  Equilibrium and dynamic behaviors of dechiralisation lines occurring below
SmC* cell boundaries in planar geometry consitute a polemic topic for several
decades. We report new observations in the SmC* phase of the strongly polarized
liquid crystal CFL08. They are compared with vortex motions in superfluids and
type-II superconductors, and we propose a simple heuristic model attempting to
explain the intriguing mismatch between bulk helix pitch and inter-lines
distance. It results from opposite effects of the helix pitch and surface lines
charge value on the equilibrium lines distance. The model assumes that the
lines electric interactions dominate the cell equilibrium state. In particular
the unwinding transition of the bulk helix is provoked by field-induced
displacements of the lines lattices. It permits to relate the lines density and
critical fields to intrinsic energy parameters, and to explain the
pitch-distance mismatch, together with its almost constant value across the
transition. We foresee the helix pitch and unwinding field variations vs.
sample width.
