Space Physics Seminar fall-2016

Hybrid-kinetic approach to solar-wind turbulence below the ion gyroradius: what have we learned?

The understanding of the kinetic processes at play in plasma turbulence is a major problem in plasma physics, on which space plasma research is currently focusing. Here we want to investigate the properties of turbulence from the end of the magnetohydrodynamic (MHD) cascade to scales well below the ion gyroradius (i.e., the so-called “dissipation” or “dispersion” range). To this end, we have performed high-resolution simulations of driven turbulence in a 2D3V phase-space (two real-space and three velocity-space dimensions) with a hybrid Vlasov-Maxwell (HVM) code. A range of values of the plasma beta parameter typical of the solar wind (SW) are investigated. Several aspects of turbulence at small-scales emerging from the simulations are presented and discussed. Finally, a comparison with completely different hybrid particle-in-cell (HPIC) simulations will be presented, showing the independence of these kinetic-scale cascades from the large-scale properties. Even wplithin the limitations of the hybrid approach in 2D3V, these results have relevant implications to understand kinetic-range turbulence and, in particular, SW turbulence.