Testing of the Taylor Frozen-in-flow Hypothesis at Electron Scales in the Solar Wind Turbulence - Sorbonne Université Accéder directement au contenu
Article Dans Une Revue The Astrophysical journal letters Année : 2019

Testing of the Taylor Frozen-in-flow Hypothesis at Electron Scales in the Solar Wind Turbulence

Fouad Sahraoui

Résumé

In single-spacecraft observations the Taylor frozen-in-flow hypothesis is usually used to infer wavenumber spectra of turbulence from the frequency ones. While this hypothesis can be valid at MHD scales in the solar wind because of the small phase speeds of the fluctuations in comparison with the solar wind flow speed, its validity at electron scales is questionable. In this paper, we use Cluster data to verify the validity of the Taylor hypothesis in solar wind turbulence using the test proposed in Sahraoui et al. based on the assumption that the spectral breaks occur at ρ i and ρ e. Using a model based on the dispersion relation of the linear whistler mode and the estimated ratios of the spectral breaks of the magnetic energy observed in the free-streaming solar wind, we find that 32% of the events would violate the Taylor hypothesis because of their high frequency (in the plasma rest frame) compared to the Doppler shift ${\boldsymbol{k}}$centerdot${\boldsymbol{V}}$(midω plas/kcenterdotV mid > 0.5). Furthermore, the model shows that those events would correspond to whistler modes with propagation angles θ kB ≤ 68°. The limitations of the method used and the implications of the results on future spacecraft measurements of electron-scale turbulence are discussed.
Fichier principal
Vignette du fichier
Huang_2019_ApJ_876_138.pdf (1.46 Mo) Télécharger le fichier
Origine : Publication financée par une institution
Loading...

Dates et versions

hal-02147138 , version 1 (04-06-2019)

Identifiants

Citer

S. Huang, Fouad Sahraoui. Testing of the Taylor Frozen-in-flow Hypothesis at Electron Scales in the Solar Wind Turbulence. The Astrophysical journal letters, 2019, 876 (2), pp.138. ⟨10.3847/1538-4357/ab17d3⟩. ⟨hal-02147138⟩
44 Consultations
85 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More