Inelastic interactions of solitons in a linear defect of the electroconvective structure of a nematic liquid crystal

The inelastic interactions of solitons in a linear defect appearing in a one-dimensional electroconvective structure of a $\pi/2$-twisted nematic liquid crystal have been studied for the first time. Linear defects in twisted nematic liquid crystals are characterized by a sufficiently extended strain field and are oriented normally to Williams domains. Hydrodynamic flows in domains have not only the tangential velocity component but also the axial component whose directions in neighboring domains are opposite. In contrast to the case of planar orientation, the flow continuity condition for an anisotropic liquid in twisted nematic liquid crystals prevents the decay of a linear defect into individual dislocations when an applied voltage increases. This behavior results in the formation of domain zigzag oscillations in the defect core. The boundaries between zig and zag regions are dislocations with the topological charges $S = +1$ and $-1$. It has been established that the periodic interaction of dislocations (kinks) with opposite topological charges $S = +1$ and $-1$ is accompanied by the formation of a breather. It has been found that the collision of a kink and the breather in the linear defect is inelastic because it leads to the decay of the breather into a kink–antikink pair. It has been shown that such interactions of dislocations with topological charges $S = +1$ and $-1$ are qualitatively well described by the perturbed sine-Gordon equation.