 1%. In parallel, it proposes an interpretation why the drift of the secondary ion populations with respect to the bulk of thermal protons is reduced to no more than approximately the local Alfven speed, as observed in earlier PSP encounters.
How to cite: Martinović, M., Klein, K., Ofman, L., Yogesh, Y., Verniero, J., Yoon, P., Howes, G., Verscharen, D., and Alterman, B.: Oblique Drift Instability in Low Beta Plasma, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22228, https://doi.org/10.5194/egusphere-egu26-22228, 2026.
We propose and verify a new statistical topology framework to study the complex magnetic field evolution of Sun-like stars, and energy outbursts in power-law probability distributions. This new framework consider self-similar topological structures as a statistical ensemble, and derive new power-law scalings for fundamental quantities such as magnetic flux, helicity, and energy in outbursts. This new framework not only successfully predicts magnetic emergence on the Sun, but also shed light on the coronal heating problem by reconciling the nanoflare theory with previous challenging observations. Part of this presenatation is published as (Xiong et. al., ApJ, 2025), while part of the work is still under consideration by journal publication by the time of this abstract submission.
How to cite: Xiong, A. and Yang, S.: New Statistical Topology Theory Predicts Turbulent Magnetic Emergence and Energy Outburts, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6240, https://doi.org/10.5194/egusphere-egu26-6240, 2026.
High-energy charged particles are ubiquitous in astrophysical, space, and laboratory plasmas, and identifying underlying acceleration mechanisms remains a fundamental challenge. In Earth’s magnetotail, it has been proposed that particles in the mid-magnetotail are initially accelerated to tens to hundreds of keV by magnetic reconnection and subsequently transported to the near-Earth magnetotail, where they are further energized to MeV energies via wave–particle interactions. However, this paradigm hasn’t been verified and particle acceleration processes remain highly controversial. Here, we identify a previously unrecognized acceleration mechanism, dubbed Magnetic Rayleigh–Taylor (MRT) instability, which produces high energy particles up to ~1MeV in the magnetotail. Once the instability is triggered, numerous instability heads characterized by sharp magnetic field enhancements with surrounding flow vortices are generated. As these heads propagate earthward, electron Kelvin–Helmholtz (KH) instabilities are excited and generate super-intense localized electric fields that efficiently accelerates both electrons and ions trapped within the heads. This process results in electron power-law energy spectra with progressively harder indices closer to Earth. These findings demonstrate that the MRT instability is an efficient particle acceleration mechanism in the magnetotail and may significantly contribute to the high-energy particle populations in Earth’s outer radiation belt.
How to cite: Wang, R.: Particle acceleration by Magnetic Rayleigh–Taylor instability in the near-Earth magnetotail, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16676, https://doi.org/10.5194/egusphere-egu26-16676, 2026.
Foreshock Bubbles (FBs) are large-scale transient structures found in Earth's foreshock region and are associated with foreshock-discontinuity interaction. FBs play a significant role in accelerating and energizing plasma through various mechanisms. In this study, we investigate the contribution of FBs to ion acceleration and energization by analyzing the key energy terms found in the equations that describe the temporal evolution of the kinetic and internal energy densities, namely, the pressure gradient term, the electromagnetic term and the pressure-strain term. To carry out this study, we employ the global hybrid-Vlasov simulation Vlasiator and compare our results with in-situ observations from the Magnetospheric MultiScale (MMS) mission. We find that FBs exhibit distinct signatures in the energy terms throughout their life cycles, from formation to decay as they interact with the bow shock. We show that the evolution of FBs involves complex energy conversions between electromagnetic, kinetic, and thermal energies. Notably, the energy term magnitudes increase during the initial phase of the FB, reach a peak, and subsequently decline as the FB dissipates, in agreement with previous studies. We find also strong energy conversion at the interface between the FB core and compressed edge due to the presence of a current sheet highlighting the complex contributions of the FB in accelerating and energizing ions.
How to cite: Dahani, S., Turc, L., Lipsanen, V., Tao, S., Suni, J., Pfau-Kempf, Y., Kalliokoski, M., Palmroth, M., Gershman, D., Torbert, R., and Burch, J.: Ion Energization and Acceleration Associated with Foreshock Bubbles: Results from a Hybrid-Vlasov Simulation and MMS Observations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10382, https://doi.org/10.5194/egusphere-egu26-10382, 2026.
Plasma energization and transport of energy are key open problems of space plasma physics. Their comprehension is a grand challenge of plasma physics that has implications on research fields that span from space weather to the understanding of the farthest astrophysical plasmas. The Earth’s Magnetospheric System is a complex and highly dynamic plasma environment where strong energization and energy transport occurs and it is the best natural laboratory to study these processes through in situ measurements. Theory, numerical simulations and previous multi-point observations from missions such as ESA/Cluster and NASA/MMS evidenced that cross-scale coupling has a fundamental role in plasma energization and energy transport. Therefore, in order to ultimately understand these key processes, simultaneous in situ measurements at both large, fluid and small, kinetic scales are required. Such measurements are currently not available. Here we present the Plasma Observatory (PO) multi-scale mission concept tailored to study plasma energization and energy transport in the Earth’s Magnetospheric System through simultaneous measurements at both fluid and ion scales. These are the scales at which the largest amount of electromagnetic energy is converted into energized particles and energy is transported. PO has an HEO 7.2x17 RE orbit, covering all the key regions of the Magnetospheric System including the foreshock, the bow shock, the magnetosheath, the magnetopause, the transition region and the magnetotail current sheet. PO baseline mission includes seven identical smallsat Sister Space Craft (SSC) in two nested tetrahedra formation. The tetrahedra separation scales cover all typical ion and fluid scales of interest in the Key Science Regions and vary between about 50 km and 5000 km. The SSC payload provides a complete characterization of electromagnetic fields and particles simultaneously at multiple locations with measurements tailored to ion and fluid scales. PO is the next logical step after Cluster and MMS and will allow us to resolve for the first time scale coupling in the Earth’s Magnetospheric System, leading to transformative advances in the field of space plasma physics. Plasma Observatory is one of the three ESA M7 candidates, which have been selected in November 2023 for a competitive Phase A with a mission selection planned in June 2026 and launch in 2037.
How to cite: Marcucci, M. F. and Retinò, A. and the Plasma Observatory Team: The ESA M7 candidate mission Plasma Observatory: unveiling plasma energization and energy transport in the Magnetospheric System with multiscale observations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13489, https://doi.org/10.5194/egusphere-egu26-13489, 2026.
Wave-particle interactions are a fundamental mechanism to control irreversible plasma energization and energy transport throughout the Heliosphere, and universally throughout astrophysical plasma domains. The most tractable paradigm to model the plasma response to perturbations by plasma waves is the 60 year old quasilinear diffusion theory. This paradigm predominates in our understanding, but within the last two decades there has been a sustained resurgence and emergence of fundamental new questions motivated by the discovery of highly variable, intense/energetic and structured electromagnetic plasma waves and wave-particle interaction plasma physics processes by single and multi-point missions. These interactions act and control plasma energization and energy transport from microscale (gyroradius/kinetic) through to the macroscale (system scale), and in addition crucially link these scales via complex coupled fluid/mesoscale plasma physics processes. We discuss recent advances, and highlight some open, fundamental questions for wave-particle interactions that the Plasma Observatory Mission can solve via multiscale observations.
How to cite: Allanson, O., Watt, C., Rae, J., Osmane, A., Ripoll, J.-F., Hartley, D., Hanzelka, M., Artemyev, A., Stawarz, J., Ratliff, D., Desai, R., Bentley, S., Forsyth, C., Chakraborty, S., Black, R., Hunter, S., Meredith, N., Zhang, X., and Olifer, L. and the ISSI team 25-640: Beyond Diffusion - Advancing Earth’s Radiation Belt Models with Nonlinear Dynamics: Multiscale Wave-Particle Interactions for Plasma Energization and Energy Transport: Open, Fundamental Questions that Plasma Observatory Can Solve, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19090, https://doi.org/10.5194/egusphere-egu26-19090, 2026.
The physical trigger of substorm onset remains one of the key unresolved problems in magnetospheric physics. Understanding how, when, and why stored energy in Earth’s magnetotail is explosively released is central to space-weather science. To identify the instability responsible for detonation, recent studies have focused on the earliest auroral signatures of onset—small-scale, quasi-periodic structures known as auroral beads. Previous work has linked these beads to plasma instabilities and to magnetotail dynamics through kinetic Alfvén waves.
To further understand the substorm onset mechanism, we use new measurements from a narrow-field, high-cadence auroral imager. By extending the Kalmoni et al. (2018) methodology, we track the temporal evolution and dispersion characteristics of “mini beads”, in effect beads-within-beads. Our analysis shows that all types of beads move in the same eastward direction but that mini beads precede the larger beads by at least one minute. However, in contrast to larger-scale beads, mini beads obey different dispersion relations, suggesting that mini beads arise from a distinct physical process and represent an earlier or new stage of the instability development leading to substorm onset. This means that we need to understand the near-Earth transition region on multiple scales far earlier than currently thought, challenging all current substorm onset paradigms.
We discuss the implications of this analysis for determining the role of multi-scale physical processes in substorm onset for multi-spacecraft missions such as Plasma Observatory.
How to cite: Carlyle, I., Rae, J., Smith, A., Townson, M., Watt, C., Michell, R., and Samara, M.: In search of multi-scale plasma instabilities at the heart of substorm onset: implications for the Plasma Observatory mission, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20099, https://doi.org/10.5194/egusphere-egu26-20099, 2026.
Magnetic reconnection events generated by tangled magnetic fields produced in turbulent plasmas have long been thought to play an important role in turbulent dynamics. These events have traditionally been challenging to examine from either a numerical or observational perspective due to their small-scale nature and complex magnetic topologies. However, multi-spacecraft measurements have provided a step-change in understanding this complex phenomenon. Since the days of Cluster, evidence has been found for turbulence-driven magnetic reconnection embedded within the turbulent fluctuations of Earth's magnetosheath, making it an ideal location for studying the physics and importance of turbulence-driven magnetic reconnection. In this presentation, we will highlight the observational insights into turbulence-driven reconnection that have been enabled by the systematic identification and analysis of reconnection events in Earth's magnetosheath by missions such as NASA's Magnetospheric Multiscale (MMS) and ESA’s Cluster missions – including the importance of so-called electron-only reconnection and estimates that suggest magnetic reconnection can account for a significant fraction of the energy dissipated in turbulent plasmas. Using kinetic simulations of turbulence reminiscent of the plasmas found in Earth’s magnetosheath, we will further demonstrate and evaluate how multi-scale measurements from a mission such as ESA’s proposed Plasma Observatory will enable key observational constraints characterizing the 3D structure and distribution of turbulence-driven magnetic reconnection events that will usher in a new era of advancements on the subject.
How to cite: Stawarz, J. E., Franci, L., Quijia Pilapaña, P., Agudelo Rueda, J., Pyakurel, P. S., Shay, M. A., Phan, T. D., Bessho, N., and Gingell, I. L.: Turbulence-Driven Magnetic Reconnection: From Cluster and Magnetospheric Multiscale to Plasma Observatory, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17097, https://doi.org/10.5194/egusphere-egu26-17097, 2026.
The Cluster mission holds a unique place in space science history: it was the first-ever fleet of four spacecraft flying together in the Earth’s magnetosphere. But its legacy goes far beyond that, it set a new benchmark for data calibration, a cornerstone of its scientific success.
Launched in 2000, each spacecraft carried 11 identical instruments. Remarkably, most of these instruments were still operating until the end of operations, late September 2024. Some showed almost no degradation after nearly 25 years in space, while others naturally experienced reduced sensitivity over time.
To achieve the highest possible data quality, Cluster PI teams employed advanced calibration methods, intertwined instrument calibration procedures, and even machine learning techniques. In this presentation, we will showcase a selection of examples drawn from the latest technical reports on these calibration efforts, gathered in a special issue of JGR Space Physics, to be published in 2026.
How to cite: Masson, A. and Escoubet, P.: Cluster mission: why do we still need to calibrate instruments after 25 years?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10374, https://doi.org/10.5194/egusphere-egu26-10374, 2026.
We revisit the use of multi-spacecraft techniques in range of applications applicable to close formation arrays of spacecraft, focusing on the curlometer, in particular, for both large and small-scale structures. The curlometer was originally applied to Cluster multi-spacecraft magnetic field data, but later was updated for different environments and measurement constraints such as the NASA MMS mission, with small-scale 4 spacecraft formations; the 3 spacecraft configurations of the NASA THEMIS magnetospheric mission, and derived 2-4-point measurements from the ESA Swarm mission. Spatial gradient-based methods are adaptable to a range of multi-point and multi-scale arrays and conjunctions of these, and other, missions can produce distributed, spatial coverage with large numbers of spacecraft. Four-point estimates of magnetic gradients are limited by uncertainties in spacecraft separations and the magnetic field, as well as the presence of non-linear gradients and temporal evolution (giving certain applicability limits which can be mitigated by supporting information on morphology. Many magnetospheric regions have been investigated directly (illustrated here by the magnetopause, ring current and field-aligned currents at high and low altitudes). In addition, the analysis can support investigations of transient and smaller-scale current structures (e.g. reconnected flux tubes, boundary layer sub-structure, or dipolarisation fronts) and energy transfer processes. We anticipate the use of complementary information from imminent missions such as SMILE and the new EISCAT-3D radar.
How to cite: Dunlop, M., Dong, X., Fu, H., Tan, X., Zhao, E., Shen, C., Escoubet, P., and Cao, J.: Curlometer and gradient techniques: application to multiscale studies, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3186, https://doi.org/10.5194/egusphere-egu26-3186, 2026.
Natural electromagnetic wave emissions of lower-band chorus and exohiss affect energetic electron populations in the Earth's outer radiation belt. Despite extensive studies, the spatiotemporal characteristics of amplitude distributions of these whistler-mode waves remain incompletely characterized. We analyze nearly seven years of Van Allen Probes data combined with over nineteen years of Cluster spacecraft measurements to quantify these distributions. We find that distributions of wave amplitudes exhibit a wide and approximately log-normal core with a variable heavy tail, both dependent on geomagnetic activity and position, while time intervals between detections follow a power-law distribution indicative of temporal clustering. Intense waves occurring predominantly near the postmidnight equatorial region have average intervals of tens of minutes to hours between their detections. These findings suggest that the bursty nature of whistler-mode waves may not be fully captured by long-term averages, which are commonly used in models of radiation belt electron dynamics.
How to cite: Santolik, O., Kolmašová, I., Taubenschuss, U., and Hanzelka, M.: Interlinked Spatiotemporal Patterns of Magnetospheric Lower-Band Whistler Mode Waves , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10302, https://doi.org/10.5194/egusphere-egu26-10302, 2026.
The interaction between localized fast plasma jets, called bursty bulk flows (BBF) or flow bursts and ambient magnetic field plays an important role in the complex chain of solar wind-magnetosphere-ionosphere coupling processes. In particular the transition region, where the magnetic field configuration changes from dipolar-like configuration to tail-like configuration and where near-Earth flow braking/bouncing processes take place, is a key region of fundamental processes such as the particle energization and wave-particle interaction. These processes, associated with magnetic and pressure disturbances, drive enhanced energy and momentum transfer from the nightside outer magnetosphere along Earth’s magnetic field lines down to the ionosphere. Across the field lines, particle injections further affect the inner magnetosphere dynamics, constituting a source population for the radiation belt and the ring current.
In this presentation we stress the importance of observations of BBFs and dipolarization fronts by multi-point measurements in an extensive region covering both equatorial and off-equatorial locations, and simultaneously at ion and fluid scales for understanding the energy transport processes. These allows us to monitor both the field-aligned and perpendicular evolution of the flux tube and enable to study the coupling with the ionosphere. By showing several examples of observations from previous studies of different scales of disturbances and fortuitous multi-spacecraft configuration at different scales, the 3D nature of the interaction between the BBF and ambient plasma, and its relationship to ionosphere including field-aligned current and aurora will be discussed.
How to cite: Nakamura, R., Panov, E., Hosner, M., Alho, M., Pänkäläinen, L., and Retino, A.: Multi-scale processes at the transition region of the Earth’s magnetotail, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12594, https://doi.org/10.5194/egusphere-egu26-12594, 2026.
Plasma Observatory is a candidate mission of the European Space Agency (ESA), with a potential launch in 2037. It aims to investigate plasma coupling across multiple scales in the Earth’s magnetosphere.
Energetic ions and electrons are sensitive tracers of plasma acceleration and transport processes. This makes high-cadence in situ measurements essential for understanding magnetospheric dynamics. On Plasma Observatory, such measurements will be provided by the Energetic Particle Experiment (EPE). The instrument utilizes the well-proven foil–magnet technique to separate electrons from ions and covers an energy range from 30 keV to 600 keV.
In this contribution, we present a novel instrument prototype, the Lorentz Electron and Ion Analyser (LEIA). The concept is based on an earlier, alternative design developed in the context of Plasma Observatory, but is independent of the currently baselined EPE instrument and not intended for flight on Plasma Observatory. It uses a single-channel approach, separating particles by means of a finely tuned magnetic field as well as a modified dE/dx-E detector stack. No foil is used.
This design aims to enable advanced particle species discrimination while significantly reducing electron–ion cross-contamination. Although LEIA is presented as a concept study rather than a mission-specific instrument, it demonstrates a promising pathway for future energetic particle measurements in magnetospheric and heliospheric science missions.
How to cite: Jürgensen, S., Ebeling, H., Berger, L., Kühl, P., Wimmer-Schweingruber, R. F., Seimetz, L., Böttcher, S., Schuster, B., Dunlop, M. W., O Vainio, R., Angelopoulos, V., and Tsai, E.: The Lorentz Electron and Ion Analyser (LEIA) – An Instrument Prototype for Low-Contamination Particle Measurements, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3810, https://doi.org/10.5194/egusphere-egu26-3810, 2026.
The crossover between fluid and ion scales in space plasmas plays a crucial role in the overall energization of the system and it’s where most of the energy exchanges between fields and particles take place. At these scales, turbulent dynamics cascading from larger fluid scales and structures from local ion microphysics typically coexist, leading to still unexplored couplings. Multi-point/multi-scale measurements are then required to fully capture this complex dynamics in situ. 7-point measurements by Plasma Observatory (PMO) in the Earth’s magnetosphere environment offer the opportunity to explore this dynamics and the fluid-ion scale coupling for the first time, in plasma environments with different typical characteristic parameters and dynamical regimes: e.g. solar wind, magnetosheath, magnetotail.
In this presentation, we review numerical simulations of plasma turbulence focussing on the transition from fluid to ion scales and its coexistence with ion kinetic processes, in particular micro-instabilities (e.g. mirror, firehose, ion-drift). This include the role played by pressure-strain interactions in controlling the turbulent cascade rate and modulating energy exchanges in the plasma, and how these aspects could be captured for the first time by a constellation like PMO.
We address the interplay between these processes and highlight the different spatial and temporal scales involved. As waves and structures from these processes are typically anisotropic, different characteristic scales can be observed, depending on the direction of the sampling, thus making multi-point measurements essential to fully capture them.
How to cite: Matteini, L., Hellinger, P., Franci, L., Verdini, A., Landi, S., Papini, E., Montagud Camps, V., Pohl, L., and Dhole, D.: Energy exchanges between particles and ion-scale waves and structures in space plasmas with multi-scale explorations: insights from numerical simulations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20284, https://doi.org/10.5194/egusphere-egu26-20284, 2026.
Plasma velocity distribution functions (VDFs) exhibit many different profiles in the heliosphere. They are often loss-cone-shaped in the presence of a dipole field, they sometimes contain a power-law tail in the high-energy part, and they sometimes have ring- or shell-shaped pickup component. Particle-in-cell (PIC) simulations are useful for exploring kinetic processes, but it is not widely known how to generate such non-Maxwellian VDFs in these simulations.
In this contribution, we present Monte Carlo recipes for generating nine non-Maxwellian VDFs by using random variables. We first present two methods for the (r,q) flattop distribution. Next we present recipes for the regularized Kappa distribution. We then propose a simple procedure for the latest Kappa loss-cone model of the subtracted-Kappa distribution (Summers & Stone 2025 PoP). Properties and numerical recipes for the ring and shell distributions with a finite Gaussian width are discussed, followed by their new variants, the ring and shell Maxwellians. Finally, recipes for the super-Gaussian and the filled-shell distributions are presented.
See also: S. Zenitani, S. Usami, and S. Matsukiyo, JGR Space Physics, in press, arXiv:2510.11890
How to cite: Zenitani, S., Usami, S., and Matsukiyo, S.: Loading non-Maxwellian velocity distributions in particle-in-cell (PIC) simulation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2467, https://doi.org/10.5194/egusphere-egu26-2467, 2026.
The purpose of the Geospace Region and Magnetospheric Boundary identification (GRMB) dataset is to provide information on the regions crossed by each of the 4 Cluster spacecraft during the entire mission. The dataset includes 15 labels, among which are: plasmasphere, plasmapause transition region (TR), plasmasheet TR, plasmasheet, lobes, polar regions, magnetopause TR, magnetopause, magnetosheath, bow shock TR, and solar wind and foreshock. The 4 remaining labels are: inside the magnetosphere, outside the magnetosphere, unknown, and no available data. This dataset has been delivered in 2024 to the Cluster Science Archive (CSA) covering the years 2001-2022: https://doi.org/10.57780/esa-85c563c.
We present updates and improvements made since this delivery. First, the available dataset publicly available at the CSA has been extended to the year 2023 and it will be extended to the end of the Cluster scientific mission (30 September 2024) by the end of 2026.
Second, a methodology update is addressing 2 aspects of the original dataset. The first one concerns IN/PLS and IN/PPTR labels following the update of the distance plots for C2, C3 and C4 completed during the first phase of the project. The second one concerns the descriptions of following inside labels: IN/PLS, IN/PPTR, IN/PSTR, IN/PSH, IN/LOB, and IN/POL to reduce the number of observations that could match 2 or more label definitions in the original methodology. The updated methodology is compatible with the original one, meaning that the updated dataset is more homogeneous. The outcome of these updates is illustrated with the years 2001-2002, which are reprocessed and delivered to the CSA in February 2026. Years 2001 to 2005 are not reprocessed to get a more precise dataset during the first years of the mission, when data availability and quality are the highest. This reprocessing shall be completed by the end of 2026.
Another important output of this dataset is to highlight the importance to identify the spacecraft location in term of Geospace environments. We therefore also discuss the possibility for the space plasma scientific community to have a normalized definition of the regions to ease multi-missions studies.
How to cite: Grison, B., Taylor, M., Darrouzet, F., Maggiolo, R., and Hajos, M.: Improvements, extension and perspectives of the Cluster GRMB (Geospace Region and Magnetospheric Boundary identification) dataset, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10927, https://doi.org/10.5194/egusphere-egu26-10927, 2026.
Ultra-low frequency (ULF) magnetosonic waves arise from the backstreaming ion population in the quasi-parallel foreshock region, participating in several key foreshock processes such as particle acceleration and shock reformation both directly and by steepening into transient structures such as SLAMS (short, large-amplitude magnetic structures). To better understand the effects of upstream solar wind conditions on these multi-scale processes, we use the 23-year Cluster dataset to study ULF waves under a range of solar wind conditions, combining Cluster data with the upstream OMNI product to produce Geocentric Interplanetary Medium (GIPM) coordinate mappings of foreshock wave properties. This method enables us to compare foreshock observations across changing solar wind conditions, by accounting for the changes in foreshock location and scale with varying IMF direction and dynamic pressure. We present the first quantitative maps of compressive and transverse foreshock wave power as a function of cone angle and Mach number, and study the ULF wave power dependence on Mach number, solar wind speed, density and background magnetic field strength, finding a slight increase in normalised foreshock wave power with increasing Mach number. We find the magnetic field strength to be the strongest determinant of foreshock wave power: wave power increases with decreasing field strength. The solar wind speed and density play more minor roles. We find that the relative changes in ULF-band power in the pristine solar wind are larger than in the foreshock under changing solar wind conditions. In the magnetosheath, we find higher ULF-band wave power on the quasi-parallel side, compared to quasi-perpendicular. These results set the context for future missions investigating waves in the solar wind, foreshock, and the magnetosheath, such as HelioSWARM and Plasma Observatory.
How to cite: Atkinson, R., Hietala, H., Manzini, D., Burgess, D., and Karlsson, T.: Statistical Maps of Foreshock Waves Utilising 23 Years of Cluster Data, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10219, https://doi.org/10.5194/egusphere-egu26-10219, 2026.
Many plasma phenomena involve physical processes spanning a wide range of spatial and temporal scales. Accurately capturing such multi-scale dynamics with fully kinetic simulations quickly becomes computationally prohibitive. Fluid models therefore remain an essential tool, but their applicability depends critically on the order at which the hierarchy of moment equations derived from the Vlasov equation is truncated and on the assumptions used to approximate neglected higher-order moments. Extended fluid models such as the 10-moment system therefore require appropriate closures to account for kinetic effects encoded in higher-order moments, such as the heat flux.
In this work, we develop data-driven closures for the 10-moment fluid model based on machine learning (ML). Using supervised learning, the ML models learn to predict the six independent components of the divergence of the heat flux tensor from lower-order moments and the electromagnetic fields. The models are trained on data obtained from two-dimensional fully kinetic Vlasov simulations of magnetic reconnection in a Harris current sheet with varying guide field strength, performed with the muphy 2 code (Allmann-Rahn et al., 2023).
We compare different machine learning architectures, including classical multilayer perceptrons (MLPs), fully convolutional networks, and Fourier Neural Operators (FNOs), assessing their ability to capture spatially structured kinetic effects across different physical regimes. The models are evaluated in terms of accuracy, generalization across guide field conditions, and their suitability for incorporation into fluid simulations. Our results highlight the potential of operator-learning approaches for constructing robust, data-driven closures and provide insight into the strengths and limitations of different ML strategies for plasma fluid modeling.
How to cite: Köhne, S., Lautenbach, S., Jeß, E., Grauer, R., and Innocenti, M. E.: Machine-learning-based closures for the 10-moment fluid model, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6528, https://doi.org/10.5194/egusphere-egu26-6528, 2026.
KHI can grow into finite-amplitude Kelvin–Helmholtz waves (KHWs), which may subsequently roll-up into large-scale vortices (KHVs). These vortices can twist magnetic field lines and trigger vortex-induced tearing mode instability (TMI). In the context of planetary magnetospheric dynamics, such instabilities are fundamental because they (i) drive substantial mass, energy, and momentum transport from the MSH into the MSP; (ii) generate ultra-low-frequency magnetospheric waves; and (iii) drive field-aligned currents coupling to the ionosphere.
In this work, we analyze two SWE events that occurred in January and November 2025, during which the Sun produced some of the strongest flares of Solar Cycle 25, associated with Earth-directed coronal mass ejections (CMEs). Our study combines in-situ magnetospheric observations from MMS and THEMIS with ionospheric measurements from Swarm. Furthermore, we employ our two-dimensional magnetohydrodynamic (MHD) model (Ivanovski et al. 2011; Biasiotti et al. 2024) to characterize the flow dynamics within the magnetopause mixing layer in the fluid limit.
Finally, we analyze predictions of solar activity for May 2039, the expected operational window of the proposed Plasma Observatory (PO) mission, to identify analogue intervals representative of the SWE conditions likely to be encountered by PO. We also examine the orbits of THEMIS, MMS, and Cluster to search for comparable magnetopause crossings. Our results indicate that the orbital configuration of PO would enable continuous monitoring of the dawnside magnetopause for 10-12 days, allowing the full evolution of KH vortices and their interaction with TMI to be captured. This represents a unique capability compared with current missions, which observe such processes only during brief and sporadic crossings.
This research has been carried out within the framework of the Space It Up project funded by the Italian Space Agency, ASI, and the Ministry of University and Research, MUR, under contract n. 2024-5-E.0 - CUP n. I53D24000060005.
How to cite: Biasiotti, L. and Ivanovski, S.: Exploring the response of planetary magnetospheres to intense space weather events, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7791, https://doi.org/10.5194/egusphere-egu26-7791, 2026.
Type II solar radio bursts are key tracers of shock waves driven by coronal mass ejections (CMEs), but identifying the precise location of the radio emission source along the extended shock front remains a major challenge. In the presented work, we investigate the origin of two successive, multi-lane metric Type II bursts observed on 16 February 2024. We utilize the novel radio imaging capabilities of the DAocheng Solar Radio Telescope (DART) in conjunction with white-light and EUV coronal observations from the Advanced Space-based Solar Observatory (ASO-S) and the Solar Dynamics Observatory (SDO). The initial Type II burst is imaged ahead of the erupting hot flux rope that develops into the CME. As the CME expands, a second, stronger Type II burst with two distinct emission lanes is detected. Our radio imaging analysis with DART unambiguously pinpoints the sources of these two lanes to the northern and southern flanks of the CME. Crucially, these sources correspond spatially and temporally to the interaction regions between the CME-driven shock and adjacent, dense coronal streamers. The significant enhancement of the radio emission at these locations provides direct evidence that shock-streamer interactions amplify the efficiency of particle acceleration. These observations demonstrate that different lanes in a multi-lane burst can originate from physically distinct regions along a non-uniform, rippled shock front, offering vital constraints on theories of particle energization in the solar corona and inner heliosphere.
How to cite: Lu, L., Feng, L., Yan, J., Cheng, X., Su, Y., and Deng, L.: Radio imaging of the interaction bewteen an coronal mass ejection and nearby coronal structures, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10898, https://doi.org/10.5194/egusphere-egu26-10898, 2026.
Magnetic helicity is a key geometrical parameter to describe the structure and evolution of
solar coronal magnetic fields. The accumulation of magnetic helicity is correlated with the
nonpotential magnetic field energy, which is released in the solar eruptions. Moreover, the
relative magnetic helicity fluxes can be estimated only relying on the line-of-sight magnetic
field (e.g. Démoulin and Berger 2003). The payload Full-disk MagnetoGraph (FMG) on the
Advanced Space-based Solar Observatory (ASO-S) currently has been supplying the con-
tinuous evolution of line-of-sight magnetograms for the solar active regions, which can be
used to estimate the magnetic helicity flux. In this study, we use eight-hour line-of-sight
magnetograms of NOAA 13273, at which the Sun–Earth direction speed of the satellite is
zero to avoid the oscillation of the magnetic field caused by the Doppler effect on polar-
ization measurements. We obtain the helicity flux by applying fast Fourier transform (FFT)
and local correlation tracking (LCT) methods to obtain the horizontal vector potential field
and the motions of the line-of-sight polarities. We also compare the helicity flux derived
using data from the Heliosesmic and Magnetic Imager (HMI) on board the Solar Dynamics
Observatory (SDO) and the same method. It is found that the flux has the same sign and the
correlation between measurements is 0.98. The difference of the absolute magnetic helicity
normalized to the magnetic flux is less than 4%. This comparison demonstrates the reliabil-
ity of ASO-S/FMG data and that it can be reliably used in future studies.
How to cite: Yang, S., Liu, S., Su, J., and Deng, Y.: Modelling magnetic helicity flux through solar photosphere from ASO-S/FMG, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17034, https://doi.org/10.5194/egusphere-egu26-17034, 2026.
Quasi-periodic pulsations (QPPs) at sub-second periods are frequently detected in the time series of X-rays and radio emissions during stellar flares, and they can be seen in solar radio emissions. However, such short-period QPPs are rarely reported in the hard X-ray (HXR) emission of solar flares. We explored the QPP patterns at short periods in HXRs, γ-ray continuum and radio emissions produced in two solar flare on 2024 October 03 (X9.0) and 2025 January 19 (C8.2). The short period at about 1 s is simultaneously observed in wavebands of HXR and γ-ray continuum during the X9.0 flare, and the restructured images show that the HXR sources move significantly during the short-period QPP, suggesting that the short-period QPP may be caused by the interaction of hot plasma loops that are rooted in double footpoints. The similar short-period QPP is also detected in wavebands of HXR and low-frequency radio emission during the impulsive phase of a C8.2 flare, which could be associated with non-thermal electrons that are periodically accelerated by the intermittent magnetic reconnection.
How to cite: Li, D.: Detection of short-period pulsations in solar hard X-ray and radio emissions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8951, https://doi.org/10.5194/egusphere-egu26-8951, 2026.
Observations from the Parker Solar Probe (PSP) reveal that electrons play a crucial role in shaping coronal and solar wind dynamics (Halekas et al. 2021, 2022, 2025). We investigate how nonthermal ( κ ) and core/strahl electron distributions modify the onset threshold of the ion-ion acoustic instability (IIAI) observed by PSP between 15-25 solar radii (Mozer et al. 2021, 2023; Kellogg et al. 2024) and modeled by Afify et al. (2024). We find that (Afify et al. 2025):
- lower κ values tend to stabilize IIAI due to higher electron phase space density at the resonance velocity, which leads to enhanced Landau damping in the electrons;
- the presence of a strahl population shifts the resonance velocity with respect to that obtained with the core distribution alone, thus modifying the IIAI threshold. An effective temperature can be calculated from core and strahl parameters (Jones et al. 1975), which allows to map the core-strahl system to one with a single electron population and simplify threshold and growth rate calculations;
- Applying the field-particle correlation technique (Klein & Howes 2016) to fully kinetic Vlasov simulations reveals detailed velocity-space energy transfer in the presence of the different electron distributions (Afify et al. 2026) and indicates that Landau damping plays a significant role in reducing free energy and contributing to heating.
Future work will address the interplay between electron and ion anisotropies in low-β regimes.
References
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Afify, M. S., Dreher, J., O'Neill, S., & Innocenti, M. E. 2025, A&A, 702, A277
Afify, M. S., Klein, K. G., Martinović, M. M., & Innocenti, M. E. 2026, arXiv:2601.08329.
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How to cite: Ibrahim, M. S. A. A., Dreher, J., Klein, K. G., O'Neill, S., Martinović, M. M., and Innocenti, M. E.: How do electrons shape the proton distribution functions near the Sun?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14170, https://doi.org/10.5194/egusphere-egu26-14170, 2026.
We investigate ion velocity-space dynamics within the exhaust region of asymmetric magnetopause reconnection using global hybrid-Vlasov simulations. To quantify the complexity of velocity-space structures arising from the mixing of magnetospheric and magnetosheath ion populations, we employ the Hermite transform and Gaussian Mixture Model (GMM) analyses. In the Hermite representation, we use a fixed number of 22 harmonics to ensure computational feasibility. From this expansion, we compute a scalar measure of enstrophy—the total power contained in the non-zero Hermite modes—which characterizes the available free energy in the system. For the GMM approach, we test different numbers of ion populations and evaluate the corresponding multi-beam thermal energy for each decomposition. We further define the thermal energy drop as the relative difference between the thermal energy of an equivalent single-Maxwellian distribution and the total multi-beam thermal energy. Both enstrophy and thermal energy drop diagnostics (for any number of beams considered) exhibit consistent trends during the phase of plasma thermalization and anisotropic acceleration, demonstrating that the redistribution of thermal energy can be effectively captured even with a limited number of Hermite modes.
How to cite: Zaitsev, I., Papadakis, K., Alho, M., Hoilijoki, S., Ganse, U., Roos, T., and Palmroth, M.: Quantification of non-Maxwellian properties in plasma mixing during magnetopause reconnection, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9730, https://doi.org/10.5194/egusphere-egu26-9730, 2026.
Multipoint measurements offer a powerful framework for dissecting spatiotemporal dynamics in physical fields, particularly in plasma environments. This presentation, tailored to the Cluster-Plasma Observatory Workshop, emphasises applications in ionospheric and magnetospheric studies, with a focus on Cluster mission data.
Notable uses include characterising field structure size and orientation. Ionospheric irregularities have been mapped via GNSS total electron content and LOFAR radio observations . In the magnetosphere, Cluster measurements near the bow shock have revealed nonlinear magnetic structures, demonstrating transferability to vector field deformations.
Drift velocities are derived using correlation and spectral spaced-antenna methods . Drift dispersion follows from scintillation analysis, while Cluster configurations enable wave arrival direction estimation. These techniques also quantify inter-scale energy flows, advancing plasma turbulence models.
Multipoint analysis thus underpins Cluster's legacy in plasma physics, informing space weather and field modeling.
How to cite: Grzesiak, M., Przepiórka-Skup, D., Matyjasiak, B., and Rothkaehl, H.: Multipoint Measurements for Analysis of Physical Fields, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20458, https://doi.org/10.5194/egusphere-egu26-20458, 2026.
The ESA M7 mission candidate Plasma Observatory (PO) proposal’s Group on Simulation Numerical Support (GIANNI) is tasked with supporting the proposal's Science Study Team with simulation data, to help evaluate the proposal's science impact, assess possible descoping options and their effects on science output, and provide constraints for the PO constellation parameters.
In this presentation, we summarize the composition and capabilities of the group and the represented simulation models. This includes collating a repository of tools and short manuals and tutorials for the sorts of simulation datasets available and their possible use cases, and how to work with us to set up virtual observatories in the varied numerical models. We present an overview of the group's science support activities.
How to cite: Alho, M., Trotta, D., and Valentini, F. and the Plasma Observatory’s Group on Simulation Numerical Support (GIANNI): Plasma Observatory’s Group on Simulation Numerical Support (GIANNI), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19230, https://doi.org/10.5194/egusphere-egu26-19230, 2026.
Plasma Observatory (PO) is one of the three candidate ESA M7-class missions currently in Phase A. Its primary goal is to investigate the fundamental multi-scale processes that govern plasma energization and energy transport within Earth's magnetospheric system. To address these objectives, PO will deploy a constellation of seven spacecraft in a double-nested tetrahedral configuration with a common vertex, enabling simultaneous measurements at both fluid and ion scales and, crucially, their coupling.
Compared to previous multi-spacecraft missions such as Cluster and MMS, PO's expanded constellation introduces unprecedented opportunities to resolve multi-scale dynamics in space plasmas. However, these opportunities come with significant challenges. Realizing PO's full scientific potential requires the development and application of novel multi-point and advanced data analysis methodologies capable of exploiting measurements from more than four spacecraft.
The Multi-Point and Advanced Data Analysis Methods Working Group has been established to support the mission's Science Study Team (SST) in evaluating how PO's science goals can be achieved through its unique configuration. The Working Group brings together expertise in multi-spacecraft diagnostics and the analysis of in situ plasma observations. We present the composition and ongoing activities of the Working Group, highlight the represented analysis methods (both established and under active development), and outline ongoing efforts to assess and enhance the scientific capabilities of the PO mission.
How to cite: Cozzani, G., Chasapis, A., and Stawarz, J. and the The Plasma Observatory Multi-Point Working Group Members and Contributors: Plasma Observatory's Multi-Point and Advanced Data Analysis Methods Working Group, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2371, https://doi.org/10.5194/egusphere-egu26-2371, 2026.
The main aim of the ESA Class-M7 Plasma Observatory (PO) mission currently in Phase A, is to explore the multiscale physics governing energy transfer and particle energization in near-Earth space plasmas. Flying a constellation of seven spacecraft in a double nested tetrahedral configuration, PO will deliver simultaneous measurements of fields, waves, and particles across ion, sub-ion, and MHD scales in various regions of the near-Earth space, within 7 to 13 Earth radii. While the mission core science focuses on regions such as the bow shock, magnetosheath, magnetopause, and plasma sheet, the orbital design naturally enables extensive coverage of additional regions, including the inner magnetosphere, the flanks of the magnetopause, and the ambient solar wind. The Synergies and Additional Science Working Group investigates the scientific opportunities enabled by PO observations beyond the primary science regions and aims to broaden the mission scientific impact through cross-disciplinary synergies. The solar-wind-driven magnetosphere is a highly dynamic system in which key processes can only be resolved through multipoint, multiscale observations.
With seven-point measurements, PO will allow the multiscale characterization of M-I coupling and plasma sources of both solar wind and ionospheric origin under varying geomagnetic conditions. In the inner magnetosphere, PO will address fundamental questions on wave propagation and wave-particle interactions at the edge of the outer radiation belt. Multipoint observations of ULF, EMIC, chorus, and whistler-mode waves will enable direct in-situ identification of acceleration, transport, and loss processes of energetic particles. PO will also resolve the multiscale structure and evolution of plasmaspheric plumes of cold plasma and assess their role in wave generation and radiation belt dynamics. At the flank magnetopause and in the upstream solar wind, PO will probe the coupling between large-scale plasma dynamics, turbulence, and kinetic dissipation. Simultaneous measurements at multiple scales will allow detailed investigations of Kelvin-Helmholtz instability, reconnection, plasma mixing, and turbulent energy transfer, as well as accessing the fine structure of solar wind transients that control mass and energy input into the magnetosphere.
PO will further enable strong synergies with other heliophysics missions, laboratory plasma experiments, and space weather research. PO multiscale observations will improve constraints on M-I coupling currents, geomagnetically induced currents, and CME-driven disturbances, while providing a unique space-based counterpart to laboratory reconnection experiments. This contribution summarizes recent progress within the Synergies and Additional Science Working Group and outlines future perspectives supporting PO during Phase A.
How to cite: Benella, S., Ripoll, J.-F., Norgren, C., Allanson, O., Biasiotti, L., Gasparini, S., Gkioulidou, M., Ivanovski, S. L., Ji, H., Matyjasiak, B., Miyoshi, Y., Nakamura, R., Pitna, A., Przepiórka-Skup, D., Quattrociocchi, V., Settino, A., Stepanova, M., Toledo-Redondo, S., Turner, D., and Yordanova, E.: The Plasma Observatory Synergies and Additional Science Working Group, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19304, https://doi.org/10.5194/egusphere-egu26-19304, 2026.
We know that plasma energization and energy transport occur in large volumes of space and across large boundaries in space. However, in situ observations, theory and simulations indicate that the key physical processes driving energization and energy transport occur where plasma on fluid scales couple to the smaller kinetic scales, at which the largest amount of electromagnetic energy is converted into energized particles. Energization and energy transport involve non-planar and non-stationary plasma structures at these scales that have to be resolved experimentally. Remote observations currently cannot access these scales, and existing multi-point in situ observations do not have a sufficient number of observations points.
The Plasma Observatory (PO) multi-scale mission concept is a candidate for the ESA Directorate of Science M7 mission call, currently in a Phase A study, with potential down selection to Phase B in Summer 2026. Plasma Observatory will be the first mission to have the capability to resolve scale coupling and non-planarity/non-stationarity in plasma energization and energy transport.
During the Phase A study, Scientific guidance of the mission is provided by the ESA nominated Science Study Team (SST). In support of this group is the Cross Disciplinary working group, who provide close support to the SST and study activities. To ensure a broad input and wide community involvement the SST has organised several working groups in order to expand the community and citizen science involvement. These working groups cover Ground-based coordination, Public outreach and Numerical Simulation, multipoint and advanced data analysis methods, plasma astrophysics and scientific synergies. In addition an Early Career Researcher network has been set up.
This paper provides an overview of these entites and how you can get involved in Plasma Observatory.
How to cite: Taylor, M. and the Plasma Observatory Science Study Team Working Group Leads: Science Study Team Working Groups of the ESA M7 Mission candidate Plasma Observatory , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3463, https://doi.org/10.5194/egusphere-egu26-3463, 2026.
Plasma Observatory (PO) is the first multiscale mission tailored to study plasma energization and energy transport in the Earth's Magnetospheric System through simultaneous measurements at both ion and fluid scales. PO consists of seven identical small satellites (Sister SpaceCraft, SSC) that move on an equatorial elliptical orbit with an apogee of ~17 and a perigee of ~7 Earth radii in a two tetrahedra with a common vertex formation. The payload on board the SSCs give a full characterization of the plasma at the ion and fluid scales in the key science regions: bow shock, magnetosheath, magnetopause, transition region and magnetotail current sheet. In particular, resolving ion composition in 3D is needed since energization mechanisms work differently for different ion species (e.g. heavy ion effects on reconnection rate). The Ion Mass Composition Analyser (IMCA) will be able to provide the three-dimensional (3D) distribution functions for the near-Earth main ion species (H+, He++ and O+) with an energy range covering the thermal and suprathermal energies and an energy and angular resolution permitting to study the non-Maxwellian features in the ions distribution functions. IMCA will be embarked on at least four of the seven Sister SpaceCraft (one SSC of the inner tetrahedron and the three outer SSCs) in order to provide mass resolved 3D distribution at the fluid scales. Embarking IMCA on all the seven SSCs is currently under consideration. Here we will report on the IMCA objectives, design and consortium.
How to cite: Marcucci, M. F. and the The Plasma Observatory IMCA Team: The Plasma Observatory Ion and Mass Composition Analyzer [IMCA], EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10626, https://doi.org/10.5194/egusphere-egu26-10626, 2026.
The proposal of the Plasma Observatory mission was selected for a competitive phase A with two other missions in the framework of the seventh call for medium mission (M7) organized by ESA. The mission selection is planned in 2026 for a launch in 2037. Its main objectives are to unveil how are particles energized in space plasma and which processes dominate energy transport and drive coupling between the different regions of the terrestrial magnetospheric system? After the Mission Consolidation Review by ESA in February 2025 followed by reformulation discussions, the mission now consists of seven identical small satellites (Sister spacecraft, SSC) equipped by an updated payload, still evolving along an equatorial elliptical orbit with an apogee ~17 and a perigee ~8 Earth radii. The seven satellites will fly forming two tetraedra and allowing simultaneous measurements at both fluid and ion scales. The mission will include three key science regions: dayside (solar wind, bow shock, magnetosheath, magnetopause), nightside transition region (quasidipolar region, transient near-Earth current sheet, field-aligned currents, braking flow region) and the medium magnetotail. Plasma Observatory mission is the next logical step after the four satellite magnetospheric missions Cluster and MMS. The search-coil magnetometer (SCM), strongly inherited of the SCM designed for the ESA JUICE mission, is now required on the seven SSC. SCM will be delivered by LPP and LPC2E and will provide the three components of the magnetic field fluctuations in the [1Hz-8kHz] frequency range, after digitization by the wave analyser board (WAB) within the electric and magnetic electronics box (BOX-W), relevant for the three key science regions. Continuous waveforms and snapshots every 4 s, will be sampled at 512 Hz and 16 kHz respectively. SCM is planned to be mounted on a 1.5-2 m boom and will have the following sensitivity performances [10-3, 1.5x10-6, 5x10-9, 10-10, 5x10-10] nT2/Hz at [1, 10, 100, 1000, 8000] Hz. Associated with the electric field instrument (EFI) of the WAVES instrument suite, SCM will allow to fully characterize the wave polarization and estimate the direction of propagation of the wave energy. These measurements are crucial to understand the role of electromagnetic waves in the energy conversion and partitioning processes, the plasma and energy transport, the acceleration and the heating of the plasma.
How to cite: Le Contel, O., Kretzschmar, M., Retino, A., Gironnet, J., Jannet, G., Mehrez, F., Alison, D., Revillet, C., Mirioni, L., Agrapart, C., Geyskens, N., Berthod, C., Sou, G., Chust, T., Froment, C., Berthomier, M., Fiachetti, C., Khotyaintsev, Y., Crips, V., and Marcucci, M. F.: The SCM instrument for the ESA Plasma Observatory mission, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12241, https://doi.org/10.5194/egusphere-egu26-12241, 2026.
In the last decades, magnetometers have been an important part of scientific space explorations, giving insights in the behavior of space plasmas and how they change throughout the solar system. We plan to contribute a fluxgate magnetometer for the Plasma Observatory Mission, which is an M7 candidate of ESA for making multi-point measurements in Earth's magnetosphere. This magnetometer builds on a heritage design that was already used on missions like Rosetta, BepiColombo, and JUICE. The next design iteration of the electronics introduces improvements in the feedback loop, making feedback faster and better adjusted to the currently measured values. This poster shows how the new design works and first measurements of the new electronics.
How to cite: Timmermann, G., Fischer, D., Poetzsch, C., Hillenmaier, O., Panov, E., Richter, I., Auster, H.-U., and Plaschke, F.: Improved Design of Fluxgate Magnetometer Electronics for Geospace Observation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7134, https://doi.org/10.5194/egusphere-egu26-7134, 2026.
The fluxgate magnetic field instrument (MAG) onboard seven small Plasma Observatory (PO) spacecraft is a collaborative effort between the Space Research Institute in Graz (AT), the Technical University of Braunschweig (DE) and the Imperial College London (UK). MAG is a dual-sensor fluxgate magnetometer that measures the vector of the magnetic field in space. The science objective of MAG is to provide the magnetic field measurements that are crucial for analyzing plasma processes in six key science regions of Plasma Observatory: foreshock, bowshock, magnetosheath, magnetopause, transition region and tail current sheet. MAG measures the background magnetic field in the near-Earth space in the range ± 10,000 nT with frequencies up to 256 Hz, a noise floor of less than 10 pT/√Hz at 1Hz and an error of less than ±0.5 nT. The targeted value range in terms of static and variational field for PMO is in the order of 100 nT. The maximum sampling frequency of 256 Hz allows for a sufficient overlap with concurrent Search Coil Magnetometer measurements. The poster gives an overview over the magnetometer design as well as its scientific goals.
How to cite: Panov, E. V., Plaschke, F., Matteini, L., Fischer, D., Timmermann, G., Brown, P., Auster, H. U., Cupido, E., Magnes, W., Nakamura, R., Narita, Y., Richter, I., Settino, A., Vörös, Z., and Roberts, O.: Fluxgate Magnetic Field Instrument for Seven Small Plasma Observatory Spacecraft, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3438, https://doi.org/10.5194/egusphere-egu26-3438, 2026.
The Waves instrument suite for the ESA Plasma Observatory mission provides coordinated measurements of electromagnetic fields in space plasmas to address key phenomena affecting particle energization, including plasma waves, turbulence, and wave-particle interactions. The suite consists of an Electric Field Instrument (EFI) and a Search Coil Magnetometer (SCM), enabling simultaneous observations of electric and magnetic field fluctuations and the spacecraft potential. Both electric and magnetic sensors are connected to a common electronics unit, BOX-W, which performs synchronized sampling and on-board processing. BOX-W supports both waveform capture and spectral products, enabling efficient use of telemetry while retaining scientifically relevant information. The combined EFI and SCM measurements enable full characterization of electromagnetic fluctuations, facilitating the determination of wave polarization, propagation properties, and energy flux.
How to cite: Khotyaintsev, Y., Le Contel, O., Kretzschmar, M., Morawski, M., Norgren, C., Soucek, J., Cripps, V., Puccio, W., Giono, G., Colin, F., Jannet, G., Aleksiejuk, K., Szewczyk, P., and Rothkaehl, H.: Waves instrument suite for the ESA Plasma Observatory mission, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12854, https://doi.org/10.5194/egusphere-egu26-12854, 2026.
Plasma energization and energy transport are ubiquitous in cosmic plasmas. The Earth’s Magnetospheric System is a key example of a highly structured and dynamic cosmic plasma environment where massive energy transport and plasma energization occur and can be directly studied through in situ spacecraft measurements. Despite the available in situ observations, however, we still do not fully understand how plasma energization and energy transport work. This is essential for assessing how our planet works, including space weather science, as well as for the comprehension of distant astrophysical plasma environments. In situ observations, theory and simulations suggest that the largest amount of plasma energization and energy transport occur through the coupling between large, fluid scales and the smaller, ion kinetic scales. Remote observations currently cannot access these scales, and existing multi-point in situ observations do not have a sufficient number of observation points to resolve the fluid-ion scale coupling. Plasma Observatory will be the first mission having the capability to resolve scale coupling in the Earth’s Magnetospheric System through measurements at seven points in space, covering simultaneously the ion and the fluid scales in key regions where the strongest plasma energization and energy transport occur: the foreshock, bow shock, magnetosheath, magnetopause, magnetotail current sheet, and transition region. By resolving scale coupling in plasma processes such as shocks, magnetic reconnection, turbulence, plasma instabilities, plasma jets, field-aligned currents and their combination, these measurements will allow us to address the two Plasma Observatory Science Objectives (SO1) How are particles energized in space plasmas? and (SO2) Which processes dominate energy transport and drive coupling between the different regions of the Earth’s Magnetospheric System? Going beyond the limitations of Cluster, THEMIS and MMS multi-point missions, which can only resolve plasma processes at individual scales, Plasma Observatory will transform our understanding of the plasma environment of our planet with a major impact on the understanding of other planetary plasmas in the Solar System and of distant astrophysical plasmas.
How to cite: Retinò, A. and Marcucci, M. F. and the Plasma Observatory Team: Unveiling plasma energization and energy transport in the Magnetospheric System through multi-scale observations: the science of the ESA M7 Plasma Observatory mission candidate, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13019, https://doi.org/10.5194/egusphere-egu26-13019, 2026.
Plasma Observatory is a candidate for the European Space Agency's upcoming M7 science mission. It will investigate how particles are energized in space plasmas and how energy is transported across different scales and regions of the Earth’s magnetosphere. For this, the Energetic Particle Experiment (EPE) provides electron and ion measurements in the energy range from 30 to 600 keV, with an optional extension of measurements down to around 20 keV for electrons and ions and up to 1.5 MeV for ions. Both electron and ion measurements have an energy resolution of 20 % or better. The design of the EPE is based on the well-proven magnet-foil technique and features two geometrical factors for both electrons and ions in order to increase the dynamic range of observable fluxes.
To validate and demonstrate the EPE's capabilities, GEANT4 Monte Carlo simulations of the current instrument design were performed, which allowed to derive the geometrical factors and energy-dependent responses to electrons and protons. Based on these results, the instrument’s performance in the expected particle flux environments during the Plasma Observatory mission were investigated.
How to cite: Ebeling, H., Jürgensen, S., Liu, C., Kühl, P., Berger, L., Wimmer-Schweingruber, R. F., Angelopoulos, V., Tsai, E., Caron, R., Wilkins, C., Dunlop, M. W., Ulusen Aksoy, D., Prydderch, M., Steven, A., Vainio, R., and Lehti, J.: Simulations of Plasma Observatory's Energetic Particle Experiment, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3730, https://doi.org/10.5194/egusphere-egu26-3730, 2026.
The general idea for instruments arcitecture for the PMO mission is to have the identical set of instruments located on the board of seven identical spacecraft, via the two independent interface connections to the spacecraft managed by two electronic boxes: BOX-W and BOX-P
The Polish contribution to the PMO mission includes scientific, instruments and management aspects for both BOX-P and BOX-W units. CBK PAS leads the activity in the frame of BOX-P at management and system engineering.
The BOX-P instrument serves as a common electronics box, housing the front-end electronics for the flux gate magnetometer MAG and its sensors, a common power supply unit PSU, and a common Data Processing Unit DPU. The BOX-P electronics box also implements the common power and
data interface for the particle diagnostics instruments: iEPC, EPE and IMCA. BOX-P implements the single communication interface for the entire sisters spacecraft payload. All sets of instruments are dedicated to the in situ, multi-scale, multi-point study, through simultaneous measurements, of plasma energisation and energy transport in the Earth's Magnetospheric System.
CBK PAS leads the activity for EFI, the Electric Field Antenna and the manufacturing EFI-ADA sensor. The Electric Field Dipole Antenna (EFI-ADA) is connected to the BOX-W suit instrument, which measures the AC electric field from DC to 100 kHz. The EFI-ADA sensor consists of a single dipole antenna. The sensor will be mounted near the end of the rigid magnetometer boom on which SCM is mounted and will feature an orthogonal-to-the-boom dipole antenna, approximately 4.0 meters from tip to tip.
CBK PAS will also design and manufacture the power supply unit, PSU unit for BOX-W .
How to cite: Rothkaehl, H., Morawski, M., Aleksiejuk, K., Szewczyk, P., Ptasiński, G., Matyjasiak, B., Przepiórka Skup, D., and Barciński, T.: Polish contribution to the PMO mission, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15134, https://doi.org/10.5194/egusphere-egu26-15134, 2026.
Plasma Observatory is a candidate mission of the European Space Agency (ESA) with a possible mission selection foreseen in 2026 and possible mission adoption in 2029. The mission aims to investigate cross-scale coupling and plasma energization across key regions of the magnetosphere, including: the bow shock, magnetopause, magnetotail and transition regions. To achieve this aim, Plasma Observatory will investigate the rich range of interesting plasma phenomena in these regions in the Earth’s magnetosphere, using a constellation of seven sister spacecraft. This allows configuration of the spacecraft in two nested tetrahedra to probe coupling on both ion and fluid scales. Since energetic particles are sensitive tracers of energization processes, altering the energy (or velocity) of both ions and electrons, measuring these effects in situ and at high cadence is of high importance for the mission. Energetic electrons and ions will be measured by the Energetic Particle Experiment (EPE). Here we present the instrument, which is a compact, dual-particle telescope, solid state detector design originally based on ELFIN’s EPD instrument. Using three telescopes (sensor heads), it achieves near 3-D distributions for ions and electrons (135 x 360 deg). The development consists of deflecting magnets on the ion side (to screen out electrons) and Aluminized Kapton foil covers to screen out low energy ions on electron side. The baseline energy range (30-600 keV) for both species (with a goal for 20-600 keV at spin cadence) is targeted on low-end, suprathermal energies (minimising the effective gyro-scales for the computation of moments, PAD (e) and VDF determination). An extended energy range of up to 1.5 MeV at lower cadence is possible for ions. This arrangement allows the potential for spatial differences to be resolved on at least ion to fluid scales and to sense plasma boundaries. Detector layering is based on expected dynamic energy range and allows coincident/anti-coincident logic to be applied to separate out the higher energy species.
How to cite: Angelopoulos, V., Dunlop, M., Vainio, R., Wimmer-Schweingruber, R., Ulusen Aksoy, D., Tsai, E., Prydderch, M., Berger, L., Liu, C., Caron, R., Lehti, J., Steven, A., Grainger, W., Melzack, N., Nalagatla, M., Jürgensen, S., Kühl, P., Ebeling, H., and Wilkins, C.: The Energetic Particle Experiment on Plasma Observatory, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15442, https://doi.org/10.5194/egusphere-egu26-15442, 2026.
In this presentation we report on the development of an Ion mass instrument onboard of small Sat as part of the Plasma Observatory mission. This new Ion Mass Spectrometer that will be developed for this mission is similar to the IES-D instrument successfully flown on the Cluster II mission. The IMS instrument developed for the THOR mission. The TOF (Time of Flight) section is similar but smaller than designed for the THOR mission. That clearly indicates a high level of heritage of this Mass Spectrometer. Hence this IMCA like instrument for Plasma Observatory this is a new instrument that will have a smaller TOF chamber we have redesigned the TOF section by using SIMION and TRIM simulations to evaluate the performance/geometric factor of this new instrument and the effect of thin carbon foils. The first results of this study indicated that we will be able to measure Hydrogen, Helium and Oxygen ions with sufficient high statistic in all science areas of this mission. covering the thermal and suprathermal energies, with a time resolution enabling to resolve ion scales and an energy and angular resolution permitting to study the non-Maxwellian features in distribution functions. Thus, the energy range will be 10eV - 30keV with a 20% resolution, a temporal resolution: 2s and an angular resolution: 22.5°. It is also planned to add a flux reducer to this sensor the handle a large dynamic range. In this presentation we will report on the current status of this development.
How to cite: Kucharek, H., Kistler, L., Mouikis, C., De Angelis, E., Alata, Y., Fraenz, M., Marcucci, F., Retino, A., and Brin, A.: Development of a Time of Flight section for a Mass Spectrometer for the future Plasma Observatory mission., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15945, https://doi.org/10.5194/egusphere-egu26-15945, 2026.
Plasma Observatory is one of the three candidates currently being evaluated by ESA as the future M7 mission. Its objectives are to determine how particles are energized, identify the main processes that transport energy in space plasma, and understand the interactions between the different regions of the Earth's magnetosphere with multi-scale measurements in situ. To achieve these scientific objectives, Plasma Observatory (PMO) is deseigned as seven identical sister spacecrafts (SSCs) in a two nested tetrahedra configuration.
The Laboratory for Instrumentation and Research in Astrophysics (LIRA) of the Observatory of Paris is responsible for the DPU-P application software for the BOX-P instrument. The LIRA contribution includes the specification, design, implementation and testing, verification and validation, product assurance, and development of the test platform. The DPU BOX-P flight software transforms the raw data produced by the instruments into scientific products of L0 level that can be used on the ground (precise dating, synchronisation, filtering, reduction, compression), which means that a significant part of the scientific value of each instrument is directly produced by the software. Responsibility for the flight software places LIRA at the heart of defining scientific products (content, format and cadence of L0s), optimizing on-board processing and science/resource trade-offs, in direct interaction with the instrument teams and mission constraints. The LIRA team has recognized expertise in complex scientific flight software, demonstrated on missions such as PLATO and Solar Orbiter.
Here we present the DPU-P software and we discuss its contribution to the science of Plasma Observatory.
How to cite: Griton, L., Plasson, P., Issautier, K., Maksimovic, M., Peccoux, T., Gouel, P.-V., Berthomier, M., Fiachetti, C., Rothkaehl, H., Ptasinski, G., D'Amicis, R., Marcucci, M., and Retino, A.: The DPU BOX-P flight software of Plasma Observatory, a LIRA contribution, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20732, https://doi.org/10.5194/egusphere-egu26-20732, 2026.
Plasma Observatory (PMO) is one of the three ESA M7 candidates, which have been selected in November 2023 for a competitive Phase A with a mission selection planned in June 2026 and launch in 2037. PO scientific theme is unveiling plasma energization and energy transport in the near-Earth plasma environment through multiscale observations. The baseline mission includes seven identical smallsat Sister Space Craft (SSC) embarking state of the art instruments for electromagnetic fields and particle measurements. This work presents the results of preliminary surface charging analyses performed for the PMO.
Surface charging phenomenon is induced by the interaction of the spacecraft with the surrounding plasma environment and can lead to several potentially harmful consequences, including interference with ground communications, on-board electronics and scientific instruments. Since PMO aims to investigate the plasma properties in the near-Earth environment with high precision, any perturbation to the instruments generated by surface charging represents a concern for science return. Moreover, the charging phenomenon can lead to the development of variable electric and magnetic fields and, in most extreme scenarios, the onset of electrostatic discharges that may cause temporary malfunctions or, in worst cases, mission loss. These discharges occur when the potential difference between near surfaces, exceeds a critical threshold. Such conditions are more likely to occur when the spacecraft structure includes both conductive and dielectric materials. For PMO this risk is expected to remain low, as per baseline the seven spacecrafts will be predominantly conductive, allowing fast charge redistribution. However, as the PMO spacecraft will traverse multiple plasma regions of the Earth’s magnetospheric system during the Key Science Phases (KSPs), evaluating the resulting charging effects is essential. These analyses are crucial not only for PMO but for all space missions, as they support the development of reliable spacecraft designs and ensure safe operation in diverse plasma conditions.
How to cite: Michelagnoli, M., Marcucci, M. F., Retinò, A., Berthomier, M., Khotyaintsev, Y., Eriksson, A., Soucek, J., Johansson, F., Cipriani, F., Focardi, M., and Merola, P.: Preliminary analyses of Surface Charging effects for the Plasma Observatory (PMO) mission, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19522, https://doi.org/10.5194/egusphere-egu26-19522, 2026.
The ion and Electron Plasma Camera (iEPC) onboard the Plasma Observatory mission will provide the 3D velocity distribution function of thermal and supra-thermal ions and electrons in the 10 eV to 25 keV energy range with 12% energy resolution, 22.5° angle resolution, and at 250 ms cadence. It will be deployed on all the 7 satellites of the mission, allowing the first characterization of multi-scale particle acceleration processes in space plasmas. We present the capability of the iEPC instrument concept, which is based on the donut analyser topology (Morel et al., 2017), further optimized for the Plasma Obervatory mission (Hénaff and Berthomier, jgr 2025), and tested at LPP (Hénaff et al, jgr 2025). The iEPC is the first plasma spectrometer with a 3D instantaneous field-of-view with 128 look directions in an energy range relevant for magnetospheric plasmas. Altough being a very compact sensor, the iEPC geometric factor reaches 10-3 cm2.sr.eV/eV per look direction, which will provide excellent counting statistics, even in the dilute magnetospheric plasmas.
How to cite: Berthomier, M., Hénaff, G., Forsyth, C., Lavraud, B., Génot, V., Leblanc, F., Brockley-Blatt, C., Techer, J.-D., Alata, Y., Seneret, E., Poggia, G., Retino, A., and Le Contel, O.: The ion and Electron Plasma Camera of the Plasma Observatory Mission, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20405, https://doi.org/10.5194/egusphere-egu26-20405, 2026.
Magnetic reconnection in Earth’s magnetotail is inherently intermittent, yet the physical processes governing its cessation and subsequent restart remain poorly understood, largely due to the multiscale nature of the system. In this study, we use high-resolution, multi-point observations from the Magnetospheric Multiscale (MMS) mission to investigate a three-phase event from the terrestrial magnetotail in which reconnection is initially active, subsequently absent for several minutes, and then reinitiates.
The event begins with an off-equatorial, field-aligned ion jet indicative of ongoing reconnection. This jet is replaced by a prolonged quiet interval characterized by a duskward ion flow carried by a hot population, negligible ExB drift, and the absence of conventional reconnection signatures. During this interval, the total plasma plus magnetic pressure increases, and the observations reveal evidence for current sheet thickening followed by thinning.
The first indication of renewed activity is an injection of energetic field-aligned ions detected off-equatorially, followed by the gradual formation of an equatorial plasma jet and the subsequent arrival of dipolarization fronts. The first dipolarization front clearly separates ions originating from the pre-existing plasma sheet and the lobes, signalling the arrival of magnetic flux tubes that were among the first to reconnect during onset. At the onset of the emerging jet, prior to the arrival of the first dipolarization front, ions briefly become demagnetized and a northward electric field is observed, opposite in sign to the typical Hall electric field expected in the ion diffusion region. These signatures highlight the complex and transient nature of the plasma environment during the evolution of a reconnection outflow jet and point to processes that cannot be fully resolved with the MMS tetrahedron alone.
These observations demonstrate that to understand reconnection intermittency requires simultaneous measurements spanning electron, ion, and magnetohydrodynamic scales. Plasma Observatory, providing coordinated multi-point coverage across these scales, is essential for capturing the coupled evolution of particles, fields, and currents during reconnection cessation and onset—processes that cannot be resolved with present-day multi-spacecraft constellations.
How to cite: Norgren, C., Hesse, M., Phan, T., Khotyaintsev, Y., and Richard, L.: Cessation and restart of reconnection -- observations from the exhaust, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12905, https://doi.org/10.5194/egusphere-egu26-12905, 2026.
Interaction between a turbulent plasma flow like solar o stellar wind and a magnetic field as an obstacle is very common for space and astrophysical plasmas. The magnetosphere of the Earth is formed precisely as a result of such interaction, and there is a vast amount of evidence suggesting that the geomagnetic tail is like a turbulent wake behind an obstacle. These solar wind turbulent fluctuations are strongly amplified after crossing the bow shock,
forming the plasma flows in the magnetosheath. At the same time, the geomagnetic tail contains the plasma sheet filled by dense and turbulent plasmas and tail lobes filled by a rare quasi-laminar plasmas. The Large-scale vortices in the wake are able to generate turbulent transport that takes place both along the plasma sheet, in the X and Y directions, and across the plasma sheet, in the Z direction. Thus, turbulent fluctuations in all directions should be taken into consideration when analyzing plasma transport in the plasma sheet, and stability of the plasma sheet itself. The interaction between the turbulent plasma sheet and the inner magnetosphere regions is important for understanding of the key magnetospheric processes such as geomagnetic storms and substorms. At the same time, the variations in the solar wind density, velocity, and interplanetary magnetic field consonantly change the plasma conditions both in the plasma sheet and the inner magnetosphere, but due to different and not fully understood mechanisms. Data from CLUSTER, and Themis satellites are used to analyse the stability of turbulent plasma sheet and turbulent transport for different solar wind conditions and geomagnetic activity.The results obtained show that the level of turbulence in the plasma sheet, characterized by the eddy diffusion, correlates with the dawn-dusk electric field, and depends of the solar wind and IMF parameters for both quiet and disturbed geomagnetic conditions.
How to cite: Stepanova, M., Pinto, V., Espinoza, C., Diaz Peña, J., and Antonova, E.: Impact of Turbulence on the Stability and Transport Processes of the Plasma Sheet, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22057, https://doi.org/10.5194/egusphere-egu26-22057, 2026.
We investigate the space–time variability of intermittent magnetic turbulence in the terrestrial foreshock using fluxgate magnetometer observations from the Magnetospheric Multiscale (MMS) mission. Intermittency is quantified through sliding-window probability density function analysis and scale-dependent flatness of temporal magnetic field increments, over a broad range (0.2–256 s) of scales. The analysis is complemented by spectral diagnostics of the magnetic time-series. By organizing the analysis in terms of the field-aligned distance from the bow shock and the angle between the interplanetary magnetic field and the shock normal, we resolve systematic differences between quasi-parallel and quasi-perpendicular foreshock regions. The multi-spacecraft character of MMS enables us to directly probe spatial intermittency at the scale of the inter-spacecraft separations (~20 km), and compare spatial and temporal statistics, providing insight into the applicability of the Taylor hypothesis in a highly dynamic foreshock environment. We find that intermittency persists both below and beyond ion temporal scales, with enhanced intermittency in the quasi-parallel foreshock at sub-second scales and a reversal of this trend at larger scales. The latter finding is likely resulted in by intense wave activity. We emphasize that the provisional Plasma Observatory mission would enable our analyses to be extended to a broader range of spatial scales, providing a decisive advance in disentangling spatial and temporal variability and in understanding energy transfer in collisionless space plasmas.
Our study is conducted in the framework of the ESA-supported SWIFT project, which aims to investigate how solar wind dynamics drive turbulence and large-scale current structures within the coupled terrestrial magnetosphere–ionosphere system.
How to cite: Kovacs, P. and Madar, A.: Multi-scale intermittency and energy transfer in the terrestrial foreshock, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11936, https://doi.org/10.5194/egusphere-egu26-11936, 2026.
The magnetic field in the chromosphere and low corona near the boundaries of equatorial coronal holes in the quiet Sun is thought to reconfigure through interchange reconnection (IR). This process occurs in low-beta plasma with a strong guiding field and may produce an ion distributions known as “hammerhead.” These distributions have been observed in coronal plasma associated with current sheets and in regions whose footpoints lie near equatorial coronal holes. They usually consist of a core plus a perpendicularly diffuse beam feature at a specific velocity relative to the core. The mechanism we propose involves the interpenetration of two plasmas with different properties—one on closed field lines and one on open field lines. In the chromosphere and low corona, these distributions can generate ion-sound and ion-cyclotron waves once the beam’s relative velocity exceeds a threshold. As such plasma distributions travel toward the solar wind through a funnel region where the magnetic field and plasma density rapidly drop, they may become unstable and produce Alfvén-type magnetic perturbations that can evolve nonlinearly into switchback structures. These threshold conditions are likely met near the transition from sub-Alfvénic to super-Alfvénic wind.
How to cite: Krasnosselskikh, V., . Zaslavsky, A., Sulem, P.-L., Jebaraj, I. C., Dudok de Wit, T., Verniero, J., Roytershteyn, V., Agapitov, O., and Balikhin, M.: Interchange Reconnection and ion kinetic instabilities in coronal plasma, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18602, https://doi.org/10.5194/egusphere-egu26-18602, 2026.
The tearing instability, which takes free energy from oppositely directed magnetic fields, and the Weibel instability, which takes free energy from temperature anisotropies, at first glance, appear to be entirely different instabilities. However, the opposing magnetic fields enforce a current between them, and the associated drift of the plasma leads to an effective thermal spread that is larger along the direction of the flow. This modified thermal spread acts as a temperature anisotropy that helps drive the instability. We investigate the connection between the two instabilities using 2D semi-implicit particle-in-cell simulations (with the code ECSIM), starting from a Harris equilibrium and no guide field. We find that for thin current sheets (thinner than the ion Larmor radius), where the assumptions of the kinetic tearing instability from Zelenyi & Krasnosel'skikh (1979) break down, the Weibel theory gives a better estimate for the growth of the instability.
How to cite: Schoeffler, K., Aravindakshan, H., and Innocenti, M. E.: Are the tearing and the Weibel instabilities the same?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12667, https://doi.org/10.5194/egusphere-egu26-12667, 2026.
Posters virtual: Mon, 4 May, 14:00–18:00 | vPoster spot 4
EGU26-14898 | ECS | Posters virtual | VPS27
Exploring Magnetic Island Morphology through 2D MHD and Synthetic FieldsMon, 04 May, 14:42–14:45 (CEST) vPoster spot 4
In this project, we are exploring a few aspects of low frequency and wavenumber magnetic field energy spectra in the context of space physics, following observations of 1/f behavior (e.g. [1]-[4]). The origin of this phenomena is still debated; however studies have suggested that these processes could be generated from scale-invariant processes in the corona or further within the dynamo of the Sun. One of the paradigms that has been discussed ([5],[6]) for achieving scale invariant structure is the merger of two dimensional or quasi-two dimensional magnetic flux tubes or flux ropes. This may be particularly relevant in the corona. To further explore this connection, it becomes necessary to understand the distributions of size and magnetic flux content, as well as the morphology of magnetic structures/”islands” in two dimensional turbulence representations. These features of the magnetic field will be explored using methods described herein [7]. These will be implemented using magnetic fields obtained from synthetic construction and 2D simulation.
[1]Burlaga, L. F., & Ness, N. F. 1998, JGR, 103, 29 719
[2]Matthaeus, W. H., & Goldstein, M. L. 1986, PhRvL, 57, 495
[3]Wang, J., Matthaeus, W. H., Chhiber, R., et al. 2024, SoPh, 299, 169
[4]Pradata, R. A., Roy, S., Matthaeus, W. H., et al. 2025, ApJL, 984, L23
[5]Matthaeus, W. H., & Goldstein, M. L. 1982, JGR, 87, 6011
[6]Mullan, D.J.: 1990, Astron. Astrophys. 232, 520.
[7]Servidio, S., Matthaeus, W., Shay, M., et al. 2010, Physics of Plasmas, 17
How to cite: Pradata, R., Khan, M. B., Pecora, F., Matthaeus, W., Roy, S., and Adhikari, S.: Exploring Magnetic Island Morphology through 2D MHD and Synthetic Fields, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14898, https://doi.org/10.5194/egusphere-egu26-14898, 2026.
