Kinetic simulations of the coupling between current instabilities and reconnection in thin current sheets

Abstract. We investigate the coupling between current and tearing instability modes of a thin current sheet using the particle code GISMO. We identify pure tearing modes (k_x≠ 0), instabilities in the current flow direction (k_y≠ 0) and general 3D reconnection modes (k_x≠ 0 and k_y≠ 0). Our results give evidence that the coupling between tearing modes and current instabilities plays an important role for spontaneous magnetic reconnection. These modes give a substantial contribution to magnetic reconnection, additional to the well known 2D tearing mode. When allowing reconnection to occur in three spatial dimensions, a configuration, which was initially invariant in the current How direction, develops into a configuration with no invariant direction.