MAVEN observations of electron-induced whistler mode waves in the Martian magnetosphere - Archive ouverte HAL Access content directly
Journal Articles Journal of Geophysical Research: Space Physics Year : 2016

MAVEN observations of electron-induced whistler mode waves in the Martian magnetosphere

, , , , , (1) , , , , , , , , , , ,
1
Y. Harada
  • Function : Author
L. Andersson
  • Function : Author
C. M. Fowler
  • Function : Author
D. L. Mitchell
  • Function : Author
J. S. Halekas
  • Function : Author
J. Espley
  • Function : Author
G. A. Dibraccio
  • Function : Author
J. P. Mcfadden
  • Function : Author
D. A. Brain
  • Function : Author
S. Xu
  • Function : Author
S. Ruhunusiri
  • Function : Author
D. E. Larson
  • Function : Author
R. J. Lillis
  • Function : Author
T. Hara
  • Function : Author
R. Livi
B. M. Jakosky
  • Function : Author

Abstract

We report on narrowband electromagnetic waves at frequencies between the local electron cyclotron and lower hybrid frequencies observed by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft in the Martian induced magnetosphere. The peaked electric field wave spectra below the electron cyclotron frequency were first observed by Phobos-2 in the Martian magnetosphere, but the lack of magnetic field wave data prevented definitive identification of the wave mode and their generation mechanisms remain unclear. Analysis of electric and magnetic field wave spectra obtained by MAVEN demonstrates that the observed narrowband waves have properties consistent with the whistler mode. Linear growth rates computed from the measured electron velocity distributions suggest that these whistler mode waves can be generated by cyclotron resonance with anisotropic electrons. Large electron anisotropy in the Martian magnetosphere is caused by absorption of parallel electrons by the collisional atmosphere. The narrowband whistler mode waves and anisotropic electrons are observed on both open and closed field lines and have similar spatial distributions in MSO and planetary coordinates. Some of the waves on closed field lines exhibit complex frequency-time structures such as discrete elements of rising tones and two bands above and below half the electron cyclotron frequency. These MAVEN observations indicate that whistler mode waves driven by anisotropic electrons, which are commonly observed in intrinsic magnetospheres and at unmagnetized airless bodies, are also present at Mars. The wave-induced electron precipitation into the Martian atmosphere should be evaluated in future studies.
Fichier principal
Vignette du fichier
JGR Space Physics - 2016 - Harada - MAVEN observations of electron%u2010induced whistler mode waves in the Martian magnetosphere.pdf (5.23 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

insu-03669419 , version 1 (16-05-2022)

Licence

Copyright

Identifiers

Cite

Y. Harada, L. Andersson, C. M. Fowler, D. L. Mitchell, J. S. Halekas, et al.. MAVEN observations of electron-induced whistler mode waves in the Martian magnetosphere. Journal of Geophysical Research: Space Physics, 2016, 121, pp.9717-9731. ⟨10.1002/2016JA023194⟩. ⟨insu-03669419⟩
11 View
16 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More