Density Depletions Associated With Enhancements of Electron Cyclotron Harmonic Emissions: An ERG Observation

Y. Kazama, H. Kojima, Y. Miyoshi, Y. Kasahara, H. Usui, B. J. Wang, S. Y. Wang, S. W.Y. Tam, T. F. Chang, P. T.P. Ho, K. Asamura, A. Kumamoto, F. Tsuchiya, Y. Kasaba, S. Matsuda, M. Shoji, A. Matsuoka, M. Teramoto, T. Takashima, I. Shinohara

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1 Citation (Scopus)

Abstract

In this study, we describe small-scale density depletions of cold electrons associated with electrostatic electron cyclotron harmonic (ECH) waves observed by the ERG (Exploration of energization and Radiation in Geospace) spacecraft during a plasmapause crossing near the magnetic equator in the postmidnight sector. The total electron density was roughly 2 orders of magnitude larger than that of the hot electrons, indicating existence of a cold and dense electron population below ∼20 eV. The cold electron density profile showed small-scale density depletion regions, in which the ECH emissions were intensified. Moreover, a flux enhancement of hot electrons in the perpendicular direction was also associated with the ECH emissions intensity. This relation suggests perpendicular energization of electrons by electric field oscillation of the ECH waves.

Original languageEnglish
Pages (from-to)10,075-10,083
JournalGeophysical Research Letters
Volume45
Issue number19
DOIs
Publication statusPublished - 2018 Oct 16

Fingerprint

cyclotrons
depletion
harmonics
electron
augmentation
radiation
electrons
hot electrons
electron density
plasmapause
magnetic equator
electron density profiles
spacecraft
sectors
electrostatics
electric field
oscillations
electric fields
oscillation
cold

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

Cite this

Kazama, Y., Kojima, H., Miyoshi, Y., Kasahara, Y., Usui, H., Wang, B. J., ... Shinohara, I. (2018). Density Depletions Associated With Enhancements of Electron Cyclotron Harmonic Emissions: An ERG Observation. Geophysical Research Letters, 45(19), 10,075-10,083. https://doi.org/10.1029/2018GL080117
Kazama, Y. ; Kojima, H. ; Miyoshi, Y. ; Kasahara, Y. ; Usui, H. ; Wang, B. J. ; Wang, S. Y. ; Tam, S. W.Y. ; Chang, T. F. ; Ho, P. T.P. ; Asamura, K. ; Kumamoto, A. ; Tsuchiya, F. ; Kasaba, Y. ; Matsuda, S. ; Shoji, M. ; Matsuoka, A. ; Teramoto, M. ; Takashima, T. ; Shinohara, I. / Density Depletions Associated With Enhancements of Electron Cyclotron Harmonic Emissions : An ERG Observation. In: Geophysical Research Letters. 2018 ; Vol. 45, No. 19. pp. 10,075-10,083.
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Kazama, Y, Kojima, H, Miyoshi, Y, Kasahara, Y, Usui, H, Wang, BJ, Wang, SY, Tam, SWY, Chang, TF, Ho, PTP, Asamura, K, Kumamoto, A, Tsuchiya, F, Kasaba, Y, Matsuda, S, Shoji, M, Matsuoka, A, Teramoto, M, Takashima, T & Shinohara, I 2018, 'Density Depletions Associated With Enhancements of Electron Cyclotron Harmonic Emissions: An ERG Observation', Geophysical Research Letters, vol. 45, no. 19, pp. 10,075-10,083. https://doi.org/10.1029/2018GL080117

Density Depletions Associated With Enhancements of Electron Cyclotron Harmonic Emissions : An ERG Observation. / Kazama, Y.; Kojima, H.; Miyoshi, Y.; Kasahara, Y.; Usui, H.; Wang, B. J.; Wang, S. Y.; Tam, S. W.Y.; Chang, T. F.; Ho, P. T.P.; Asamura, K.; Kumamoto, A.; Tsuchiya, F.; Kasaba, Y.; Matsuda, S.; Shoji, M.; Matsuoka, A.; Teramoto, M.; Takashima, T.; Shinohara, I.

In: Geophysical Research Letters, Vol. 45, No. 19, 16.10.2018, p. 10,075-10,083.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Density Depletions Associated With Enhancements of Electron Cyclotron Harmonic Emissions

T2 - An ERG Observation

AU - Kazama, Y.

AU - Kojima, H.

AU - Miyoshi, Y.

AU - Kasahara, Y.

AU - Usui, H.

AU - Wang, B. J.

AU - Wang, S. Y.

AU - Tam, S. W.Y.

AU - Chang, T. F.

AU - Ho, P. T.P.

AU - Asamura, K.

AU - Kumamoto, A.

AU - Tsuchiya, F.

AU - Kasaba, Y.

AU - Matsuda, S.

AU - Shoji, M.

AU - Matsuoka, A.

AU - Teramoto, M.

AU - Takashima, T.

AU - Shinohara, I.

PY - 2018/10/16

Y1 - 2018/10/16

N2 - In this study, we describe small-scale density depletions of cold electrons associated with electrostatic electron cyclotron harmonic (ECH) waves observed by the ERG (Exploration of energization and Radiation in Geospace) spacecraft during a plasmapause crossing near the magnetic equator in the postmidnight sector. The total electron density was roughly 2 orders of magnitude larger than that of the hot electrons, indicating existence of a cold and dense electron population below ∼20 eV. The cold electron density profile showed small-scale density depletion regions, in which the ECH emissions were intensified. Moreover, a flux enhancement of hot electrons in the perpendicular direction was also associated with the ECH emissions intensity. This relation suggests perpendicular energization of electrons by electric field oscillation of the ECH waves.

AB - In this study, we describe small-scale density depletions of cold electrons associated with electrostatic electron cyclotron harmonic (ECH) waves observed by the ERG (Exploration of energization and Radiation in Geospace) spacecraft during a plasmapause crossing near the magnetic equator in the postmidnight sector. The total electron density was roughly 2 orders of magnitude larger than that of the hot electrons, indicating existence of a cold and dense electron population below ∼20 eV. The cold electron density profile showed small-scale density depletion regions, in which the ECH emissions were intensified. Moreover, a flux enhancement of hot electrons in the perpendicular direction was also associated with the ECH emissions intensity. This relation suggests perpendicular energization of electrons by electric field oscillation of the ECH waves.

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DO - 10.1029/2018GL080117

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SP - 10,075-10,083

JO - Geophysical Research Letters

JF - Geophysical Research Letters

SN - 0094-8276

IS - 19

ER -