Title:  Observations and Context of Magnetotail Reconnection in the MMS Era

Abstract:  Magnetic reconnection is a fundamental physical process of
energy exchange between magnetic fields and plasma which accompany
topological changes in the magnetic field.  The Magnetospheric
MultiScale mission (MMS) suite of instruments and tetrahedron formation
of identically equipped spacecraft allow us to probe this process in
unprecedented detail.  Using these facilities, we propose methods by
which we can identify regions of magnetic reconnection, specifically ion
diffusion regions, using MMS data in the geomagnetic tail. These tools
in hand, we find that the distribution of reconnection regions in the
geomagnetic tail is not uniform.  Possible reasons for the asymmetric
distribution are discussed in terms of tail current sheet dynamics and
geometry, as well as recent simulation results reported by Lu et
al.(2018) and Liu et al.(2019).