Evidence for extended active magnetic reconnection X-lines in three-dimensional plasma turbulence

The nature and role of magnetic reconnection in plasma turbulence has been a decades-long topic. Using a newly developed method based on magnetic flux transport (MFT), we can definitely identify active reconnection in turbulence, both in numerical simulations and in-situ observations of heliospheric plasmas [1,2]. This work demonstrates first evidence of such identification in a three-dimensional (3D) gyrokinetic turbulence simulation. Reconnection takes place in small-scale current sheets formed between turbulent flux ropes as they interact, in the form of flux rope merging, and in elongated current sheets inside flux ropes, which produces smaller-scale flux ropes. Contrary to ideas that reconnection in 3D turbulence would be patchy and unpredictable in nature, spatially extended and regular active reconnection X-lines, extending over the order of the system size, are present. These reconnection X-lines are plentiful throughout the volume. This work has implications on the nature of reconnection in heliospheric turbulent plasmas, including the solar corona and magnetospheres. MFT is applicable to in situ observations by spacecraft missions such as MMS and PSP, and laboratory experiments such as FLARE. 

[1] Tak Chu Li, Yi-Hsin Liu, and Yi Qi, "Identification of Active Magnetic Reconnection Using Magnetic Flux Transport in Plasma Turbulence," ApJL, 909, L28, 2021

[2] Yi Qi et. al. "Magnetic Flux Transport Signatures for Active Reconnection," in prep, 2021