PS2.3 | Space environments of unmagnetized or weakly magnetized solar system bodies and the effects of space weather on these systems
EDI
Space environments of unmagnetized or weakly magnetized solar system bodies and the effects of space weather on these systems
Co-organized by ST4
Convener: Martin Volwerk | Co-conveners: Charlotte Götz, Beatriz Sanchez-Cano, Pierre Henri
Orals
| Mon, 24 Apr, 14:00–17:45 (CEST)
 
Room 1.14
Posters on site
| Attendance Tue, 25 Apr, 16:15–18:00 (CEST)
 
Hall X4
Posters virtual
| Attendance Tue, 25 Apr, 16:15–18:00 (CEST)
 
vHall ST/PS
Orals |
Mon, 14:00
Tue, 16:15
Tue, 16:15
The ionospheres and (induced) magnetospheres of unmagnetized and weakly magnetized bodies with substantial atmospheres (e.g. Mars, Venus, Titan, Pluto and comets) are subject to disturbances due to solar activity, interplanetary conditions (e.g. solar flares, coronal mass ejections and solar energetic particles), or for moons, parent magnetospheric activity. These objects interact similarly as their magnetized counterparts but with scientifically important differences.
As an integral part of planetary atmospheres, ionospheres are tightly coupled with the neutral atmosphere, exosphere and surrounding plasma environment, possessing rich compositional, density, and temperature structures. The interaction among neutral and charged components affects atmospheric loss, neutral winds, photochemistry, and energy balance within ionospheres.
This session invites abstracts concerning remote and in-situ data analysis, modelling studies, comparative studies, instrumentation and mission concepts for unmagnetized and weakly magnetized solar system bodies.

Orals: Mon, 24 Apr | Room 1.14

14:00–14:10
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EGU23-2582
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Highlight
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On-site presentation
Hans Nilsson

We present two new methods to study the electric fields and their effect on ions and electrons in a cometary environment. One method is to look at the energy spectra of cometary ions, ions that are produced by ionisation of the gas emanating from the comet nucleus. The new production of such ions falls off with distance r to the nucleus proportionally to the fall-off of the parent neutral gas, as 1/r2. For ions having been significantly accelerated, the energy of observed ions shows the electric potential difference between the point of ionisation and the observation point. When such ionisation occurs in a homogeneous electric field, the ion flux as function of energy is predicted to show a simple power law relation, the flux falling off as 1/E2. This is indeed sometimes seen. We also discuss the possibility to interpret ion energy spectra in terms of somewhat inhomogeneous electric fields.

To this we can now add a new method where by comparing the speed of solar wind H+ and He2+ after interaction with the comet environment we can estimate the electric potential of the observation point relative to the upstream solar wind. Combining these methods opens up a whole new possibility to study in detail the electric fields acting on small scales when two plasma populations interact. Our study is specific to the cometary environment we are looking at, but the physical interactions we study are universal.

 

How to cite: Nilsson, H.: Electric fields in a small scale comet magnetosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2582, https://doi.org/10.5194/egusphere-egu23-2582, 2023.

14:10–14:20
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EGU23-8912
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ECS
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On-site presentation
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Anja Moeslinger, Hans Nilsson, Gabriella Stenberg Wieser, and Hayley Williamson

The ion spectrometer ICA onboard the Rosetta mission has provided us with detailed measurements of the plasma environment around comet 67P/Churyumov-Gerasimenko. The distribution of cometary ions is an important indicator for the cometary plasma environment and its interaction with the solar wind. The cometary ion production at a comet decreases with increasing radial distance from the comet. The fluxes of observed ions are therefore also expected to fall off proportional to their point of origin relative to the comet. Due to electric fields, ions that are born further away are observed at higher energies at the spacecraft. The exact relation between the flux and the observed energy depends on the density distribution of cometary ions and the electric field around the comet.
We derive the bulk flow properties of the cometary pickup ion population with a fitting procedure. In our study, cometary pickup ions are all heavy ions with an energy above 40 eV as observed by ICA. The particle drift speed of the bulk flow can be used to estimate the average local electric field. This gives us a 3D estimate for the electric field close to the comet nucleus. Using this E-field estimate, we can back-trace the observed particles to determine an approximate location of where they were born. This ionisation point is further away for particles with higher energies. The relation between the flux of the observed ions and their origin provides us with information about the inhomogeneity of the cometary plasma environment between the observation point (30 km from the nucleus) and the ionisation point of the particle (hundreds of km away from the nucleus). 
We will present results of the ion distribution of cometary pickup ions above 40eV on a selected day (April 19th, 2016) of the Rosetta mission, along with the derived electric field estimate close to the nucleus. We will also show the results and implications of the particle trajectory backtracing.

How to cite: Moeslinger, A., Nilsson, H., Stenberg Wieser, G., and Williamson, H.: E-field at a low-activity comet derived from cometary ion velocity distributions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8912, https://doi.org/10.5194/egusphere-egu23-8912, 2023.

14:20–14:30
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EGU23-9003
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On-site presentation
Francesco Pucci, Etienne Behar, Pierre Henri, Cyril Simon Wedlund, and Giulio Ballerini

We present a numerical work in which the interaction between a comet and the solar wind is studied in 2D in the plane perpendicular to the solar wind mean field direction. Our simulations are conducted with the hybrid Particle-in-Cell (PIC) code Menura that allows for the injection of a turbulent solar wind [1].

First, we consider the case of laminar solar wind and we present a study on the equivalent Mach number of the two-ion-species (cometary and solar wind) plasma surrounding the comet. We develop an expression for the Mach number having suitable limits in the two asymptotic cases of infinite cometary and solar wind ion density; our expression is derived by extending previous studies on bi-ion plasma models [2]. Through numerical simulations in which the cometary activity is varied, we show how our Mach number is able to unambiguously describe  the existence and location of the cometary shock.

Second, we compare two runs, one with a laminar and one with a turbulent solar wind in the case of moderate cometary activity. We divide the simulation domain into the regions upstream and downstream the cometary shock. We analyze how plasma turbulence properties are affected by the passage through the shock in the case of a turbulent solar wind. Then, we divide the downstream region into three different regions identified by different solar wind-to-cometary ion density ratios. We study the downstream turbulence properties in the case of laminar and turbulent impinging solar wind and how they vary in those regions.

 

[1] Behar, E., Fatemi, S., Henri, P., & Holmström, M. (2022, May). Menura: a code for simulating the interaction between a turbulent solar wind and solar system bodies. In Annales Geophysicae (Vol. 40, No. 3, pp. 281-297). Copernicus GmbH.

[2] Dubinin, E. M., Sauer, K., McKenzie, J. F., & Chanteur, G. (2002). Nonlinear waves and solitons propagating perpendicular to the magnetic field in bi-ion plasma with finite plasma pressure. Nonlinear Processes in Geophysics, 9(2), 87-99.

How to cite: Pucci, F., Behar, E., Henri, P., Simon Wedlund, C., and Ballerini, G.: Plasma turbulence within cometary plasma environments, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9003, https://doi.org/10.5194/egusphere-egu23-9003, 2023.

14:30–14:40
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EGU23-9550
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On-site presentation
Timothy Stubbs, Antoinette Galvin, Stefano Livi, Kevin Delano, Lorna Ellis, Lynn Kistler, Ryan Dewey, Jim Raines, Susan Lepri, David Lario, Geraint Jones, Samuel Grant, Peter Wurz, Harald Kucharek, Christopher Owen, Andrei Fedorov, Philippe Louarn, Lorenzo Matteini, Lars Berger, and Robert Wimmer-Schweingruber and the The Heavy Ion Sensor (HIS) Science Team

Around 17 December 2021, the Solar Orbiter spacecraft was predicted to have had its closest approach to comet C/2021 A1 (Leonard) with a minimum streamline distance < 0.01 AU. This encounter provided an unprecedented opportunity to investigate in situ comet Leonard's interaction with the solar wind and the composition of pick-up ions produced by ionization and dissociation of outgassed neutrals from its coma. It was a long-period comet originating from the Oort Cloud with a nucleus about 1 km in diameter, with ground-based telescope observations after its perihelion pass (at ~0.62 AU on 3 January 2022) indicating that it had subsequently disintegrated. Prior to perihelion, outbursts had been reported as well as variations in brightness, which had resulted in speculation about an impending disintegration. However, the dimming in November 2021, before the Solar Orbiter encounter, was argued to be due to a transition from outgassing dominated by carbon dioxide to water. Comet Leonard was the brightest comet of the year and noted for its spectacular ion tail with complex structures, including knots and streamers. Preliminary analysis of in situ Solar Orbiter observations have revealed tell-tale signatures of a cometary encounter around the time of predicted closest approach, such as evidence for magnetic field line draping. However, the clearest evidence has come from Solar Wind Analyzer-Heavy Ion Sensor (SWA-HIS) observations of singly-charged oxygen ions, which are typically not of solar origin and are usually produced when the solar wind interacts with a comet or other Solar System body. In this presentation we use SWA-HIS and EDP-STEP data to investigate aspects of the solar wind interaction and composition of cometary pick-up ions from this active, long-period comet shortly before its disintegration.

How to cite: Stubbs, T., Galvin, A., Livi, S., Delano, K., Ellis, L., Kistler, L., Dewey, R., Raines, J., Lepri, S., Lario, D., Jones, G., Grant, S., Wurz, P., Kucharek, H., Owen, C., Fedorov, A., Louarn, P., Matteini, L., Berger, L., and Wimmer-Schweingruber, R. and the The Heavy Ion Sensor (HIS) Science Team: Solar Orbiter Observations of Ion Species during the Encounter with the Tail of Comet Leonard, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9550, https://doi.org/10.5194/egusphere-egu23-9550, 2023.

14:40–14:50
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EGU23-9
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ECS
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Virtual presentation
Jiawei Gao, Zhaojin Rong, Yong Wei, and Haoyu Lu

Using magnetic field data collected by Mars Atmosphere and Volatile EvolutioN (MAVEN), we investigated the external magnetic field distribution over low crustal field regions in the Martian ionosphere. Both draping and looping magnetic field are observed in the Martian dayside and nightside ionosphere at attitude range 150-600 altitude. Draping magnetic field is formed by the draped interplanetary magnetic field around the ionosphere obstacle, which is formed by the well-known induced magnetosphere current system. Looping magnetic field, observed in both ionosphere and magnetosphere, indicates a new current system coupling the ionosphere and magnetosphere. This new current system, different with the induced magnetosphere current system, has sunward component in the magnetosphere, and tailward component in the low altitude ionosphere. This current system is validated by both MAVEN observation and a global multi-fluid magnetohydrodynamic (MHD) simulation, which is most likely a universal phenomenon for a non-magnetized planetary with ionospheres interacted with high-speed solar wind.

How to cite: Gao, J., Rong, Z., Wei, Y., and Lu, H.: A new magnetosphere-ionosphere current system on Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9, https://doi.org/10.5194/egusphere-egu23-9, 2023.

14:50–15:00
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EGU23-490
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ECS
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On-site presentation
Qi Zhang, Mats Holmström, Xiaodong Wang, and Hans Nilsson

We apply a recently presented method to estimate ion escape to Mars. The method combines in-situ observations and a hybrid plasma model (ions as particles, electrons as a fluid). Observed upstream solar wind conditions from the Mars Atmosphere and Volatile Evolution (MAVEN)  are used as input to the model.  We then vary ionospheric ion production until the solution fits the observed bow shock location.  With this method, we investigate how upstream conditions, including solar EUV, solar wind dynamic pressure, Interplanetary Magnetic Field (IMF) strength and cone angle, affect the heavy ions loss. The results indicate that the heavy ions escape rate is higher in high EUV and the tail flux is sensitive to EUV variety while the plume is not. The ion escape rate increases as solar wind dynamic pressure increases. 

How to cite: Zhang, Q., Holmström, M., Wang, X., and Nilsson, H.: The influence of upstream conditions on heavy ion escape at Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-490, https://doi.org/10.5194/egusphere-egu23-490, 2023.

15:00–15:10
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EGU23-3122
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ECS
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On-site presentation
Praveen Basuvaraj, František Němec, Leonardo Regoli, Christopher Fowler, Zdeněk Němeček, and Jana Šafránková

Since September 2014, NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft has been measuring the in-situ ionospheric constituents of Mars. Recently, MAVEN detected the presence of large-scale plasma depletions (at least ten-fold) within the Martian ionosphere, also known as Plasma Depletion Events (PDEs). Geometrically, the Martian PDEs appear to be bubble-like plasma structures. Although the origin and formation of PDEs are not entirely understood, they are known to occur primarily on the nightside and in regions with stronger crustal magnetic fields.

In this study, we analyze the variation of magnetic field magnitude and direction and electric field power (2–100 Hz) associated with PDEs. We show that, in most cases, the magnetic fields do not considerably change within the plasma-depleted region. Conversely, the low-frequency electric field wave power is enhanced by up to two orders of magnitude at the peak depletion. Both ions and electrons within PDEs are highly magnetized. We present possible formation mechanisms of PDEs supported by recent findings.

How to cite: Basuvaraj, P., Němec, F., Regoli, L., Fowler, C., Němeček, Z., and Šafránková, J.: Ionospheric Plasma Depletions at Mars: MAVEN Observations of In-situ Plasma and Wave properties, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3122, https://doi.org/10.5194/egusphere-egu23-3122, 2023.

15:10–15:20
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EGU23-5058
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On-site presentation
Jijie Ma, Wenya Li, Linggao Kong, Yiteng Zhang, Peter Wurz, André Galli, Bingbing Tang, Lianghai Xie, Limin Wang, Fuhao Qiao, Lei Li, and Chi Wang

The Mars Ion and Neutral Particle Analyzer (MINPA), one of the three scientific payloads onboard the Tianwen-1 orbiter, was designed to measure ions and energetic neutral atoms (ENAs) at Mars. From November 2021, MINPA started to collect scientific data around Mars. Here, we present MINPA's first results of the solar-wind ENAs, which are produced through the charge exchange process between the solar wind hydrogen ions and the Martian neutral exosphere. We perform a comprehensive comparison between the inflight ENA data and ground calibration results to understand the energy and angular distributions of the solar-wind ENA signals. The possible contamination of these observations by ions and solar extreme ultraviolet (EUV) is evaluated by comparing the ENA measurements with the ion data. We will present several cases of the solar wind ENA observations, and their intensities are estimated to be 10^5~10^6 cm^-2 sr^-1 s^-1, which is in good agreement with previous in situ measurements and predictions using models.

How to cite: Ma, J., Li, W., Kong, L., Zhang, Y., Wurz, P., Galli, A., Tang, B., Xie, L., Wang, L., Qiao, F., Li, L., and Wang, C.: Solar Wind Energetic Neutral Atom Observation at Mars by MINPA Onboard the Tianwen-1 Orbiter, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5058, https://doi.org/10.5194/egusphere-egu23-5058, 2023.

15:20–15:30
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EGU23-9425
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On-site presentation
Hassanali Akbari, Christopher Fowler, and Laila Andersson

Accelerated electron populations observed in the nightside ionosphere of Mars are investigated using measurements obtained by MAVEN’s Solar Wind Electron Analyzer. The measurements are of particular interest as they extend to altitudes as low as 130 km and to regions characterized by strong crustal magnetic fields, allowing us to investigate the evolution of the electron distributions in the complex crustal fields and determine the rate by which the accelerated populations precipitate into the Martian upper atmosphere.

The majority of the observed accelerated electrons are trapped in the crustal fields, bouncing between mirror points, presumably drifting across magnetic field lines, but without instantaneous access to the collisional atmosphere. The average energy flux of these electrons is significant when compared to that of the much more common ‘unaccelerated’ sheath electrons. Considering that the Martian crustal magnetic fields do not provide a closed path for drifting particles, the trapped electrons are bound to exit the crustal fields and either precipitate into the atmosphere or escape. Currently, we estimate that, despite their low detection rate (< 1%), the accelerated electrons account for about 10% of the total energy that is deposited into the nightside ionosphere by electron precipitation. Further, the peak energy of the accelerated electrons is generally found in the range of tens to hundreds of eV, consistent with the energy range previously suggested for the generation of discrete aurora emissions observed on Mars.

How to cite: Akbari, H., Fowler, C., and Andersson, L.: Precipitation of accelerated electrons at Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9425, https://doi.org/10.5194/egusphere-egu23-9425, 2023.

15:30–15:45
Coffee break
Chairpersons: Martin Volwerk, Beatriz Sanchez-Cano
16:15–16:25
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EGU23-2958
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ECS
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On-site presentation
Shaosui Xu, Rudy Frahm, Yingjuan Ma, David Mitchell, Janet Luhmann, and Moa Persson

Venus lacks a significant intrinsic magnetic field, and thus, its atmosphere and ionosphere interact directly with the solar wind flow and magnetic field from the Sun. Interplanetary magnetic fields (IMF) can penetrate into the ionosphere when the upstream solar wind dynamic pressure is stronger than the ionospheric plasma pressure. Magnetic topology can be inferred at Venus if it is defined as the magnetic connectivity to the collisional atmosphere/ionosphere, rather than connectivity to the planet’s surface. Magnetic topology can be inferred from the pitch angle and energy distribution of superthermal (> ~1 eV) electrons. More specifically, the presence of loss cones in electron pitch angle distributions infers connectivity to the nightside collisional atmosphere and the presence of ionospheric photoelectrons (identified from electron energy distributions) indicates connectivity to the dayside collisional ionosphere. We design automated procedures to determine magnetic topology with electron and magnetic field measurements by the Venus Express spacecraft over its entire mission (2006-2014). This allows us to provide the first statistical mapping of magnetic topology at Venus. We also examine how the upstream drivers affect the low-altitude magnetic topology, revealing different magnetized states of the Venus ionosphere. We find that open and closed (a surprising topology not expected at Venus) fields cluster around the terminator and draped fields dominate other regions. Our results also reveal that there is more dayside magnetic connectivity in the -E (solar wind motional electric field) hemisphere than the +E hemisphere, and during solar maximum. During solar minimum, however, there is more nightside magnetic connectivity. Last but not the least, to understand the true nature of these magnetic topologies and broadly speaking the planet-solar wind interaction, we need to think about possible ways to measure the deeply penetrated magnetic fields at Venus and Mars.

How to cite: Xu, S., Frahm, R., Ma, Y., Mitchell, D., Luhmann, J., and Persson, M.: Statistical Mapping of Magnetic Topology at Venus, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2958, https://doi.org/10.5194/egusphere-egu23-2958, 2023.

16:25–16:35
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EGU23-14802
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ECS
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Virtual presentation
Dibyendu Sur and David Malaspina

Understanding the plasma interactions between induced Venus magnetosphere and solar wind is crucial, especially at the kinetic scale (below the proton Larmor radius). This is because different kinetic-scale electric field structures that are associated with plasma instabilities such as double layers are good indicator of wave-particle energy transfer (Malaspina et al., Geophysical Research Letters, 47, 2020). Structures such as double layers, phase-space holes can emit radio waves (Goodrich and Ergun, The Astrophysical Journal, 809, 2015) or scatter electrons with energy of the order of keV (Vasko et al., Journal of Geophysical Research: Space Physics, 122, 2017). Double layers can create plasma instabilities (Newman et al., Physical Review Letters, 87, 2001), provide heating and acceleration to different particles (Ergun et al., Journal of Geophysical Research: Space Physics, 109, 2004). These structures have already been found in several parts of the earth’s magnetosphere. But due to a lack of high resolution data, observations of these processes are sparse in the magnetospheres of the other planets. The seven encounters that the Parker Solar Probe (PSP) spacecraft will make with Venus’s induced magnetosphere will provide excellent opportunities to measure these processes in this planet. The current talk describes the presence of kinetic-scale electric field structures during the 4th encounter of PSP with Venus’s induced magnetosphere. For this purpose, high resolution electric field data from the PSP FIELDS instrument were used with alongside the FIELDS magnetometer data and data from the Solar Wind Electrons Alphas and Protons (SWEAP) instrument. From these observations, it is found that the PSP passed through Venus’s magnetosheath and tail region during this encounter.  This talk describes the possible presence of plasma double layers when PSP was at the boundary of the magnetosheath region. Phase-space holes are also identified near some of the double layers in this region.

How to cite: Sur, D. and Malaspina, D.: Observation of Possible Kinetic Structures at the Venus Magnetosphere using High Resolution Parker Solar Probe Data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14802, https://doi.org/10.5194/egusphere-egu23-14802, 2023.

16:35–16:45
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EGU23-7071
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ECS
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On-site presentation
Lina Hadid and the BepiColombo - MSA team (and members from MIA, MEA and MPO-MAG teams)

On August 10, 2021, the Mercury-bound BepiColombo spacecraft flew for the second time by Venus for a Gravity-Assist Maneuver. During this second flyby of Venus, a limited number of instruments were turned on, allowing unique observations of the planet and its environment. Among these instruments, the Mass Spectrum Analyzer (MSA) that is part of the particle analyzer consortium onboard the magnetospheric orbiter (Mio) was able to acquire its first plasma composition measurements in space. As a matter of fact, during a limited time interval upon approach of the planet, substantial ion populations were recorded by MSA, with characteristic energies ranging from about 20 eV up to a few hundreds of eVs. Comparison of the measured Time-Of-Flight spectra with calibration data reveals that these populations are of planetary origin, containing both Oxygen and Carbon ions. The Oxygen observations are to some extent consistent with previous in situ measurements from mass spectrometers onboard Venus Express and Pioneer Venus Orbiter. On the other hand, the MSA data provide the first ever in situ evidences of Carbon ions in the near-Venus environment at about 6 planetary radii. We show that the abundance of C+ amounts to about ~30% of that of O+. Furthermore, Changes in the orientation of the magnetic field suggest that these planetary ions are located in the distant magnetosheath flank in the immediate vicinity of the bow-shock region.

How to cite: Hadid, L. and the BepiColombo - MSA team (and members from MIA, MEA and MPO-MAG teams): Evidence of planetary Oxygen and Carbon ions in the outer flank of Venusmagnetosheath, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7071, https://doi.org/10.5194/egusphere-egu23-7071, 2023.

16:45–16:55
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EGU23-3369
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Highlight
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On-site presentation
Dominique Delcourt, Lina Hadid, Yoshifumi Saito, Markus Fränz, Shoichiro Yokota, Björn Fiethe, Christophe Verdeil, Bruno Katra, Frédéric Leblanc, Henning Fischer, Yuki Harada, Dominique Fontaine, Norbert Krupp, Harald Michalik, Jean-Marie Illiano, Jean-Jacques Berthelier, Harald Krüger, Go Murakami, and Shoya Matsuda

On June 23rd 2022, BepiColombo performed its second gravity assist maneuver (MFB2) at Mercury. Just like the first encounter with Mercury that took place on October 1st 2021, the spacecraft approached the planet from dusk-nightside to dawn-dayside down to an extremely close distance (within about 200 km altitude from the planet surface). Even though BepiColombo is in a so-called “stacked configuration” during cruise, meaning that the instruments cannot be fully operated yet, these instruments can still make interesting observations. Particularly, despite their limited field-of-view, the particle sensors allow us to get a hint on the ion composition and dynamics very close to the planet well before the forthcoming orbit insertion around Mercury in December 2025. In this study, we present observations of the Mass Spectrum Analyzer (MSA) at Mercury during MFB2. MSA is part of the low energy sensors of the Mercury Plasma Particle Experiment (MPPE) consortium (PI: Y. Saito), which is a comprehensive instrumental suite for plasma, high-energy particle and energetic neutral atom measurements (Saito et al., 2021) onboard the Mercury Magnetospheric Orbiter (Mio). MSA is a “reflectron” time-of-flight spectrometer that provides information on the plasma composition and the three-dimensional distribution functions of ions with energies up to ~ 38 keV/q and masses up to ~ 60 amu (Delcourt et al., 2016). In this study, we show that both H+ and He2+ ions in the 1-10 keV range are present throughout the innermost magnetosphere near closest approach. In addition, during this MFB2 sequence, MSA observations provide evidences of He+ ions with energies of several hundreds of eVs. These ions likely originate from the planet exosphere and are rapidly circulated within the magnetosphere. During the outbound sequence of MFB2, MSA measurements also reveal copious amounts of keV protons of solar wind origin that propagate upstream after being reflected from the bow shock.

How to cite: Delcourt, D., Hadid, L., Saito, Y., Fränz, M., Yokota, S., Fiethe, B., Verdeil, C., Katra, B., Leblanc, F., Fischer, H., Harada, Y., Fontaine, D., Krupp, N., Michalik, H., Illiano, J.-M., Berthelier, J.-J., Krüger, H., Murakami, G., and Matsuda, S.: BepiColombo second Mercury flyby :  Ion composition measurements from the Mass Spectrum Analyzer (MSA), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3369, https://doi.org/10.5194/egusphere-egu23-3369, 2023.

16:55–17:05
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EGU23-13257
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ECS
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On-site presentation
Sae Aizawa, Nicolas Andre, Yoshifumi Saito, Moa Persson, Jean-Andre Sauvaud, Andrei Fedorov, Shoichiro Yokota, Alain Barthe, Emmanuel Penou, Mathias Rojo, and Go Murakami

BepiColombo was launched in October 2018 and is currently en route to Mercury. Although its orbit insertion is planned for December 2025, BepiColombo will acquire new measurements during planetary flybys. During the cruise phase, the two spacecraft are docked together with Mio being protected behind the MOSIF sun shield. Thus, only partial observations of plasma distribution functions can be obtained by the Mercury Plasma Particle Experiment (MPPE) onboard Mio. However, since electrons have small Larmor radii and more isotropic distributions even in the solar wind, the two Mercury Electron Analyzer (MEA) of MPPE will provide us with new and unique measurements in the range of 5 eV to 3 keV when in solar wind mode and 3 eV to ~ 26 keV when in magnetospheric mode. We will present the interesting observations obtained by MEA onboard Mio/BepiColombo during its second Mercury flyby that happened on the 23rd of June, 2022. In particular we will focus on the properties of the low- and high-energy electron populations observed during its crossing of Mercury’s magnetosphere.

How to cite: Aizawa, S., Andre, N., Saito, Y., Persson, M., Sauvaud, J.-A., Fedorov, A., Yokota, S., Barthe, A., Penou, E., Rojo, M., and Murakami, G.: Electron populations observed by Mercury Electron Analyzer onboard Mio/BepiColombo during its second Mercury flyby, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13257, https://doi.org/10.5194/egusphere-egu23-13257, 2023.

17:05–17:15
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EGU23-12906
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ECS
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On-site presentation
Daniel Schmid, David Fischer, Werner Magnes, Yasuhito Narita, Martin Volwerk, Wolfgang Baumjohann, Ayako Matsuoka, Hans-Ulrich Auster, Ingo Richter, Daniel Heyner, Ferdinand Plaschke, and Rumi Nakamura

BepiColombo MPO and Mio spacecraft encounter the Mercury magnetosphere six times from 2021 to 2025 during the flyby maneuvers. Each flyby trajectory is unique and includes the magnetospheric regions that were not covered by MESSENGER. Mio/MGF magnetic field data were successfully retrieved during the Mercury flyby-2 in June 2022 and the data were calibrated for the scientific use. The MGF measurements show a short-time intense magnetic field depression in close proximity to the planet at local midnight, which is neither expected from the earlier observations (Mariner-10, MESSENGER) nor from the hybrid plasma simulations of the Mercury magnetosphere. Both time-dependent and time-independent scenarios are possible, including the occurrence of a transient event driven by sudden changes in the solar wind (e.g., pressure puls) or in the magnetosphere (e.g., magnetic reconnection) and the crossing of a localized current layer separating the dipolar field region from the stretched tail-like magnetic field region. While more dedicated analyses (wave analysis, variation analysis), combination with the other data (plasmas and imaging), and numerical simulations for different scenarios would improve the quality of scientific interpretation of the depression event, our study demonstrates the scientific potential of BepiColombo that it will detect various kinds of transient events and localized structures in Mercury’s magnetosphere already during the flyby maneuvers.

How to cite: Schmid, D., Fischer, D., Magnes, W., Narita, Y., Volwerk, M., Baumjohann, W., Matsuoka, A., Auster, H.-U., Richter, I., Heyner, D., Plaschke, F., and Nakamura, R.: Unexpected local magnetic depression around Mercury: BepiColombo flyby-2 discovery, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12906, https://doi.org/10.5194/egusphere-egu23-12906, 2023.

17:15–17:25
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EGU23-10183
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On-site presentation
Xianzhe Jia and Changkun Li

Mercury possesses a miniature but dynamic magnetosphere driven primarily by the solar wind through magnetic reconnection. A prominent feature of the dayside magnetopause reconnection that has been frequently observed is flux transfer events (FTEs), which are thought to be an important player in driving the global convection at Mercury. Using the BATSRUS Hall MHD model with coupled planetary interior, we have conducted a series of high-resolution global simulations to investigate the generation and characteristics of FTEs under different solar wind Alfvénic Mach numbers (MA) and IMF orientations. In all simulations driven by steady upstream conditions, FTEs are formed quasi-periodically with recurrence time ranging from 2 to 9 seconds, and their characteristics vary in time as they evolve and interact with the surrounding plasma and magnetic field. Our statistical analysis of the simulated FTEs reveals that the key properties of FTEs, including spatial size, traveling speed and core field strength, all exhibit notable dependence on the solar wind MA and IMF orientation, and the trends identified from the simulations are generally consistent with previous MESSENGER observations. It is also found that FTEs formed in the simulations contribute a significant portion of the total open flux created at the dayside magnetopause that participates in the global circulation, suggesting that FTEs indeed play an important role in driving the Dungey cycle at Mercury.

How to cite: Jia, X. and Li, C.: Global Hall MHD simulations of Mercury's magnetosphere: Formation and properties of flux transfer events (FTEs) under different solar wind conditions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10183, https://doi.org/10.5194/egusphere-egu23-10183, 2023.

17:25–17:35
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EGU23-11546
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On-site presentation
Daniel Heyner, Kristin Pump, David Hercik, Willi Exner, Yasuhito Narita, Ferdinand Plaschke, Daniel Schmid, Jim Slavin, and Martin Volwerk

Mercury possesses a weak planetary dipole moment and is subject to a strong solar wind inflow. Thus, a small magnetosphere is formed. On the nightside, a neutral current sheet elongates the magnetic field lines to form a magnetotail. From hybrid simulations it is known that this current sheet reacts to changes in the interplanetary magnetic field (IMF). In order to understand the magnetospheric reaction to changes in the solar wind, it is essential to further assess the neutral current sheet movements. The strongly radial IMF at Mercury facilitates magnetopause reconnection in high latitudes which decreases the magnetic pressure in one of the magnetospheric lobes depending on the radial IMF polarity. This produces a northward (or southward) shift of the neutral sheet. Here, we present statistical results from in-situ MESSENGER magnetic field data analysis on the IMF direction as well as the neutral sheet displacement. MESSENGER was a single probe in orbit around Mercury and, as such, it was blind to the solar wind state after having entered the bow shock. Thus, we need to estimate the current IMF radial polarity for the time frame with the probe located inside the magnetosphere. For this, we evaluate different interpolation methods with an adapted bootstrap analysis method on data taken within the upstream solar wind at Mercury. Eventually, the outcome of the statistical analysis on the neutral sheet displacement is compared to the results from hybrid simulations done in the past.

How to cite: Heyner, D., Pump, K., Hercik, D., Exner, W., Narita, Y., Plaschke, F., Schmid, D., Slavin, J., and Volwerk, M.: Neutral Current Sheet Displacement in Reaction to the Radial Interplanetary Magnetic Field at Mercury: Statistical Results from MESSENGER Data., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11546, https://doi.org/10.5194/egusphere-egu23-11546, 2023.

17:35–17:45

Posters on site: Tue, 25 Apr, 16:15–18:00 | Hall X4

Chairperson: Charlotte Götz
X4.288
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EGU23-3699
Yaxue Dong, David Brain, Robin Ramstad, Xiaohua Fang, Yingjuan Ma, James McFadden, Jasper Halekas, Jared Espley, and Shannon Curry

Ions originating from the upper atmosphere of Mars may be picked up by the impinging solar wind and interplanetary magnetic field (IMF), which forms an energetic ion plume from the dayside of the planet as a key feature of the Martian induced magnetosphere and an important ion escape channel. Consisting of mostly ions in the beginning phase of the pickup process, the orientation and morphology of the plume are largely controlled by upstream IMF conditions.

Using data from the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, we will perform a thorough investigation of the pickup ion plume under different upstream IMF conditions. Previous statistical ion flux maps by Dong et al. [2015; 2017] from MAVEN data show the plume as a more spatially spread-out feature than that in many simulation models [e.g. Jarvinen et al. 2016 and others], which is possibly due the effects of highly variable IMF conditions for the data used in those maps. We will investigate how the plume appears with selected data under quasi-steady IMF conditions. Furthermore, we will compare the plume under strong and weak IMF conditions, as well as the conditions with IMF approximately perpendicular or parallel to the solar wind direction. The morphology of the plume and characteristics of escaping pickup ions under different IMF conditions will be discussed and compared with available model results to better understand how IMF affects the formation of the plume and ion escape through this channel.

How to cite: Dong, Y., Brain, D., Ramstad, R., Fang, X., Ma, Y., McFadden, J., Halekas, J., Espley, J., and Curry, S.: Mars pickup ion plume under different IMF conditions from MAVEN observations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3699, https://doi.org/10.5194/egusphere-egu23-3699, 2023.

X4.289
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EGU23-5405
Mingyu Wu

Hot flow anomalies (HFAs) are not only a terrestrial, but also a solar-system-wide phenomenon that could cause strong perturbations of the planetary magnetosphere and ionosphere. Based on the observations of Mars Atmosphere and Volatile EvolutioN (MAVEN) upstream of the Martian bow shock from 2014 to 2020, we have investigated the statistical properties of HFAs around Mars in this study. Our observation results show that HFAs can distribute in a wide region from the dayside to the terminator region of Mars. On average, these HFAs can last 63 seconds and have a thickness of 28 local proton gyroradii. They are more prevalent when the ambient solar wind is denser and faster. HFAs occur most preferentially for IMF magnitude from 1-4 nT. Most of HFAs around Mars are formed during the interaction between tangential discontinues and the bow shock. Heavy ions originating from Mars do not appear to affect the formation of HFAs. Martian HFAs can lead to tens of times variations of solar wind dynamic pressure only in tens of seconds, which could strongly influence the heights of Martian ionopause and induced magnetosphere boundary.

How to cite: Wu, M.: Statistical Properties of Hot Flow Anomalies around Mars, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5405, https://doi.org/10.5194/egusphere-egu23-5405, 2023.

X4.290
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EGU23-6347
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Highlight
Eduard Dubinin, Markus Fraenz, Martin Paetzold, Silvia Tellmann, Ginna DiBraccio, and James McFadden

We report on observations made by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft at Mars, in the region of the ion plume. We observe that in some cases, when the number density of oxygen ions is comparable to the density of the solar wind protons interaction between both plasmas leads to formation of mini induced magnetospheres (iMagnetospheres)  possessing all typical features of induced magnetospheres  observed at Mars or Venus: a pileup of the magnetic field at the ‘head’ of the ion cloud, magnetospheric cavity, partially void of solar wind protons, draping of the interplanetary magnetic field around the mini obstacle, formation of a magnetic tail with a current sheet, in which protons are accelerated by the magnetic field tensions. These new observations may shed a light on the mechanism of formation of induced magnetospheres.

How to cite: Dubinin, E., Fraenz, M., Paetzold, M., Tellmann, S., DiBraccio, G., and McFadden, J.: The mini induced magnetospheres at Mars., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6347, https://doi.org/10.5194/egusphere-egu23-6347, 2023.

X4.291
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EGU23-6512
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ECS
Christopher Fowler, Zack Ortiz, Shaosui Xu, David Mitchell, Kathleen Hanley, Jared Espley, Laila Andersson, James McFadden, Janet Luhmann, and Shannon Curry

The interaction between Mars' crustal magnetic fields and the solar wind produces a variety of magnetic topologies whose characteristics depend upon the plasma regions that the magnetic field is embedded in. We utilize in-situ Mars Atmosphere And Volatile EvolutioN (MAVEN) measurements to identify localized ionospheric structures, observed as the spacecraft flies through this patchwork of different magnetic topologies. Events are characterized by sharp ‘drop outs’ in magnetic field strength that we term ‘magnetic depletions’. The plasma pressure dominates within magnetic depletions, while the magnetic pressure typically dominates outside of them. Abrupt changes in magnetic topology are coincident with the depletion boundaries. A preliminary statistical study spanning 3 months shows that events occur on ∼4% of MAVEN orbits, between altitudes of 170–360 km. Ionospheric electrons are collisionless and thus magnetized at these altitudes, and combined with the fact that magnetic diffusion timescales range from minutes to an hour, these characteristics suggest that such structures can be observed sporadically by MAVEN on its ∼4.5 hour orbit before being smeared out by magnetic diffusion. At lower altitudes high collision rates lead to diffusion timescales of seconds, while at higher altitudes electromagnetic waves, instabilities and other transport processes driven by the Mars-solar wind interaction can distort the magnetic field, making magnetic depletion events difficult to identify. Magnetic depletions highlight the ability of magnetic topology to drive localized ionospheric structure at Mars, a result that stems from the unique interaction between the solar wind, Mars' crustal magnetic fields, and it's ionosphere.

How to cite: Fowler, C., Ortiz, Z., Xu, S., Mitchell, D., Hanley, K., Espley, J., Andersson, L., McFadden, J., Luhmann, J., and Curry, S.: The influence of magnetic topology on ionospheric structure at Mars: Observations of localized “magnetic depletions”, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6512, https://doi.org/10.5194/egusphere-egu23-6512, 2023.

X4.292
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EGU23-7650
|
ECS
The Width of the Martian Bow Shock and Implications on Thermalization
(withdrawn)
Sara Nesbit-Östman, Herbert Gunell, Maria Hamrin, Hermann Opgenoorth, Laila Andersson, and Charlotte Götz
X4.293
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EGU23-9448
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ECS
|
Anna Turner, Christopher Fowler, and Laila Andersson

The thermal electron temperature, Te, is an important quantity in planetary ionospheres because many photochemical reaction rates depend on it. Te thus plays a role in driving ion composition, structure and dynamics. In addition, enhancements in Te with altitude have been shown to drive ambi-polar electric fields that can energize cold planetary ions and lead to ion escape to space.

The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission acquires Te profiles on each orbit and as a result, a comprehensive data set exists that spans the full range of Mars local times, latitudes and solar zenith angles, allowing us to determine which physical processes control the Te profile shapes and temperature values. We focus on the “transition region,” where Te values can rapidly increase from small values (<500 K) at lower altitudes, to larger values (>1000 K), over a relatively narrow altitude range. The suite of plasma instruments carried by MAVEN allows us to investigate the role of, for example, electron-neutral collisions, ion temperature, wave heating, etc. This study focuses on the effect of electron-neutral collisions on the location and width of the Te transition region. We utilize observations of the neutral atmosphere made by MAVEN’s Neutral Gas and Ion Mass Spectrometer (NGIMS) instrument to calculate electron–neutral collision frequencies, which are compared to measured Te profiles. The calculated collision frequencies provide insight on when collisional processes dominate (over transport and electromagnetic waves, for example), and allow us to identify trends between driving processes and the shape and location of the Te transition region. Understanding the physical processes that control the form of Te profiles will inform us of the mechanisms key to structuring the current day Mars ionosphere. Such understanding will also provide key insight needed for studies of ionospheric escape to space and long-term evolution of the Martian atmosphere. 

How to cite: Turner, A., Fowler, C., and Andersson, L.: Determining the Relation Between Electron-Neutral Collisions and Thermal Electron Temperature Profiles in the Mars Ionosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9448, https://doi.org/10.5194/egusphere-egu23-9448, 2023.

X4.294
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EGU23-12193
Romain Maggiolo, Maria Luisa Alonso Tagle, Herbert Gunell, Johan De keyser, Gaël Cessateur, Giovanni Lapenta, Vivianne Pierrard, and Ann Carine Vandaele

Water was abundant on early Mars but disappeared, likely escaping into interplanetary space.

Large-scale planetary magnetic fields were long thought to shield planetary atmospheres and limit atmospheric escape, suggesting that Mars lost most of its water after its intrinsic magnetic field vanished. However, observations of atmospheric escape from Mars, Venus and Earth as well as recent numerical models question the protective effect of planetary magnetic fields on atmospheric erosion.

We use a semi-empirical model of atmospheric escape to investigate the past oxygen and hydrogen escape rate from Mars. This model uses physical considerations and a magnetic field model to extrapolate present-day observations to past solar and planetary conditions. It accounts for the variation of the planetary magnetic field and of the solar wind dynamic pressure and EUV/UV flux. Our modelling results show that for a more active Sun, atmospheric escape peaks for a weak planetary magnetization level as both unmagnetized escape processes like ion pick-up and sputtering can occur at the same time as magnetized escape processes in the polar regions. This study suggests that the water loss rate from the Martian atmosphere may have peaked when Mars was (still) magnetized rather than when it was unmagnetized.

How to cite: Maggiolo, R., Alonso Tagle, M. L., Gunell, H., De keyser, J., Cessateur, G., Lapenta, G., Pierrard, V., and Vandaele, A. C.: Investigating the past atmospheric escape rate from Mars using a semi-empirical model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12193, https://doi.org/10.5194/egusphere-egu23-12193, 2023.

X4.295
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EGU23-6449
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Highlight
Niklas J. T. Edberg, Anders I. Eriksson, Hans Nilsson, Herbert Gunell, Charlotte Goetz, Ingo Richter, Pierre Henri, and Johan de Keyser

With the upcoming Comet Interceptor mission aiming for a flyby of an hitherto unknown long-period comet, we investigate the expected scale size of the plasma environment to be encountered during this mission. As the target comet is not known, and may not be known before the launch of Comet Interceptor in 2029, we do not know the expected outgassing rate from the nucleus. Therefore, we have no knowledge of the expected scale size of the plasma environment, which can vary by orders of magnitude. Taking the bow shock size as a characteristic size of the plasma environment, we are interested in knowing how this grows with increasing outgassing rate. Previous cometary flyby missions have generated a small statistical dataset of outgassing rates vs. bow shock distances, while computer simulations of the solar wind interaction with various comets have yielded additional datapoints of this. We combine the measured values with a large fraction of these simulations to build up a dataset that spans over four orders of magnitude in both outgassing rate and bow shock distance. The bow shock distances are normalized to the solar wind conditions (400 km/s, 5 cm-3) and ionisation rate (7e-7 s-1) at 1 AU, and also to a flow velocity of 1 km/s of the outgassing neutrals. We then compare this dataset with the gas-dynamic model of Biermann et al., (1967) which was later expanded by Koenders et al., (2013) and find a good model-data agreement. Furthermore, assuming that the bow shock takes the shape of a conic section (as has been found empirically to be the case for most planetary bow shocks) we provide an outgassing rate-dependent bow shock model. This might be useful when planning the operation time-line of Comet Interceptor, or for any other future cometary flyby mission.

How to cite: Edberg, N. J. T., Eriksson, A. I., Nilsson, H., Gunell, H., Goetz, C., Richter, I., Henri, P., and de Keyser, J.: Scale size of cometary bow shocks, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6449, https://doi.org/10.5194/egusphere-egu23-6449, 2023.

X4.296
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EGU23-13641
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ECS
Hayley Williamson, Gabriella Stenberg Wieser, Hans Nilsson, Anja Moeslinger, Martin Wieser, and Romain Canu-Blot

Inside the cometopause of comet 67P/Churyumov-Gerasimenko, where cometary ions dominate the ionosphere, is a region of great interest for studying the mass loading of the solar wind. The Rosetta Ion Composition Analyzer (ICA) observed both cometary and solar wind ions in this region during Rosetta’s two year mission orbiting comet 67P. Analysis of this data is complicated by instrumental and spacecraft effects on low energy cometary ion data, which comprises the bulk of the plasma. Recent work has been able to correct the ICA ion distributions for these effects and retrieve low energy ion Maxwellian temperatures and velocities, showing both a cold (< 1 eV) newly ionized plasma and higher energy, warmer pickup ions. Here, we present the varying cometary and solar wind ion temperatures inside the cometopause, with discussion of the causes for the changes in velocity and temperature throughout the time periods studied. In particular, pickup ion distributions vary significantly, from distributions similar to the newly ionized plasma at higher energies to one that decays exponentially with energy. Further, we calculate thermal and dynamic pressures of the cometary and solar wind ions using the retrieved temperatures and velocities, allowing us to analyze the pressure balance between the different plasma components. 

How to cite: Williamson, H., Stenberg Wieser, G., Nilsson, H., Moeslinger, A., Wieser, M., and Canu-Blot, R.: Plasma parameters inside the cometopause of comet 67P-Churyumov/Gerasimenko, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13641, https://doi.org/10.5194/egusphere-egu23-13641, 2023.

X4.297
|
EGU23-8319
Lubomir Prech, Nicolas André, Benoit Lavraud, Christophe Verdeil, Andrei Fedorov, and Jakub Vaverka and the LEES Technical and Scientific Teams

Comet Interceptor is the ESA F1 space mission aiming to explore a comet very likely entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star, scheduled for launch in 2029 together with the ESA L-class Ariel spacecraft. Following the mission adoption in June 2022, the spacecraft and scientific payload development have advanced to the Phase C. In our contribution we present the status of development of the Low-energy electron spectrometer (LEES) that is a part of the Dust-Fields-Plasma multi-instrument suite deployed at the main spacecraft A (DFP-A).

The DFP-A/LEES sensor will determine the thermal and suprathermal electron densities, temperatures, and the velocity distribution functions of the local plasma environment of both the solar wind and coma. It will also measure the local properties of negatively charged ions and dust, and detect photoelectrons resulting from neutral-plasma interactions in order to infer the magnetic connectivity between the cometary environment and the spacecraft. The LEES measurements are needed to understand the ionization sources of the cometary neutral gas as well as to infer the plasma boundaries of the induced magnetosphere of the comet. The electron spectrometer is a further miniaturized version of the top-hat analyser inherited from the Stereo, Maven and BepiColombo missions. We present the overall design, simulation of the spacecraft electromagnetic and particle environment influence to the LEES measurements and the intermediate results of testing of the LEES components to survive a potential harsh dust environment during the comet flyby.   

How to cite: Prech, L., André, N., Lavraud, B., Verdeil, C., Fedorov, A., and Vaverka, J. and the LEES Technical and Scientific Teams: Low-energy electron spectrometer to study the far environment of a dynamically new comet as a part of the Comet Interceptor payload, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8319, https://doi.org/10.5194/egusphere-egu23-8319, 2023.

X4.298
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EGU23-9224
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ECS
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Daniel Teubenbacher, Yasuhito Narita, Gunter Laky, Ali Varsani, Daniel Schmid, Uwe Motschmann, Simon Töpfer, Willi Exner, Philippe Bourdin, and Horia Comişel

The study of the structure and dynamics of Mercury’s magnetosphere is still an open research topic in space physics. Upon other mission objectives, the on-going BepiColombo mission will study the plasma environment around Mercury with multiple field and particle instruments. One of them is the Planetary Ion Camera (PICAM). It is an ion spectrometer designed to measure low-energy pick-up heavy ions (e.g. sodium). Due to ejection mechanisms and the solar wind influence, these particles are emitted from the surface of Mercury. The resulting electric currents, like perpendicular and field-aligned currents need to be studied to understand the global magnetospheric current structure as well as its variability due to the solar wind conditions.

In this study, numerical simulations with a global 3D hybrid model are used to investigate and forecast the typical ion profile with energies up to 5 keV during the BepiColombo flyby trajectories in the years 2021-2025. Magnetotail reconnection causes the acceleration of particles towards the planet. The resulting field-aligned current is studied to about 3 RM in tailward direction. The simulations are conducted with the AIKEF (Adaptive Ion Kinetic Electron Fluid) model. The kinetic treatments of the ions will enable to directly compare magnetospheric particle species model results with PICAM observations.

How to cite: Teubenbacher, D., Narita, Y., Laky, G., Varsani, A., Schmid, D., Motschmann, U., Töpfer, S., Exner, W., Bourdin, P., and Comişel, H.: Expectations of the Ion-Profile in Mercury’s Magnetosphere during BepiColombo's Flybys 2021-2025, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9224, https://doi.org/10.5194/egusphere-egu23-9224, 2023.

X4.299
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EGU23-11568
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ECS
Emanuele Cazzola, Dominique Fontaine, and Ronan Modolo

While waiting for further insights from the upcoming data from the BepiColombo mission, this work presents some results from full-scale 3D hybrid (ions kinetic and electrons fluid) computer simulations of the near-Mercury environment under different interplanetary conditions. During its orbit Mercury passes from an high density high magnetic field intensity region (Perihelion) to a low density low magnetic field intensity region (Aphelion). Such environment change drastically influences the response of its magnetic environment, including the stand-off distance of both Bow-Shock and Magnetopause. Being these latter not distant from each other nor from the Hermean exosphere, such a dynamics may lead to important interactions between the planetary and interplanetary environments, as well as lead to unpredictable scenarios whenever the interplanetary conditions occasionally result more extreme than those average values curretly known.

Here we aim to give more insights  into the near-Mercury environments under more significant interplanetary conditions by means of full-scale 3D multi-species hybrid simulations, including the Aphelion and Perihelion conditions known to date, as well as more extreme conditions, and compare these results with currently available in-situ observations and recent similar computer simulations. 

How to cite: Cazzola, E., Fontaine, D., and Modolo, R.: On the Response of the near-Mercury Environment to Different Interplanetary Conditions from full-scale 3D Hybrid Simulations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11568, https://doi.org/10.5194/egusphere-egu23-11568, 2023.

X4.300
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EGU23-12605
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ECS
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Konstantin Kim, Niklas Edberg, Oleg Shebanits, Jan-Erik Wahlund, and Erik Vigren

Titan’s  magnetotail is formed as a result of the interaction of Saturn’s magnetospheric flow with Titan’s ionosphere. While the ionosphere is created mainly by EUV radiation and impinging magnetospheric particles on the atmosphere, the tail is more governed by plasma outflow processes, the upstream magnetospheric flow properties (density, flow velocity) and the upstream magnetic field direction. The properties of Titan’s tail has previously been studied with both numerical simulations and in-situ measurements. For instance,  the escape rate has been shown to be of the order  of order ~1024 s-1, and case studies have revealed a highly dynamic tail structure.

In this work we make an attempt to combine observations of electrons and ions in Titan’s tail for all of the Cassini flybys. We use the Langmuir probe (RPWS/LP) and the Cassini Plasma Spectrometer (CAPS) ion and electron measurements. We put a spatial constraint on the tail’s geometry  and its orientation based on the measurements of electron and ion densities. The estimation of escape rate is revisited, and different sources of variability and their impact on the tail structure are discussed. Furthermore, the link between the convectional electric field E = -B and the electron densities distribution is studied. The interim result is that the electron density tends to have higher densities in the hemisphere of positive upstream electric field. This is observed in the altitudes below the dynamo region, which is the chemistry-dominated region. The explanation of the observed distribution tendency is discussed.

How to cite: Kim, K., Edberg, N., Shebanits, O., Wahlund, J.-E., and Vigren, E.: Titan's tail structure: the multi-instrument study as observed by Cassini, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12605, https://doi.org/10.5194/egusphere-egu23-12605, 2023.

Posters virtual: Tue, 25 Apr, 16:15–18:00 | vHall ST/PS

vSP.5
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EGU23-8206
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ECS
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Nadim Maraqten and Viktoria Kutnohorsky and the MVSE Mission Team

The dynamics of induced magnetospheres raise several unsolved questions. Among the most pressing is the interaction between the solar wind and induced magnetospheres, and the corresponding changes in magnetospheric structure and variation in heating processes. Furthermore, the reactions of an induced magnetosphere to solar eruptive events such as interplanetary coronal mass ejections, corotating interaction regions and solar flares are not well understood. The Magnetospheric Venus Space Explorers (MVSE) mission is designed to fill this gap by studying how the Sun drives the dynamics of the induced Venusian magnetosphere. Venus is an ideal laboratory for this due to its proximity to the Sun, similarity to Earth, and its accessibility. Investigating the induced Venusian magnetosphere enables direct comparisons with Earth’s active magnetosphere and other induced ones, such as those of several other planets, moons and comets. This complements former missions like Venus Express (VEX) and Pioneer Venus Orbiter (PVO) by filling data and knowledge gaps, hence improving magnetospheric modeling.

 

Figure 1: Orbits of the three scientific spacecraft and transfer/communication spacecraft around Venus facilitating simultaneous measurements in solar wind, bow shock and magnetotail

Three identical spin-stabilised scientific spacecraft equipped with in-situ plasma instrumentation are deployed in resonant orbits around Venus by a transfer stage, which then further operates as a communication relay station. With a phase difference of 180° relative to each other, two scientific spacecraft orbit Venus circularly with a 20 h period (r = 6 Venusian radii RV). The third spacecraft is in a resonant inner elliptical orbit with a 10 h period (pericythe = 1.3 RV; apocythe = 6 RV) . This configuration enables simultaneous measurements in three regions of interest (ROIs): i) up and ii) downstream the bow shock, as well as iii) in the magnetotail. In these ROIs, the magnetic field, the electric field and the ion-electron distribution functions are measured. To observe at least 10 coronal mass ejection events, a mission duration of three years around the solar maximum is planned.

Figure 2: Spacecraft stack consisting of one tansfer/communications vehicle and three scientific spacecraft

The concept of the MVSE mission was developed during ESA’s Alpbach Summer School 2022. It has been refined by adapting the concurrent engineering method during the Post Alpbach Summer School Event 2022. A total of 32 students from both engineering and science backgrounds worked on the mission with appreciated advice from experts of ESA and academia.

How to cite: Maraqten, N. and Kutnohorsky, V. and the MVSE Mission Team: MVSE Mission Phase A/0 Study: A Proposal for Understanding the Dynamics of Induced Magnetospheres, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8206, https://doi.org/10.5194/egusphere-egu23-8206, 2023.