Identifying active magnetic reconnection in simulations and in situ observations of plasma turbulence using magnetic flux transport*

For decades, magnetic reconnection has been suggested to play an important role in the dynamics and energetics of plasma turbulence by spacecraft observations, numerical simulations and theory. Reliable approaches to study reconnection in turbulence are essential to advance this frontier topic of plasma physics. A new technique based on magnetic flux transport (MFT) has been recently developed to identify reconnection activity in turbulent plasmas. Applications to gyrokinetic simulations of two- and three-dimensional (2D and 3D) plasma turbulence, and MMS observations of reconnection events in the magnetosphere have demonstrated the capability of MFT in identifying active reconnection in turbulence. In 2D, MFT identifies three active reconnection X-lines; two of them have developed bi-directional electron and ion outflow jets, observational signatures for reconnection, while the third X-line does not have bi-directional electron or ion outflow jets, beyond the category of electron-only reconnection recently discovered in the turbulent magnetosheath [1]. In 3D, plentiful reconnection X-lines are identified through MFT, and new properties of reconnection in 3D turbulence can be studied. In space, MMS observations have demonstrated evidence for MFT signatures of active reconnection under varying conditions throughout Earth's magnetosphere [2]. MFT is applicable to in situ observations by heliospheric spacecraft missions, including PSP and Solar Orbiter, and laboratory experiments.

[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 Identification of Active Reconnection: MMS Observation in the Earth’s Magnetosphere,' in prep, 2021