Space plasmas are probably the best laboratory for the study of plasma turbulence, as the Earth’s environment has become accessible to increasingly accurate direct measurements (Bruno and Carbone, 2013). In situ observations in the terrestrial magnetosheath have provided the possibility of obtaining relevant constraints on the turbulent energy spectra (Bale et al, 2005; Alexandrova et al, 2008; 2009; Sahraoui et al, 2009; 2010; Chen et al, 2010; Matthaeus and GoldStein, 1982; Bieber et al, 1996), determining the typical picture of turbulence, where the fluctuation energy is injected at large scales, and nonlinear interactions among eddies lead to a cascade of energy from large to small scales (dirrect cascade), giving rise to a typical power-law turbulence spectrum, (Lesieur, 2008; Biskamp, 2003; Frisch, 1996), in the so called inertial range. Here, is the power spectral density at wavenumber k, and is the spectral index. On the other hand, a large number of instabilities typical of plasmas, both at the large scales governed by magnetohydrodynamics (MHD), and at the micro scales governed by kinetic plasma physics, can feed fluctuations into space plasmas, which then evolve into a power-law spectrum by means of nonlinear interactions (Biskamp, 2003; Verma, 2004; Muller, 2009; Cerri and Califano, 2017).

Project members:

• Khatuna Elbakidze (Principal Investigator)