Characteristics of the Poynting flux and wave normal vectors of whistler-mode waves observed on THEMIS

Autor: J. B. Tao, Richard M. Thorne, Yukitoshi Nishimura, Lunjin Chen, Jacob Bortnik, Wen Li, O. LeContel, Christopher Cully, John W. Bonnell, Vassilis Angelopoulos
Přispěvatelé: Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Jazyk: angličtina
Rok vydání: 2013
Předmět:
Zdroj: Journal of Geophysical Research Space Physics
Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2013, 118 (4), pp.1461-1471. ⟨10.1002/jgra.50176⟩
Journal of Geophysical Research Space Physics, 2013, 118 (4), pp.1461-1471. ⟨10.1002/jgra.50176⟩
ISSN: 2169-9380
2169-9402
DOI: 10.1002/jgra.50176⟩
Popis: International audience; The characteristics of the Poynting flux and wave normal vectors of whistler-mode waves outside the plasmapause are investigated for the lower (0.1-0.5 fce) and upper bands (0.5-0.8 fce), where fce is the equatorial electron cyclotron frequency. To analyze the wave properties, we utilized high-resolution waveform data from multiple THEMIS spacecraft in the near-equatorial magnetosphere from June 2008 to November 2012. Full measurements of the wave electric and magnetic fields are used to calculate the Poynting fluxes and construct the wave normal vectors, which are then used to calculate the polar and azimuthal angles with respect to the background magnetic field. Statistical results show that the majority of whistler-mode waves propagate away from the magnetic equator, suggesting that the major source region is very close to the equator. The lower band wave normal angle distribution shows a major peak close to the field line direction and a secondary peak near the resonance cone. In contrast, the wave normal distribution of upper band waves exhibits a broad distribution between 0° and 60° with the largest probability at ~0°. The azimuthal component of the wave normal vector predominantly points radially outward for both lower and upper band waves, but a tendency for azimuthal propagation is observed for lower band waves in the day and dusk sectors probably due to pronounced azimuthal density gradients in the afternoon sector. Our statistical results provide crucial information on the Poynting fluxes and wave normal vectors of whistler-mode waves, which play a significant role in radiation belt electron dynamics.
Databáze: OpenAIRE
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