The Inertia-Based Model for Reconstruction of the Electron Diffusion Region

The present study is focused on the problem of reconstruction of the magnetic configuration in the magnetic reconnection electron diffusion region (EDR). The problem is addressed in the frame of electron magnetohydrodynamics with kept electron inertia term. We introduce the new reconstruction model independent of divergence of the electron pressure tensor and reconnection electric field. The model is tested on the magnetotail reconnection event of July 11, 2017 observed by the Magnetospheric Multiscale (MMS) spacecraft in the course of crossing the very core part of the reconnection region, the internal EDR. This new model demonstrates considerably better accuracy of the longitudinal electron velocity reconstruction due to the lower sensitivity to the configuration deviation from the two-dimensional time-independent model adopted in our study. We suggest also a new technique to estimate the guide field, implementing the reconstruction of magnetic potential of the in-plane magnetic field and relying on symmetric properties of magnetic reconnection. Plain Language Summary Magnetic reconnection is a fundamental plasma process responsible for the magnetic field reconfiguration and transforming magnetic energy to kinetic and thermal energy of plasma. In the Earth's magnetosphere, the magnetospheric conditions are monitored by several spacecraft missions. Among them, the NASA Magnetospheric Multiscale (MMS) mission is designed for exploring the process of reconnection. On July 11, 2017 at about 22:34 UT MMS was located in the magnetotail at a very fortunate position, intersecting the reconnection region in its very central part, the so-called electron diffusion region (EDR). Since MMS consists of four identical spacecraft, MMS provides an excellent tool for testing analytical models of reconnection. Taking the data of one probe as the boundary condition for the analytical model, one can compare the results of calculations with other probes data. In the present paper we suggest a new model of EDR, and compare it to the existing one using the data of 2017/07/11 event. This comparison has shown that the electron inertia term plays an important role in the EDR physics; the proper handling of this term allows considerable improvement of the EDR reconstruction accuracy.

Automated summary

This study focuses on the reconstruction of magnetic configuration in the magnetic reconnection electron diffusion region, introducing a new reconstruction model independent of divergence of the electron pressure tensor and reconnection electric field. The model is tested on a magnetotail reconnection event observed by the MMS spacecraft, showing improved accuracy in electron velocity reconstruction and suggesting a new technique to estimate the guide field based on magnetic potential reconstruction. The study highlights the significance of electron inertia in the physics of the electron diffusion region, leading to considerable improvement in reconstruction accuracy.