EGU25-6978, updated on 14 Mar 2025
https://doi.org/10.5194/egusphere-egu25-6978
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Poster | Wednesday, 30 Apr, 14:00–15:45 (CEST), Display time Wednesday, 30 Apr, 14:00–18:00
 
Hall X4, X4.128
Mercury's Nightside Magnetosphere: Predictions for Mercury's Magnetotail Twist at the Orbits of MPO and Mio
Willi Exner1,2 and Norberto Romanelli3,4
Willi Exner and Norberto Romanelli
  • 1European Space Agency, ESTEC, Leiden, Netherlands (willi.exner@esa.int)
  • 2Institute for Geophysics and Extraterrestrial Physics, Technische Universität Braunschweig, Braunschweig, Germany
  • 3NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • 4Department of Astronomy, University of Maryland, College Park, MD, USA

Planetary magnetospheres exhibit significant twisting of the magnetotail with increasing downstream distances.
However, Mercury's tail twist observed by MESSENGER indicate a rather small twist of up to 3 degrees.
Here, we model Mercury's magnetotail response to different Interplanetary Magnetic Field (IMF) directions and determine what MPO and Mio might observe in their orbital phase with the hybrid model AIKEF.
Our hybrid model results indicate that Mercury's magnetotail topology exhibits a similar small twist at MPO altitudes, comparable to MESSENGER results.
The tail twist observed by Mio, however, indicates a strong dependency on the upstream IMF direction, becoming much more Earth-like.
In addition, kinetic effects warp and bend the neutral sheet significantly, disallowing easy determinations of the twist angles.

How to cite: Exner, W. and Romanelli, N.: Mercury's Nightside Magnetosphere: Predictions for Mercury's Magnetotail Twist at the Orbits of MPO and Mio, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6978, https://doi.org/10.5194/egusphere-egu25-6978, 2025.