EGU21-7255
https://doi.org/10.5194/egusphere-egu21-7255
EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Foreshock wave transmission into the magnetosheath and magnetosphere: results from global hybrid-Vlasov simulations

Lucile Turc1, Markus Battarbee1, Urs Ganse1, Andreas Johlander1, Yann Pfau-Kempf1, Vertti Tarvus1, Hongyang Zhou1, Markku Alho1, Maxime Dubart1, Maxime Grandin1, Kostis Papadakis1, Jonas Suni1, and MInna Palmroth1,2
Lucile Turc et al.
  • 1University of Helsinki, Faculty of Science, Department of Physics, Helsinki, Finland (lucile.turc@helsinki.fi)
  • 2Finnish Meteorological Institute, Helsinki. Finland

The foreshock, extending upstream of the quasi-parallel shock and populated with shock-reflected particles, is home to intense wave activity in the ultra-low frequency range. The most commonly observed of these waves are the “30 s” waves, fast magnetosonic waves propagating sunward in the plasma rest frame, but carried earthward by the faster solar wind flow. These waves are thought to be the main source of Pc3 magnetic pulsations (10 – 45 s) in the dayside magnetosphere. A handful of case studies with suitable spacecraft conjunctions have allowed simultaneous investigations of the wave properties in different geophysical regions, but the global picture of the wave transmission from the foreshock through the magnetosheath into the magnetosphere is still not known. In this work, we use global simulations performed with the hybrid-Vlasov model Vlasiator to study the Pc3 wave properties in the foreshock, magnetosheath and magnetosphere for different solar wind conditions. We find that in all three regions the wave power peaks at higher frequencies when the interplanetary magnetic field strength is larger, consistent with previous studies. While the transverse wave power decreases with decreasing Alfvén Mach number in the foreshock, the compressional wave power shows little variation. In contrast, in the magnetosheath and the magnetosphere, the compressional wave power decreases with decreasing Mach number. Inside the magnetosphere, the distribution of wave power varies with the IMF cone angle. We discuss the implications of these results for the propagation of foreshock waves across the different geophysical regions, and in particular their transmission through the bow shock.

How to cite: Turc, L., Battarbee, M., Ganse, U., Johlander, A., Pfau-Kempf, Y., Tarvus, V., Zhou, H., Alho, M., Dubart, M., Grandin, M., Papadakis, K., Suni, J., and Palmroth, M.: Foreshock wave transmission into the magnetosheath and magnetosphere: results from global hybrid-Vlasov simulations, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7255, https://doi.org/10.5194/egusphere-egu21-7255, 2021.

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