Electromagnetic Ion Cyclotron Waves Detected by Kaguya and Geotail in the Earth's Magnetotail

Tomoko Nakagawa, Masaki N. Nishino, Hideo Tsunakawa, Futoshi Takahashi, Hidetoshi Shibuya, Hisayoshi Shimizu, Masaki Matsushima, Yoshifumi Saito

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Narrowband electromagnetic ion cyclotron waves first discovered by the Apollo 15 and 16 Lunar Surface Magnetometers were surveyed in the magnetic field data obtained by the Kaguya satellite at an altitude of ∼100 km above the Moon in the tail lobe and plasma sheet boundary layer of the Earth's magnetosphere. The frequencies of the waves were typically 0.7 times the local proton cyclotron frequency, and 75% of the waves were left hand polarized with respect to the background magnetic field. They had a significant compressional component and comprised several discrete packets. They were detected on the dayside, nightside, and above the terminator of the Moon, irrespective of the lunar magnetic anomaly, or the magnetic connection to the lunar surface. The waves with the same characteristics were detected by Geotail in the absence of the Moon in the magnetotail. The most likely energy source of the electromagnetic ion cyclotron waves is the ring beam ions in the plasma sheet boundary layer.

Original languageEnglish
Pages (from-to)1146-1164
Number of pages19
JournalJournal of Geophysical Research: Space Physics
Issue number2
Publication statusPublished - Feb 2018

All Science Journal Classification (ASJC) codes

  • Space and Planetary Science
  • Geophysics


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