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 a mother and six daughter 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 Experiments (EPE) on the main (-M) and six daughter (-D) spacecraft. Here we present the EPE-D instrument, which is a compact, dual-particle telescope, solid state detector design based on ELFIN’s EPD instruments. Using three telescopes, 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 a Lexan foil cover on electron side (to screen out low energy ions). The energy range (30-600 keV) for both species is targeted on low-end, suprathermal energies (minimising the effective gyro-scales for the computation of moments, PAD (e) and FDF determination), and so allowing spatial differences to be resolved. Detector layering is based on expected dynamic energy range and allows anti-coincident logic to be applied to separate out the higher energy species.

How to cite: Dunlop, M. W., Angelopoulos, V., Vainio, R., Wimmer-Schweingruber, R. F., Ulusen Aksoy, D., Tsai, E., Prydderch, M., Lethi, J., Grainger, W., Liu, C., Caron, R., Steven, A., Bowett, O., Berger, L., Jürgensen, S., and Kühl, P.: The Energetic Particle Experiment on the Plasma Observatory Daughter Spacecraft, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6783, https://doi.org/10.5194/egusphere-egu25-6783, 2025.

Magnetic reconnection is a fundamental plasma process that converts electromagnetic energy into bulk kinetic and thermal energy of the plasma through topological rearrangement of the magnetic field. This process is often accompanied by kinetic instabilities and wave activity, which can influence energy conversion. The electron firehose instability (EFI) is one such kinetic instability, which arises when the electron population has significant temperature anisotropy, and the parallel component of the temperature sufficiently exceeds the perpendicular component relative to the background magnetic field. The plasma in the reconnection outflow region can be unstable to the EFI and the presence of EFI-generated waves could potentially modify the energy distribution in the plasma.

We use data from the NASA Magnetospheric Multiscale (MMS) mission in Earth's magnetotail to investigate energy conversion associated with magnetic reconnection in different regions, including the Electron Diffusion Region (EDR) and the reconnection outflow hosting EFI-generated waves. To quantify energy conversion, we analyze various measures such as J.E (where J is the current density and E is the electric field), pressure-strain interaction, and the Higher-ORrder Non-Equilibrium Terms (HORNET) power density.

How to cite: Cozzani, G., Kretzschmar, M., and Cassak, P.: Investigating energy conversion at the electron scales in Earth's magnetotail, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10260, https://doi.org/10.5194/egusphere-egu25-10260, 2025.

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. 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.

This paper provides an overview of these WG and how you can get involved in Plasma Observatory.

How to cite: Taylor, M., Marcucci, F., and Retino, A. and the Plasma Observatory WG team: Science Study Team Working Groups of the ESA M7 Mission candidate Plasma Observatory , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11909, https://doi.org/10.5194/egusphere-egu25-11909, 2025.

Plasma Observatory (PO) is one of the three Class-M7 ESA missions currently in Phase A, and is designed to investigate fundamental processes at the base of energization and energy transport, such as collisionless shocks, plasma jets, wave, turbulence, and magnetic reconnection by gathering unprecedented multipoint and multiscale measurements of near-Earth plasma environments. The mission concept consists of a constellation of seven spacecraft in a double nested tetrahedron formation with a common vertex. The key science regions (KSRs) of the PO mission are Earth bow shock, foreshock, magnetosheath, magnetopause, tail plasma sheet and transition region. However, additional science regions (ASRs) such as inner magnetosphere, flank magnetopause, and pristine solar wind will be traversed by the constellation during the orbit, thus allowing for additional scientific targets. In this context, the Synergies/Additional Science Working Group aims to systematically investigate the major scientific advancements that can be achieved by leveraging the PO constellation in the various regions explored outside the KSRs, and to maximize the scientific return of the mission by broadening the PO science community by including space plasma scientists from other fields.

Since the magnetospheric system is a highly dynamic environment subjected to the solar wind forcing, especially during solar wind transient events, important physical processes can be studied by observing the magnetospheric response to them. New multiscale measurements of fields and particles at more than four points, for instance, are crucial for investigating the magnetosphere-ionosphere coupling for different levels of geomagnetic activity. Moreover, PO will provide measurements at the edge of the outer radiation belt, allowing to study fundamental plasma processes such as particle acceleration, transport and loss, wave-particle interactions and so forth. Large scale phenomena developing in ASRs such as solar wind and flank magnetopause, such as turbulence, reconnection, and instabilities are connected to ion and sub-ion scales where the energy is dissipated. In this spirit, simultaneous multiscale observations gathered in the ASRs are crucial for investigating the connection between MHD-scale plasma structure dynamics, turbulent energy transfer and the energy conversion occurring at small-scales. Beyond the ASRs observed in situ by the spacecraft constellation, there are strong synergies with laboratory activities. How does magnetic reconnection couple global MHD scales to local dissipation scales is an outstanding open question, some aspects of which can be addressed with the support of current and upcoming multiscale laboratory experiments that are, therefore, highly relevant for PO scientific objectives.

This contribution summarizes all the recent advancements made regarding the Synergies/Additional Science Working Group activities for PO and will discuss inputs and future perspectives supporting the mission Phase A.

How to cite: Benella, S., Ripoll, J. F., Norgren, C., Allanson, O., Biasiotti, L., Gasparini, S., Gkioulidou, M., Ji, H., Miyoshi, Y., Nakamura, R., Pitna, A., Przepiórka-Skup, D., Settino, A., Stepanova, M., Toledo-Redondo, S., Turner, D., and Yordanova, E.: Progress and Updates from the Plasma Observatory Synergies/Additional Science Working Group, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11978, https://doi.org/10.5194/egusphere-egu25-11978, 2025.

Plasma Observatory is a candidate mission of the European Space Agency (ESA) with a possible selection foreseen in 2026 and a launch in 2037. It aims to investigate the plasma coupling across different scales. To achieve this aim, Plasma Observatory will investigate different regions in the Earth’s magnetosphere which is rich in many interesting plasma phenomena. It consists of a mother and six daughter spacecraft. This allows to configure the spacecraft in two nested tetrahedra to investigate cross-scale coupling.

Energetic particles are sensitive tracers of processes which can alter the energy (or velocity) of ions and electrons. It is thus of high importance to measure them in situ at high cadence. They are bound to magnetic field lines but can be scattered onto others by various processes.

Energetic electrons and ions will be measured by the Energetic Particle Experiments (EPE) on the main (M) and six daughter (D) spacecraft. Here we present different instrument concepts for EPE-M, all of which which cover the energy range from 30 keV – 600 keV for electrons and up to 8 MeV for ions. The current (baseline) design utilizes the foil-magnet technique to separate electrons from ions. The experiment consists of two sensors each with two bidirectional telescopes and thus has eight viewing directions. Together with the spacecraft spin (2 rpm) EPE-M covers a field of view of nearly 4π steradians. Higher time resolution is possible at reduced angular resolution. Alternative design concepts have been derived and are presented as well.

How to cite: Jürgensen, S., Wimmer-Schweingruber, R. F., Berger, L., Kühl, P., Dunlop, M. W., Vainio, R. O., and Angelopoulos, V.: The Energetic Particle Experiment on the Plasma Observatory Mother Spacecraft, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12644, https://doi.org/10.5194/egusphere-egu25-12644, 2025.

The overarching goal of the Plasma Observatory Missions is to use multiscale multi-spacecraft observations to investigate in detail plasma energization and plasma transport in the near-Earth region. Thus, the prime goals of that mission are: How are particles energized in that plasma environment? And what processes are dominant in transporting Energy in the Magnetospheric System.

The achieve these science goals electromagnetic fields and three-dimensional particle distributions will be measured in high resolution and accuracy. IMS (the Ion Mass Spectrometer) will measure the full three-dimensional distribution functions of near-Earth main ion species (H⁺, He⁺, He⁺⁺ and O⁺) at high time resolution (~150 ms for H+ , ~ 300 ms for He⁺⁺) with energy resolution down to ~10% in the range 10 eV/q to 30 keV/q and angular resolution _ ~10 .

Such high time resolution is achieved by mounting multiple sensors around the spacecraft body, in similar fashion to the MMS/FPI instrument. Each sensor combines a top-hat electrostatic analyser with deflectors at the entrance together with a time-of-flight section to perform mass selection. IMS electronics includes a fast sweeping high voltage board that is required to make measurements at high cadence. Ion detection includes Micro Channel Plates (MCP) combined with Application-Specific Integrated Circuits (ASICs) for charge amplification, discrimination and time-to-digital conversion (TDC). IMS will be designed to address directly many of the Plasma Observatory science objectives, in particular ion heating and acceleration by turbulent fluctuations in foreshock, shock and magnetosheath regions. In this presentation we will report on initial performance measurements of the IMS instrument and relate these mensurements to potential recordings at keys science areas.

How to cite: Kucharek, H., Marcucci, M. F., Retino, A., Lavraud, B., Kistler, L., DeKeyser, J., Galli, A., Bundock, J., and Techer, J.-D.: The Ion Mass Spectrometer instrument for Plasma Observatroy – IMS, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13482, https://doi.org/10.5194/egusphere-egu25-13482, 2025.

Comparison of THEMIS spacecraft observations with kinetic simulations suggested that the kinetic Ballooning/Interchange Instability (BICI) may lead to erosion and thinning of the magnetotail current sheet at fluid scales due to side vorticity and associated an FLR effect and at ion scales by means of EMIC waves. The FLR effect may lead to ion temperature asymmetry on the two sides of BICI heads in the course of ion redistribution between the dusk- and dawnside vortices around the neutral sheet. On top of that, the EMIC waves may propagate in both azimuthal directions and modulate the ion density and velocity above and below the neutral sheet. As this activity may be important for turning Bz southward and possibly initiating magnetic reconnection in the magnetotail, we show high-resolution MMS ion observations with signatures of the two processes now in the MMS magnetotail bursty bulk flow observations and aim at finding evidence that the field and particle behaviour was caused by the two effects.

How to cite: Panov, E. V., Nakamura, R., and Baumjohann, W.: Ion behaviour in the vicinity of ballooning-interchange heads, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15349, https://doi.org/10.5194/egusphere-egu25-15349, 2025.

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? The mission consists of seven satellites, a main platform (mothercraft, MSC) and six smaller identical satellites (daughtercraft) 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 (near-Earth reconnection region, fast flow formation region). 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 only included in the Fields instrument suite of the MSC. SCM will be delivered by LPP and LPC2E and will provide the three components of the magnetic field fluctuations in the [0.1Hz-8kHz] frequency range, after digitization by the Low frequency Receiver (LFR) within the Field and Wave Processor (FWP), relevant for the three Key science regions. It will be mounted on a 6m boom and will allow to reach the following sensitivities [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), 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 processes, the plasma and energy transport, the acceleration and the heating of the plasma.

How to cite: Le Contel, O., Kretzschmar, M., Retino, A., Mehrez, F., Jannet, G., Alison, D., Revillet, C., Mirioni, L., Agrapart, C., Sou, G., Geyskens, N., Berthod, C., Chust, T., Berthomier, M., Fiachetti, C., Khotyaintsev, Y., Cripps, V., and Marcucci, M. F.: The SCM instrument for the ESA Plasma Observatory mission, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16777, https://doi.org/10.5194/egusphere-egu25-16777, 2025.

The availability of multi-point in situ data from space missions orbiting in solar wind and near-Earth environments offers valuable insights into fundamental physical phenomena such as shocks, magnetic reconnection, turbulence, waves, jets and so on. All these processes are related to dynamical evolving plasma structures in both space and time. In this context, invariant quantities derived from the gradient tensor method allows us to study the evolution of topological structures in velocity and magnetic fields across various regions of interplanetary space at different scales. The use of gradient tensors is primarily based on the availability of multi-point data from missions involving at least four satellites arranged in a tetrahedral formation.

Here we present some theoretical and observational results based on the analysis of gradient tensor invariants. We derive equations governing the temporal evolution of these quantities to get insights into the topological and morphological changes of these structures in time. These evolution equations also allow us to identify the dominant physical terms driving the observed changes. A preliminary analysis, based on MMS multi-point observations, suggests that the plasma in the near-Earth solar wind predominantly behaves like a fluid, whereas velocity and magnetic field interactions play a more significant role in the magnetosheath region.
We further introduce a novel approach for studying gradient tensor characteristics using the Schur transformation. This technique decomposes the velocity and magnetic field gradient tensors into a matrix representing eigenvalue contributions and another term associated with pressure and dissipative effects. This decomposition enables the identification of regions where dissipative effects are more prominent. These studies are of critical importance for future space missions which will extend the current multi-point paradigm, based on a single tetrahedron constellation, to multi-scale multiple tetrahedra configurations such as the NASA mission HelioSwarm (in the solar wind) and the ESA Phase A Plasma Observatory (in the near-Earth plasma).

How to cite: Quattrociocchi, V., Consolini, G., Materassi, M., and Benella, S.: Investigating structures through gradient tensors in turbulent space plasmas: invariants’ evolution equations and Schur decomposition, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17806, https://doi.org/10.5194/egusphere-egu25-17806, 2025.

The Magnetospheric System is the highly dynamic plasma environment where the strongest energization and energy transport occurs in near-Earth space.  Previous multi-point observations from missions such as ESA/Cluster and NASA/MMS have evidenced the fundamental role for these processes of cross-scales coupling . In the Magnetospheric System, the electromagnetic energy is converted into energized particles and energy is transported mainly at the ion and fluid scales. Simultaneous measurements at both large, fluid and small, kinetic scales are required to resolve scale coupling and ultimately fully understand plasma energization and energy transport processes. 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 with the first simultaneous in situ measurements at both fluid and ion scales. PO baseline mission includes one mothercraft (MSC) and six identical smallsat daughtercraft (DSC) in a two tetrahedra formation with MSC at the common vertex for both tetrahedra. PO baseline orbit is an HEO 8x17 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 current sheet. Spacecraft separation ranges from fluid (5000 km) to ion (30 km) scales. The MSC payload provides a complete characterization of electromagnetic fields and particles in a single point with time resolution sufficient to resolve kinetic physics at sub-ion scales and fully characterize wave-particle interactions. The DSCs have identical payload, simpler than the MSC payload, yet giving a full characterization of the plasma at the ion and fluid scales and providing the context where energization and transport occurs. 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 2026 and launch in 2037.  

How to cite: Marcucci, M. F. and Retinò, A. and the The Plasma Observatory Team: The ESA M7 Plasma Observatory mission, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17870, https://doi.org/10.5194/egusphere-egu25-17870, 2025.

Plasma Observatory (PO) is an ESA mission proposal to study for the first time plasma transport and energization in the near-Earth environment simultaneously at both fluid and ion scales, with a constellation of 7 spacecraft: 1 mother and 6 daughters. 
In the PO mission framework, MAG-M is the proposed fluxgate magnetometer onboard the Mothercraft, to be built at Imperial College London.
It is a dual-sensor instrument mounted on a rigid boom dedicated to high-resolution measurements of the DC magnetic field, with strong design heritage from previous missions. In this presentation we review MAG-M main characteristics and its development stage. 
We also discuss the key role of magnetic field measurements in the goals of the mission and how MAG-M will contribute, both with single-point and multi-point measurements, to the investigation of the nature of waves and structures in the plasma at both fluid and kinetic scales, their vector anisotropies, the 3-dimensional shapes of eddies and boundaries in the plasma as well as to the determination of the flows of energy acting between particles and fields in the near-Earth environment.

How to cite: Matteini, L., Brown, P., Tomes, M., and Hodgkins, J.: The MAG-M magnetometer onboard Plasma Observatory, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17894, https://doi.org/10.5194/egusphere-egu25-17894, 2025.

The standard conditions considered for magnetic reconnection to occur are usually antiparallel magnetic field configurations with a shear angle of 180^◦. Reconnection is often observed with an additional out-of-plane component of the magnetic field (guide field). We performed two sets of 2D fully kinetic simulations using SMILEI code of asymmetric reconnection. The first set was performed initially by Dargent et al., 2017 with and without cold ions. While the second set with and without cold ions each conducted in the presence of a moderate guide field. The simulation domain size is set to (x_max , y_max) = (320, 128) d_i, enabling us to study these effects in the electron diffusion region (EDR) as well as the coupling across different scales, including ion diffusion region (IDR), outflow jets, and extended separatrices far from diffusion region. When the density gradient is combined with a guide field component at the magnetopause, it was suggested by Swisdak et al., 2003 that the electron diamagnetic drift governs the motion of the X-line.

Our simulations reveal the development of an asymmetry in the reconnection plane as expected and a motion of the X-line in the opposite direction of the electron diamagnetic drift. This finding challenges the previously proposed explanation. We also report our progress in investigating the impact of cold ions in reinforcing the electron dynamics and further investigate the impact of adding a moderate guide field in their presence. These effects are expected to influence the energization, energy partitioning across scales, and potentially the suppression of reconnection. Fluid scales coupling with smaller ion scales aligns with the primary objective of the Plasma Observatory (PO) mission which aims to study plasma energization and energy transport. Our findings will contribute to the preparation of the PO mission and aim at improving its science return.

How to cite: Baraka, M., Le Contel, O., Retino, A., Dargent, J., Beck, A., Toledo-Redondo, S., Cozzani, G., Fuselier, S., Chust, T., and Alqeeq, S.: 2D fully kinetic simulations of dayside magnetic reconnection in the presence of cold ions and a moderate guide field., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18438, https://doi.org/10.5194/egusphere-egu25-18438, 2025.

Plasma Observatory (PMO) is a candidate for the ESA Directorate of Science M7 mission call, currently in Phase A. It is a multi-scale mission concept with the capability to resolve scale coupling and non-planarity/non-stationarity in plasma energization and energy transport.

On board the mothercraft, the Particle Processing Unit (PPU-M) will be the single interface between the spacecraft and all the particle instruments: the Electron Particle Chamber (EPC-M), the Ion Mass Spectrometer (IMS) and the Energetic Particle Experiment (EPE-M). The PPU-M provides a single power, telemetry, and control interface to the spacecraft as well as power switching, commanding and data handling for the particle instruments. The PPU-M will have a fully redundant configuration, with two CPU boards (nominal and redundant), based on the dual-core LEON3FT processor and two groups of 3 Compression and Scientific Processing (CSP) boards based on FPGAs.

The approach of a common data processing unit for all the particle instruments allows to efficiently handle the data rate from all the particle instruments and the data processing on board, also facilitating interoperation with the other instruments on the spacecraft. Moreover, it allows technical and programmatic synergies giving the possibility to optimize and save spacecraft resources. Here, we will describe the PPU-M characteristics and functionalities.

How to cite: Rota, E., D'Amicis, R., Marcucci, M. F., De Marco, R., Rispoli, R., Berthomier, M., Wimmer-Schweingruber, R., and Valentini, F.: The Particle Processing Unit (PPU-M) on-board the Plasma Observatory Mother Spacecraft, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18777, https://doi.org/10.5194/egusphere-egu25-18777, 2025.

The ESA M7 mission candidate Plasma Observatory 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 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19321, https://doi.org/10.5194/egusphere-egu25-19321, 2025.

Plasma Observatory (PO) is a Heliophysics mission that will explore plasma energization and energy transport in the Earth’s Magnetospheric System, for the first time through multi-scale observations covering simultaneously the ion and fluid scales. PO is currently in a competitive ESA Phase A study as one of the three candidates for the future ESA M7 mission. From its  equatorial, 8 by 18 R_E (geocentric perigee and apogee, respectively, in Earth radii), 15^o inclination orbit, PO will  addresses the following science questions: (Q1) how particles are energized in space plasmas and (Q2) which processes dominate energy transport and drive coupling across regions of Earth’s magnetosphere. The aforementioned science questions being pursued by PO are aligned with the goals of NASA’s SMD^3,4: to understand the physical processes, and Sun-Earth connections. The PO baseline mission will achieve this objective with a comprehensively instrumented mother spacecraft (MSC) or mothercraft, and six identical smallsat daughtercraft (DSC). After highly successful missions such as Cluster, Themis, and MMS, this will be the next logical step to gain transformative insights into fundamental processes of the Magnetospheric System.

A team of US scientists from three major institutions will provide significant parts of three instruments for the P.O. payload.  UNH (University of New Hampshire) will provide the time-of-flight and detector section and some electronics for the Ion Mass Spectrometer (IMS-M) that will measure the 3D distributions of (H⁺ , He⁺ , He⁺⁺ and O⁺ ) at high time resolution. This ion spectrometer will be placed on the mothercraft. The University of Berkeley (UCB) will provide  the spin-plane double-probe electric field sensors of the electric field instrument EFI-M onboard the mothercraft,  based on the ones flown on RBSP. The University of California in Los Angeles will be providing the mechanical design of the detectors, telescopes and electronics box, and the design of the power and digital processing electronics boards for the energetic particle instrument EPE-D on each of the six daughtercraft, based on heritage from the ELFIN mission.  These contributions are critical for the success of the PO mission and its science return. The US team is currently collaborating with the PO consortium in the ESAPhase A study to determine how to efficiently provide the payload that will return the best quantity measurements.  In this presentation we will introduce the capability of these instruments and the current achievements and progress that were obtained during the ongoing phase A study.

How to cite: Kistler, L. M., Kucharek, H., Angelopoulos, V., Bale, S. D., Bonnell, J., Dunlop, M., Khotyaintsev, Y., Retinò, A., and Marcucci, M. F.: US Contributions to the Plasma Observatory Mission , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21857, https://doi.org/10.5194/egusphere-egu25-21857, 2025.

Plasma Observatory is one of three “M-class” missions that are going through Phase A study.  An unprecedented seven spacecraft mission to understand plasma energisation across both ion and fluid scales, Plasma Observatory will bring step-change understanding in how particles are accelerated in astrophysical plasmas.  In order to gain the best possible scientific breakthroughs, it is essential that collaboration and coordination with ground-based instruments and facilities occurs as quickly as possible.  Here we discuss the scientific and practical aspects of ground-based facilities and the synergies with Plasma Observatory across all of the mission profile.  We also seek to recruit more interested participants in the ground-based working group through the Phase A process and beyond. 

How to cite: Rae, J. and the Plasma Observatory Ground-Based Coordination Working Group:  The Plasma Observatory Ground-Based Coordination Working Group , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21888, https://doi.org/10.5194/egusphere-egu25-21888, 2025.

Studies have long suggested that shocks can undergo cyclical self-reformation as a result of shock nonstationarity. Until now, providing solid evidence for shock reformation in spacecraft observation and identifying its generating mechanisms remain challenging. In this work, by analyzing Magnetospheric Multiscale (MMS) spacecraft observations, we unambiguously identified shock reformation occurring in a quasi-perpendicular shock. A 2-D particle-in-cell simulation reproduces and explains the observed shock reformation. It reveals two distinct stages: in the early stage, whistler waves generated by the modified two-stream instability (MTSI) dominate the foot region, while whistler precursors driven by the gradient catastrophe instability dominate the ramp. In the later stage, MTSI-driven whistlers extend to the ramp and take over the role of reducing gradients, so precursors no longer develop. Both types of whistlers can result in shock reformation: one single wave period induces the magnetic field pile-up, ion accumulation and reflection, and upstream-pointing electric field, finally evolving into a new shock front. Our results give evidence that the shock reformation in the present regime can be driven by ion-scale whistler waves and demonstrate the detailed kinetic processes how it happens, providing valuable insights into the shock dynamics.

How to cite: Xu, S., Sun, J., Wang, S., Li, J., Zhou, X., Hao, Y., Zong, Q., and Yue, C.: Shock Reformation Induced by Ion-scale Whistler Waves in Quasi-perpendicular Bow Shock, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5814, https://doi.org/10.5194/egusphere-egu25-5814, 2025.

The recently released US Heliophysics Decadal Survey recommends that the identity of the solar and space physics community needs to be solidified, in order to unify under a common and recognized name. This would greatly benefit collaboration, recruitment, education, and public outreach. The obvious identify for our field is Heliophysics. Heliophysics is the study of the Sun and its effects throughout the solar system. It covers an incredible range of scales, from plasma physics at the electron scale to the boundary that separates our solar system from interstellar space. The components of Heliophysics sit at the boundaries of Earth science, Planetary science, and Astrophysics: Aeronomy at the boundary of our atmosphere and space; Solar physics at the boundary of the sun and interplanetary space; Heliospheric science at the boundaries of the solar wind and planets, and at the boundary of our solar system and interstellar space. Space plasma physics, the science of how ionized and partially ionized plasmas behave in the presence of electromagnetic fields, undergirds the field. Many of the biggest unanswered science questions that remain across Heliophysics center around the interconnectivity of the different physical systems, and the role of mesoscale dynamics in modulating, regulating, and controlling that interconnected behavior. Answering these long-standing questions on the Sun-Heliosphere and Geospace as system-of-systems requires a coordinated, deliberate, worldwide scientific effort, akin to the highly successful ISTP program. In this talk we describe the next steps in creating a unified, worldwide, vibrant Heliophysics community, building upon the previous efforts of ISTPNext. This next step will put in place concrete elements to usher in the next era of Heliophysics, focused on cross-scale and cross-regional coupling, combining in situ, remote and ground-based observations with state-of-the-art modeling, amongst the worldwide Heliophysics community.  

How to cite: Kepko, E. and the COSPAR Task Group on Establishing an International Geospace Systems Program: The Heliophysics Accords: A blueprint for a unified, worldwide, Heliophysics community, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11741, https://doi.org/10.5194/egusphere-egu25-11741, 2025.