EGU23-1863, updated on 08 Jan 2024
EGU General Assembly 2023
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Statistical study of extreme magnetopause locations

Niklas Grimmich1, Ferdinand Plaschke1, Martin Archer2, Daniel Heyner1, Johannes Mieth1, Rumi Nakamura3, and David Sibeck4
Niklas Grimmich et al.
  • 1TU Braunschweig, Institut für Geophysik und Extraterrestrische Physik, Braunschwig, Germany (
  • 2Department of Physics, Imperial College London, London, UK (
  • 3Institut für Weltraumforschung, Österreichische Akademie der Wissenschaft, Graz, Austria (
  • 4NASA Goddard Space Flight Center, Greenbelt, Maryland, US (

The magnetopause (MP) is the boundary that separates the solar wind plasma from the Earth’s (inner) magnetosphere. To first order, its equilibrium position is defined by the pressure balance across it. The boundary moves under the influence of varying solar wind conditions and transient foreshock phenomena, thereby sometimes reaching unusually large and small distances from Earth. We investigate the occurrence of such extreme MP distortions. Therefore, we construct a database of magnetopause crossings observed by the THEMIS spacecraft in the years 2007 to mid-2022 using machine learning techniques. Crossing events deviating from the Shue et al. (1998) MP model by more than the reported uncertainties are denoted as extreme distortions. The occurrences of these extreme events in terms of expansion or compression of the magnetosphere are linked to different solar wind parameters. The results should be applied to future magnetopause models and may be validated by MP observations in soft x-ray images by the upcoming SMILE mission.

How to cite: Grimmich, N., Plaschke, F., Archer, M., Heyner, D., Mieth, J., Nakamura, R., and Sibeck, D.: Statistical study of extreme magnetopause locations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1863,, 2023.