Session 14 - Scientific and technological aspects of planetary space weather

Christina Plainaki (ASI - Agenzia Spaziale Italiana), Nicolas André (IRAP, France)
Friday 9/11, 11:15-12:45
MTC 01.03

Planetary Space Weather (PSW) is strongly determined by the interactions between the body in question and its local space environment. Different aspects of the conditions at the Sun, and of the solar wind and magnetospheric plasmas at different distances from the Sun, can influence the performance and reliability of space-borne technological systems throughout the Solar System. In this context, Planetary Space Weather Services (PSWS) aim at extending the concept of space situational awareness also to planetary bodies in our Solar System other than the Earth.

This session welcomes papers on space weather impacts that affect planetary exploration, e.g. environmental assessment for future planetary missions (approved or candidate under current calls) and lessons learned from recent and existing missions.
Focus will be given in cross-disciplinary issues, including:

• the interaction of solar wind/magnetospheric plasmas with planetary/satellite ionospheres and atmospheres, including the generation of auroras
• the satellite interactions with their neutral environments and dust
• the variability of the magnetospheric regions under different solar wind conditions
• the inter-comparisons of space weather conditions in different planetary environments.

Contributions addressing new studies, methods, interfaces, and functionalities distributed over the PSWS domains of Prediction, Detection, Modelling, and Alerts are welcome.
Inter-comparisons and interpretation of measurements at different planetary systems and quantification of the possible effect of the environment interactions on components and systems (e.g. radiation dose studies) are strongly encouraged.

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Talks : Time schedule

Friday November 9, 11:15 - 12:45, MTC 01.03

11:15	Planetary Space Weather at Mercury: correlations between Na exosphere and IMF	Mangano, V et al.	Invited Oral
	Valeria Mangano, Stefano Massetti, Stefano Orsini, Anna Milillo
	INAF-IAPS, Rome, Italy
	The Na exosphere of Mercury is being studied since its discovery in mid ‘80s from Earth-based telescopes, and it has revealed a high dynamics and variability. Although the processes and their relationships characterising the Hermean exosphere generation and dynamics are still not exhaustively understood, there are no doubts on a tight interconnection among the planet's surface, exosphere, intrinsic magnetic field, the Solar Wind and the Interplanetary Magnetic Field (IMF). Thanks to a database of 8 years of Earth-based observations by using the solar telescope THEMIS, in the Canary Islands, it’s been possible to perform a comprehensive statistical study of the recurrent Na emission patterns, and also their potential relationship with the IMF variability thanks to the contemporary in-situ measurements of the IMF by the magnetometer on-board the MESSENGER spacecraft (subset in years 2011-2013). The double peak is the most frequent Na emission pattern, supporting the view that the solar wind ion precipitation through the polar cusps has an important role in the generation of the observed Na exosphere. A subset of quasi-full disk images evidenced that the double peak Na emission is typically aligned along the meridian, mostly occurring in the pre-noon sector. Moreover, the comparison with the IMF data indicates that the contribution of the IMF BX component to the magnetic reconnection is generally weak, while a noticeable correlation occurs between positive IMF BX and symmetric double peak pattern. Negative IMF BZ values are usually connected to double peak emission, whereas positive IMF BZ values are more frequently associated to single peaked equatorial Na emission. Further short-term ground-based observations during prolonged period (some days) of globally Na 2-peak pattern, exhibits fluctuations in the time range of tens of minutes which are compatible with the response time of the Na exospheric release, as induced by impulsive events, likely caused by ion precipitation along the cusps to reach the planet surface. A longer-term variation in the south/north emission ratio was also detected, on a timescale of about 1 h, which could be compatible with the Na photoionization lifetime and the fastest decay lifetime of simulated global Na exosphere, which takes place at small values of True Anomaly Angles. Finally, we found the first evidence at Mercury of direct relation between Coronal Mass Ejection transit and Na exosphere dynamics (occurred on Sept 20 2012), showing that Earth-based Na exosphere observations are a valid proxy of planetary space weather at Mercury.
11:30	Pushing the P-DBM to its limits	Del moro, D et al.	Oral
	Francesco Berrilli[1], Alice Cristaldi[1], Dario Del Moro[1], Roberta Forte[1], Luca Giovannelli[1], Gianluca Napoletano[2], Ermanno Pietropalo[2]
	[1] University of Rome "Tor Vergata", [2] University of L'Aquila
	ICME (Interplanetary Coronal Mass Ejection) are violent phenomena of solar activity that affect the whole 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 employed the P-DBM (Probabilistic Drag Based Model – Napoletano et al. 2018) to propagate a sample of ICMEs from their sources on the solar surface into the heliosphere. We made use of recent works by Prise et al. (2015) and Witasse et al. (2017) which tracked the ICMEs through their journey using data from several spacecraft, tracing the ICMEs trajectory further than Earth. In one case, we were able to propagate the ICME up to 31AU and even further to Voyager 2 position at 111AU, thus stretching the P-DBM capabilities to the very limit. Whenever a measured Time of Arrival (ToA) was available, we computed the differences between measured and forecast ToA, and found that the discrepancies were within the estimated errors up to Neptune orbit and beyond. Considering the extremely short computation time needed by the P-DBM to propagate ICMEs into the whole heliosphere, and its extreme accuracy in reproducing the observations, we remark that it is a promising candidate for ICME ToA computation for the need of present and future interplanetary missions, since it could be used as quick tool to forecast the arrival of ICME to planetary bodies in our Solar System other than the Earth.
11:45	Investigating interplanetary space weather events with spacecraft engineering	Lester, M et al.	Oral
	Mark Lester[1], Olivier Witasse[2], Robert F. Wimmer-Schweingruber[3], Jingnan Guo[3], Beatriz Sánchez–Cano[1], Michel Denis[2], Jeffrey J. Plaut[4], Emmanuel Grotheer[2]
	[1]University of Leicester, [2] European Space Agency, [3] University of Kiel, [4] Jet propulsion laboratory, NASA
	While space weather has been a growing field of research and applications over the last 15-20 years, “planetary space weather” is an emerging discipline. To this end, scientists use plasma and magnetic field data from planetary missions. However, not all spacecraft provide relevant instrumentation. Nevertheless, some studies have demonstrated that a spacecraft not equipped with dedicated sensors can act as a space weather monitor. The effects of impacting energetic particles can be identified in selected engineering data sets. Here we test this idea with ESA’s Mars Express and Venus Express housekeeping data. High-energy particles which hit the computer memory of a spacecraft can cause memory errors due to the charge deposited in the physical memory cells. Such errors are caught and corrected by the EDAC (Error Detection And Correction Code) algorithm. Once a correction is done, the relevant EDAC counter is incremented by 1. We studied the evolution of these housekeeping parameters on Mars and Venus Express spacecraft, and found that they successfully identified some, but not all, space weather events. The objective of this study is to assess the properties of space weather events that can be identified with this method.
12:00	New results from Galileo's first flyby of Ganymede: Reconnection driven flows at the low-latitude magnetopause boundary, crossing the cusp, and icy ionospheric escape	Collinson, G et al.	Invited Oral
	Glyn Collinson
	NASA
	On the 27th of June 1996, the NASA Galileo spacecraft made humanity's first flyby of Jupiter's largest moon, Ganymede, discovering that it is the only moon known to possess an internally generated magnetic field. Resurrecting the original Galileo Plasma Subsystem (PLS) data analysis software, we processed the raw PLS data from G01, and for the first time present the properties of plasmas encountered. Entry into the magnetosphere of Ganymede occurred near the confluence of the magnetopause and plasma sheet. Reconnection-driven plasma flows were observed (consistent with an Earth-like Dungey cycle), which may be a result of reconnection in the plasma sheet, magnetopause or might be Ganymede's equivalent of a Low-Latitude Boundary Layer. Dropouts in plasma density combined with velocity perturbations afterwards suggest that Galileo briefly crossed the cusps into closed magnetic field lines. Galileo then crossed the cusps, where field-aligned precipitating ions were observed flowing down into the surface, at a location consistent with observations by the Hubble Space Telescope. The density of plasma outflowing from Ganymede jumped an order of magnitude around closest approach over the north polar cap. The abrupt increase may be a result of crossing the cusp, or may represent an altitude-dependent boundary such as an ionopause. More diffuse, warmer field-aligned outflows were observed in the lobes. Fluxes of particles near the moon on the nightside were significantly lower than on the dayside, possibly resulting from a diurnal cycle of the ionosphere and/or neutral atmosphere.
12:15	Space weathering at Ganymede	Carnielli, G et al.	Oral
	Gianluca Carnielli[1], Marina Galand[1], Ronan Modolo[2], François Leblanc[3], Arnaud Beth[1], Xianzhe Jia[4]
	[1] Department of Physics, Prince Consort Road, Imperial College London, London SW7 2AZ, UK, [2] LATMOS/IPSL, UVSQ Université Paris-Saclay, UPMC Univ. Paris 06, Guyancourt, France, [3] LATMOS/IPSL, CNRS, Sorbonne Université, UVSQ, Paris, France, [4] Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI 48109-2143, USA
	Space weathering at Ganymede involves primarily the surface sputtering from two ion sources: Jovian magnetospheric ions, including H$^+$, O$^{n+}$, S$^{n+}$ (Mauk+, 2004), and Ganymede’s ionospheric ions. Sputtering from Jovian ions has been previously estimated (Ip+, 1997; Paranicas+, 1999), while the contribution from ionospheric ions has been neglected so far due to our poor knowledge of the properties of the moon’s ionosphere. The sputtering process is directly linked to the formation of Ganymede’s exosphere which is the source of its ionosphere, and therefore has a big impact on the particle environment around the moon. Using a 3D test particle ionospheric model developed specifically for Ganymede (Carnielli+, under review), which has recently been updated to include collisions, we calculated the contribution to the sputtering rate from ionospheric ions. By adapting the model to incorporate the Jovian ions we made new estimates of the contribution to sputtering from the Jovian source, considering both the thermal population, H$^+$ and O$^+$ in the keV range (Kivelson+, 2004) and the energetic population, H$^+$, O$^{++}$ and S$^{+++}$ in the keV – MeV range (Mauk+, 2004). We will present the results of our simulations, including: impact maps of the different impacting species and the sputtering rate contribution from each species (and from each energy range considered for the case of the Jovian energetic population), emphasizing the relative importance, in terms of total contribution, between the two sputtering sources. The results of our simulations suggest that the sputtering rate from ionospheric ions is comparable to that from Jovian ions, and that the process occurs primarily in the equatorial region, which was previously considered to be shielded from sputtering due to closed magnetic field lines acting as a barrier for the Jovian magnetospheric ions. However, this consideration did not take into account ionospheric ions as well as very energetic magnetospheric ions which are able to penetrate in the equatorial region, as found by our simulations. Implications for models of Ganymede’s exosphere will be discussed.
12:30	Recurrent magnetic dipolarization process at Saturn: Cassini measurements	Yao, Z et al.	Oral
	Zhonghua Yao, A. Radioti, D. Grodent
	University of Liege
	Planetary magnetospheres often receive plasma and energy from the Sun or moons of planets, and consequently form stretched magnetic field lines. The process may last for varied time scales at different planets. From time to time, energy is rapidly released in the magnetosphere, and subsequently precipitated into the ionosphere and upper atmosphere. Usually, this energy dissipation process is associated with a magnetic dipolarization process in the magnetosphere. During this process, plasma acceleration and field-aligned current formation are accompanied, and subsequently auroral emission are often significantly enhanced. Using measurements from multiple instruments onboard the Cassini spacecraft, we report three recurrent dipolarization events at Saturn. During these events, recurrent energisation of plasma (electrons or ions) were also detected, which clearly demonstrate that these processes shall not be simply attributed to modulation of planetary periodic oscillation. We discuss the physical mechanism for generating the recurrent dipolarization process in a comprehensive view, including aurora and energetic neutral atom emissions.

Posters

1	Monte Carlo simulations of atmospheric cascades in Saturn and Mars	Tezari, A et al.	p-Poster
	P. Paschalis[1], A. Tezari[1,2], M. Gerontidou[1], H. Mavromichalaki[1]
	[1] Athens Cosmic Ray Group, Faculty of Physics, University of Athens, Greece [2] Medical Physics Laboratory, Medical School, University of Athens, Greece
	DYnamic Atmospheric Shower Tracking Interactive Model Application (DYASTIMA) is a software application for the modelling of the atmospheric showers created in the atmosphere of a planet due to the interactions of the primary cosmic rays with the atmospheric molecules. Monte Carlo simulations are performed, based on the well-known Geant4 simulation toolkit. DYASTIMA has already been successfully launched for the atmospheres of Earth and Venus. In this work, simulations for the atmosphere of Saturn and Mars are performed during solar minimum and solar maximum conditions and preliminary results are presented. The study of the evolution and properties of the atmospheric showers for various planets of our solar system is crucial for Planetary Space Weather studies, especially in the context of future missions.
2	Modelling radiation shielding effects for future manned spatial missions	Botek, E et al.	p-Poster
	Edith Botek, Fabiana Da Pieve, Ann-Carine Vandaele and Viviane Pierrard
	Royal Belgian Institute for Space Aeronomy
	The ambitious plans of future missions outside the near-earth environment requires a rigorous investment of efforts for mitigating radiation effects over spacecraft equipment and human beings. Such effects imply single high energetic particles events or long term exposition during the whole mission. New materials are proposed and intensively investigated theoretically and experimentally to deal with such a challenging task. At present it is well stated that light composite materials merging several specific functionalities as absorbing, attenuating or deviating radiation as well as resisting extreme temperatures and loads should be the best choice. See for example: (1) and (2). In the present work, dose calculations using GEANT4 tools, under a radiation environment evaluated by the SPENVIS system, are compared for different trial materials containing molecular combinations with particular properties to be useful for designing potential radiation shielding materials for future manned missions. References (1) Thibeault, Sheila A., et al. "Nanomaterials for radiation shielding." MRS Bulletin 40.10 (2015): 836-841. (2) Cordero, Radames JB. "Melanin for space travel radioprotection." Environmental microbiology 19.7 (2017): 2529-2532.
3	Proton Aurora on Mars	Ritter, B et al.	p-Poster
	Birgit Ritter[1,2], Jean-Claude Gérard[1], Benoit Hubert[1], Luciano Rodriguez[2], Leonardos Gkouvelis[1]
	[1] LPAP, Université de Liège, Liège, Belgium; [2] Royal Observatory of Belgium
	Introduction: Three kinds of aurora have been detected on Mars by the ultraviolet spectrometers SPICAM (Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars) on board Mars Express and IUVS on board MAVEN: the discrete aurora [1,2,3,4], the diffuse aurora [5] and the proton aurora [6,7]. We present a brief overview of the three kinds of aurorae and measurement results from SPICAM for the proton aurora. Electron Aurorae: The discrete and the diffuse aurora are seen on the Martian nightside. Both result from energetic electron impact on the upper atmosphere. Their emission in the UV includes features from CO (Cameron bands, Fourth Positive bands), CO2+ and atomic oxygen. The discrete aurora is spatially confined and linked to the topology of the crustal magnetic field of Mars. It is seen at altitudes of about 140 km. The diffuse aurora on the other hand is neither restricted in location nor linked to the Martian magnetic field, but is thought to be globally extended. The long lasting (days) features extend down to altitudes of 60 km and are observed following periods of enhanced solar activity. SPICAM observations of the proton aurora: The proton aurora has been observed on the dayside of Mars. It originates from precipitating protons onto the Martian hydrogen corona that partially convert by charge transfer to fast neutral hydrogen atoms. It can be identified by an intensity enhancement over the ubiquitous Lyman-α dayglow at 121.6 nm at altitudes between 120 and 150 km. It is not related to the residual Martian magnetic field. Its occurrence is correlated with the arrival at Mars of coronal mass ejections or corotating interaction regions from the Sun. During an observational period of 7 years of Mars Express data, Lyman-α emission signatures of the proton aurora have been positively identified in about 4% of the limb observations of the dayside of the planet. References: [1] Bertaux et al., Nature, 2005. [2] Leblanc et al., JGR, 2006. [3] Gérard et al., JGR, 2015. [4] Soret et al., Icarus, 2016. [5] Schneider et al., Science, 2015. [6] Deighan et al., AGU, 2016. [7] Ritter et al., GRL, 2018.
4	Comparative statistical analysis of magnetosheath turbulence/variability at Venus and Earth	Echim, M et al.	p-Poster
	Marius Echim[1,2], Peter Kovacs[3], N. Dwivedi[4], E. Yordanova[5], E. Teodorescu[2]
	[1] Royal Belgian Institute for Space Aeronomy, Brussels, Belgium, [2] Institute of Space Science, Magurele, Romania, [3] Mining and Geological Survey of Hungary, Budapest, Hungary, [4] Space Research Institute, Austrian Academy of Sciences, Graz, Austria,[5] Swedish Institute of Space Physics, Uppsala, Sweden
	The magnetic variability in the magnetosheaths of Venus and Earth is studied with data from Cluster and Venus Express missions. We use the magnetosheath traversals included in the FP7 STORM database and perform a spectral analysis of magnetic field fluctuations. The database includes more than 1400 data intervals and the analysis provides more than 4000 Power Spectral Density spectra organized in catalogues. We evidence statistical trends of spectral slopes suggesting that in the magnetosheath of Venus the spectral behavior of turbulence shows evidence for an inertial range of turbulence while in the case of the Earth this evidence is less clear. We discuss the possible role of the bow shock geometry on the spectral properties of turbulence. We also investigate plasma parameters controlling the observed spectral breaks and evidence differences and similarities between Venus and the Earth.
5	Auroral beads at Saturn and their relation to plasma instabilities: Cassini proximal orbits	Radioti, A et al.	p-Poster
	Aikaterini Radioti[1], Zhonghua Yao[1], Denis Grodent[1], Benjamin Palmaerts[1], Jean-Claude Gérard[1], Elias Roussos[2], Kostas Dialynas[3], Donald Mitchell[4], Zuyin Pu[5], Sarah Badman[6], Wayne Pryor[7], Bertrand Bonfond[1]
	[1] LPAP, Université de Liège, Belgium, [2] Max Planck Institute for Solar System Research, Germany, [3] Academy of Athens, Greece, [4] APL, Maryland, USA, [5] School of Earth and Space Sciences, Peking University, China, [6] Department of Physics, Lancaster University, UK, [7] Central Arizona College, USA
	During the Grand Finale Phase of Cassini the Ultraviolet Imaging Spectrograph onboard the spacecraft detected repeated detached small scale auroral structures. We describe the structures as 'auroral beads', a term that is adopted from the terrestrial aurora. The auroral beads at Saturn extend from 20 LT to 11 LT and rotate with the planet, though at a lower angular velocity than the rigid planetary rotation. We suggest that they are related to plasma instabilities in the magnetosphere, which in turn generate wave perturbations. In particularly, we propose a combination of shear flow, plasma pressure gradient and centrifugal instabilities to generate the observed auroral beads. Energetic neutral atoms enhancements are observed simultaneously with the auroral observations and are indicative of plasma pressure gradient and field aligned currents. During the same interval we observe conjugated periodic enhancements of energetic electrons, which are consistent with wave perturbations and creation of field aligned currents supporting our proposed scenario. Finally, based on auroral observations we suggest that magnetospheric instabilities could initiate a global magnetospheric configuration. Our study indicates that beads auroral structure is caused by fundamental plasma processes that commonly exist at Earth and giant planets.
6	Monitoring the passage of interplanetary coronal mass ejections and high-speed solar wind streams in the interplanetary medium: results from LISA Pathfinder and perspectives with future space interferometers	Grimani, C et al.	p-Poster
	C. Grimani[1,2], S. Benella[1,2], A. Cesarini[1], M. Fabi[1], N. Finetti[2,3]
	[1] University of Urbino "Carlo Bo", Italy [2] INFN Section in Florence, Italy [3] University of L'Aquila, Italy
	The first and second generation interferometers for gravitational wave detection in space will carry particle detectors for galactic cosmic-ray (GCR) and solar energetic particle (SEP) integral flux measurements above tens of MeV/n. These detectors will constitute natural multipoint observatories to study the effects of interplanetary structure propagation in modulating the cosmic-ray flux and the characteristics of SEPs over small and large intervals in heliolongitude. The results obtained with particle detectors flown on LISA Pathfinder (LPF) allowed to study GCR flux recorrent and non-recurrent short-term depressions within 1% statistical uncertainty. The LPF data will be presented at the conference. The perspectives open by these data for the future space interferometers will be discussed.
7	The PSWS Space Weather VOEvent alerts service of the CDPP	Gangloff, M et al.	p-Poster
	M. Gangloff[1], N. André[1], V. Génot[1], Baptiste Cecconi[2], Pierre Le Sidaner[3], Antoine Goutenoir[1], Myriam Bouchemit[1], Elena Budnik[1]
	[1] IRAP, Université de Toulouse, CNRS, CNES, UPS, (Toulouse), France [2] LESIA, Observatoire de Paris, PSL Research University, Meudon, France [3] DIO, Observatoire de Paris, CNRS, UMS2201, PSL Research University, Meudon, France
	The CDPP (Centre de Données de la Physique des Plasmas,(http://cdpp.eu/), the French data center for plasma physics, is engaged for two decades in the archiving and dissemination of plasma data products from space missions and ground observatories. Under Horizon 2020, the Europlanet Research Infrastructure includes PSWS (Planetary Space Weather Services), a set of new services that extend the concepts of space weather and space situation awareness to other planets of our solar system. One of these services is an Alert service associated with solar wind prediction made using the CDPP Heliopropa service (http://heliopropa.irap.omp.eu), and detection of meteor shower, lunar flash and cometary tail crossing. This Alert service, is based on VOEvent, an international standard proposed by the IVOA and widely used by the astronomy community. The VOEvent standard provides a means of describing transient celestial events in a machine-readable format. VOEvent is associated with VTP, the VOEvent Transfer Protocol that defines the system by which VOEvents may be disseminated to the community. VTP is managed with Comet, a freely available and open source software. Comet is used by PSWS for its Alert service and several partners of PSWS, including the CDPP and Observatoire de Paris. This presentation will focus on the latest version of the alert system ( https://alerts-psws.irap.omp.eu ) implemented with the current version of the VOEvent standard. Europlanet 2020 RI has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement 654208.