Electric field induced transient effects in a nematic liquid crystal in the presence of a stabilizing magnetic field

A homeotropically aligned nematic liquid crystal with positive dielectric a nd diamagnetic anisotropies is subjected to a destabilizing ac electric fie ld (E) in the bend geometry in the presence of a stabilizing magnetic field (B). When the applied voltage (V) is gradually increased at a given freque ncy, the distortion that results above a threshold (V-th) is spatially peri odic with the wavevector depending on the electric frequency f. Sudden appl ication of a voltage step, V-s, higher than V-th causes a temporal evolutio n of the director field, which finally attains the homogeneously distorted (HD) state; the nature of temporal evolution depends on V-s. If V-s is slig htly higher than V-th, the transient deformation is periodic and the waveve ctor of periodicity depends on V-s. When V-s is high enough, the transition to HD occurs via a turbulent state.