Fully kinetic PiC simulations of current sheet instabilities for the solar corona

In the Solar corona, magnetic energy is conjectured to be released through current sheets to be transformed to particle, plasma energy and heating by magnetic reconnection. Since the coronal plasma is collisionless, these are essentially kinetic plasma processes. Their nonlinear physics and properties can be described best by Particle-in-Cell (PiC) numerical simulations. Since the coronal plasma is magnetically dominated, and in contrast to previous kinetic simulations of current sheets, the presence of large guide magnetic fields has to be taken into account. We aim at finding and describing the resulting dominating kinetic instabilities, turbulent processes and anomalous (collisionless) transport effects. In order to validate our methods, first we analyze the limit case of zero guide field (antiparallel configuration). We find several instabilities driven by temperature anisotropy inhibiting the tearing mode. They might be numerically induced when more realistic parameters (high mass ratios) are used in PiC simulations. This numerical temperature anisotropy can be efficiently reduced by using higher order shape functions. For current sheets in the presence of small guide fields, we show evidence of non collisional resistivity in the generalized Ohm’s law. And in the limit of infinite guide fields, we compare our kinetic simulation results with gyrokinetic theory. Although there is agreement in some quantities such as reconnection rates between both plasma models, we find a magnetic field generation only in PiC simulations with finite guide fields, due to an initial shear flow in the force free current sheet initialization. In addition, we also find signatures of cross-streaming instabilities producing anisotropic electron heating and acceleration.