Magnetospheric Ion Bombardment of Europa’s Surface

Jupiter’s moon Europa is exposed to constant bombardment by magnetospheric charged particles, which are expected to be a major source of physical and chemical surface modification. Here we have investigated the flux of magnetospheric ions at Europa’s surface by carrying out single particle tracing within realistic electromagnetic fields from multifluid magnetohydrodynamic simulations of the moon’s interaction with Jupiter’s magnetosphere. We find that magnetic field line draping and pileup leads to shielding and drastically reduced flux at low latitudes across Europa’s trailing (upstream) hemisphere. Furthermore, we find that magnetic induction within Europa’s subsurface ocean leads to additional shielding when the moon is located at high magnetic latitudes in Jupiter’s magnetosphere. Overall, we find that the high-latitude and polar regions on Europa receive the largest flux of magnetospheric ions. Both spacecraft and ground-based observations have previously identified a non–water ice surface species concentrated at Europa’s trailing (upstream) hemisphere, possibly hydrated sulfuric acid formed from radiolysis of water ice with implanted S ions. Our results demonstrate that the S ion flux across Europa’s equatorial trailing (upstream) hemisphere is strongly reduced, possibly indicating that the formation of the observed non–water ice species is controlled primarily by energy input from magnetospheric electrons, rather than the flux of S ions. We find that that O and S ions at >1 MeV energies have nearly uniform access to the surface, while energetic protons in this energy range are constrained to a “bull’s-eye” centered on the trailing (upstream) hemisphere.

Mathematical Modelling of Water-Based Fe3O4 Nanofluid Due to Rotating Disc and Comparison with Similarity Solution

The current research demonstrates the revolving flow of water-based Fe3O4 nanofluid due to the uniform rotation of the disc. This flow of nanofluid is investigated using CFD Module in COMSOL Multiphysics. However, the similarity solution for this flow is also obtained after transforming the given equation into a non-dimensional form. In the CFD Module, streamlines and surface plots are compared with the similarity solution for the magnitude of the velocity, radial velocity, tangential velocity, and axial velocity. The results from the direct simulation in the CFD Module and the solution of dimensionless equations represent a similar solution of velocity distribution. The derived results show that increasing the volume concentration of nanoparticles and effective magnetic parameters decrease the velocity distribution in the flow. Results in the CFD Module are important for monitoring the real-time particle tracing in the flow and, on the other hand, the dimensionless solution is also significant for the physical interpretation of the problem. Both methods of solution empower each other and present the physical model without sacrificing the relevant physical phenomena.

Sun Planet Interactions Digital Environment on Request (VESPASPIDER) for Europlanet RI H2024: status after 2 years

<p>The H2020 Europlanet-2020 programme, which ended on Aug 31<sup>st</sup>, 2019, included an activity called PSWS (Planetary Space Weather Services), which provided 12 services distributed over four different domains (A. Prediction, B. Detection, C. Modelling, D. Alerts) and accessed through the PSWS portal (http://planetaryspaceweather-europlanet.irap.omp.eu/):</p> <p>A1. 1D MHD Solar Wind Prediction Tool – HELIOPROPA,</p> <p>A2. Propagation Tool,</p> <p>A3. Meteor showers,</p> <p>A4. Cometary tail crossings – TAILCATCHER,</p> <p>B1. Lunar impacts – ALFIE,</p> <p>B2. Giant planet fireballs – DeTeCt3.1,</p> <p>B3. Cometary tails – WINDSOCKS,</p> <p>C1. Earth, Mars, Venus, Jupiter coupling- TRANSPLANET,</p> <p>C2. Mars radiation environment – RADMAREE,</p> <p>C3. Giant planet magnetodiscs – MAGNETODISC,</p> <p>C4. Jupiter’s thermosphere, D. Alerts.</p> <p>In the framework of the ongoing Europlanet-2024 programme, SPIDER will extend PSWS domains (A. Prediction, C. Modelling, E. Databases) services and give the European planetary scientists, space agencies and industries access to 6 unique, publicly available and sophisticated services in order to model planetary environments and solar wind interactions through the deployment of a dedicated run on request infrastructure and associated databases.</p> <p>C5. A service for runs on request of models of Jupiter’s moon exospheres as well as the exosphere of Mercury,</p> <p>C6. A service to connect the open-source Spacecraft-Plasma Interaction Software (SPIS) software with models of space environments in order to compute the effect of spacecraft potential on scientific instruments onboard space missions. Pre-configured simulations will be made for Bepi-Colombo and JUICE missions,</p> <p>C7. A service for runs on request of particle tracing models in planetary magnetospheres,</p> <p>E1. A database of the high-energy particle flux proxy at Mars, Venus and comet 67P using background counts observed in the data obtained by the plasma instruments onboard Mars Express (operational from 2003), Venus Express (2006–2014), and Rosetta (2014–2015);</p> <p>E2. A simulation database for Mercury and Jupiter’s moons magnetospheres and link them with prediction of the solar wind parameters from Europlanet-RI H2020 PSWS services.</p> <p>A1. An extension of the Europlanet-RI H2020 PSWS Heliopropa service in order to ingest new observations from Solar missions like the ESA Solar Orbiter or NASA Solar Parker Probe missions and use them as input parameters for solar wind prediction;</p> <p>The developments performed during the second year of the project will be discussed in the presentation.</p> <p>The Europlanet 2020 Research Infrastructure project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208.</p>

The effect of Europa's perturbed electromagnetic fields and induced dipole on energetic proton depletions in the Alfvén wings

<p>We investigate energetic proton depletions during Europa flybys E17 and E25A* by the Galileo mission. Energetic ion observations along trajectories like those of E17 & E25A are suitable for isolating the characteristics of the global configuration of the interaction region of Europa (or any Galilean moon) with the Jovian magnetosphere. Both of these flybys passed through Europa’s Alfvén wings further away from the moon, where ionospheric effects are small.</p> <p>We simulate the measured flux with a Monte Carlo particle tracing code and investigate the effect of the following factors: inhomogeneous electromagnetic fields, Europa's induced dipole, atmospheric charge exchange and plumes.</p> <p>We find that the homogeneous fields do not explain the Galileo data. We propose that the perturbed fields associated with the Alfvén wings affect the proton depletions. The inhomogeneous fields and induced dipole alter the pitch angle distribution of the depletion along the trajectory. The plumes that are investigated in this study have a minor effect on the proton depletions compared to the inhomogeneous fields and Alfvén wings. The contribution of atmospheric charge exchange to the depletion is negligible for these flybys. Finally, we compare the simulations to the measured proton flux and discuss the contribution of the effects we have considered.</p> <p>* E25A is a segment of the Io flyby I25</p>

River Sediment Transport Modeling of Ele River using Computational Fluid Dynamics Model of COMSOL Multiphysics Program

Excessive sediment deposition results to hydro-ecological problems particularly for shallow streams that experience significant point-source pollution. In recent times, models have been employed to investigate sediment transport in river systems. The aim of this research work is to model sediment transport of Ele River using particle tracing methodology. The governing equations of fluid flow and particle movement were modelled using COMSOL Multiphysics 5.3a. The result was validated using experimental data and the model result showed good agreement with coefficient of determination of 0.99. Study results showed that sediment at the river banks posses lower velocities compared to sediments in midstream. This implies higher sediment deposition at the banks due to low flow velocity. These sediments deposition constitute problems to the river system through degradation of water quality and blocking irrigation nozzles, impacting irrigation efficiency and crop production.

Study of Wind Flow Patterns and Heavy Gas Pollutants Dispersion Under Isolated Building Terrain

Experiment and simulation were used to study the dispersion characteristics of heavy gas pollutants represented by carbon dioxide in isolated building terrain. Wind tunnel experiment and laser particle tracing technology were used to characterize the features of wind flow and the dispersion of pollutants. The influences of the distance from the building to the release source and the size of the building were explored. The results show that the height of the building has a significant effect on the wind speed and turbulence intensity on the windward and leeward sides of the building, and the side width of the building has a slightly weaker effect. The area of the recirculation region on the leeward side of the building and the barrier effect on pollutants are dominated by the windward area of the building, that is, the larger the windward area, the larger the recirculation region and the lower the concentration of pollutants on the leeward side. At the same time, the decline rate of pollutants on the windward side increases with the increase of the windward area. The heavy gas pollutants tend to spread around the building side with the wind flow, unless the distance from the building to the source is too short or the building is too long. And when the pollutants climb to the top of the building, the dispersion of them will slows down as the width of the building side increases. The RNG k-ε model was used for simulation to provide a visible result for wind flow, and its applicability and accuracy were verified.

Sustained oxygen spectral gaps and their dynamic evolution in the inner magnetosphere

<p>Van Allen Probes observations of ion spectra often show a sustained gap within a very narrow energy range throughout the full orbit. To understand their formation mechanism, we statistically investigate the characteristics of the narrow gaps for oxygen ions and find that they are most frequently observed near the noon sector with a peak occurrence rate of over 30%. The magnetic moment (μ) of the oxygen ions in the gap shows a strong dependence on magnetic local time (MLT), with higher and lower μ in the morning and afternoon sectors, respectively. Moreover, we find through superposed epoch analysis that the gap formation also depends on geomagnetic conditions. Those gaps formed at lower magnetic moments (μ < 3000 keV/G) are associated with stable convection electric fields, which enable magnetospheric ions to follow a steady drift pattern that facilitates the gap formation by corotational drift resonance. On the other hand, gaps with higher μ values are statistically preceded by a gradual increase of geomagnetic activity. We suggest that ions within the gap were originally located inside the Alfven layer following closed drift paths, before they were transitioned into open drift paths as the convection electric field was enhanced. The sunward drift of these ions, with very low fluxes, forms a drainage void in the dayside magnetosphere manifested as the sustained gap in the oxygen spectrum. This scenario is supported by particle-tracing simulations, which reproduce most of the observed characteristics and therefore provide new insights into inner magnetospheric dynamics.</p>