  The solar wind is a continuous outflow of charged particles from the Sun's
atmosphere into the solar system. At Earth, the solar wind's outward pressure
is balanced by the Earth's magnetic field in a boundary layer known as the
magnetopause. Plasma density and temperature differences across the boundary
layer generate the Chapman-Ferraro current which supports the magnetopause.
Along the dayside magnetopause, magnetic reconnection can occur in electron
diffusion regions (EDRs) embedded into the larger ion diffusion regions (IDRs).
These diffusion regions form when opposing magnetic field lines in the solar
wind and Earth's magnetic field merge, releasing magnetic energy into the
surrounding plasma. While previous studies have given us a general
understanding of the structure of the diffusion regions, we still do not have a
good grasp of how they are statistically differentiated from the non-diffusion
region magnetopause. By investigating 251 magnetopause crossings from NASA's
Magnetospheric Multiscale (MMS) Mission, we demonstrate that EDR magnetopause
crossings show current densities an order of magnitude higher than regular
magnetopause crossings - crossings that either passed through the reconnection
exhausts or through the non-reconnecting magnetopause, providing a baseline for
the magnetopause current sheet under a wide range of driving conditions.
Significant current signatures parallel to the local magnetic field in EDR
crossings are also identified, which is in contrast to the dominantly
perpendicular current found in the regular magnetopause. Additionally, we show
that the ion velocity along the magnetopause is highly correlated with a
crossing's location, indicating the presence of magnetosheath flows inside the
magnetopause.
