On the fractal pattern of the current structure at ion scales in turbulent space plasmas

Abstract

The recent ability to investigate the features of magnetic field fluctuations at ion/sub-ion scales employing both measurements and simulations has clearly demonstrated how, at these scales, the current has a filamentary structure, i.e., it is not a compact structure. This points toward the idea that the current and the dissipation field may have a fractal structure. An intriguing question immediately arises: is there a relationship between the fractal topology of currents at ion/sub-ion scales and the observed spectral features at the same scales? The goal of this work is to investigate the fractal topology of currents at the Low-end of MHD inertial domain and at ion scales using Hall-MagnetoHydroDynamics and Hybrid Vlasov-Maxwell simulations. The results show a clear relationship between the fractal dimension of the current pattern and the spectral features at ion scales. The relevance of this link is discussed in connection with the dynamics of coherent plasma structures at these scales.