Proton temperature anisotropy and current sheet stability: 2-D hybrid simulations

Abstract

The solar wind is a weakly collisional non homogeneous plasma; gradients associated to density, velocity shears and current sheets are often observed. In situ observations also show that the solar wind plasma is far from thermal equilibrium and particle distribution functions are not isotropic. The presence of a temperature anisotropy can be the source of free energy for kinetic instabilities and their unstable fluctuations may grow and propagate in the plasma. However, how these fluctuations evolve in a non homogeneous medium and how they interact and influence local coherent structures, is still an open question. We report preliminary numerical simulations that describe the evolution of current sheets in a non thermal plasma, focusing on the interaction between kinetic effects driven by a proton temperature anisotropy and magnetic reconnection processes.