Spacecraft Potential Changes Associated With EMIC Waves in the Inner Magnetosphere

Khan Hyuk Kim, Junhyun Lee, Jong Woo Kwon, Ensang Lee, Hee Eun Kim, Ho Jin, Hyuck Jin Kwon, Seul Min Baek, John Wygant, Forrest S. Mozer

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Although electromagnetic ion cyclotron (EMIC) waves are commonly observed in the magnetosphere and are believed to energize background cold ions, it is not clear whether EMIC waves play a significant role in determining spacecraft potential change. In this paper, we present two strong He-band EMIC wave events observed by the Van Allen Probe-B spacecraft inside the plasmasphere. One event occurred on 11 March 2016 when the spacecraft was on the dayside, and the other occurred on 9 October 2016 when the spacecraft was in the postmidnight sector. When a strong He-band EMIC wave activity was detected, low-energy ion flux enhancements occurred nearly simultaneously with the EMIC wave power enhancements. Both events presented in this study are clearly unique in that He-band wave power and enhanced proton flux are extremely high. During the wave activity interval, we found that the spacecraft charged more positively without a significant change in the ambient electron density. We discuss whether low-energy ions energized by EMIC waves can contribute to the spacecraft potential change.

Original languageEnglish (US)
Article numbere2022JA030337
JournalJournal of Geophysical Research: Space Physics
Issue number9
StatePublished - Sep 2022

Bibliographical note

Funding Information:
The work of K.‐H. Kim was supported by Korea Polar Research Institute (KOPRI) grant funded by the Ministry of Oceans and Fisheries (KOPRI PE22020). The work of H.‐J. Kwon was supported by the Basic Science Research Program through NRF funded by NRF‐2020R1C1C1003640. H. Jin was supported by NRF Grant NRF‐2021M1A3A4A06098620.

Publisher Copyright:
© 2022. American Geophysical Union. All Rights Reserved.


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