  We study the role of the Hall current and electron inertia in collisionless
magnetic reconnection within the framework of full two-fluid MHD. At spatial
scales smaller than the electron inertial length, a topological change of
magnetic field lines exclusively due to electron inertia becomes possible.
Assuming stationary conditions, we derive a theoretical scaling for the
reconnection rate, which is simply proportional to the Hall parameter. Using a
pseudo-spectral code with no dissipative effects, our numerical results confirm
this theoretical scaling. In particular, for a sequence of different Hall
parameter values, our numerical results show that the width of the current
sheet is independent of the Hall parameter while its thickness is of the order
of the electron inertial range, thus confirming that the stationary
reconnection rate is proportional to the Hall parameter.
