Point defects and ring defects in a nematic liquid crystal in a cylindrical capillary

The bidirectional escape into the third dimension of a linear disclination of strength m=1 (L-+1(p)) in a cylindrical capillary with normal boundary c onditions is investigated. It is shown that in this case two types of defec ts arise in the capillary: point defects and ring defects, each of which ca n be of the radial or hyperbolic type. Exact solutions are obtained for the equation of equilibrium of the elastic field. The free energy of the point and ring defects is calculated approximately in a narrow, long capillary. New scenarios are proposed for the escape of the disclination L-+1(p). (C) 1999 American Institute of Physics. [S1063-7842(99)00607-8].