Electron and wave characteristics observed by the THEMIS satellites near the magnetic equator during a pulsating aurora - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research Space Physics Année : 2012

Electron and wave characteristics observed by the THEMIS satellites near the magnetic equator during a pulsating aurora

A. Nakajima
  • Fonction : Auteur
K. Shiokawa
  • Fonction : Auteur
K. Sakaguchi
  • Fonction : Auteur
Y. Miyoshi
S. Lee
  • Fonction : Auteur
V. Angelopoulos
  • Fonction : Auteur
Olivier Le Contel
J. P. Mcfadden
  • Fonction : Auteur
J. W. Bonnell
  • Fonction : Auteur
K.-H. Fornacon
  • Fonction : Auteur
E. Donovan
  • Fonction : Auteur

Résumé

Based on conjugate ground and THEMIS satellite observations, we show electron spectra and wave characteristics near the magnetic equatorial plane during a pulsating aurora event on the high latitude side of the auroral oval. The pulsating aurora was observed by a 30-Hz sampled all-sky imager (ASI) at Gillam (56.4°N, 265.4°E), Canada, at ˜0840-0910 UT on 8 January 2008. The auroral intensity pulsation at the possible THEMIS D (THD) footprints had frequency peaks at ˜0.1-0.2 Hz. The footprint of THD was in the poleward part of the proton aurora observed by a meridian-scanning photometer. After auroral pulsation began at ˜0842 UT, both THD and THEMIS E which was near THD in the mid-tail at 11.6-11.8 RE, observed enhanced field-aligned electron fluxes at energies of 1-10 keV. However, the amplitudes of whistler mode waves and electrostatic cyclotron harmonics (ECH) waves observed by THD with the highest sampling rate of 8 kHz were not significant, showing a marked contrast to the recent report of clear correlation between whistler mode waves and auroral pulsations observed at 5-9 RE. We suggest that the observed field-aligned electrons, which are probably caused by Fermi-type acceleration associated with earthward plasma flow in the mid-tail plasma sheet, are modulated by some wave processes to cause pulsating auroras.

Dates et versions

hal-01553719 , version 1 (03-07-2017)

Identifiants

Citer

A. Nakajima, K. Shiokawa, K. Sakaguchi, Y. Miyoshi, S. Lee, et al.. Electron and wave characteristics observed by the THEMIS satellites near the magnetic equator during a pulsating aurora. Journal of Geophysical Research Space Physics, 2012, 117, pp.3219. ⟨10.1029/2011JA017066⟩. ⟨hal-01553719⟩
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