  The Electron Diffusion Region (EDR) is the region where magnetic reconnection
is initiated and electrons are energized. Because of experimental difficulties,
the structure of the EDR is still poorly understood. A key question is whether
the EDR has a homogeneous or patchy structure. Here we report Magnetospheric
MultiScale (MMS) novel spacecraft observations providing evidence of
inhomogeneous current densities and energy conversion over a few electron
inertial lengths within an EDR at the terrestrial magnetopause, suggesting that
the EDR can be rather structured. These inhomogenenities are revealed through
multi-point measurements because the spacecraft separation is comparable to a
few electron inertial lengths, allowing the entire MMS tetrahedron to be within
the EDR most of the time. These observations are consistent with recent
high-resolution and low-noise kinetic simulations.
