Solar wind vs magnetosheath turbulence and Alfvén vortices
- LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris Diderot; 5 Place Jules Janssen, 92190 Meudon, France
- now at: Institute of Geophysics and Meteorology, University of Cologne, Germany
Abstract. In this paper we give firstly a broad review of the space plasma turbulence around the ion characteristic space and temporal scales within two natural laboratories, the solar wind and the Earth magnetosheath. In both regions power law spectra of magnetic fluctuations are observed. In both regions these spectra have a break in the vicinity of the ion cyclotron frequency. A distinctive feature of the magnetosheath turbulence is the presence of Alfvén vortices at scales of the spectral break. The Alfvén vortices are multi-scale nonlinear structures. We give a review of the main theoretical features of incompressible Alfvén vortsices in the second part of the paper. Finally, we analyze the spectral properties of the Alfvén vortex solution and of the network of such vortices. We show that the observed magnetosheath spectrum in presence of the Alfvén vortices can be described, at least partially, by the vortex network model.