Dynamics of a screw dislocation in smectic A liquid crystals

Abstract

The velocity field and the layer structure of a straight screw dislocation moving with constant velocity perpendicular to the screw axis in a smectic A liquid crystal are derived by solving the hydrodynamic equations. The energies, the effective mass, the dissipation, the forces and the Magnus torque related to the motion are given. Implications for shear flow, Couette or Poiseuille, in smectics A, for string-like oscillations of a screw dislocation and for phase transitions are discussed. Limitations of the gradient expansion are considered.