  We present a theory and numerical evidence for the existence of a previously
unexplored in-plane electric field in collisionless asymmetric magnetic
reconnection. This electric field, dubbed the "Larmor electric field," is
associated with finite Larmor radius effects and is distinct from the known
Hall electric field. Potentially, it could be an important indicator for the
upcoming Magnetospheric Multiscale (MMS) mission to locate reconnection sites
as we expect it to appear on the magnetospheric side, pointing Earthward, at
the dayside magnetopause reconnection site.
