Poster presentations and abstracts

Io is one of the most active bodies of the solar system, with an intense volcanism powered by tidal forces. Directly or indirectly, the outgassing from the volcanoes is the source of particles populating both the tenuous and patchy atmosphere of Io and the magnetosphere of Jupiter. We report here on the observations of Io with a narrow-band NaI filter on the TRAPPIST-south telescope (ESO La Silla, Chile) during 15 nights between December 4, 2014 and March 31, 2015. The images are strongly contaminated by Jupiter in the field of view. However, we developed and tested several image processing techniques to remove the background and reveil spectacular sodium jets. We detected these jets on 6 nights out of 15. We will discuss the main properties of these jets, such as their length, which can be up to 7 Jovian radii long.

How to cite: Bonfond, B., Jehin, E., and Despiegeleire, A.: Io sodium jets observed by the TRAPPIST telescopes, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-323, https://doi.org/10.5194/epsc2020-323, 2020.

The Io Torus plasma is mostly composed of singly and multi-charged S and O ions. These ions interact with the neutrals of Io’s atmosphere (S, O, SO₂ and SO) through symmetrical (i.e. O⁺ + O => O + O⁺) and asymmetrical (i.e. S⁺⁺ + O => S + O⁺⁺) charge-exchanges. Charge-exchange cross-sections were estimated in Johnson & Strobel, 1982 and McGrath & Johnson, 1989 at 60 km/s (the plasma corotation velocity in Io’s frame), and are used in numerical simulations of the torus/neutral cloud interaction (i.e. Delamere and Bagenal, 2003).

Dols et al., 2008 proposed numerical simulations of the multi-species chemistry interaction at Io using these cross-sections at 60 km/s. The plasma/atmosphere interaction at Io is strong and the flow velocity and ion temperature are drastically reduced close to Io (v < 10 km/s). Thus, velocity-dependent charge-exchange cross-sections are critical for such numerical simulations and their effect on the local plasma and neutral supply at Io should be explored.

We propose to revisit the calculation of ion/neutral charge-exchange cross-sections following Johnson & Strobel, 1982’s approach for plasma velocities relevant to the local interaction at Io (V=10-120 km/s). More sophisticated calculations were proposed in McGrath & Johnson, 1989 but both publications offered very few details about their procedure.

We will illustrate the effect of using velocity-depend charge-exchange cross-sections in numerical simulations of the multi-species plasma/atmosphere interaction at Io.

More generally, this presentation aimed at providing an incentive for the community to expand the work of McGrath & Johnson, 1989.

Johnson & Strobel, Charge-exchange in the Io torus and exosphere, JGR, 87,1982

McGrath & Johnson, Charge exchange cross sections for the Io plasma torus, JGR, 94, 1989

Delamere & Bagenal, Modeling variability of plasma conditions in the Io torus, JGR, 108, 2003

Dols, Delamere, Bagenal, Kurth, Paterson, A multi-species chemistry model of Io’s local interaction with the plasma torus, JGR, 113, 2008

How to cite: Dols, V., Johnson, R., and Bagenal, F.: The plasma/atmosphere interaction at Io: revisiting the ion/neutral charge-exchange cross-sections and their ion-velocity dependency, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-496, https://doi.org/10.5194/epsc2020-496, 2020.

The electromagnetic interaction between Jupiter and its innermost Galilean moon Io is a prime example for moon-planet and star-planet interaction. Very striking features are the Io Foot Prints (IFP) in Jupiter’s upper atmosphere. With the Juno spacecraft orbiting Jupiter, new insights about the complex structure of the IFP and the associated tail have been achieved which can not be fully explained by existing models. A deeper understanding is necessary to explain these Juno observations [Mura et al. 2018]. For that purpose a simulation of the system with the single fluid MHD-Code Pluto is set up to study the Alfvén wing generated by Io in detail. In our study, we use a model similar to Jacobsen et al. 2007 with a constant magnetic field and spatially varying density. Then we increase the complexity of this model by including a more realistic wave generator, i.e. Io, and a more complex model of the Jovian inner magnetosphere. Here, we focus on the reflection pattern of the Alfvén wings at the torus boundary and the Jovian ionosphere and how it affects the morphology and the properties of the Alfvén wings.

How to cite: Schlegel, S. and Saur, J.: Io's auroral footprints: MHD simulations of the interaction between Io and Jupiter, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-646, https://doi.org/10.5194/epsc2020-646, 2020.

Abstract:

Sublimation support of Io’s sulfur dioxide atmosphere is very sensitive to small variations in its surface temperature. As Io passes into Jupiter’s shadow each orbit, its sublimation-supported atmosphere rapidly collapses, leaving volcanic outgassing as the primary mechanism sustaining Io’s thin atmosphere. Using an optical echelle spectrograph at the Apache Point Observatory (APO) 3.5m telescope, we observe Io’s atomic emissions excited solely by electron impact or ion recombination while Io is in umbra. Red line oxygen 6300Å and the sodium D doublet are Io’s brightest emissions at several kiloRayleighs (Bouchez et al. 2000). We observed these emissions falling quickly in just several minutes following Io’s ingress, with sodium airglow declining more rapidly than oxygen. Although the atomic atmosphere is not in vapor pressure equilibrium like SO₂, Na and O airglow drops with similar timescales to a decline in SO₂ column density that Tsang et al. (2016) reported post-ingress. Interpretation of this behavior warrants care since airglow emissions depend both on photochemical pathways producing neutral atoms and on the plasma conditions: electron density and temperature.

While no new species are identified, several previously unreported emissions in atomic neutrals are observed in the far-red and near-infrared spectral range. Emissions here range from 0.5 up 4 kiloRayleighs when averaged over Io’s disk, and our measurements are insufficiently sensitive to record their temporal response to ingress. Co-added exposures reveal the potassium D doublet and a second doublet of neutral sodium near 8189Å. Laboratory experiments of electrons impacting SO₂ produce O I triplets at 7774Å and 8446Å, as well as S I at 9225Å at energy thresholds of 25eV or more (Ajello et al., 2008). Since this threshold is more energetic than the bulk ~5eV population within Io’s plasma torus, detection of these three triplets offers a new tracer for the superthermal plasma population local to the Io–torus interaction region. These spectra can now identify the emissions seen in the Cassini ISS near-infrared filters as it the passed near Io (Geissler et al. 2004), and bright spots near Io’s equator that ISS imaged reaffirm our assertion that Io’s near-IR emissions can be a tracer for energetic electrons. To the best of our knowledge, this is the first time that several of these emissions have been reported in a planetary atmosphere other than the Earth’s.

1. Technique:

Ground-based observations of Io in eclipse require precise timing and non-sidereal blind tracking with high accuracy. Successful blind tracking can be confirmed by evaluating pointing errors in offsets to adjacent satellites. Quadrature geometries far from opposition optimize the geometry required to see Io ingress or egress, whilst the moon is well separated from Jupiter’s bright limb. Optical spectra are still strongly contaminated by Jupiter’s scattered light even under optimal geometry. To mitigate this issue, Jupiter spectra are smoothed, aligned, fit, and subtracted from the eclipsed data. A residual airglow spectrum from the Earth and Io remain, which can be separated by Doppler shift. In regions where telluric absorption interferes with the data, such as O I 6300Å, telluric features are characterized and removed using blue fast rotator (BFR) and A0V stars. A Gaussian is then fit to Io’s line spread functions and integrated to give total brightness. Jupiter’s reflectance spectrum is used as a “standard candle” to calibrate absolute flux, and a correction is made for the fact that Io does not fill the slit aperture, so brightness levels reported here are effectively disk-averages.

2. Temporal response of the brightest emissions

Fig. 1 and 2 show the changes Jovian scatter, which is subtracted to isolate Io’s airglow. Fig. 3 shows the temporal evolution of Io’s emission Rayleighs, where the two sodium D lines are summed. It is clear that immediately after Io enters the Jovian umbra both Na D and O6300 lines sharply decrease, with Na falling more rapidly. On the timescales permitted by this observation it remains unclear if these emissions have reached a new steady state associated with an atmosphere solely supported by volcanism.

3. Detection of far-red and near infrared O and S airglow

Io’s eclipse behind Jupiter presents an opportunity to study fainter emissions that are usually swamped by bright surface reflectance. Large cross-sections for several near-IR emissions are known from laboratory spectra of electrons smashing sulfur dioxide (Ajello et al. 2008). To search for these faint emissions, we repeated the above procedure, but co-added all the residuals, thereby averaging any temporal behavior. This indeed reveals oxygen transitions in highly excited states near 11 eV. A sulfur triplet near ~9225Å also indicates transitions from 7.9 eV to 6.5 eV which are somewhat more intense by comparison, but still require a co-addition of exposures to readily identify.

While detections of these lines are marginal individually, together, the three triplets in Fig. 4-6 indicate dissociative excitation of SO₂ produces measureable near-IR emission at Io. This in turn constrains the dissociative excitation contribution to the FUV emissions, since the gas states cascade to produce the intense O I 1356Å, 1304Å and S I 1900Å multiplets, respectively. Similarly, near-IR sodium transitions cascade to the produce the intense D lines.

References

[1] Bouchez, A.H., Brown, M.E., Schneider, N.M., 2000. Eclipse spectroscopy of Io’s Atmosphere. Icarus 148, 316–319

[2] Constantine C. C. Tsang, John R. Spencer, Emmanuel Lellouch, Miguel A. Lopez‐Valverde, Matthew J. Richter, The collapse of Io's primary atmosphere in Jupiter eclipse, Journal of Geophysical Research: Planets, 10.1002/2016JE005025, 121, 8, (1400-1410), (2016).

[3] Geissler P., McEwen A., Phillips C., 2004. Surface changes on Io during the galileo mission. Icarus 169, 29–64

[4] Joseph M. Ajello, Alejandro Aguilar, Rao S. Mangina, Geoffrey K. James, Paul Geissler, Laurence Trafton, Middle UV to near‐IR spectrum of electron‐excited SO2, Journal of Geophysical Research: Planets, 10.1029/2007JE002921, 113, E3, (2008).

[5] Schmidt, C., Moullet, A., de Kleer, K., Schneider, N., Roth, L., Spencer, J "A Multi-Wavelength Study of Io's Atomic Oxygen and Sulfur Emission", American Geophysical Union, Dec 2019

How to cite: Sharov, M., Schmidt, C., Gray, C., Schneider, N., and Withers, P.: Io's Optical Airglow in Jovian Eclipse, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-457, https://doi.org/10.5194/epsc2020-457, 2020.

We model energetic and thermal ion dynamics in the perturbed electromagnetic fields at Jupiter’s moon Europa. At the location of its orbit, Europa experiences a periodic variation in background electromagnetic field strength and orientation as well as plasma conditions while Jupiter completes a synodic rotation. We use a hybrid simulation (kinetic ions, fluid electrons) to model field perturbations due to the interaction of the corotating plasma with the ionosphere and induced dipole moment under these varying background conditions. For three cases, (I) Europa at the center of the plasma sheet, (II) Europa at its maximum distance north of the plasma sheet, and (III) Europa at its maximum distance south of the plasma sheet, we calculate surface precipitation maps of energetic magnetospheric ions using a backtracing tool. The effects of the time-varying field perturbations on surface precipitation have not previously been modeled. For three of the dominant ion species (H⁺, O²⁺, and S³⁺), we model the spatial distribution of surface flux over the full range of ion energies observed by the Galileo spacecraft (100 eV to about 10MeV). Our results show that the field perturbations drastically affect surface fluxes. While polar regions receive consistently high particle flux, low-latitude and equatorial regions are partially shielded by draped magnetic field lines close to the moon. These shielded regions migrate in longitude and latitude across Europa’s surface as Jupiter progresses through a full synodic rotation.

How to cite: Addison, P., Liuzzo, L., Arnold, H., and Simon, S.: Influence of Europa’s Time-Varying Electromagnetic Environment on Energetic Ion Precipitation, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-42, https://doi.org/10.5194/epsc2020-42, 2020.

The flux of energetic protons (80 keV-1.04 MeV) near the Galilean moons was measured by the Energetic Particle Detector (EPD) on the Galileo mission (1995 - 2003). Near Galilean moons (such as Io and Europa) depletions of the energetic ion flux, of several orders of magnitude, were observed (see Figure 1).

Such energetic ion depletions can be caused by the precipitation of these particles onto the moon’s surface or charge exchange with the neutral atmosphere. In addition, a magnetic field gradient can restrict access of the ions to certain regions, creating a “forbidden region.” To interpret the depletion features in the EPD data, a Monte Carlo particle tracing code has been developed. The expected flux of the energetic ions is simulated under different scenarios including those with and without an atmosphere, plume or inhomogeneous electromagnetic field.  By comparing the simulated distribution to the EPD data, the cause of the depletion features can be investigated.

We identify the following causes of energetic proton depletions near Europa:

• Depletions are consistent with plumes during the flybys E12 and E26. These plumes coincide with the source location of Jia et al., 2018 and Arnold et al., 2019.
• Depletions are consistent with atmospheric charge exchange during the flyby E26
• Depletions coincide with Europa’s Alfvén wing during the flybys E17 and E25A. The Alfvén wings are two cylindrical regions extending to the north and south of Europa in which the low-energy plasma and the magnetic field are modified compared to the upstream conditions.

Furthermore, we investigate the effect of varying the atmospheric properties (scale height, density, presence of a sputtered component) and plume properties (density, location) on the depletions.

Figure 1: Normalized flux of H+ (220 to 550 keV)  during the Galileo flybys of Europa. Depletions shown as darker colors.

How to cite: Huybrighs, H., Blöcker, A., Roussos, E., van Buchem, C., Krupp, N., Futaana, Y., Barabash, S., Holmberg, M., and Witasse, O.: Energetic proton depletions near Europa: plumes, atmospheric charge exchange and Alfvén wings, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-266, https://doi.org/10.5194/epsc2020-266, 2020.

This study examines the bombardment of energetic magnetospheric electrons onto Ganymede as a function of Jovian magnetic latitude. We use the output from a hybrid model to constrain features of the electromagnetic environment during the G1, G8, and G28 Galileo encounters when Ganymede was far above, within, or far below Jupiter's magnetospheric current sheet, respectively. To quantify electron fluxes, we use a test-particle model and trace electrons at discrete energies between 4.5 keV ≤ E ≤ 100 MeV while exposed to these fields. For each location with respect to Jupiter's current sheet, electrons of all energies bombard Ganymede's poles with average number and energy fluxes of 1·10⁸ cm^-2 s^-1 and 3·10⁹ keV cm^-2 s^-1, respectively. However, precipitation is inhomogeneous: poleward of the open-closed field line boundary, fluxes are enhanced in the trailing (but reduced in the leading) hemisphere. Within the Jovian current sheet, closed field lines of Ganymede's mini-magnetosphere shield electrons below 40 MeV from accessing the equator. Above these energies, equatorial fluxes are longitudinally inhomogeneous between the sub- and anti-Jovian hemispheres, but the averaged number flux (4·10³ cm^-2 s^-1) is comparable to the flux deposited by each of the dominant energetic ion species near Ganymede. When outside of the Jovian current sheet, electrons below 100 keV enter Ganymede's mini-magnetosphere via the downstream reconnection region and bombard the leading apex, while electrons of all energies are shielded from the trailing apex. Averaged over a synodic rotation, electron flux patterns agree with brightness features observed across Ganymede's polar and equatorial surface.

How to cite: Liuzzo, L., Poppe, A., Paranicas, C., Nénon, Q., Fatemi, S., and Simon, S.: Variability in the energetic electron bombardment of Ganymede, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-30, https://doi.org/10.5194/epsc2020-30, 2020.

Abstract

Results for 2D molecular kinetics models of single- and multi-component Callisto-like atmospheres are presented. The evolution of these neutral atmospheres is driven by the diurnal changes in surface temperatures, intermolecular collisions, and thermal escape.

Galileo and Hubble Space Telescope (HST) observations of Callisto, the outermost Galilean moon of Jupiter, have shown it possesses an atmosphere. However, the origin, composition, and evolution of this atmosphere are still not well understood. It ranges from a surface-bound exosphere to a collisional atmosphere with an exobase located above the surface. These spatial and temporal variations are driven by the diurnal changes in surface temperatures as well as by incident plasma and UV photons.

Galileo first observed a tenuous CO₂ atmosphere on Callisto via airglow emissions [1]. Several processes, such as radiolysis, were suggested to be the source of the atmosphere, and its extent was suggested to be global, driven by the diurnal variations of surface temperatures and the volatility and mobility of CO₂. Galileo radio occultations indicated the presence of a substantial ionosphere via measured electron density profiles near the terminator region [2]. Analogous to the O₂ atmosphere on Europa, a much thicker O₂-dominated atmosphere was suggested to exist at Callisto. UV auroral emissions were not detected in subsequent HST-Space Telescope Imaging Spectrograph (STIS) observations, but upper limits of C and O were estimated [3].

Based on these observations, a range of chemical and photochemical models were applied to Callisto-like atmospheres [4]. Photoionizaton of the observed CO₂ was shown to be insufficient to generate the observed electron density profiles and, thus, a more dense, predominantly O₂ atmosphere was suggested to exist at Callisto. In addition, chemical reactions in a porous regolith were shown to recycle the H₂O, whose photochemical products suppressed the accumulation of O₂, thereby preventing the O column density from exceeding the estimated upper limit.

Using the HST-Cosmic Origins Spectrograph (COS), O emissions from Callisto's atmosphere were detected, likely generated by photo-electrons in an O₂-dominated atmosphere [5]. The density of this inferred O₂ atmosphere was about an order of magnitude lower than was previously inferred. This difference in densities is likely due to Callisto's orbit relative to Jupiter and the Sun: the HST-COS observations occurred when Callisto's sunlit hemisphere was opposite its ram-side hemisphere, whereas the radio occultations occurred when the two hemispheres aligned. The HST-STIS observations were recently revisited and faint emissions from an atomic hydrogen corona, likely a photochemical product of H₂O vapor, were detected [6]. Contrary to the aforementioned O₂ asymmetries, the derived H corona was larger on the sunlit leading hemisphere than on the sunlit trailing hemisphere. This was suggested to be a result of the leading hemisphere's lower albedo and, thus, higher surface temperatures, which would enhance the H₂O sublimation rate.

A Monte-Carlo model was used to simulate surface-bound Callisto-like ballistic exospheres, which varied in surface temperature and composition as well as atmospheric sources and sinks [7]. A subsequent study improved this model by differentiating between the cold and hot parts of the Jovian magnetosphere and considering the influence of ionospheric shielding [8].

Our recent study demonstrated the influence of collisions and thermal escape in single- and multi-component 1D Callisto-like neutral atmospheres [9]. Therein we assumed that the constituents of the atmospheres (O₂, CO₂, H₂) were radiolytic products which thermally desorb from the surface according to the local temperature and on returning to the surface they permeate the porous regolith and become trapped in the radiation-damaged ice. Using the direct simulation Monte Carlo (DSMC) method [10] we calculated translational and internal energy exchanges via intermolecular collisions between test particles. Our results demonstrated that collisions can suppress or enhance H₂ thermal escape relative to Jeans (ballistic) escape and collisions between the escaping H₂ and O₂ and CO₂ affected the heavier species' structure, producing non-isothermal profiles. We also compared these results to ballistic models and demonstrated where the latter breaks down.

Model

Here we expand our previous models to 2D to include the diurnal variation of surface temperatures as well as include H₂O sublimation, which is extremely sensitive to Callisto's surface temperatures, varying ~15 orders of magnitude from noon (T₀ = 155 K) to midnight (T₀ = 80 K). The additional dimension in these models varies along Callisto's subsolar latitude (SSL), where the surface temperature varies from noon (SSL = 0) to midnight (SSL = 180). We track test particles from their original SSL to the SSL they return to the surface at or, in the case of H₂, they escape from. Thus, local as well as global fluxes and subsequent return and escape rates can be calculated as a means to better understand the distribution of Callisto's neutral atmosphere. Moreover, thermal winds induced by collisions of particles from the warmer regions of the atmosphere with particles from the colder regions are observed, thereby influencing the local distribution.

References

[1] Carlson, R.: A tenuous carbon dioxide atmosphere on Jupiter's moon Callisto, Science, 1999.

[2] Kliore, A., et al.: Ionosphere of Callisto from Galileo radio occultation observations, Journal of Geophysical Research: Space Physics, 2002.

[3] Strobel, D., et al.: Hubble Space Telescope space telescope imaging spectrograph search for an atmosphere on Callisto: A Jovian unipolar inductor, The Astrophysical Journal Letters, 2002.

[4] Liang, M.-C., et al.: Atmosphere of Callisto, Journal of Geophysical Research: Planets, 2005.

[5] Cunningham, N., et al.: Detection of Callisto's oxygen atmosphere with the Hubble Space Telescope, Icarus, 2015.

[6] Roth, L., et al.: Detection of a hydrogen corona at Callisto, Journal of Geophysical Research: Planets, 2017.

[7] Vorburger, A., et al.: Monte-Carlo simulation of Callisto's exosphere, Icarus, 2017.

[8] Vorburger, A., et al.: 3D-modeling of Callisto's surface sputtered exosphere environment, Journal of Geophysical Research: Space Physics, 2019.

[9] Carberry Mogan, S., et al.: The influence of collisions and thermal escape in Callisto's atmosphere, Icarus, 2020.

[10] Bird, G.: Molecular gas dynamics and the direct simulation of gas flows, Clarendon Press, 1994.

How to cite: Carberry Mogan, S., Tucker, O., Johnson, R., Tafuni, A., Sahin, I., Sreenivasan, K., and Kumar, S.: Local and global transport in Callisto's atmosphere, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-35, https://doi.org/10.5194/epsc2020-35, 2020.

Abstract

The surfaces of Jupiter's icy moons are continually irradiated by charged particles from the Jovian plasma environment. This irradiation triggers chemical reactions in the surface ice and also acts as an atmospheric release process. Remote observations, theoretical modelling, and laboratory experiments must be combined to understand
this plasma-ice interaction. Here, we present new experiment results concerning the chemistry of irradiated water ice samples relevant for icy moons and other icy objects in the solar system. 

Introduction

The University of Bern is developing the neutral gas mass spectrometer for ESA's Jupiter Icy moons Explorer (JUICE, Grasset et al. 2013), 
planned to reach the Jupiter system in 2029. We therefore strive to fill knowledge gaps about the basic physics of the surfaces and atmospheres of Jupiter’s icy moons before the arrival of JUICE. We combine the available facilities for developing and calibrating mass spectrometers and ion/electron spectrometers (Marti et al. 2001) with the sample preparation techniques and diagnostics of the Planetary Imaging Group (Pommerol et al. 2019).

Experiment setup

To study the effects of electrons irradiating water ice, we subjected a variety of ice samples (thin amorphous ice films and macroscopic samples of porous ice with customizable grain size) to an electron beam of energies between 200 eV and 10 keV at pressures and temperatures representative for the surfaces of Jupiter's icy moons. The physical and optical properties of these macroscopic ice samples make them realistic analogues for planetary surfaces beyond the ice line. The effect of chemical impurities in the water ice, such as NaCl, can also be investigated. The particles released from the ice were monitored with a newly designed time-of-flight (TOF) mass spectrometer and (in the case of the water ice film) with a microbalance. 

Preliminary results

Electron irradiation of pure water ice results mostly in the creation and release of H₂ and O₂ from H₂O in a stoichiometric 2:1 ratio, which is in agreement with the results based on an older quadrupole mass spectrometer (Galli et al. 2018). This seems to hold true for any type of water ice sample, independent of grain size and crystallinity. We also derive upper limits for rare radiolysis products (such as OH and H₂O₂) and the time scales for the build-up and release of radiolysis products. The O₂ release lags behind the immediate H₂ release by typically ~ 10 s and is reminiscent of the time-dependent sputtering yield of O₂ from water ice upon ion irradiation (Teolis et al. 2005). This delayed O₂ release has implications for the O₂/H₂O ratio observed at the surface of icy objects in the solar system, such as Ganymede, Europa, Callisto (Calvin et al. 1996, Spencer and Calvin 2002), and 67P/Churyumov-Gerasimenko (Bieler et al. 2015).

How to cite: Galli, A., Cerubini, R., Rubin, M., Pommerol, A., Vorburger, A., Wurz, P., Ligterink, N. F. W., Oza, A., and Thomas, N.: Electron-induced radiolysis and sputtering on the surface of icy moons: insights from laboratory experiments, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-54, https://doi.org/10.5194/epsc2020-54, 2020.

How to cite: Holmberg, M., Cipriani, F., Déprez, G., Imhof, C., Witasse, O., Altobelli, N., Huybrighs, H., and Wahlund, J.-E.: Variability of the plasma environment of the Jovian magnetosphere and implications for future particle and fields measurements by JUICE, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-899, https://doi.org/10.5194/epsc2020-899, 2020.