  Equation of long-range particle drift and diffusion on three-dimensional
physical lattice is suggested. This equation can be considered as a lattice
analogof space-fractional Fokker-Planck equation for continuum. The lattice
approach gives a possible microstructural basis for anomalous diffusion in
media that are characterized by the non-locality of power-law type. In
continuum limit the suggested three-dimensional lattice Fokker-Planck equations
give fractional Fokker-Planck equations for continuous media with power-law
non-locality that is described by derivatives of non-integer orders. The
consistent derivation of the fractional Fokker-Planck equation is proposed as a
new basis to describe space-fractional diffusion processes.
