  A new look at the structure of the electron diffusion region in collisionless
magnetic reconnection is presented. The research is based on a particle-in-cell
simulation of asymmetric magnetic reconnection, which include a temperature
gradient across the current layer in addition to density and magnetic field
gradient. We find that none of X-point, flow stagnation point, and local
current density peak coincide. Current and energy balance analyses around the
flow stagnation point and current density peak show consistently that current
dissipation is associated with the divergence of nongyrotropic electron
pressure. Furthermore, the same pressure terms, when combined with shear-type
gradients of the electron flow velocity, also serve to maintain local thermal
energy against convective losses. These effects are similar to those found also
in symmetric magnetic reconnection. In addition, we find here significant
effects related to the convection of current, which we can relate to a
generalized diamagnetic drift by the nongyrotropic pressure divergence.
Therefore, only part of the pressure force serves to dissipate the current
density. However, the prior conclusion that the role of the reconnection
electric field is to maintain the current density, which was obtained for a
symmetric system, applies here as well. Finally, we discuss related features of
electron distribution function in the EDR.
