Articles | Volume 35, issue 4
Ann. Geophys., 35, 879–884, 2017
https://doi.org/10.5194/angeo-35-879-2017
Ann. Geophys., 35, 879–884, 2017
https://doi.org/10.5194/angeo-35-879-2017

Regular paper 28 Jul 2017

Regular paper | 28 Jul 2017

Investigation of  ∼ 20–40 mHz ULF waves and their driving mechanisms in Mercury's dayside magnetosphere

Elisabet Liljeblad and Tomas Karlsson Elisabet Liljeblad and Tomas Karlsson
  • Department of Space and Plasma Physics, School of Electrical Engineering, Royal Institute of Technology (KTH), Stockholm, Sweden

Abstract. Ultra-low-frequency (ULF) waves in the  ∼  20–40 mHz range are frequently observed in the Mercury magnetosphere using Mercury Surface Space Environment Geochemistry, and Ranging (MESSENGER) magnetic field data. The majority of these waves have very similar characteristics to the waves likely driven by Kelvin–Helmholtz (KH) ULF waves (which are retained as a subset of the wave events studied in this paper) identified in a previous study. Significant ULF wave activity is observed in the dawn sector of the magnetosphere. This indicates that Mercury KH waves may be more common between 6 and 12 magnetic local time than previously predicted and that magnetospheric ULF waves in the frequency band  ∼ 20–40 mHz can be used as a detection tool for Hermean KH waves.

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Short summary
MESSENGER magnetic field data from the magnetosphere of Mercury have been investigated to identify ultra-low-frequency (ULF) waves. ULF waves in the Kelvin–Helmholtz (KH) wave frequency range are frequently observed in the magnetosphere. These ULF waves often have similar characteristics to previously identified, likely KH-driven ULF waves, indicating that ULF waves in a specific frequency band can be used as a detection tool for KH waves on Mercury.