Willi Exner

    Research Fellow

     

    Main Research Fields

    • Magnetospheres of small bodies, e.g., Mercury and Ganymede
    • Analyzing magnetic field data of BepiColombo and MESSENGER
    • Computational modeling of the magnetospheric environment
    • Exosphere interaction with surface and magnetosphere
    • Extreme solar wind condition effects on magnetospheres

    Keywords

    • Mercury
    • BepiColombo
    • Magnetosphere
    • Exosphere
    • Computational modeling

    Ongoing collaborations

    • BepiColombo MPOMAG team: Daniel Heyner, Karl-Heinz Glassmeier, Uwe Motschmann (TU Braunschweig, Germany)
    • SHOTS modeling initiative: Sae Aizawa, Lea Griton, Shahab Fatemi, Hideyuki Usui, Federico Lavorenti
    • Solar wind modeling, ICME propagation from Sun to Spacecraft: Kazumasa Iwai, Daikou Shiota, Go Murakami, Kanya Kusano, Miyoshi Yoshizumi
    • MESSENGER MAG and FIPS teams: Jim Slavin, Gankai Poh, Ryan Dewey, Jim Raines, Austin Glass, Norberto Romanelli, Gina DiBraccio
    • Exosphere of Mercury: Liam Morrisay, Rosemary Killen

    Publications

    First Author:

    • Determining the Influence of the IMF and Planetary Magnetic Field Models on Mercury's Magnetosphere Along Spacecraft Trajectories of MESSENGER, BepiColombo and MPO, Journal of Geophysical Research: Space Physics, 2024, http://dx.doi.org/10.1029/2023JA032248, doi.org/10.1029/2023JA032248

    • Influence of Mercury’s exosphere on the structure of the magnetosphere, Journal of Geophysical Research: Space Physics, 2020, doi.org/10.1029/2019JA027691.

    • Coronal Mass Ejection at Planet Mercury: A.I.K.E.F. Hybrid-Simulations compared to MESSENGER Data, Planetary and Space Science, 2018, doi.org/10.1016/j.pss.2017.12.016.

     

    Co-Author:

    • Revised Magnetospheric Model Reveals Signatures of Field-Aligned Current Systems at Mercury, Journal of Geophysical Research: Space Physics, 2024, doi.org/10.1029/2023JA031529.
      • I conducted and provided numerical hybrid model results of current sheet displacement within Mercury’s magnetosphere under different IMF directions.
    • Galactic Cosmic Rays at 0.7 A.U. with Venus Express Housekeeping Data, Planetary and Space Science, 2024, doi.org/10.1016/j.pss.2024.105867
      • I supervised the first author (Master Student) in his first paper in data analysis and writing the manuscript.
    • Solar wind entry into Mercury’s magnetosphere: Simulation results for the second swingby of BepiColombo, Astronomy & Astrophysics, 2023, doi.org/10.1051/0004-6361/202347789
      • I supervised the first author (PhD student) in his first paper. I conducted and provided numerical hybrid model results of Mercury’s magnetosphere at BepiColombo’s second swingby to enable particle energy distribution analysis along the trajectory.
    • Ion density and phase space density distribution of planetary ions Na+, O+ and He+ in Mercury’s magnetosphere, Icarus, 2022, doi.org/10.1016/j.icarus.2021.114734. 
      • I conducted and provided numerical hybrid model results of Mercury’s magnetosphere under average solar wind conditions to facilitate statistical comparisons with an MHD model and test-particle modeling. 
    • The Mie representation for Mercury’s magnetospheric currents, Earth, Planets and Space, 2021, doi.org/10.1186/s40623-021-01536-8.
      • I conducted and provided numerical model results of Mercury’s magnetosphere under southward IMF direction to disentangle the magnetospheric current system into poloidal and toroidal components.
    • The BepiColombo Planetary Magnetometer MPOMAG: What can we Learn From the Hermean Magnetic Field?, Space Science Reviews, 2021, doi.org/10.1007/s11214-021-00822-x.
      • I conducted and provided numerical model results of Mercury’s magnetosphere with a significant sodium exosphere and showed how BepiColombo orbits will see magnetic field signatures of the sodium ions.
    • Cross-comparison of global simulation models applied to Mercury’s dayside magnetosphere, Planetary and Space Science, 2020, doi.org/10.1016/j.pss.2021.105176.
      • I took part in the managing of the SHOTS-initiative and organized the different hybrid model workgroups. I conducted and provided numerical hybrid model results of Mercury’s magnetosphere under southward IMF direction to compare it against other modeling efforts within the BepiColombo community.
    • Magnetic fields in comet 67P/Churyumov-Gerasimenko, Bulletin of the Astronomical Society of Brazil, vol.32, no.1, p. 180-181, 2020, ISSN 0101-3440.
      • I analyzed magnetic field data obtained by the ROSETTA mission and helped identify possible cometary outburst signatures.
    • The Induced Global Looping Magnetic Field on Mars, The Astrophysical Journal Letters, 2019, doi:10.3847/2041-8213/aaff6e.
      • I provided Mars related hybrid modeling and helped visualizing the complex looping magnetic field pattern.

    Project/mission at ESA

    BepiColombo

    Useful Links:

    ORCID

    ResearchGate