Structure and dynamics of solitons in a nematic liquid crystal in a rotating magnetic field

We study the structure and speed of movement of dynamic solitons in a thin layer of nematic liquid crystal, with homeotropic boundary conditions, in a rotating magnetic field. Based on numerical integration of the equations of motion, we find that the soliton must be described as a two-dimensional object with unconstrained director motion. From some qualitative features of the soliton structure seen in our numerical results, we are able to deduce an approximate analytic theory of the physics of the soliton structure and dynamics that accounts accurately for the observations. The basic elements of this picture are a tilted plane in which the director rotates as the soliton passes a point, with the tilt angle of the plane being dictated by a second Freedericksz transition within the soliton.