Magnetic reconnection and plasma turbulence are ubiquitous processes important for laboratory, space, and astrophysical plasmas. Reconnection has been suggested to play an important role in the energetics and dynamics of turbulence by observations, simulations, and theory for two decades. The fundamental properties of reconnection at kinetic scales, essential to understanding the general problem of reconnection in magnetized turbulence, remain largely unknown at present. Here, we present an application of the magnetic flux transport method that can accurately identify reconnection in turbulence to a three-dimensional simulation. Contrary to ideas that reconnection in turbulence would be patchy and unpredictable, highly extended reconnection $X$ lines, on the same order of magnitude as the system size, form at kinetic scales. Extended $X$ lines develop through bidirectional reconnection spreading. They satisfy critical balance characteristic of turbulence, which predicts the $X$-line extent at a given scale. These results present a picture of fundamentally extended reconnection in kinetic-scale turbulence.

• Received 6 October 2022
• Revised 2 June 2023
• Accepted 18 July 2023

DOI:https://doi.org/10.1103/PhysRevLett.131.085201