EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Molecular and metalic ions in the magnetosphere: ISSI team preliminary results 

Masatoshi Yamauchi1, Iannis Dandouras2, Ingrid Mann3, Stein Haaland4, Peter Würz5, John Plane6, Daniel Kastinen1, Tinna Gunnarsdottir3, Andrew Yau7, Lynn Kistler8, Doug Hamilton9, Steve Christon10, Yoshufumi Saito11, Shigeto Watanabe12, and Satonori Nozawa13
Masatoshi Yamauchi et al.
  • 1Swedish Institute of Space Physics (IRF), Kiruna, Sweden (
  • 2Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France
  • 3UiT, Arctic University of Norway, Tromsø, Norway
  • 4University of Bergen, Norway
  • 5University of Bern, Switzerland
  • 6University of Leeds, UK.
  • 7University of Calgary, Canada
  • 8University of New Hampshire, Durham, USA.
  • 9University of Maryland, USA.
  • 10Focused Analysis and Research (FAR), Charleston, USA.
  • 11Institute of Space and Astronautical Science, Sagamihara, Japan
  • 12Hokkaido Information University, Japan
  • 13Nagoya University, Japan

Molecular and metallic ions are vastly unexplored in near-Earth space because only a few terrestrial missions have been equipped with dedicated instrumentation to separate these molecular and metallic ions, within only a limited energy range (cold ions of < 50 eV and energetic ions of ~100 keV).  Nevertheless, existing data from past and on-going missions including those not designed for the required mass separation are capable of detecting many of these ions with available tools, although severe limitations exist (sensitivity and energy range in addition to mass resolution and mass range).  By combining these patchy and incomplete data, we found several features that indicate sources of these heavy ions.
(1) Combination of Kaguya and Cluster/RAPID during high flux events of solar wind heavy ions suggests that the Moon can be a substantial source for low charge-state metallic ions in the magnetosphere when the Moon is located upstream of the Earth.  This interpretation is consistent with Geotail/STICS statistics of increased flux of low charge-state heavy ions near new-Moon for medium activity (Kp=2-4).
(2) The major route of molecular ion supply (<10 keV) to the inner magnetosphere can be via low-latitude (< 60° invariant latitude, according to e-POP/IRMS) in addition to the cusp (according to Cluster/CIS and Akebono/SMS) during high outflow flux period.  This indicates extraordinary upward convection (or ion flow) at the sub-auroral region.
(3) A case study of lidar data during high flux events of solar wind heavy ions suggests that upward expansion of Na signal can be associated with molecular ion escape to the magnetosphere that is also observed by Cluster/RAPID and e-POP/IRM, although this expansion can be related to a major magnetic storm rather than solar wind event.

How to cite: Yamauchi, M., Dandouras, I., Mann, I., Haaland, S., Würz, P., Plane, J., Kastinen, D., Gunnarsdottir, T., Yau, A., Kistler, L., Hamilton, D., Christon, S., Saito, Y., Watanabe, S., and Nozawa, S.: Molecular and metalic ions in the magnetosphere: ISSI team preliminary results , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1297,, 2022.

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