Spontaneous Reconnection in Three-Dimensional Particle-In-Cell Simulations of Collisionless Plasma Turbulence

Abstract:

We use 3D fully kinetic particle-in-cell simulations to study the spontaneous formation of magnetic reconnection as a self-consistent component of the turbulent cascade under solar-wind-like conditions. We simulate anisotropic decaying Alfvénic turbulence created by the collision of counter-propagating low-frequency Alfvén waves. The initial wavevector anisotropy is consistent with critical-balance theory. We observe the creation of small-scale current density structures such as current filaments and current sheets as well as the formation of magnetic flux ropes as part of the turbulent cascade. We develop a new set of indicators to find reconnection regions in 3D Particle-in-cell simulations. According to the application of these indicators, we observe the spontaneous creation of reconnection events in the simulation domain. We analyse one of the reconnection events associated with a twisted flux rope in detail. This event is highly dynamic and asymmetric. We study the profiles of plasma bulk quantities recorded by artificial-spacecraft trajectories passing near and through the reconnection region. Our results suggest that the particle heating and acceleration related to asymmetric small-scale reconnection events are located within magnetic flux tubes produced by the anisotropic Alfvénic turbulent cascade in the solar wind.