Global three-dimensional simulation of Earth's dayside reconnection using a two-way coupled magnetohydrodynamics with embedded particle-in-cell model: initial results

摘要

We perform a three-dimensional (3D) global simulation of Earth'smagnetosphere with kinetic reconnection physics to study the flux transferevents (FTEs) and dayside magnetic reconnection with the recently developedmagnetohydrodynamics with embedded particle-in-cell model (MHD-EPIC). Duringthe one-hour long simulation, the FTEs are generated quasi-periodically nearthe subsolar point and move toward the poles. We find the magnetic fieldsignature of FTEs at their early formation stage is similar to a `crater FTE',which is characterized by a magnetic field strength dip at the FTE center.After the FTE core field grows to a significant value, it becomes an FTE withtypical flux rope structure. When an FTE moves across the cusp, reconnectionbetween the FTE field lines and the cusp field lines can dissipate the FTE. Thekinetic features are also captured by our model. A crescent electron phasespace distribution is found near the reconnection site. A similar distributionis found for ions at the location where the Larmor electric field appears. Thelower hybrid drift instability (LHDI) along the current sheet direction alsoarises at the interface of magnetosheath and magnetosphere plasma. The LHDIelectric field is about 8 mV/m and its dominant wavelength relative to theelectron gyroradius agrees reasonably with MMS observations.