Three dimensional anisotropic k spectra of turbulence at subproton scales in the solar wind
Publication date: 28 September 2010
Authors: Sahraoui, F. et al.
Journal: Physical Review Letters
Page: 131101-[4 pages]
Copyright: The American Physical Society
We show the first three dimensional (3D) dispersion relations and k spectra of magnetic turbulence in the solar wind at subproton scales. We used the Cluster data with short separations and applied the k-filtering technique to the frequency range where the transition to subproton scales occurs. We show that the cascade is carried by highly oblique kinetic Alfvén waves with wplas below 0.1wci down to kperpRhoi ~ 2. Each k spectrum in the direction perpendicular to Bo shows two scaling ranges separated by a breakpoint (in the interval [0.4, 1]kperpRhoi): a Kolmogorov scaling kperp-1.7 followed by a steeper scaling kperp-4.5. We conjecture that the turbulence undergoes a transition range, where part of the energy is dissipated into proton heating via Landau damping and the remaining energy cascades down to electron scales where electron Landau damping may predominate.Link to publication