  The fundamental dislocation processes of glide, climb, and annihilation are
studied on diffusive time scales within the framework of a continuum field
theory, the Phase Field Crystals (PFC) model. Glide and climb are examined for
single edge dislocations subjected to shear and compressive strain,
respectively, in a two dimensional hexagonal lattice. It is shown that the
natural features of these processes are reproduced without any explicit
consideration of elasticity theory or ad hoc construction of microscopic
Peierls potentials. Particular attention is paid to the Peierls barrier for
dislocation glide/climb and the ensuing dynamic behavior as functions of strain
rate, temperature, and dislocation density. It is shown that the dynamics are
accurately described by simple viscous motion equations for an overdamped point
mass, where the dislocation mobility is the only adjustable parameter. The
critical distance for the annihilation of two edge dislocations as a function
of separation angle is also presented.
