Turbulence is a universal process that is ubiquitous fluids of everyday life and in plasmas. In…
Turbulence is a universal process that is ubiquitous fluids of everyday life and in plasmas. In astrophysics, turbulence plays a key role in a variety of energetic processes such as the accretion of matter around compact objects (e.g., black holes), star formation in the interstellar medium or the heating of the solar corona and wind. This role is all the more important since in these plasmas the usual energy dissipation processes (friction and/or electric resistivity) are nearly inexistent. In the near-Earth space plasmas (i.e., the magnetosphere and the solar wind) it is possible to study turbulence in great detail thanks to in-situ measurements made on board various orbiting spacecraft. Thanks to new theoretical models (developed at the LPP) and multi-point measurements of NASA’s MMS space mission, it was possible for the first time to measure the rate of turbulent energy cascade (or dissipation) at very small scales (<100km) in the terrestrial magnetosheath (part of the solar downstream of the terrestrial bow shock). These measurements highlight the predominant role played by density fluctuations on the small scales even when their effect is negligible on the larger scales. Ultimately, these theoretical and observational works should help resolving (at least partially) the thorny question of the energy partition (resulting from the turbulent cascade coming from large scales) between ions and ...