Using topology to locate the position where fully three-dimensional reconnection occurs

Abstract

In two-dimensional magnetic reconnection, involving neutral sheets and magnetic islands it is generally a straightforward task to recognize reconnection sites when detailed data sets or simulations are available. In fully three-dimensional reconnection, their analogues can be challenging to identify. In this study, we demonstrate how locations of high reconnective activity can be detected in highly complex turbulent plasmas. We use a recently developed topological measure of reconnection based on the magnetic winding number, which measures the entanglement of pairs of field lines, to identify sub-regions of magnetic field lines which are reconnecting. This diagnostic is combined with established measures of magnetic field complexity, such as quasi-separatrix layers and regions of high magnetic twisting, to characterize the spatial and temporal distributions of reconnective activity of the field. It is demonstrated that the regions with the highest reconnective activity do not always coincide with the largest QSL signatures are, thus indicating this is a more complete methodology for quantifying reconnective activity than standard methods. This framework can serve as a model for reconnection analysis in future studies, in combination with established methods for identifying the specific form of reconnection once its location is established.