  Historically Gordon decomposition of Dirac current played an important role
in the interpretation of Dirac equation. We revisit it to understand the
correspondence between Maxwell-Dirac and Maxwell-Lorentz theories. Arguments
are presented to show that classical charge current corresponds to Gordon
current. Consistency with Maxwell-Dirac theory leads to a new result:
antisymmetric spin tensor in spin magnetization current of Dirac electron must
be hidden as internal part of classical Maxwell tensor. It becomes natural to
extend our previous interpretation in which electromagnetic field tensor
represents angular momentum of photon or spacetime fluid (aether!) in the
presence of sources such that the duality between field and source disappears.
Both Gordon current and spin current are proposed to have 'spinning origin'.
Formal expression of Gordon current makes it possible to apply the idea of
optical vortex in this case, and quantized vortex and quantized orbital angular
momentum could be related with the conjecture of mechanical interpretation of
electric charge. Separate mass and charge centers for spinning point charge are
well known in the literature; we discuss them in the context of two-vortex
model of electron and Gordon decomposition.
