Originally the term ‘space weather’ referred to the way in which “the variable conditions on the Sun can influence, throughout space and in the Earth’s magnetic field and upper atmosphere, the performance of space-borne and ground-based technological systems and endanger human life or health”(1). In the last years it has been extended to all the objects of the Solar Systems, becoming “Planetary Space Weather”.
The different aspects of the interactions induced by the Sun with the many objects of the Solar System should be studied in comparison with the Earth case, to help understanding the processes involved. In fact, possible comparative studies have already proven to be a powerful tool in understanding the different effects and interactions of space weather occurring around all the bodies of the Solar System.
In the present session, we welcome abstracts from all planets’ upstream solar wind activities and their relation to planetary space weather, including especially magnetized bodies (like Mercury, the Earth, Saturn and Jupiter) as well as comparisons with unmagnetized bodies (Mars and Venus).
Nevertheless, a special focus of this session will be on the planet Mercury whose environment in a few years will be the main goal of the dual ESA/JAXA mission BepiColombo. Bepicolombo will perform the first of six flybys at the end of 2021, and will begin its orbiting phase in 2026. One of the two spacecraft, the Japanese MIO, is especially designed to study the magnetospheric environment. Additional instrumentation onboard the European planetary spacecraft, orbiting closer to the planet, will measure the inner magnetosphere interactions with the exosphere and the surface.
In this frame, we welcome studies on:
• magnetosphere-ionosphere coupling dynamics (and auroras where present);
• the solar wind interaction with planets and moons (nb: for smaller bodies refer to session PS2.3 and for pure studies on unmagnetized bodies refer to session PS1.2)
• inter-comparisons of planetary environments;
• observations of space weather effects from space probes and Earth-based instrumentation;
• theoretical modeling and simulations, especially in view of measurement analysis and interpretation;
• potential impacts of space weathering on technological space systems.

(1) from US National Space Weather Plan (2000)

Public information:
Welcome to the session PS1.4-ST4.7 Planetary Space Weather.
The schedule will include 10 displays and it will start with our solicited talk by Chuanfei Dong.
Then, we will follow the order you will find in the list of displays.
To actively participate, you are supposed to have already read all the displays.
Nevertheless, to help you in participation to the session, we will introduce the authors who will briefly tell us about their research work.
Then, we will open to questions for about 10 minutes each, and authors will answer live.
If we will have still time, we will have a short general discussion at the end.
Enjoy our session then!
Valeria, Zhonghua, Philippe and Markus

Co-organized by ST4
Convener: Valeria Mangano | Co-conveners: Philippe Garnier, Markus Fränz, Zhonghua Yao
| Attendance Fri, 08 May, 08:30–10:15 (CEST)

Files for download

Download all presentations (63MB)

Chat time: Friday, 8 May 2020, 08:30–10:15

Chairperson: Valeria Mangano, Zhonghua Yao, Philippe Garnier
D2525 |
| Arne Richter Award for Outstanding ECS Lecture
Beatriz Sánchez-Cano

Planetary Space Weather is an emerging topic of increasing interest. Forecast this planetary space weather, however, is currently very challenging mainly due to the lack of continuous solar wind observations for each planet. In the particular case of Mars, understanding the ionospheric behaviour following Space Weather activity is essential in order to assess the response of the Martian plasma environment to the dissipation of energy from solar storms. Moreover, it gives information on the effects on the current technology deployed on the red planet. Despite the recent considerable exploration, however, there is still no continuous upstream solar wind observations at Mars. This fact makes the analysis of the different Martian plasma datasets challenging, relying on solar wind models and upstream solar wind observations at 1 AU (e.g. at Earth’s L1 point, STEREO, etc.) when Mars and those satellites are in apparent opposition or perfectly aligned in the Parker spiral.

This lecture will focus on our current knowledge of the Martian ionosphere, which is the layer that links the neutral atmosphere with space, and acts as the main obstacle to the solar wind. In particular, I will focus on our recent advances in the understanding of the Martian ionospheric reaction to different Space Weather events during the solar cycle, both from the data analysis and ionospheric modelling perspectives. Some important aspects to consider are the bow shock, magnetic pileup boundary, and ionopause characterization, as well as the behaviour of the topside and bottomside of the ionosphere taking into account the planet’s orbital eccentricity. Moreover, I will show the effect of electron precipitation from large Space Weather events in the very low Martian ionosphere, a region that it is non-accessible to in-situ spacecraft observations. Finally, I will conclude the presentation by giving my perspective on some of the key outstanding questions that remain unknown, and I consider they constitute the next generation of Mars’ ionospheric and Space Weather science and exploration.

How to cite: Sánchez-Cano, B.: Space Weather effects on Mars’ ionosphere: From our current knowledge to the way forward, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7422, https://doi.org/10.5194/egusphere-egu2020-7422, 2020.

D2526 |
| solicited
Chuanfei Dong, Liang Wang, Ammar Hakim, Amitava Bhattacharjee, James Slavin, Gina DiBraccio, and Kai Germaschewski

For the first time, we explore the tightly coupled interior‐magnetosphere system of Mercury by employing a three‐dimensional ten‐moment multifluid model. This novel fluid model incorporates the nonideal effects including the Hall effect, electron inertia, and tensorial pressures that are critical for collisionless magnetic reconnection; therefore, it is particularly well suited for investigating collisionless magnetic reconnection in Mercury's magnetotail and at the planet's magnetopause. The model is able to reproduce the observed magnetic field vectors, field‐aligned currents, and cross‐tail current sheet asymmetry (beyond magnetohydrodynamic approach), and the simulation results are in good agreement with spacecraft observations. We also study the magnetospheric response of Mercury to an extreme event with an enhanced solar wind dynamic pressure, which demonstrates the significance of induction effects resulting from the electromagnetically coupled interior. More interestingly, plasmoids (or flux ropes) are formed in Mercury's magnetotail during the event, indicating the highly dynamic nature of Mercury's magnetosphere. This novel ten‐moment multifluid model represents a crucial step toward establishing a revolutionary approach that enables the investigation of Mercury's tightly coupled interior‐magnetosphere system beyond the traditional fluid model and has the potential to enhance the science returns of both the MESSENGER mission and the BepiColombo mission.

How to cite: Dong, C., Wang, L., Hakim, A., Bhattacharjee, A., Slavin, J., DiBraccio, G., and Germaschewski, K.: Global Ten-Moment Multifluid Simulations of the Solar Wind Interaction with Mercury: From the Planetary Conducting Core to the Dynamic Magnetosphere, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13186, https://doi.org/10.5194/egusphere-egu2020-13186, 2020.

D2527 |
Dario Del Moro, Gianluca Napoletano, Francesco Berrilli, Luca Giovannelli, Ermanno Pietropaolo, and Raffaello Foldes

Solar wind transients, i.e. interplanetary coronal mass ejections (ICMEs) drive Space Weather throughout the heliosphere and the prediction of their impact on different solar system bodies is one of the primary goals of the Planetary Space Weather forecasting. We realized a procedure based on the Drag-Based Model (Vrsnak et al., 2013, Napoletano et al. 2018) which uses probability distributions for the input parameters, and allows the evaluation of the uncertainty on the forecast. This approach has been tested against a set of ICMEs whose transit times are known, obtaining extremely promising results.

We apply this model to propagate a sample of ICMEs from their sources on the solar surface into the heliosphere. We made use of the seminal works by Prise et al. (2015), Winslow et al. (2015) and Witasse et al. (2017) who tracked the ICMEs through their journeys using data from several spacecraft.

Considering the extremely short computation time needed by the model to propagate ICMEs, this approach is a promising candidate to forecast ICME arrival to planetary bodies and spacecraft in the whole heliosphere, with relevant application to space-mission short-term planning.

How to cite: Del Moro, D., Napoletano, G., Berrilli, F., Giovannelli, L., Pietropaolo, E., and Foldes, R.: Can we forecast the arrival of ICMEs for the whole Solar Systems?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18327, https://doi.org/10.5194/egusphere-egu2020-18327, 2020.

D2528 |
Limei Yan, Jiawei Gao, Lihui Chai, Lingling Zhao, Zhaojin Rong, and Yong Wei

On 2003 November 20–21, when the most intense geomagnetic storm during solar cycle 23 was observed at Earth, XMM-Newton recorded the strongest Martian X-ray halo hitherto. The strongest Martian X-ray halo has been suggested to be caused by the unusual solar wind, but no direct evidence has been given in previous studies. Here, based on the Mars Global Surveyor (MGS) observations, unambiguous evidence of unusual solar wind impact during that XMM-Newton observation was found: the whole induced magnetosphere of Mars was highly compressed. The comparison between the solar wind dynamic pressure estimated at Mars from MGS observation and that predicted by different solar wind propagation models suggests that the unusal solar wind is probably related to the interplanetary coronal mass ejection observed at Earth on 2003 November 20.

How to cite: Yan, L., Gao, J., Chai, L., Zhao, L., Rong, Z., and Wei, Y.: Revisiting the Strongest Martian X-Ray Halo Observed by XMM-Newton on 2003 November 19–21, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20905, https://doi.org/10.5194/egusphere-egu2020-20905, 2020.

D2529 |
Monica Laurenza, Anna Milillo, Tommaso Alberti, Valeria Mangano, Stefano Massetti, Christina Plainaki, Alessandro Mura, Elisabetta De Angelis, Rosanna Rispoli, Stavro Ivanovski, and Stefano Orsini

The interplanetary and planetary environments are characterized by several intrinsic and induced properties as magnetic fields, waves and instabilites, boundaries, and ionizing radiation components. These features usually evolve on timescales ranging from seconds up to years, mainly controlled by the solar activity.

BepiColombo and Solar Orbiter flybys will offer an interesting opportunity to investigate the dynamical features of both magnetic fields and particle populations when passing from the interplanetary to the planetary environments, thus allowing us to properly characterize different regions of the interplanetary and planetary space.

This contribution discusses some outstanding features of planetary environments (Earth, Venus, and Mercury) when they interact with the interplanetary medium by considering data coming from in-flight space missions as ACE, MESSENGER, and Venus Express. Moreover, a special attention will be devoted to BepiColombo flybys which will be helpful for deeper investigations.

How to cite: Laurenza, M., Milillo, A., Alberti, T., Mangano, V., Massetti, S., Plainaki, C., Mura, A., De Angelis, E., Rispoli, R., Ivanovski, S., and Orsini, S.: Interplanetary effects on planetary environments: Earth, Venus, and Mercury, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3489, https://doi.org/10.5194/egusphere-egu2020-3489, 2020.

D2530 |
A detailed look on the interaction of solar wind helium with Mercury’s surface in the laboratory
Herbert Biber, Paul S. Szabo, Noah Jäggi, Martin Wallner, Reinhard Stadlmayr, Anna Niggas, Marcos V. Moro, Daniel Primetzhofer, Andreas Nenning, Andreas Mutzke, Markus Sauer, Jürgen Fleig, Annette Foelske-Schmitz, Klaus Mezger, Helmut Lammer, André Galli, Peter Wurz, and Friedrich Aumayr
D2531 |
Fei He, Xiao-Xin Zhang, Zhonghua Yao, Yong Wei, and Weixing Wan

Transpolar arcs that occur primarily under northward interplanetary magnetic field (IMF) are a class of auroral features in the polar cap region. Many mechanisms have been proposed to interpret the generation of the arcs, including reconnection and sudden change in the IMF. It is now generally accepted that IMF BYcomponent plays a key role in the generation and evolution of the arcs. Here we report an interesting long-lasting and moving transpolar arc observed during a geomagnetically quiet period (Dst<10 nT and AE<50 nT) by the wide-field auroral imager (WAI) onboard the Chinese Fengyun satellite. The WAI is a recently launched imager operated in far ultraviolet wavelength (LBH band in 140-180 nm) in a sun-synchronous orbit with a height of ~840 km. It is shown that the arc was initiated at the poleward auroral boundary on dawnside after the IMF turned to be northward and persisted for more than 5 hours. The arc moved toward the noon-midnight line as the IMF BYcomponent changed its direction and then moved back toward dawnside. An interesting phenomenon was that the arc was accompanied with strong energetic proton (30-80 keV) precipitations with geomagnetic latitude greater than 70° but no significant electron precipitations. However, the origin of these energetic protons is unknown and is worthy study in future.

How to cite: He, F., Zhang, X.-X., Yao, Z., Wei, Y., and Wan, W.: Transpolar Arc Observed by the Wide-Field Auroral Imager Onboard Fengyun Satellite, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4118, https://doi.org/10.5194/egusphere-egu2020-4118, 2020.

D2532 |
Yong Wei, Jun Zhong, Fei He, and Hui zhang

Earth’s present dipolar magnetic field extends into the interplanetary space and interacts with the solar wind, forming a magnetosphere filled up with charged particles mostly originating from the Earth’s atmosphere. In the elongated tail of the magnetosphere, the particles were observed to move either Earthward or tailward with different speeds at different locations, even outside the Moon’s orbit. We hypothesize that the lunar soil, on both the nearside and farside, should have been impacted by these particles during the geological history, and the impact was controlled by the size and morphology of the magnetosphere. We predict that the farside soil could also have the features similar to those in the nearside soil, e.g., 15N-enrichment. Furthermore, we may infer the evolution of the magnetosphere and atmosphere by examining the implanted particles in the lunar soil from both sides. This hypothesis could provide an alternative way to study the evolution of Earth’s dynamo and atmosphere.

How to cite: Wei, Y., Zhong, J., He, F., and zhang, H.: Implantation of Earth’s atmospheric ions into the nearside and farside lunar soil: implications to geodynamo evolution, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7762, https://doi.org/10.5194/egusphere-egu2020-7762, 2020.

D2533 |
Lihui Chai, James Slavin, Yong Wei, Weixing Wan, Charlie F. Bowers, Gina DiBraccio, Eduard Dubinin, Markus Fraenz, Willi Exner, Moritz Feyerabend, Uwe Motschmann, Kun Li, Jun Cui, and Tielong Zhang

The induced magnetotails on Mars and Venus are considered to arise through the interplanetary magnetic field (IMF) draping around the planet and the solar wind deceleration due to the mass loading effect. They have very similar structures as that on Earth, two magnetic lobes of opposite radial magnetic fields and a plasma sheet in between. However, the orientation and geometry of the induced magnetotails are controlled by the IMF, not the planetary intrinsic magnetic field. In this study, we present another characteristic of the induced magnetotails on Mars and Venus with the observations of MAVEN and Venus Express. It is found that the magnetic flux in the induced magnetotails on Mars and Venus are inhomogeneous. There is more magnetic flux in the +E hemisphere than -E hemisphere. The magnetic flux is observed to transport gradually from the +E hemisphere to the -E hemisphere along the magnetotail. The magnetotail magnetic flux transport seems to be faster on Mars than that at Venus. Based on these observations, we suggest that the finite gyro-radius effect of the planetary ions that are picked up by the solar wind is responsible to the magnetic flux inhomogeneity and transport in the induced magnetotails. The role of the magnetic pressure gradient in the magnetotail will be discussed.

How to cite: Chai, L., Slavin, J., Wei, Y., Wan, W., Bowers, C. F., DiBraccio, G., Dubinin, E., Fraenz, M., Exner, W., Feyerabend, M., Motschmann, U., Li, K., Cui, J., and Zhang, T.: The magnetic flux transport along the -Esw direction in the magnetotails on Mars and Venus, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12469, https://doi.org/10.5194/egusphere-egu2020-12469, 2020.

D2534 |
sebastien Le Maistre, Nicolas Bergeot, Olivier Witasse, Pierre-Louis Blelly, Wlodek Kofman, Kerstin Peter, Veronique Dehant, Jean-Marie Chevalier, and Ozgur Karatekin

The NASA InSight mission is operating from the surface of Mars for more than a year. RISE (for Rotation and Interior Structure Experiment) is one of the scientific payloads of InSight. This radio-science experiment consisting in an X-band transponder and two horn-antennas enabling two-way coherent radio-link between Mars and the Earth [Folkner et al., 2018]. The main goal of RISE is to measure the slight modulations of the nutational motion of the spin axis of Mars induced by the liquid core of the planet in order to constrain its interior structure and core properties. To increase our chance to achieve this challenging goal, we must calibrate the RISE Doppler data by accounting to 2nd order effects like the Mars atmospheric noise.

This study shows the predicted contribution of the Martian ionosphere to the RISE data collected so far. To do so, we use a new empirical model of the Mars’ ionosphere called MoMo [Bergeot et al. 2019]. This model is based on the large database of Total Electron Content (TEC) derived from the subsurface mode of the Mars Express MARSIS radar. The model provides the vertical TEC as a function of solar zenith angle, solar activity, solar longitude and the location. Using MoMo, we produce vTEC maps for Mars that are then used to estimate the slant TEC in the Earth line of sight, enabling to infer the phase delay and Doppler shift affecting the RISE X-band measurements. These computed effects are shown to be of the order of 10-3mm.s-1 in Doppler observables, with a larger effect around sunrise and sunset. This is about one order of magnitude below the typical measurement noise of RISE, but it is comparable to the contribution of the liquid core in the Doppler (~10-3-10-2mm.s-1).

The MoMo model is suitable for any Mars radio-science data calibration, and in particular the forthcoming ExoMars 2020 LaRa measurements [Dehant et al. 2019]. The predictions made with MoMo will be of great use either for the data corrections or to define the timing of observations in order to avoid operating when the TEC rapidly varies (i.e. close to sunrise and sunset). The model output is further discussed here in terms of climatologic behavior of the Mars’ ionosphere. For comparison, we also investigate the contribution of the Earth ionosphere using Global Ionospheric Maps (GIMs) based on GNSS data.

How to cite: Le Maistre, S., Bergeot, N., Witasse, O., Blelly, P.-L., Kofman, W., Peter, K., Dehant, V., Chevalier, J.-M., and Karatekin, O.: MoMo’s prediction of Mars’ ionosphere contribution to InSight RISE Doppler data, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19700, https://doi.org/10.5194/egusphere-egu2020-19700, 2020.

D2535 |
Eunjin Jang, Jiutong zhao, Chao Yue, Qiugang Zong, Ying Liu, and Zhiyang Liu

Energetic ions in Mercury’s magnetosphere are very dynamic, just like in the magnetosphere of Earth. In this study, we have shown two energetic proton observations by MESSENGER near the cusp region of Mercury. For one case, we have observed large flux of energetic protons while the other case has almost no flux, indicating that the near cusp region may trap energetic particles under particular conditions. In order to understand that under what conditions the near cusp region of Mercury could trap energetic particles, we have traced the trajectories of single particle with different energies by using a modeled magnetic field, called KT17. Under different magnetic field geometry, the motions of single particle with various energies are different. The test particles can be trapped around the cusp region when the disturbance activity is strong, generating the magnetic field local minimum near the cusp region while the particles can’t be trapped and escape along the magnetic field through the dawn side cusp when there is little solar activity.

How to cite: Jang, E., zhao, J., Yue, C., Zong, Q., Liu, Y., and Liu, Z.: Energetic ion dynamics near the cusp region of Mercury, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6400, https://doi.org/10.5194/egusphere-egu2020-6400, 2020.

D2536 |
Alessandro Ippolito, Christina Plainaki, Gaetano Zimbardo, Stefano Massetti, and Anna Milillo

The magnetic foot point of Mercury on the solar disk has been reconstructed for selected case studies, in order to better understand the interaction between the solar corona and the planet. The transport of the magnetic field lines in the heliosphere is here evaluated with a Monte Carlo code that gives a random displacement at each step of the integration along the Parker magnetic field model. Such displacement is proportional to a “local” diffusion coefficient, which is a function of the fluctuation level and magnetic field correlation lengths. The simulation is tailored to specific events by using the observed values of solar wind velocity and magnetic fluctuation levels. Magnetic data from MAG/MESSENGER have been considered to compute the magnetic fluctuation level, while, concerning proton fluxes, FIPS/MESSENGER data has been taken into account. A number of SEP events observed on Mercury during 2011 and 2012 have been analysed, studying, for each event, the magnetic connection from Mercury to the solar corona, and the position of the active region possibly source of the accelerated particles observed.

How to cite: Ippolito, A., Plainaki, C., Zimbardo, G., Massetti, S., and Milillo, A.: Reconstruction of the magnetic connection from Mercury to the solar corona, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7086, https://doi.org/10.5194/egusphere-egu2020-7086, 2020.

D2537 |
Melinda Dósa, Valeria Mangano, Anna Milillo, Stefano Massetti, Zsofia Bebesi, and Anikó Timár

The dynamic changes of Mercury’s Na exosphere are investigated here, in relation to space weather conditions. Sodium plays a special role in Mercury’s exosphere: due to its strong resonance D lines at 5890-95Å it has been observed and monitored by Earth-based telescopes for decades. Different and highly variable patterns of Na-emission have been identified. In addition to the release processes already studied extensively in the past, we aim here to investigate the following factors more in detail: the distance to the Sun, position in relation to the ecliptic plane and solar wind magnetic field strength and direction. In order to better investigate the relationship of these factors, we have studied the intensity of Na-emission as a function of solar wind dynamic pressure and TAA of Mercury by means of the extended dataset images collected from 2009 to 2013 by Earth-based observations performed at the THEMIS solar telescope. Solar wind velocity and density values are propagated with the magnetic lasso method to the position of Mercury from nearby space probes and compared with Na emission intensity. Data of either ACE or one of the two STEREO spacecraft were used, depending on which spacecraft had a smaller angular distance to Mercury. Single cases are studied qualitatively, and a longer-term quantitative comparison is shown, including further parameters (solar wind magnetic field strength and direction, TAA).

How to cite: Dósa, M., Mangano, V., Milillo, A., Massetti, S., Bebesi, Z., and Timár, A.: Space weather at Mercury as observed by the THEMIS telescope from Earth, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7143, https://doi.org/10.5194/egusphere-egu2020-7143, 2020.

D2538 |
Zhonghua Yao and Ruilong Guo

Magnetic reconnection and dipolarization are crucial processes in driving magnetospheric dynamics, including particle energization, mass circulation, auroral processes etc. Recent studies revealed that these processes at Saturn are fundamentally different to the ones at Earth. The reconnection and dipolarization processes are far more important than previously expected at Saturn’s dayside magnetodisc. Dayside magnetodisc reconnection was directly identified using Cassini measurements (Guo et al. 2018), and was found to be drizzle-like and rotating in Saturn’s magnetosphere (Yao et al. 2017 and Guo et al. 2019). Moreover, magnetic dipolarization could also exist at Saturn’s dayside, which is fundamentally different to the terrestrial situation (Yao et al. 2018). We here review these recent advances and their potential implications to future investigations, for example the application to Jupiter’s magnetosphere.

How to cite: Yao, Z. and Guo, R.: Recent advances on magnetic reconnection and dipolarization at Saturn, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1974, https://doi.org/10.5194/egusphere-egu2020-1974, 2020.

D2539 |
Interplanetary shocks at 5 AU and their effects on Jupiter's decametric radio emissions
Ezequiel Echer
D2540 |
Anna Milillo, Valeria Mangano, Stefano Massetti, alessandro Mura, christina Plainaki, Tommaso Alberti, Stavro Ivanovski, Elisabetta De Angelis, and Rosanna Rispoli

The variability of Na exosphere of Mercury shows time scales from less than one hour to seasonal variations. While the faster variations, accounting of about 10-20% of fluctuations are probably linked to the planet response to solar wind and IMF variability, the seasonal variations (up to about 80%) should be explained by a complex mechanisms involving different surface release processes, loss, source and migrations of the exospheric Na atoms. Eventually, a Na annual cycle can be identified. In the past, integrated disk emission from ground-based observations and equatorial density from MESSENGER have been analysed. In this study, for a better investigation of the exospheric Na features, we have studied the local time and latitudinal distributions of the exospheric Na column density as a function of the True Anomaly Angle (TAA) of Mercury by means of the extended dataset of images, collected from 2009 to 2013, by the THEMIS solar telescope. In particular, THEMIS images, in agreement with previous results, registered a strong general increase at aphelion and a dawn ward emission predominance with respect to dusk ward and subsolar region between 90° and 150° TAA. We find a predominance of subsolar column density along the rest of the Mercury orbit. Also an unexpected relation between Northward or Southward peak emission and both TAA and local time is evidenced by our analysis requiring further investigations. Possible relationship with distance from the dust disk or IMF polarity is being considering.

How to cite: Milillo, A., Mangano, V., Massetti, S., Mura, A., Plainaki, C., Alberti, T., Ivanovski, S., De Angelis, E., and Rispoli, R.: Exospheric Na distributions along the Mercury orbit with the THEMIS telescope , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19022, https://doi.org/10.5194/egusphere-egu2020-19022, 2020.

D2541 |
Paul Stefan Szabo, Herbert Biber, Noah Jäggi, Matthias Brenner, David Weichselbaum, Markus Wappl, Marcos V. Moro, Anna Niggas, Reinhard Stadlmayr, Daniel Primetzhofer, Andreas Nenning, Andreas Mutzke, Markus Sauer, Jürgen Fleig, Annette Foelske-Schmitz, Klaus Mezger, Helmut Lammer, André Galli, Peter Wurz, and Friedrich Aumayr

In the absence of a protecting atmosphere, the surfaces of rocky bodies in the solar system are affected by significant space weathering due to the exposure to the solar wind [1]. Fundamental knowledge of space weathering effects, such as optical changes of surfaces as well as the formation of an exosphere is essential for gaining insights into the history of planetary bodies in the solar system [2]. Primarily the exospheres of Mercury and Moon are presently of great interest and the interpretation of their formation processes relies on the understanding of all space weathering effects on mineral surfaces.

Sputtering of refractory elements by solar wind ions is one of the most important release processes. We investigate solar wind sputtering by measuring and modelling the sputtering of pyroxene samples as analogues for the surfaces of Mercury and Moon [3, 4]. These measurements with thin film samples on Quartz Crystal Microbalance (QCM) substrates allow recording of sputtering yields in-situ and in real time [5]. For the simulation of kinetic sputtering from the ion-induced collision cascade we use the software SDTrimSP with adapted input parameters that consistently reproduce measured kinetic sputtering yields [4, 6].

This study focuses on investigating the potential sputtering of insulating samples by multiply charged ions [7]. Changes of these sputtering yields with fluence are compared to calculations with a model based on inputs from SDTrimSP simulations. This leads to a very good agreement with steady-state sputtering yields under the assumption that only O atoms are sputtered by the potential energy of the ions. The observed decreasing sputtering yields can be explained by a partial O depletion on the surface [4]. Based on these findings expected surface composition changes and sputtering yields under realistic solar wind conditions can be calculated. Our results are in line with previous investigations (see e.g. [8, 9]), creating a consistent view on solar wind sputtering effects from experiments to established modelling efforts.



[1]          B. Hapke, J. Geophys. Res.: Planets, 106, 10039 (2001).

[2]          P. Wurz, et al., Icarus, 191, 486 (2007).

[3]          P.S. Szabo, et al., Icarus, 314, 98 (2018).

[4]          P.S. Szabo, et al., submitted to Astrophys. J. (2020).

[5]          G. Hayderer, et al., Rev. Sci. Instrum., 70, 3696 (1999).

[6]          A. Mutzke, et al., “SDTrimSP Version 6.00“, IPP Report, (2019).

[7]          F. Aumayr, H. Winter, Philos. Trans. R. Soc. A, 362, 77 (2004).

[8]          H. Hijazi, et al., J. Geophys. Res.: Planets, 122, 1597 (2017).

[9]          S.T. Alnussirat, et al., Nucl. Instrum. Methods Phys. Res. B, 420, 33 (2018).

How to cite: Szabo, P. S., Biber, H., Jäggi, N., Brenner, M., Weichselbaum, D., Wappl, M., Moro, M. V., Niggas, A., Stadlmayr, R., Primetzhofer, D., Nenning, A., Mutzke, A., Sauer, M., Fleig, J., Foelske-Schmitz, A., Mezger, K., Lammer, H., Galli, A., Wurz, P., and Aumayr, F.: Combining Experiments and Modelling to Understand the Role of Potential Sputtering by Solar Wind Ions, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9386, https://doi.org/10.5194/egusphere-egu2020-9386, 2020.

D2542 |
Dongxiao Pan and Zhonghua Yao

Low frequency quasiperiodic (QP) magnetic field fluctuations are commonly observed in terrestrial and planetary magnetosphere.  At Earth,  these magnetohydrodynamic (MHD) waves are often observed in ultralow frequency (ULF) band (~1 mHz to 1 Hz), which could be generated by solar wind buffeting, Kelvin-Helmholtz instability and/or wave-particle interactions inside the Earth's magnetosphere. At giant planets (Saturn or Jupiter), their enormous magnetospheres often produce QP fluctuations with frequencies lower than the terrestrial ULF waves. In this study, we use Cassini spacecraft observations to analysis waves at period of 10 min to 60 min in Saturnian magnetosphere. We compare wave activities during different solar activities.

How to cite: Pan, D. and Yao, Z.: Wave activities during different phase of solar cycle : Cassini observations on Saturn, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3994, https://doi.org/10.5194/egusphere-egu2020-3994, 2020.

D2543 |
Ruilong Guo, Zhonghua Yao, Benjamin Palmaerts, William Dunn, Nick Sergis, Denis Grodent, Shengyi Ye, Zuyin Pu, Japheth Yates, Sarah Badman, and Yong Wei

Magnetic energy and mass release processes are key issues to understand the magnetospheric dynamics and aurorae processes on planets. Recent studies reveal that rotationally driven processes at dayside on giant planets are much more important than we ever expected. The discovery on the dayside magnetodisc reconnection demonstrates that the rotation effect can overcome the solar wind compression to sufficiently stretch magnetic field lines at dayside (Guo et al., 2018, doi: 10.1038/s41550-018-0461-9). A long-standing small-scale reconnection process was also shown at all local times (Guo et al., 2019, doi: 10.3847/2041-8213/ab4429). Using Cassini in situ multiple instruments data, we here proposed a wedgelet current system governing the entire magnetosphere of Saturn, which can explain the observational phenomena of quasi-periodical electron energization recurrence and beads-like structure in the main aurora region. Localized active regions with finite azimuthal lengths in the magnetosphere were discretely and azimuthally distributed along the magnetodisc and rotated with the magnetosphere. The electron energizations recurred at the spacecraft are related to each active region that passed by. These studies reveal that the dynamics in magnetodisc are global effects on giant planets, which are not always restrained at nightside.

How to cite: Guo, R., Yao, Z., Palmaerts, B., Dunn, W., Sergis, N., Grodent, D., Ye, S., Pu, Z., Yates, J., Badman, S., and Wei, Y.: A wedgelet current system on Saturn, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2537, https://doi.org/10.5194/egusphere-egu2020-2537, 2020.

D2544 |
Christina Plainaki, Stefano Massetti, Xianzhe Jia, Alessandro Mura, Milillo Anna, Davide Grassi, Giuseppe Sindoni, and Emiliano D'Aversa

The exosphere of Jupiter’s moon Ganymede is the interface region linking the moon’s icy surface to Jupiter’s magnetospheric environment. Space weather phenomena driven by the variability of the radiation environment within the Jupiter system can have a direct impact on the sputtering-induced exosphere of Ganymede.

In this work we simulate the Jovian ion precipitation to Ganymede’s surface for different moon orbital phases around Jupiter. In particular, we consider three different configurations between Ganymede’s magnetic field and Jupiter plasma sheet, similar to those encountered during the Galileo G2, G8, and G28 flyby (i.e., the moon above, inside, below the Jupiter plasma sheet). We discuss the differences between the various ion precipitation patterns and the implications in the density distribution of the sputtered-water exosphere of this moon. We also comment the possible relation of these ion precipitation patterns with the surface brightness asymmetries both between Ganymede’s polar cap and equatorial regions and between the leading and trailing hemispheres. The results of this preliminary analysis are relevant to the JUICE mission and in particular to the preparation of the future observation strategies for the environment of Ganymede.

How to cite: Plainaki, C., Massetti, S., Jia, X., Mura, A., Anna, M., Grassi, D., Sindoni, G., and D'Aversa, E.: Kinetic simulations of the Jovian ion circulation around Ganymede and space weather implications, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5405, https://doi.org/10.5194/egusphere-egu2020-5405, 2020.