Göttingen 2025 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 10: Poster Session
EP 10.11: Poster
Donnerstag, 3. April 2025, 11:00–12:30, ZHG Foyer 1. OG
Amplitudes of Magnetopause Surface Waves: Comparison of THEMIS Observations with MHD Theory — •Adrian Pöppelwerth1, Niklas Grimmich1, Rumi Nakamura2, and Ferdinand Plaschke1 — 1Institut für Geophysik und Extraterrestrische Physik, TU Braunschweig, Braunschweig, Deutschland — 2Institut für Weltraumforschung, Österreichische Akademie der Wissenschaften, Graz, Österreich
The Earth's magnetopause is the boundary between the terrestrial and the interplanetary magnetic fields. Variations in solar wind pressure and structures originating from the solar wind or foreshock regions induce constant dynamic motion of this boundary. In addition, a high velocity shear between the magnetosheath and magnetospheric plasmas can trigger the Kelvin-Helmholtz instability. All these interactions can generate waves on the magnetopause, which can either propagate along the magnetopause towards the nightside or form standing surface waves. These surface waves excite fluctuations within the ambient plasma on either side of the magnetopause and allow them to propagate away from the source region. According to magnetohydrodynamic (MHD) theory, the amplitude of these waves should decrease exponentially with distance from the boundary.
With the multi-spacecraft mission Time History of Events and Macroscale Interactions during Substorms (THEMIS), we are able to observe surface waves at different distances from the magnetopause. Here we present preliminary findings that compare these spacecraft observations with predictions from MHD theory.
Keywords: Magnetopause; Surface Waves; THEMIS; MHD